# Repair of rotten sandwich deck



## ulferlingsson (Jun 10, 2010)

A serious problem existed with the Ensenada 20 I bought in allegedly "sailable condition": A soft spot on the deck nest to the mast. There was de-lamination on the underside, in the cabin. This fix seems to have done the trick:

1. Drilled small holes on a 1 dm grid.










2. Injected an epoxy that is sold for the purpose. Some holes took nothing, others swallowed many loads of 10 mL each. As epoxy came out from other holes, I sealed them with tape.










3. Press it together (a jack was used to get the pressure). I had to do it in sections since the first epoxy started curing before I was done.










I also drilled a few holes on the outside and managed to get some more epoxy in that way. In total perhaps I injected 4 dL in 0.5 m2 deck. It was enough to make it stiff again, but for good measure I added a layer of fiberglass on the underside. Since the top gelcoat was severely cracked I also brushed crevice-filling epoxy over the deck. Add paint and it looks and feels like new.


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## sailingdog (Mar 19, 2006)

I can pretty much guarantee that you didn't really fix the problem by doing this... and it will make properly repairing it much more difficult down the road.


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## SaltyMonkey (May 13, 2010)

Absolutely agree w/ sailing dog. To properly repair a problem like this requires cutting off the top layer, cutting out the rotten core, drying it out, filling in with new core (balsa or ply), glassing in with epoxy and mat, fair, paint.

The ejection method sited not only doesn't work effectively, but it was done wrong. Sometimes people do it on the deckside, but it takes a few months for the moisture to evaporate through the holes, and the rot is still in there. Looks like you just locked it in by going underneath. Moreover, it is not evenly spread throughout the voids in either case. The voids will always be there

However, doesn't look like this boat is for a transi, and may sail locally, so you may be fine for your required sailing purpose.


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## ulferlingsson (Jun 10, 2010)

(smiling)


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## tommays (Sep 9, 2008)

While i am sure you got epoxy to stick to something like the inner skin its on the unlikely side you got the inner and outer skin to bond to a wet core

I can say for sure it does not scale up to large boats well and if you look at Git Rot Penetrating Epoxy its for dry-rotted wood NOT wet


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## LandLocked66c (Dec 5, 2009)

I agree with these guys. I'm re-coring my sole currently.

http://www.sailnet.com/forums/gear-maintenance/63795-1970-oday-23-pop-top-project-has-begun.html


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## ulferlingsson (Jun 10, 2010)

Meanwhile I am walking on my deck. The problem I had was that the deck was too soft; it is no longer too soft; thus the problem is gone. If it again would become too soft, and the same repair does NOT work again, then there would be reason for concern. But that day that worry. Don't invent problems if you don't have to!


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## eherlihy (Jan 2, 2007)

This is an interesting concept. However, it flies in the face of the experience of many of the members here, and manufacturers recommendations.

See http://www.westsystem.com/ss/assets/Uploads/Ew19Replacingcore.pdf

and this link where the owner documents the established procedure for turning this








into this








then this








this








and eventually this


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## ulferlingsson (Jun 10, 2010)

I didn't invent the method, I found it on the web, and the product is from West Systems if I'm not mistaken. It is worth noting that it was a local problem on my boat, perhaps related to a too weak deck to begin with; the starboard side is very strong since the galley is there, but the port side has no support at all. My first thought was that it was the sailing forces that had ruined the deck, not rot. And I still haven't seen any evidence to the contrary (I put in in the thread heading since I assumed there might be some degree of rot, too).


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## hellosailor (Apr 11, 2006)

Well, it is possible that both "sides" are right. Consider a soft deck. it is "soft" because as you put pressure on it, the water and softened core squish over a bit. Now add enough epoxy all around that area, and you have "clamped" all the squishy stuff into one place. Something like slapping plaster around a balloon, now the balloon seems quite solid.

Until the deck core degrades a bit more, or the epoxy lets go a bit and the soft stuff starts squishing around past it again.

If it lasts a year...great, you're sailing. But I wouldn't be surprised if it starts squishing again at some point in the future, and then needs to be recored. Unless you first remove all the moisture--nothing will properly and permanently fix a soft deck core.

If the product is from West Systems, call them. They'll provide free technical support and they'll know exactly what and how it can or can't work on.


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## mitiempo (Sep 19, 2008)

West epoxy is very good, as are the other epoxies from established companies. But it does not bond to anything wet including balsa wood. Your fix will get you sailing but it will need to be redone in the near future. 
It takes almost as long to do it wrong as it does to do it correctly, and if well done you are increasing saleability and value. Most of us have learned this after a while.


