# Rotten core around Mast Step-repair



## superiorvoyager (Jan 3, 2009)

When I bought my 32'Voyager 4 years ago it had a slight leak at the Mast step. I caulked the Bolts and it seemed to fix the problem but it turns out all it did was keep the water from coming through the bolt holes in the inner skin and the water just pooled inside and rotted out all around the Mast step causing the step to start depressing the deck. I took the mast down this fall with the intention of doing repair in the spring but discovered that the core had totally rotted out for a good foot around the step (maybe more as I haven't opened it up yet but the Fiberglass skin at the front of the step had cracked and you can see in and there is no wood left there. I've read lots of posts here about replacing the core but have had a number of people including one boatyard suggest instead of replacing the Balsa Core with the same to remove the old core and make that area solid fiberglass/West System. My father had a boat repair place repair the deck on his old boat a number of years ago and this is how they did it and it did seem to hold up well. Obviously the weight would be greater but what other disadvantages would there be? Has anyone done this?


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## knothead (Apr 9, 2003)

superiorvoyager said:


> When I bought my 32'Voyager 4 years ago it had a slight leak at the Mast step. I caulked the Bolts and it seemed to fix the problem but it turns out all it did was keep the water from coming through the bolt holes in the inner skin and the water just pooled inside and rotted out all around the Mast step causing the step to start depressing the deck. I took the mast down this fall with the intention of doing repair in the spring but discovered that the core had totally rotted out for a good foot around the step (maybe more as I haven't opened it up yet but the Fiberglass skin at the front of the step had cracked and you can see in and there is no wood left there. I've read lots of posts here about replacing the core but have had a number of people including one boatyard suggest instead of replacing the Balsa Core with the same to remove the old core and make that area solid fiberglass/West System. My father had a boat repair place repair the deck on his old boat a number of years ago and this is how they did it and it did seem to hold up well. Obviously the weight would be greater but what other disadvantages would there be? Has anyone done this?


I can't think of any disadvantages, other than the one you mentioned, to making the area solid and eliminating the rot problem completely. 
You could even lay up a 1/4" plate of aluminum to make it easier to attach deck hardware in the future.

I've had a couple of customers that have had this problem. One, whose boat was quite old and well used and who wasn't really concerned about trying to make the area look perfect, I was able to help. 
The other one, I just referred to a good fiberglass guy. He had major problems all over his deck and was way beyond what I wanted to tackle. .


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## Deadeye (Jan 8, 2009)

I must have read the OP wrong, but it sounded like there's balsa core between the mast step and the compression post ?

Balsa core is awful for compression loading. The only production sailboats I've done have been either ply(partners for keel stepped) or solid wood core (deck stepped). 

Is this standard practice in production sailboats ?


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## Stillraining (Jan 11, 2008)

Just did it...soild is the way to go.


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## superiorvoyager (Jan 3, 2009)

It is Deck Stepped and as Far as I know it is Balsa. There is nothing left in that area to be able to tell but the report that I had from the Yard that Built it said the Deck is Balsa Core and didn't indicate that there was a different core in the area of the Step. Either way it has to be replaced as it has totally roted out. Don't know yet how far I will have to cut it back though.


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## superiorvoyager (Jan 3, 2009)

Stillraining said:


> Just did it...soild is the way to go.


Any tips or suggestions for me in doing this.


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## georgefmys (Dec 28, 2008)

Though solid glass will fix problem,it's probably not best choice unless you have fiberglass experience.Check West System tech site for detailed help.I like Coosa structural foam as core material....1/4 aluminum plate for additional stiffness and thru-fastening is also a great idea. Try to make repair area symetrical,with rounded edges and at least several inches into sound existing core.Don't forget to shim deck to proper position before layup!


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## Stillraining (Jan 11, 2008)

Tip #1
If your deck surface is not damaged do all your work from underneath...that way your head liner covers your work and you don't have to have a perfect finish.

Tip #2
Use the tacky resin that they use for hull overhang repairs..for all your overhead glass work...I forget what its called.

