# Soda Blasting Hulls



## willysail (Oct 19, 2010)

Hi everyone, I was wondering if anyone had any experience with “Soda Blasting” the bottom of there hull. I have some repairs that I need to do and after talking to several people the consensus is to soda blast the hull below the waterline. I wanted to know if this is a standard procedure and would it damage the gel-coat. It would be nice to get all the years of residual bottom paint off.


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## Tim R. (Mar 23, 2003)

Soda blasting works well if done by a professional.

I stripped my previous boat's hull(35 ft.) with walnut shell blasting. Rented a compressor and blasting unit locally and bought 6 50lb bags of walnut shells. 1/2 day and it was done. Total cost abour $450.


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## willysail (Oct 19, 2010)

Treilley,
Someone told me that any kind of hard abrasive would damage the gel-coat finish.


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## sawingknots (Feb 24, 2005)

all i know is its expensive but does a good job depending on the operator,chopped up corn cobs work well too


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## willysail (Oct 19, 2010)

will this pit the surface of the boat


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## Barquito (Dec 5, 2007)

I was told by my surveyor I should do this too. Possibly consider doing a barrier coat after media blasting. This would help cover any dings from when whole walnuts and corn cobs chip the bottom of your boat so that it looks like a golf ball.:laugher (actually maybe a golfball finish on the bottom would be faster?)

My question is: How much of a mess does it make? My boat is on gravel in a boat yard. Will they be pissed if there is 300 lbs of walnuts under my boat?


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## tommays (Sep 9, 2008)

This is one of those it really depends on whose driving and wear you live as on Long Island at this point when they do bridge work its full on tent with LARGE vacuum units kind of like asbestos removal 

I am really not sure what there doing with the leftovers BUT its all HAZ-MAT and i would think just flying under the radar right now


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## hellosailor (Apr 11, 2006)

Soda blasting is just media blasting, using baking soda as the medium. Corn cob, crushed walnut shells, sand, are also used as media. Each has a different amount of abrasiveness and a different cost, and the reason for soda blasting is that it is one of the gentlest ones. it will strip the paint without harming the gelboat--if used at the right pressure, as any pro should be able to do it.

Yes this is a common way to do the job, and a safe way. Your alternative is chemical strippers ("rinse, lather, repeat") or other conventional abrasives. I think soda blasting is probably as cheap and fast as anything else, and if you can arrange your schedule to fit the guy's slack time, or get more than one boat for them to work on while they're at the yard, you can probably trim the cost down a little too.

It can even clean old paint off PLASTIC without marrring the surface, so if there's anything else on board that needs "unpainting"....


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## BarryL (Aug 21, 2003)

*soda blast*

Hello

I had my boat soda blasted in 2008 and I was VERY happy with the results.

If you want to see some pics of before / after soda blasting, go here:

http://www.sailnet.com/forums/gear-m...done-test.html

Barry


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## tommays (Sep 9, 2008)

Barry

Who is the trusted contractor on Long Island


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## sawingknots (Feb 24, 2005)

yeah it will leave a hellof a mess,you better check with the owner/manager first also if the dirty water/debris run into any nearby water you could get in hot water with the local authorities


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## Tim R. (Mar 23, 2003)

willysail said:


> Treilley,
> Someone told me that any kind of hard abrasive would damage the gel-coat finish.


Walnut shells are harder than bottom paint and softer than gelcoat. The resulting surface is etched properly to accept barrier coat.


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## willysail (Oct 19, 2010)

Does anyone know someone in the Cape Cod area that is any good


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## Tim R. (Mar 23, 2003)

I put down a tarp to catch all the paint chips and walnut shells. The shells can be run through about 3 times before they lose all their pointy edges and are ineffective. I also skirted the boat from the WL down in order for the deflected shells and paint to drop down to the tarp on the ground and control the dust. Walnut shells create A LOT of dust. You will need a good respirator.


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## gbm4th (Jul 31, 2009)

Had 20 years of bottom paint removed from my boat by soda blasting. They set up a big tent with a vacuum and a tarp underneath. You really want to be properly attired too; lots of dust in that tent.

Best leave it to a professional; very messy. Check with the marina too.

George


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## BarryL (Aug 21, 2003)

*Soda Blasting on Long Island*



tommays said:


> Barry
> 
> Who is the trusted contractor on Long Island


I used All Island Soda Blasting

http://www.allislandsodablasting.com/

They did a very professional job. They tented my boat, ran a vacuum to collect dust and left the area cleaner than when they arrived. One of the nice things about using baking soda is that the soda is non toxic and just dissolves in the rain. Of course the removed paint is toxic, so that's why they use vacuums to collect it.

Baking Soda won't damage gelcoat or the hull and leaves the hull smooth. Too smooth, so that you need to sand with 80 grit to give the hull some 'tooth' for the paint to stick too.