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## bljones (Oct 13, 2008)

ulferlingsson said:


> Don't invent problems if you don't have to!


But if you're going to attempt to solve a problem, shouldn't you actually solve it?

Let's you went to the doctor with a lingering hacking cough. The doctor tells you, "you have tuberculosis. Whenever you feel like you are going to cough, suck on a cough drop."

You ask, "will it cure the disease?"

Doc says, "No, but you'll stop coughing, which is why you came here in the first place."

Great, you cured the symptom! Did you cure the disease? Nope. You still have a mess of rotten punky core which is now TEMPORARILY solidified with epoxy. Have you found and fixed the reason why it got punky in the first place? Meanwhile, you have added a layer of fiberglass to a small section of overhead. I bet that looks pretty!

But hey,
It's your boat.
Your time.
and 
Your money.


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## DrB (Mar 29, 2007)

*A little harsh aren't we?*

Folks,

The OP has a boat that in good condition is probably in $2000 range. While his attempt to fix his flexy deck doesn't follow the standard and recommended approach to fix the deck, let's not lose sight here that it's a boat that is over 30 years old and worth at most $2000. Why spend countless hours and money to pull out core, dry out, replace, fiberglass, and then repaint the deck, for a small daysailer that doesn't need to withstand off-shore conditions and probably wouldn't be sailed in conditions that would require the boat to be in peak structural rigidity.

Could it have soft decks? Probably. Is the better fix to pull the core and replace? Generally, yes. Is it structurally unsafe with the current deck and fix? Most likely not. Can it be sailed and enjoyed as fixed. Absolutely.

OP, if you're comfortable with what you did for a fix and feel that you can trust it for the waters and conditions that you sail in, put it in the water and sail it. If it breaks, fix it again, donate it, or scrap it for parts.

DrB


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## bljones (Oct 13, 2008)

Countless hours? let's compare recoring to drill-and-fill.
1. Determine how big the problem is. No time advantage to either method.
2. D &F Drill 2 dozen holes @ two holes per minute = 12 minutes.
or, cut a square (ish) hole about 18" per side = 10 minutes with a circular saw set to depth. Advantage to recoring.
3. recoring- Peel off top skin- 10 minutes (remember it is all just rotten core underneath. Not necessary with D and F. Oops sorry, I forgot. Drill a few more holes (6) for filling from the top 3 minutes. Time advantage D&F.
4. D&F: Mix epoxy, fill syringes inject, refill, inject, patch with tape, inject, refill, inject, patch with tape, repeat., wedge and clamp @ 1 minute per hole= 1/2 hr. Recore- remove old core, clean up and sand, mix epoxy, set in new core, fill with epoxy. 45 minutes. Time advantage D&F
5. Drink beer and go to bed while epoxy sets. No time advantage to either.
6. Recore: mix epoxy, reinstall top skin and wet out cloth as needed (shouldn't be needed because your cuts were clean so all you have to do is fill, fair and sand, right?) 1/2 hour.
D&F: pull off tape, mix epoxy, wet out reinforcing cloth, lay up cloth. 1/2 hour. No advantage.

Total working time, assuming you had all the tools and materials:
Drill and Fill: 1 hr 15 minutes.
Recore: 1 hr 25 minutes.

Properly recored, it will never have to be done again. Costwise, no cloth needed, probably a similar amount of epoxy, so the only additional material required would be the core, figure about $30 for a sheet of EGB.

The savings ain't there. Of course, if the OP plans to only hang onto his boat for a season or two and sell it, then some would suggest that "good enough" is good enough. but if that is the case, how do you think a buyer will react to seeing a big patch of fiberglass stuck to the overhead? Think that might cut the resale value considerably more than the cost of the end grain balsa purchase that recoring would require?


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## JimCate (Jun 5, 2010)

Well, in my reading of the OP, nowhere is it said that there was evidence of water in the core... just delamination, apparently between the inner layer of the the deck and the core. This does happen sometimes, ya know!

And if this is the case, then his fix is appropriate and should be successful. If the core is indeed wet, then all you guys are right: not a good fix at all. I wonder if the drill chips that came out when he drilled the injection holes were wet or dry??

Cheers,

Jim and Ann s/v Insatiable II lying Iluka, NSW, Oz


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## SeaBungalow (Jun 15, 2010)

Wow, 1 hr 15 minutes to recore an area of the deck... that is some serious skill! 