Tip #3
Use a chunk of 1" or 3/4" iron pipe with a threaded collar as your jacking system..simple, cheap, cant move...get real fancy and have the coupler in the middel of two pieces.

Tip #4
Beg, barrow or rent a good respirator, buy a pair or two of those white throw away coveralls and a whole box of single use latex gloves...you will want a good small shop vac and a ton of cardboard and a big roll of that 2' wide blue painters tape to protect your boats interior...borrow or buy a cheap 500 watt halogen work lamp.

Fiberglass is an art but its not rocket science..experiment with two or three different ratios of catalyst to see what work time and heat you get..also pay attention to the kick so you learn when to stop messing with it and avoid ruining your cloth layup. Don't go for anymore then 3 layers in one day...it could overheat and turn black on you.

Tip #5
Stop in at some boat yard/ glass shop and see if you and chum up to a glass guy with an offer of rum and beer to help you out.

Good luck.


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## superiorvoyager (Jan 3, 2009)

to answers, "SOlid is the way to go" and "it's probably not the best choice" what are your reasons. As far as experience I have a lot of experience with fiberglass (west system) over the years (boat and car repair, canoe construction built a 16' glass over wood boat years ago etc.) I also have a lot of experience with wood (finishing carpenter, fine furniture and Luthier). one problem with wood is If I am going to use Balsa or Coosa I'll have to order it in where as I have everything I need for west system


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## JimsCAL (May 23, 2007)

Take a look at this article for some good ideas:

WEST SYSTEM | Projects | Fiberglass Boat Repair and Restoration - Fiberglass deck repair-Part 1, Replacing damaged balsa core


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## Deadeye (Jan 8, 2009)

Personally I'd stick with marine ply under a deck stepped mast. Were it my own job, I'd probably run one piece the thickness of the core to replace the balsa with a generous lap, say two or three times the area of the actual step. Another piece of 3/4, cut to the shape of the step with the edges chamfered would provide a pedestal of sorts to avoid the potential for water to find its way in.

Again, it's your project so it's your call, but balsa isn't commonly used in area where there's point loading like under cleats and winches but is 'fine' in areas where the entire panel is loaded (like side decks, cockpit seats, etc)


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## superiorvoyager (Jan 3, 2009)

So even if I go with wood don"t use balsa but use marine plywood. But what is it's advantage over fiberglass? I should mention that I will go in from the top since the deck requires repair where the outer skin cracked due to the compression. As far as the sugestion of stopping into a boat yard or Fiberglass place there are none here. There is a boat yard 140 km away but they don't do this type of repair anyway.


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## Stillraining (Jan 11, 2008)

superiorvoyager said:


> to answers, *"SOlid is the way to go" *and "it's probably not the best choice" what are your reasons. As far as experience I have a lot of experience with fiberglass (west system) over the years (boat and car repair, canoe construction built a 16' glass over wood boat years ago etc.) I also have a lot of experience with wood (finishing carpenter, fine furniture and Luthier). one problem with wood is If I am going to use Balsa or Coosa I'll have to order it in where as I have everything I need for west system


*It would help if you quoted your intended target... I had to go searching as to whom you were asking .*

IMHO... The only reason it was not soil to begin with in your and my boats is the builder was to cheep to do it..A lot of top of the line boats have a sold core where intended deck penetrations are..cheaper built bots not so much.

You ask why...Simply water intrusion ....intrusion and compromise of the core material rather wood or foam that you are currently facing and would not and will not ever be a future issue with solid glass core in that area.
a 
The only reason for any plywood or balsa core in the first place was for a stiffner..and cheap stiffening at that...There is an exception when an insulating factor is desired in the hulls construction..but a modern sandwich is ultra light and ultra strong..but still generally solid glass where penetrations are engineered to go through either their decks or hull.

I have no clue as to why it was suggested as a bad idea to go solid in your mast step area..maybe he will respond to his answer.