It is expensive: I paid $1700 to have the old paint removed from my 35' boat. But, I had about 20 years build up of old, hard paint. I tried chemicals, sanding and scraping. The scraping worked best but it was slow back breaking work.

Barry


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## chuckg5 (Jun 22, 2006)

Goggle 'Rhode Island soda clean' , they are the best there is ( they do work for Hinkley. they work out of Newport but will travel


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## willysail (Oct 19, 2010)

*Soda Blasting*



chuckg5 said:


> Goggle 'Rhode Island soda clean' , they are the best there is ( they do work for Hinkley. they work out of Newport but will travel


Thank you I will caal them this week


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## Wantabe (Aug 30, 2009)

This is my first post here so take what I say with a grain of salt. We used dry ice as a medium to remove paint and rust from the machine we rebuild. Nothing left but the old paint on the floor!


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## Barquito (Dec 5, 2007)

> We used dry ice as a medium to remove paint and rust from the machine we rebuild.


Any danger of being in an enclosed tent blasting away with carbon dioxide? May vent much faster than it melts (sublimates), not sure.


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## blt2ski (May 5, 2005)

Definitely check with the marina you are pulling at. My home marina ONLY allows sanding with a vacuum connected to it. In the port regs, NO sand, soda or equal blasting, ONLY grinder style sanders with vacuum attached!

BUT, from a few others local, ie puget sound that have done this at other marina's/workyards, clean up/prep etc is better than doing it via sanding. cost is about the same too.

Marty


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## Wantabe (Aug 30, 2009)

Barquito,

We blast outside and it has never been a concern. theres not much to clean up when it's done.

Just a thought, Like I said "take it witha grain of salt"


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## ontherail (Mar 24, 2011)

I had this done to my boat. It was fine. Left an even but rough surface almost like worn out sand paper - 180 grit. I disc sanded it before epoxying. I would only do it before epoxying the surface. However the hull above the water line needs lots of masking. The "Pro" that did mine did a terrible job taping and soda bounced above the tape and took the shine off the hull. He went through the water line paint in one spot. He also damaged the water line above the bottom paint (I think by blasting right through the tape). Lesson learned. Be there when it is done. I had to go home.


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## eherlihy (Jan 2, 2007)

I'm gonna post here what I posted in another thread because I would like some input...


> I recently contacted a reputable firm to soda blast the bottom of my hull. The guy came by and gave me an estimate, but said that he does not soda blast any more. He now uses "recycled glass."
> 
> Soda blasting, he says, requires that the hull be sanded with 60 grit in order to give some tooth for the paint. This is not required for glass blasting. He also said that if he used soda that the hull would need to be "neutralized" to get the PH right before painting. I understand that soda is mildly caustic, but would a hull that was soda blasted require neutralization before painting?
> 
> ...


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## turbulicity (Jan 24, 2011)

I've read in a book never to sand blast. I don't know the exact reason but just keep in mind and do some research.


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## ontherail (Mar 24, 2011)

After soda blasting, I washed the bottom of the boat with lots of water and waited a couple days before putting interlux epoxy on. The soda is definitely less abrasive than recycled glass. I have seen blister jobs that use sand blasting and it left a very uneven surface. But that was below the gel coat where there are different densities of materials. It is common practice to epoxy over a soda blasting but mine was a little rough and I sanded it with 80 grit on a random disk sander. between that and the water, it was clean. Perfectly white with no more paint residue. It did make a rougher surface on the fairing putty on the keel. 

Special note. stuff a rag in all closed sea-cocks. And the exhaust. it will fill your boat with powder if you leave a drain open. The guy that did mine blasted inside the Marlon through hulls and they looked clean but it abraded the part of the ball that faces outward. I wish I had protected that.

I think other softer media materials like walnuts could do a good job too. It has to be completely tented as it will cover the marina with white powder if not.


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## 2Sheets2TheWind (Jan 21, 2005)

In 2003, we had the 20 year old 34 foot Citation we bought the year before soda blasted after talking to folks for advice. We decided sand blasting is best for barges or tug boats, not fiberglass. I think soda was still a relatively new concept at the time. The guy told us he could take it down just to to the barrier coat after I asked him about it. Soda blasting allows more precision than sand I think. He took off all the bottom paint and it turns out there wasn't any barrier paint (but no blisters, either) but he did leave the gelcoat intact. A guy who does sand blasting came over while I was working on it the next day and said it was too smooth to hold barrier paint. It was an unsolicited expert opinion. I don't think I sanded it with 80 or 60 grit paper, but I'm sure I washed the bottom before applying about 5 or 6 coats of 2000E barrier coat. We've hauled every other year ('05, '07, '09, and will again in a couple of months). Haven't had any problems. The soda blaster did a great taping and tenting the project. Don't know how loud a sand blaster is but the soda blaster was very loud. The place I haul out now doesn't allow blasting because of the noise due houses and condos going up in the last 7 years.


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