This is assuming you go from underneath, otherwise sanding and fairing will take much longer to have a non-lumpy deck, not to mention then having to match the rest of the deck (painting, non-skid, etc). 

Though I have hung fiberglass wetted strips overhead it would be quite a trick to see keeping the core in place, filling the voids with epoxy filler, sanding that smooth so the removed skin could be put back in place, and keeping that in place while trying to keep strips of wetted glass from falling loose all in under 90 minutes, much less days.

Much easier to do it from the top, just my experience.


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## DrB (Mar 29, 2007)

*Agree w/SeaBungalow....*



bljones said:


> Countless hours? let's compare recoring to drill-and-fill.
> 1. Determine how big the problem is. No time advantage to either method.
> 2. D &F Drill 2 dozen holes @ two holes per minute = 12 minutes.
> or, cut a square (ish) hole about 18" per side = 10 minutes with a circular saw set to depth. Advantage to recoring.
> ...


I think your recore estimates re: time are low. If 1.5 hours to recore a 2.25 f2 area, I could do my deck in 16 h, and I know that ain't the case. More like 40 h min, and that is before repainting the deck and if I don't need to remove hardware or break the deck sections when taking it apart.

As far as resale value, yes you are probably right, the inside fiberglass patch will detract from the future sale, but the boat is worth no more that $2K in good condition, it really can't go a lot lower. If he sails it for 3 years then sells it for $1000, his cost is $333/year. Doing a proper recore, may bring the boat to $1500, so his cost is $167/year. You got to ask yourself, is it worth my time and cost to do a full recore fix on boat to potentially save $500 on a resale in 3 years (or what ever time frame) or do I have better things to do with my time and money and a quick, inexpensive "fix" will suffice for the short term?

DrB


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## bljones (Oct 13, 2008)

SeaB, It was I hr 25 minutes. 
I was discussing doing it from the top down and yeah, my time estimate was "quick and dirty", comparable to the OPs approach. No fairing, just get her done to get sailing. but if you make your cuts clean and don't try to fit 1" end grain into a 1/2" void, you don't have a whole lot of fairing and sanding to do.


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## bljones (Oct 13, 2008)

DrB said:


> I think your recore estimates re: time are low. If 1.5 hours to recore a 2.25 f2 area, I could do my deck in 16 h, and I know that ain't the case. More like 40 h min, and that is before repainting the deck and if I don't need to remove hardware or break the deck sections when taking it apart.
> 
> As far as resale value, yes you are probably right, the inside fiberglass patch will detract from the future sale, but the boat is worth no more that $2K in good condition, it really can't go a lot lower. If he sails it for 3 years then sells it for $1000, his cost is $333/year. Doing a proper recore, may bring the boat to $1500, so his cost is $167/year. You got to ask yourself, is it worth my time and cost to do a full recore fix on boat to potentially save $500 on a resale in 3 years (or what ever time frame) or do I have better things to do with my time and money and a quick, inexpensive "fix" will suffice for the short term?
> 
> DrB


 Ain't working on boats funny? a small job takes small time, but if you extrapolate over larger area, the time/area ratio never works out? Larger areas take larger time, simply because of the logistics. making four cuts without having to move, mixing small batches of epoxy, only having one cure period instead fo several, etc. YES, recoring a WHOLE deck takes "countless hours" and wouldn't make sense on an Ensenada 20. As for whether the fix will suffice, there's the risk. The durability is the issue. if the core is pulp, it might last a couple of years, it might last a couple of months. If the OP is a 300 lb former frat boy who races with 3 other former frat boys, figure on that deck getting spongy sooner rather than later, and then the OP is doing it all over again, and ANY time and $ benefit to taking a short cut is lost.

As far as resale, again, you may be right- it may only affect the resale by 5 bills. Maybe you are much wealthier than I am, but, to me, $500 depreciation because I didn't spend an extra $30 in material and an extra 20-30 minutes would make me want to kick my own a$$.


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## ulferlingsson (Jun 10, 2010)

Could add that there was one oval hole already ground in the underside of the deck to the core for inspection. The core was structurally solid plywood in that site, there was just delamination. I figure the delamination was the reason for the softness when stepping on it.

As for value, this boat was purchased for work more than fun. I'll be diving and doing research from it. It's a renewable-energy powered research vessel ;-) Esthetics on the inside is almost irrelevant. I'll be mounting whatever hardware is necessary to hold equipment next.


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## eherlihy (Jan 2, 2007)

Jeez, this is like ulferlingsson offered us a gift horse, and everyone is checking it's teeth...