FWIW...repairing it from the top will be WAY easier..just way harder to get your top gel-coat looking factory nice that's all..as you will have gravity working for you not against you...as I said earlier practice with 2 or three goes at mixing and saturating some scrap pieces together to get the hang of saturating and working with mat and resin..it ain't rocket science..learn to work all the air and excess resin out of the mat..gobbing on way to much resin is a beginners fist mistake..you dont want any unsaturated areas but you dont want it swimming in the stuff either..it will be brittle and crack.

You say you have lots of experiance with glass...Then Go For it!..If I was there I would help you.


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## mitiempo (Sep 19, 2008)

I'd go solid not wood core of any kind under the mast. Stillraining is right - the only reason builders use plywood is that it is cheaper and is also faster than multiple layers of glass. I'd use epoxy (West as I know it well) and rather than mat and cloth or roving I'd use 1708 biaxial - stitched as opposed to woven roving with mat already attached to one side. It's easier to use and fully compatible with epoxy - some mat isn't epoxy compatible. If your deck is already needing repair going from the top is always the best way - it's easier and the job will turn out better. I'd paint after instead of gelcoat. For a good rundown of this see Tim Lackey's site - Northern Yacht Restoration | Tim Lackey: One Man, One Boat at a Time. He recores decks on a regular basis in his restoration business and documents everything with lots of pics. Just click on one of his projects and follow it along. 
Hope this helps.
Brian


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## gwp (Apr 9, 2003)

*try this....?*

I've done this before. If there is only a 1 ft area use stiff wire to dig out all rot wood. Attach vacuum to small tube to help. Get west sys epoxy in a empty caulk tube and attach small tube to end of caulk tube end. Stick tube in access hole and pump away. Don't peel away cabintop. Unless U R a fbgls pro it will never look right


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## mitiempo (Sep 19, 2008)

I think gwp is wrong. The area is over 1 square foot. That's a large area to fill with epoxy that way. Besides, there is little strength to epoxy without fibreglass imbedded in it. And this will be under a mast so it requires strength. You will have to paint, but it's easy to get a fair surface. Just build it up layer by layer (1708 biaxial is about 1/8" per layer I think) and when you are almost level with the deck surface, sand and squeegie a fairing coat of epoxy mixed with fairing filler (West #407). sand and refill any low spots with fairing again until there are no more low spots. Sand lightly and finish with a coat of straight epoxy put on smoothly. Then prepare for the paint you choose. It isn't hard to do it just takes a bit of time. If you can read instructions you can accomplish this.
Brian


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## georgefmys (Dec 28, 2008)

I suggested you replace with core material so that deck structure with similar qualities of stiffness and flexibility as originally designed can be maitained.Also,a heavy,solid lay-up can be difficult to fair without removing glass again. Since it is mast step area,all epoxy and 17 oz. material will definitely do the job-I missed the size and type of boat-just be aware if cabin top is lightly built and supposed to give a bit ,it probably won't anymore


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## mitiempo (Sep 19, 2008)

george
The cabin top is not supposed to give under the mast step. It should be a solid step supported by a bulkhead, compression post or beam belowdecks. If it was solid from the date of manufacture he wouldn't have this problem.
Brian


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## Deadeye (Jan 8, 2009)

mitiempo said:


> the only reason builders use plywood is that it is cheaper and is also faster than multiple layers of glass


Respectfully Brian, I think you're forgetting about about the intent of laminate construction being to provide two skins held at a fixed distance apart to provide MORE panel stiffness than the same amount of material as a single skin. The key to that stiffness lies in the compression strength of the core.
Also, it's not faster...it adds time because it has to be added as it's own step which disrupts the layup timing. Then it has to be flood-coated before the inner lams start going on.

Another take on gwp's suggestion: remember here that the OP wants to use West System because that's what he's got (or what he's most familiar with). Ignoring the cost of filling 1/2" void left by the core, the exotherm will at least cause the glass to print through the gel and will at worst cook the gel, permanently discoloring it.

With that in mind, the exotherm will also make a solid casting a tricky job for someone who is fairly new to it. While they add a ton of strength, fibers don't do much to dissipate the heat. Remember that the heat vs cure curve for epoxy is much different that poly based resins.

