best way to remove bottom paint

[motoryacht lover]

I am contemplating striping my boat bottom and barrier coating and bottom painting my boat and saving some money. I don't want to make any rookie mistakes and was wondering if any of you have rented a soda blaster and stripped your own bottom paint. Can the soda blaster do damage or is it relatively idiot proof. Or are there are products that do a better easier job. Thanks for your time.

 

[67hat34c]

Dont think you can hurt anything with soda blasting. Takes alot of material however and it is costly. Done regular sandblasting and cant see how soda will be any different so why not go for it.

 

[yachtsmanbill]

Walnut shells or cocoa bean shells are cheaper (sometimes free!) you just need the blasting equipment. FWIW... shells wont do any "un directed" damage. Sand or glass beads will bounce off and scratch the finish. With shells, just keep 6" from your target and they will follow your' lead. That will also leave a nice featheredge up to the water line. ws

 

[motoryacht lover]

Thank you both for your replies. Where do I buy the soda or other material? Also it seems that chemical paint strippers are not the way to go. Thanks again.

 

[34Hatt]

Well I have donre the chemical way and the blasting way!
You asked ( best way to remove bottom paint )
I say by paying someone to sodablast it it is a Crappy job let someone else do it!!!!!

 

[Brian Degulis]

I've never done soda blasting We sandblast on a daily basis. It's one of those things that if your set up for it it's great but if your not the intense set up protection recovery etc usually isn't worth the time saved. To blast the bottom of say a 50' boat you will want at least a 200 CFM compresser and around 3000 lbs of sand. Then I'm sure the boat yard is going to want you to contain the dust protect the ground and remove all the used sand or bi carb.

Just getting set up and cleaning up is probably more work than getting some good disc sanders and doing the job the hard way. All the work we do is on steel boats I've never blasted anything fiberglass but I would think the procedures are the same.

Brian

 

[Capt K]

Depending upon where you are, find someone who uses The Farrow system. It is less aggressive than sand blasting (only about 45-55 lbs pressure) and it uses volcanic pumice in a slurry. Soda blasting is ok, but it leaves a residue that must be neutralized before priming/barrier coating (ask Interlux, not the soda guy). Also, it leaves too smooth a finish and must still be sanded.

None of these are "fun" jobs, but they do all get it done.

Check around before tackling it yourself. You may find it is not a great savings to do it yourself unless you have the time and free labor.

Good luck!

K

 

[bobk]

What is the condition of your hull and paint? Is a barrier coat really necessary? And what are you contemplating using to barrier coat? Just looking to start a dialogue. ;>

Bob

 

[Boatsb]

What paint is on it? Is it ablative or do you have build up that needs to be removed? Is there blisters? If it aint broke don't fix it.

 

[motoryacht lover]

I have a Petit hard coating. It is not an ablative. I want to go back to an ablative. What I have now is areas were it is so thick that it cracks and then an edge of paint will lift up and then flake off leaving a bare spot. I suppose I could keep chipping off and spot painting but I may have the time coming up. Someone mentioned sanding discs is that a viable option or will I almost instantly clog up the disc. Thanks for all of you alls help.

 

[J's Dream]

How about the wet sandblasting they do at the marinas? Scott and Steve I'm sure are familiar with it, as Cape Marina does it on a daily basis. I have never heard of any damage from this type of paint removal. I'm curious about it too, as in the near future I may consider it.

 

[Boatsb]

From someone who had a yard and worked in a bunch the removal of bottom paint suc*s. It's not a job for weekend warriors and the toxic waste it produced is a pain to clean up. I would have it scraped/blasted or what ever method makes sense by someone set up to do it. After that the sanding, prep and barrier coats can be done and the ablative paint put on by you.

I personally do not see the savings in do it yourself blasting unless you have the gear and the experience. I would use my time on projects where I get a better pay off like finish work, electronics or even structural repairs if needed.

 

[Maynard Rupp]

Several years ago we removed 17 coats of bottom paint from our '86 36C Hatteras. We used the cheapest Home Depot stripper and lots of it; 38 gallons to be exact. Stripper won't harm the gell coat on the bottom, as gravity keeps it from soaking in. We then ground it with 60 grit, dug out and epoxyed about 20 blisters. Next we rolled on 7 coats of Interprotect 2000 followed by bottom paint. That was 5 years ago and our bottom still looks perfect. This spring we sanded the VC-17 off. That was simple as that stufff has no thickness. We applied Petit Trinidad Pro because the boat is in Miami. Our barrier coat was perfect and we had no blisters after 5 years.

 

[Brian Degulis]

If most of your build up is bottom paint then a very strong caustic degreaser or stripper followed by pressure washing with a rotating 0 tip is going to be the fastest and easiest. Then when you get down to removing the barrier coat a light weight high speed disc sander.

Brian

 

[fissioneng]

Most people I know have paid to have the bottom peeled before barrier coating. It is much cleaner (the tool just vacuums up the stuff) than blasting and leaves a very smooth surface to start with. Blasting tends to leave a rough surface that requires sanding and smoothing. Peeling also removes the gel coat which is the root of your blister problems.

One person I know put several coats of epoxy on before the barrier coat.

 

[Pete]

One consideration from my experience renewing the bottom of our boat last year, do you have a prior barrier coat on the boat. I did and this changes the options. Blasting basically relies on the material to be removed being "softer" than what you want to stay. Works great when the two materials are softer bottom paint and harder polyester resin. When you have a coat of epoxy over the polyester resin, it is an almost impossible task to remover the harder epoxy without "digging" pits all over the polyester surface. I decided to sand, using 50 grit disks. For a 48 footer it took two of us, full time, two weeks to clean off the bottom down to the gel coat. Another two weeks of blister repair with West epoxy and biaxial glass. Seven coats of Sea Hawk "Tuff Stuff" barrier coat, Pettit Ultima bottom paint, and she looked good as new. Hopefully, it will look equally good when we haul this Fall. Big, dirty job. But, I am an absolute believer that if you want something done right, do it yourself. Good Luck

Pete

 

[REBrueckner]

I see metal boats being stripped to bare metal, above and below the water line, with a portable truck....something like 40 to 50 thousand psi water!!!! ....in New Bedford Mass, DN Kelley Shipyard....it was a USCG cutter being refitted most recently...no apparent waste material..might be worth checking to see if they do glass and get an estimate...

 

[yachtsmanbill]

I think that with any kind of blasting the operators discretion plays a key role in the job. We had a tug water blasted while in drydock last year, and the operator couldve taken it all down to white steel, but left most of the coal tar undercoat on. The process is dust free which is good, but the EPA doesnt want the stuff to get water borne.
On fiberglass I would use a shell media so that you dont inadvertantly blast damage into the gel coat. Bottom paint is generally pretty easy to remove this way. Even if the barrier coat is 75% intact, that makes an easy job out of fixing the bad stuff, profiling it for bottom paint, and applying IMHO. In Chicago, we have the plant that makes Cocoa Puffs and they give away truck loads of shells from the beans. Just about ANYTHING will work with 150 psi of air pushing it! ws