Most of the participants here would like to see you do your repair the established way, as it has better long term prospects for success. However, the injection method of preforming repair has been done many times before, and it is less cosmetically disruptive. Bottom line: *if it works for you, it works for you*.

However, if you think that you have _fixed _the problem, you are likely mistaken. I suggest that you have actually patched it.

How long will "the fix" last? In all probability, a couple of years at best, a couple of weeks at worst. A lot depends on the overall condition and construction of the original deck, and the presence, or lack, of moisture in the cavity that you just filled. I believe that the repair will likely be far more brittle than the surrounding deck, and that it, or the surrounding area, will likely start flexing again soon.

Just for grins, I would love for you to post a follow up after 6 months (that'll be December) and again after a year. Let us know how she holds up.

THANK YOU for taking the time and effort to make the original post!


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## Ulladh (Jul 12, 2007)

Sounds like an optimal solution for a desired outcome, not a perfect solution for an ideal outcome.


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## ulferlingsson (Jun 10, 2010)

Ulladh, my previous boat was Havsfidra 355, from 1974. The buyer bought it as a half ready boat, and did the interior himself. Much nicer than the factory boat - the guy was a stainless steel welder at a company making dairy equipment, so there was a ton (almost) of stainless, even the structure for holding the (custom) canvas in the winter was marine grade stainless. 

All of these comments have given me a second thought: Maybe it was neither too much force, nor rot, but termites. They could have entered through screw holes from removed equipment. It would be typical behaviour for drywood termites, and termite labyrinths would explain why some holes took no epoxy, and others were virtually bottomless. Seemingly randomly. And it might explain the presence of a fumigation canister in the bilge... Hmmm. I'll do some more investigation and get back with the result. Incidentally, if it was termites then the problem really is solved now, since their labyrinths have been filled, the delamination fixed, and they cannot survive without access to outside air (they figuratively die of their own farts).


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## Ulladh (Jul 12, 2007)

Ulf
The Havsfidra is a great little boat, not fast, but very stable. I have #159.

I have used a penetrating epoxy injected into termite infested joists and subfloors for house restorations, after treating for termites, then adding additional treated joist sisters. Epoxy saturated termite damaged wood does not have much structural property as the termites will have removed the cellulose part of the wood structure.


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## ulferlingsson (Jun 10, 2010)

Ulladh said:


> Epoxy saturated termite damaged wood does not have much structural property as the termites will have removed the cellulose part of the wood structure.


I removed, by axe, some termite infested wood last year, and noticed that either they have eaten it out so it is empty, or it is as new (between their paths). They can't selectively eat some molecules and leave others... So if you fill the voids with epoxy it should be solid.

Furthermore I saved their nest with termites in a glass jar, gave them some drops of water, but kept the lid so tight that they would not escape. They died. Apparently for lack of oxygen. So, if all holes in the deck are sealed there should be no chance of termites inside... even if they have some dampness.


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## Ulladh (Jul 12, 2007)

Epoxy is a relatively brittle material, fiberglass strands or mat provide tensile properties.

Cellulose oriented cell walls provide tensile properties to wood. Loose the cellulose and you loose tensile properties. Filling the voids with epoxy will provide compressive properties but only minimal tensile properties.

The cabin top and deck with voids filled with epoxy within a fiberglass sandwich (inner and outer shell) will probably be OK for most loads. However it may be wise to add oversize fender washers and or backing plates at any through bolt attachments to spread loads, particulary at shrouds.


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## deniseO30 (Nov 27, 2006)

I've heard of using acetone to dry the wet core...I dunno that I ever want to even start trying to fix the few soft spots on my cabin top.


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## tommays (Sep 9, 2008)

The Op is happy i am happy 

But in my Plywood core removal task

1. The wood never dries i have had plywood OUT for weeks that was still damp 

2. The poly resin is often stuck like heck to the deck or has large areas with ZERO adhesion 

3. The only thing holding Plywood is the thin outer skins SO even the still stuck sections come right out sans the final ply 

4. NOT one section of inner skin has taken any effort to remove

5. Marine plwood rots nice


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## SaltyMonkey (May 13, 2010)

DrB - we have lost sight of the fact that #1) its a cheap boat #2) since he's probably not headed out to sea, its probably good enuf to get him out sailing.

However, it's not a proper fix. Clear and simple. And epoxy pseudo-solutions such as Git-Rot don't work. The cancer is still in there and will spread.