Also, given the temps he's likely to see over the next while, he will NOT get a sufficient cure to re-step the mast, re-rig, and sail the boat anytime soon. Personally, I wouldn't feel comfortable restepping the mast on a solid epoxy layup that hadn't progressed very far beyond initial cure. I think it's important to point out as well that the exotherm enables the initial cure. Sure, it may feel hard, but only time can fully cure epoxy.

I can't really think of any issues with a solid layup of epoxy and cloth, again as long as the exotherm is dealt with. A continuous layup (always adding the next layer while the previous is cool but still green) will give all the units a primary bond but should allow the heat to dissipate. Once you compare the added cost to the properties gained, I'd still go with plywood core.
Just different strokes I guess.

Plywood has more compression strength than solid wood in this application unless he wants to cut short pieces and use the endgrain similar to the way a butcher block is made (and the way the balsa is laid).

Plywood has more panel strength than solid wood, so will do a much better job of spreading the loading evenly all around the step. THAT is the primary reason it's used in decks and steps, where balsa is used in cabin sides and coamings. Core materials are an insignificant proportional cost in any well-found production boat. Balsa is easier (read:quicker) to work and lighter than ply.

Again, this is just what my experience has shown me, for right or wrong.


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## mitiempo (Sep 19, 2008)

I doubt that Hinckley, Morris or other premium builders put ply under the mast step. Cost really isn't a factor for these builders - quality is. I suggested using multiple layers of biax. Not all at once. Even if you wait until one layer is hard it's easy to wash the amine off with a nylon pad and some water. Exotherm is not an issue if done this way. West epoxy is usable down to 35 degrees f. At these cold temps exotherm is less of an issue. Plywood does have more compression strength than solid wood - of the same species. Fir or mahogany plywood still compresses and under a mast fully rigged it will eventually happen. If any moisture gets in it will deteriorate and that's where we started. As far as core material where core should be used, balsa is far superior in several ways than plywood. Less chance of moisture travelling with end grain balsa, less weight with balsa where the weight is not an advantage, and better bonding to curved surfaces with balsa than with plywood. The following is taken from West's fibreglass repair manual which is free on line here.http://westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf
Brian


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## Crapaud (Jul 31, 2009)

I hate to jump in to ask another question, but would there be an issue in using both plywood and glass? 

Using just plywood - would you have an problem effectively "tying" the new core to the origanal core?


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## mitiempo (Sep 19, 2008)

Yes plywood could be used - the original builder did. But solid epoxy and fibreglass is I think the ultimate solution. Never again will it compress or absorb water as has happened to get us here. If the plywood is adhered properly and coated in epoxy totally it would work. I think it would take almost as long and be almost as expensive to do this with plywood as with biaxial and epoxy all the way through. The fairing, prepping for paint, and painting will take the longest - and you have to do this with plywood as well as all epoxy and glass. I think the goal is to fix it better than new, not necessarily copy what the builder did. 
Brian


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## dieselboy (Aug 29, 2009)

Im sorry but i have been watching this and have wanted to ask this but was afraid of sticking my nose where it was not wanted...

Has any one ever thought of a using vacuum bag process and building a carbon fiber step assm and bonding it in? The best of both worlds, strong, light and tough as hell. I have made some rather complicated and large items in this manner. 
A vac-bag step assm will be so compressed that air can not penetrate much less water .


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## Stillraining (Jan 11, 2008)

dieselboy said:


> Im sorry but i have been watching this and have wanted to ask this but was afraid of sticking my nose where it was not wanted...
> 
> Has any one ever thought of a using vacuum bag process and building a carbon fiber step assm and bonding it in? The best of both worlds, strong, light and tough as hell. I have made some rather complicated and large items in this manner.
> A vac-bag step assm will be so compressed that air can not penetrate much less water .


Please stick your nose in...In short my answer is yes ,but with galss not CF.

Please walk us through the process on the cheap so to speak.


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## dieselboy (Aug 29, 2009)

Wow, the process is simple enough. 
You build a rudimentary mold to make a part, figure out size shape and how you are going to mount, said part. Calculate how much strength you will want lay the carbon mat then pour in the resin.
slip a special bad over it and draw a vacuum with either an ac type vac pump or even a hand held brake bleeder pump.
The resin will cure in a vacuum and all the air in the structure will be drawn out. Leaving a VERY strong object. The Vacuum has the effect of drawing the layers very very tight.

2 layers of weave and a thin resin leave behind an extremely strong but quite thin part that is air and cavity free. I buy a bunch of stuff from a company called Max Bond while i am not here to push any product they do have a very good 4 min video on vac-bag process on a very low budget.

You will have to wade through the sales pitch but read up on the process and it will show one in action.. 
CARBON FIBER FABRIC 3K 2X2 TWILL WEAVE 6 OUNCE 50" WIDE - eBay (item 220500561712 end time Nov-24-09 16:02:23 PST)


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## Stillraining (Jan 11, 2008)

Ah, gotcha ...different train of thought...I was thinking more in place as in overhead vacuum techniques to suck everything up defying gravity so to speak.


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## dieselboy (Aug 29, 2009)

Stillraining said:


> Ah, gotcha ...different train of thought...I was thinking more in place as in overhead vacuum techniques to suck everything up defying gravity so to speak.


While there would be a few challenges but if there we a hatch to got on both sides of it..... It could be done!
Super strong and air free.. Rather than pile on the glass and resin you could use Styrofoam as a filler or supports. As funny as that founds all F-1 cars use Styrofoam much in the way boat builders used balsa wood. 
It could be done, i wish i were closer to this guy, we could do a few tests to see but i dont see why not.


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## Stillraining (Jan 11, 2008)

Hmmm...there again though your entering in a compressabal elliment where you do not want one...I would just like a quick clean way to vac any weard inplace profile with solid glass build up myself.

As an example..I would not mind adding 1/4" of roving or bi-directional to my whole hull...but adhering such a large area with quality is tough to do .


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## Deadeye (Jan 8, 2009)

For the record, I can't think of any application in a boat where you would use plywood with_out_ glassing over it, even if it's just a single unit of 6oz to protect the epoxy barrier from abrasion like you see in plywood boats. In this application, the plywood provides an inexpensive core material to space the two laminates apart without any significant compressibility within the core material.

I haven't worked much with carbon, so I have a couple questions myself.
Would the weight savings be worth the cost of the material for this application ? I can see it if that's how the rest of the boat is built, but as a retro on an admittedly-inexpensive boat it seems like money better spent elsewhere.
What would be the advantage of carbon in this application ?

Dieselboy, if by 'Styrofoam' you mean blue- and pink-board, I gotta disagree with you. Yes it's used for body panels in many custom vehicles, but only where an inexpensive material is needed to hold shape. Using it as coring in a structural panel cause it to fail in long cracks that subject the glass to wicked shearing forces along a sharp line in the same place on the inner and outer laminates. If you can point me to a true unibody (structural) application that uses it for coring I'll happily stand corrected because it'll give me a lot more options in my own work once I figure out how they get the resin to saturate it...



mitiempo said:


> Yes plywood could be used - the original builder did.


According to the OP, it was the fact that balsa core and NOT plywood was used for core that got him here. There are many (most?) production boats out there with plywood that never gives a worry as long as it's encapsulated. Plywood coring just doesn't fail without help - either through water ingress or mechanical damage.


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## mitiempo (Sep 19, 2008)

If the original builder used balsa under a mast it was a mistake. The force downward of a mast rigged on a boat will guarantee a failure if this is (was) the case. Plywood is a step better but still compressable over time and when the compression occurs there will inevitably be at least hairline cracking that will allow water in. The water will cause rot because even if the plywood is sealed it will lose the integrity of that seal when enough force is applied to it (tight rigging trying to force the mast downward not to mention the sailing loads). If you're in a colder climate there is the freeze/thaw cycles which are guaranteed to open any hairline cracks further over time. If the skins were thick enough to prevent this over time there would probably have been no reason to use the plywood to start with as the skins would not in any way be in need of a core. Many boats by many builders were built this way and they are having problems 20, 30, or 40 years on. Cores work well if they are kept dry and not crushed by large forces. I don't believe that this is good engineering for all time, just for a while. As to carbon - it would be a waste of money in this case as it's only purpose really is to save weight - a square foot of glass/epoxy 3/8" or 1/2" thick can't weigh more than 5 or 6 lbs. The mast step doesn't have to be super strong on its own - just be non-compressable to transfer the force to the bulkhead or compression post below.
I don't believe that F-1 cars are built with styrofoam - in the crash testing videos I have seen it looked like a carbon fibre laminate without foam.
Brian