In some ways this is an incredible opportunity to learn. If this is such a cheap boat, why not take the time to master the skill? There is very little risk in things going wrong. I'd be all over the thing. And re-laminating a deck should not take too much time or be expensive on a boat of this size. The opportunity is there. Take it.


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## ulferlingsson (Jun 10, 2010)

Now you're talking, SaltyMonkey. If problem returns, can't be fixed easily, try a more thorough fix. Rebuild the deck - or add a sturdy oak deck beam underneath. Seriously, though, I think the deck was not strong enough to begin with. That's why I added material, and if that's not enough, I'll add some more until I'm satisfied. "Good as new is not good enough."


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## DrB (Mar 29, 2007)

*Salty, with you on the good learning op*

However, the OP already did what he wanted before he posted, so his post, if looking for advice on how to fix, was a day late and a dollar short.

Had he asked before he drilled and filled, then the advice given is probably the best approach and, as you point out, it could have been a great learning op and how to do without the fear of wrecking a Mega $$$ boat.

My biggest gripe, if you really want to call it that, is that a lot of times folks on this forum give great advice for a full blown repair or fix, that requires time, $, or skill set, for a problem that either exceeds the actual cost of the item being fixed or is an way overkill solution. Many, my self included, sometimes can't see the forest for the trees, of the situation. This not a knock on any of the respondents to this thread.

I had a guy work for me many moons back. Great hands on patient individual. We use to use ball valves to control the flow of resin into composite molds. The resin we used could be melted at low heat to induce flow and then would set rigid when more elevated heat was applied.

One day I came into the lab and saw my technician warming up the ball valves to drain out the unkicked resin. I asked him why was doing this and he replied, to save the valves. Good answer until I asked him how much time he spend cleaning each valve. 15 minutes was the answer. At his burdended labor rate, it was costing me (my project) $25 to save a $3.50 ball valve. I said it doesn't make fiscal sense to do this, just by more ball valves and throw these away. Yes, he did have a solution to the problem that was correct and resource (equipment) saving, but not financially prudent. His failed to see the overall big picture in his solution.

Everyone just has different opinions what's important when problem solving/fixing on their boat. Some folks want it done right, with pains-taken detail and precision, and will spend time and $ to do so, while others will say hey, its a $2K boat, I just need to do the minimal fix, at minimal cost, so that I can use it. I am not concerned to much abut aesthetics.


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## eherlihy (Jan 2, 2007)

...But his was the "Green" solution.. .

WOW! $100 an hour ($200K/year) as an individual contributor?  

Are you hiring?  (Seriously, PM me if so)


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## DrB (Mar 29, 2007)

*Burdened Labor vs His salary*

I'd love to be making $100/h too, but his rate was the burdened rate to the project. The Burdened rate included all the G&A, Benefits, Overhead, etc. I worked for a Contract R&D firm and we billed clients about 3.3 to 3.6, depending whether it was gov't or commerical, of our hourly rate. So my technician was in the $23 to 28/h range for salary. I can remember the exact number of the top of my head, but it was nowhere near $200K.

DrB


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## ulferlingsson (Jun 10, 2010)

DrB, 
That's why some run businesses and some work for a living  You gotta focus on what's most cost-effective for solving the problem AS DEFINED.
Over and out


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## SaltyMonkey (May 13, 2010)

Well, I should just warn, on a larger boat if this came back you might have a horrible expense because it would spread like wild fire. Just saw a 37' boat last weekend, where the whole starboard side had delaminated because they delayed a year thinking there wasn't any moisture to worry about. With this boat, your call if it spreads...


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## ulferlingsson (Jun 10, 2010)

If you live in a cold climate (i.e., frost in the winter) then you cannot afford to have moisture in the deck or the hull. But there is no frost here. As for rot, remember Wasa? Wood is preserved very well in water if there is no access to oxygen. If it is just sealed in completely, and doesn't freeze, nothing will happen. But again, I don't think it was rot. I think it was a structural failure due to too high load, and possibly something else, but mainly overload due to poor design. Time will tell.


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## ulferlingsson (Jun 10, 2010)

*Update ONE YEAR later*

The repair has held up without any problem. In fact, the repaired part of the deck is now the part that feels most solid to walk on.


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## rbrasi (Mar 21, 2011)

Uh-oh! You'd better pull the core from the rest of the deck and do it the right way!


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## ulferlingsson (Jun 10, 2010)

*Rofl*

If you have nothing better to do with your life than repairing what isn't broken, then YOU do it


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