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## Stillraining (Jan 11, 2008)

Deadeye said:


> . There are many (most?) production boats out there with plywood that never gives a worry as long as it's encapsulated. Plywood coring just doesn't fail without help - either through water ingress or mechanical damage.


 Yes this is a very factual statement.

All a couple of us are trying to stress is that when you have a penetration into that core material you now have created a path for water ingress.

There are a couple ways to prevent this at construction but which are seldom used by the cheaper builders...One is as several have mentioned a solid glass core in those areas..or secondly over drilling the diameter of the area by 1/2" or more, sealing the core edges with penetrating epoxies then filling that area with thickened epoxy..next you re drill through your solid cored area to the desired bolt size needed. This takes more time then building it that way in the first place but has the benefit in exact placement for the mounted hardware.

Nothing wrong with building a large area back to the original way it was using plywood or whatever core material you prefer..but as long as you have it open why not use say a 2" hole saw or cut out a larger area for say a mast step with a saber saw in your known deck penetration areas and make those solid..it would only take a few minutes longer to glass up solid. The problem is cured forever. That's all were saying..to each his own though.

Carry on!


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## Stillraining (Jan 11, 2008)

FWIW...Here is an example of where plywood or any compressabal core material should have never been used..It dosent have any anymore...Problum fixed forever.

To clarify the pictures..The first is Irwins origional lay up of their mast steps on their 41' ketches..you can see they layed op a solid 1" layer under the plywood and then a soild 1/2" over it but inbetween was 2" of plywood core just plain saturatrated and copressed almost 3/8 of an inch. What did thay save maybe 50 bucks back in 1983..woopee.


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## superiorvoyager (Jan 3, 2009)

Well The Weather warmed up (+10C) and all the snow melted so I decided to open up the deck and see what I have. Turns out the wood core was only 1/4" thick (the fiberglass skin on the out side is quite thick and is mat between cloth) so I will probably just go with fiberglass. The problem I found is that the rot is worse than I thought. I cut out a 12" X12" square where the mast step and found it was a soaking wet mush. Used a Coat hanger to poak in and see how far back the rot went and discovered that the area that is rotten is about 3'X5'. The only part that is structural is right under the Mast so my thought is to just replace a 1'-2' section under the mast (make it solig glass), clean out about 6"-8" rot around the edge and put glass and epoxy in that and then inject epoxy into the rest. the rest of the roof feels prety solid despite the rot, probably because the glass is already so thick. How does this sound for a solution. Obviously I won't do the fiberglassing part untill the spring as it is dropping well below frezzing at nights now. With it open and tented now it should allow the area to dry out over the winter.


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## mitiempo (Sep 19, 2008)

There is not much strength to epoxy resin without cloth reinforcement. As well, if you have to clean out rotten core 6-8" past the cut out you cannot reliably remove it without cutting the top layer off. 6-8" is too far without better access. I'd cut the top skin until I found dry core and replace the rotten core with ply or balsa and solid glass under the step as you plan. Then reglass the top, fair and paint. Make sure you grind a good bevel at the edges, they say 12-1 ratio but 8 or 10 to 1 should be ok. This means if the top layer is 1/4" thick the bevel should be 2"+ to get a good overlap, each side.
Brian


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## superiorvoyager (Jan 3, 2009)

mitiempo said:


> There is not much strength to epoxy resin without cloth reinforcement. As well, if you have to clean out rotten core 6-8" past the cut out you cannot reliably remove it without cutting the top layer off. 6-8" is too far without better access. I'd cut the top skin until I found dry core and replace the rotten core with ply or balsa and solid glass under the step as you plan. Then reglass the top, fair and paint. Make sure you grind a good bevel at the edges, they say 12-1 ratio but 8 or 10 to 1 should be ok. This means if the top layer is 1/4" thick the bevel should be 2"+ to get a good overlap, each side.
> Brian


The problem with that is that from what I found by probing with a coat hanger the rot goes right to the edge of the cabin so I would have to remove the entire cabin deck. That would be a major job (5'X4' minnimum) and probably more than I am prepared to do. Hopefully there is a way to repair this with out having to replace the entire cabin.


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## mitiempo (Sep 19, 2008)

Not really - without accessing it the repair cannot be properly done. If it deserves repairing it should to be done right.
Brian


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## Stillraining (Jan 11, 2008)

I agree with mitiempo

It will always be a compromised repair but it could be "Good enough" compared to the value of the boat and all that jazz..Resin will not adhere to wet material though and they make a product that will penetrate and reinforce rotten wood better then epoxy..I would use that instead if you decide to go that route. The rest sounds like a great plan.


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## mitiempo (Sep 19, 2008)

I don't know what product Stillraining is referring to but I'm not aware of one that will "reinforce rotten wood better than epoxy". It will still be rotton wood with not much more strength than rotten wood - albeit "petrified". If you have to cut open the deck to repair the mast step all it means is a bigger area. Same process expanded by a few square feet. If the area is 3 times the size it won't mean 3 times the work. More materials, a bit more labour and a much better result.
Brian


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## superiorvoyager (Jan 3, 2009)

Although it is a great boat and serves us well it is a 1979 that I picked up for $2700 so I suppose that I am looking for a "good enough" fix. I want to make sure that it is structurally sound (ie. around the mast) but when you walk on the deck despite the fact that it would appear the core is rotten the deck itself is pretty solid probably because the fiberglass is so thick. I should mention that my plan also includes washing the entire area with acetone and than flooding the rotten areas with acetone and letting it then evaporate out untill spring. Experience from the past has taught me that rotten and or wet wood can be dried out fairly well in this way. The issue will likely be the joint where the repair is made and potential of cracking there.


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## Stillraining (Jan 11, 2008)

I will bow out mitiempo...I have never used the stuff just read about it and heard others praise of it...Just wanted to get across that epoxy will not adhere to or penetrate wet wood where the other stuff is supposed to seek out moisture.

Carry on


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## mitiempo (Sep 19, 2008)

I understand your reluctance to do the whole cut open and repair job. But remember that with freeze/thaw cycles if it remains moist the deck won't be solid forever. I'd like to hear more about this magic fluid that seeks out moisture though.
Brian


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## superiorvoyager (Jan 3, 2009)

mitiempo said:


> I understand your reluctance to do the whole cut open and repair job. But remember that with freeze/thaw cycles if it remains moist the deck won't be solid forever. I'd like to hear more about this magic fluid that seeks out moisture though.
> Brian


If you are referring to my comment about acetone it is an old practice that is commonly used in antique restoration ect. The acetone doesn't "seek out moisture" but rather if it comes in contact with wet wood will combine with the water and simply speed up the evaporation of the water (many people say it wicks the water away) that is already in the wood. Try it sometime. Take two pieces of equally wet and rotten wood and soak one in acetone and leave the other as is. Put them both in a warm dry environment and the one with the acetone will dry twice as fast. If you take a moisture meter and measure the moisture content in a piece of wood and then soak it in acetone. Let the acetone dry out and measure it again and you will find the moisture level has dropped. The problem I see with doing this on a a core is that first you have to get the acetone into that area and then it has to be able to evaporate out, therefor I am not sure how well it will work in this situation. I guess my reluctance with doing the whole thing is the difficulty I see in trying to do a nice job of joining a new roof to the sides of the cabin. Pluss the cost and time of the full Job.


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## mitiempo (Sep 19, 2008)

No, i was referring to Stillraining's mention of a product better than epoxy for reinforcing rotten wood. You shouldn't have to go right to the edge with the cut, just closer than 8". I'd leave a lip of about 2" to taper the new glass to. It should be fairly easy to gouge the wet core out if 2" is as far as you have to reach. The cabin sides are probably not cored as thay usually aren't. I agree that the acetone helps but it still requires good evaporation to take place.
Brian


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## superiorvoyager (Jan 3, 2009)

Yes I would love to know what that material is as well. I do remember reading about a company that claimed their epoxy could be used to reconstitute rotten wood but when it came down to it the rotten wood had to be totally dry and the epoxy ended up just holding the fibers together. With the wet core I am dealing with where I cut the outer skin away I didn't have to scape or gouge the rot out. It is so rotten I just used a shop vac and vacumed it up.


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## mitiempo (Sep 19, 2008)

Based on my experience and reading it doesn't exist - or exists but doesn't really live up to the claims made for it. According to West Epoxy you can thin epoxy with acetone, lacquer thinner or denatured alcohol upto 5% but the loss in strength is 35%. This will hold true for any brand as really they are formulators, working with the same basic items in different proportions. 
Here's a link to West's Fibreglass boat repair manual. http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf
The information that concerns your repair is in section 5, pages 28 to 33. But it wouldn't hurt to download the whole pdf as it's full of good info that would apply to any brand of epoxy. I prefer West and have been using it for almost 20 years. (I paid for my manual as the internet didn't exist then) I hope this helps. I've also included below a section from their Wooden boat repair manual concerning thinning epoxy.
Brian


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## sailingdog (Mar 19, 2006)

While there are some epoxy manufacturers/sellers that claim their epoxy products will restore wood's strength... I'd have to point out that very few of them will work well if the wood isn't BONE DRY. Cutting out the wet, rotting material and then laying the area up with a new core and leaving a ring of solid glass around the opening itself is really the best way to repair something like this.


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## superiorvoyager (Jan 3, 2009)

This has been very helpful in putting together a plan of Action. weathers getting cold again and looks like snow so I will now put this project to rest till the spring and do lots of research. The other big project for the spring will be dealing with the blistering gelcoat but that is for another post. The West system manual looks like it will have lots of great ideas.


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## superiorvoyager (Jan 3, 2009)

Well I ended up just cutting out the area around the Mast step (not the whole cabin deck) and laying it up with solid epoxy and glass. Made a rock solid repair there but with the rest of the deck rotten and spongy I decided to try some other options. Taking the advise here, but not wanting to replace the whole cabin deck (4x6 feet) I tried something different. I drilled a series of 1" holes in the deck, used a coat hanger to dig out rotten material and then pored epoxy resin into the hole followed by strips of resin soaked fiberglass cloth then patched over the holes and painted with a non slip paint. You couldn't tell there was a repair and the deck ended up totally ridged. I know this isn't the proper way to repair it but it seems to have worked and I now have a totally solid deck. After a season of sailing it is holding up great. Here are a couple of pictures. Unfortunately I didn't take any pictures of the finished product.

FIrst I drilled the holes


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## superiorvoyager (Jan 3, 2009)

Then I dug out as much rot as I could


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## mitiempo (Sep 19, 2008)

If you removed all the moist core it should work. But if not the moisture left will cause rot and with freezing cause delamination as well. By using epoxy in the holes you drilled any future repair becomes much tougher to accomplish.


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## superiorvoyager (Jan 3, 2009)

Filled it full of epoxy and fiberglass cloth

And then patched the holes. Worked great and quite easy


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## superiorvoyager (Jan 3, 2009)

There really isn't anything left to rot in there as the entire core was totally rotted. After sitting with a 2 foot section cut out at the mast step for the winter it was fairly dry (after the -50 weather we had this winter it was freeze dried). My hope is that there is enough fiberglass in there that is bridging the inner and outer skin that it will keep for years to come. If it does fail it will mean removing the whole deck but repairing it properly would have meant that anyway. Here's hoping.


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## superiorvoyager (Jan 3, 2009)

After 2 years of heavy sailing my solution has been holding up well so for someone who doesn't want to replace an entire cabin deck this may be an ok solution.


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