Crushed glass for taking bottom to gelcoat

[cburger]

Boat has been pulled from water after being in water for almost six years. There are evidence of blisters underneath the barrier coat and I want to remove all coatings down to the gel coat. I started removing some of the paint and barrier coat last weekend with a scraper and there are places where gel seems very thin, evidence of repairs with what appears to be Bondo that needs to be removed and lots of blisters.

I fast came to the conclusion that I don't have the desire to do this work by hand and have contacted a local "Soda Blaster" who looked at the vessel yesterday and is indicating the baking soda won't be aggressive enough to remove the barrier coat and wants to shoot crushed glass to accomplish the work. As part of the conversation he indicates the glass will leave the bottom "Rough" and if there are any voids may open them up. Something else he said that was interesting is he feels barrier coat is only effective for about 10 years.

Wondering if anyone has ever had crushed glass used to strip their bottom and how the job turned out?

[Pete7]

No experience of using crushed glass, but if the gelcoat is thin and full of bondo in places why not peel the hull down to GRP and let it dry out properly. It will also show up any other areas that need attention. I wouldn't mess about with glass, soda, volcanic ash or coconut husks.

https://www.youtube.com/watch?v=b_qR1d9Cu5g&t=475s

[cburger]

No interest in peeling gelcoat off, laminate is not wet, just need to get down to bare bottom let boat dry for a couple of months make repairs to the larger blisters and reapply fresh barrier coat and bottom paint. I am concerned about blasters comment that bottom will be rough, thinking this may be good to give a good bond to the barrier coat. Would really like to hear from some members who have had experience with blasting with the crushed glass?

[JPA Cate]

cburger,

Is it possible that what you're thinking is blisters may be poorly done repairs? I may be very wrong here, but I did not think Westsail 32's were blister prone....

Ann

[flyingfin]

It is the bottom of the boat, not the hood of a Ferrari. Sandblast paint to rough up gel coat, pop any blisters over 1 inch diameter, leave the rest alone.
Apply two coats of barrier coat, then one or two coats of two part epoxy or urethane, then bottom paint. Dont spend your valuable time and money on making the fish view perfect.

[Cheechako]

It sounds like you need a peel , not blasting. It's very hard to stop long term blisters. But peeling is your best chance. The WS should be thick enough to just peel and smooth without laying more glass... may even be a good thing! I had one boat that had hidden blister history when I bought it, within two years it had blisters INSIDE the hull below the floor! Not a thin hull either.
It sounds like you need to go deeper than just removing the gel coat.

[cburger]

Originally Posted by JPA Cate

cburger,

Is it possible that what you're thinking is blisters may be poorly done repairs? I may be very wrong here, but I did not think Westsail 32's were blister prone....

Ann

Ann nice to hear from you again, the boats reputation is not to have blisters, but alas blisters through gel coat, water weeping. Put moisture meter on keel indicating high levels of moisture. However visually doesny appear to be laminate issues. Hope all is well.

[cburger]

Originally Posted by flyingfin

It is the bottom of the boat, not the hood of a Ferrari. Sandblast paint to rough up gel coat, pop any blisters over 1 inch diameter, leave the rest alone.
Apply two coats of barrier coat, then one or two coats of two part epoxy or urethane, then bottom paint. Dont spend your valuable time and money on making the fish view perfect.

LMAO with this post, very pragmatic advise,

[Cheechako]

Certainly there are many options. One less expensive is to get it blasted or sanded to remove the gel coat... rather than the expense of peeling etc. Then let it dry a good long time, as having the glass fibre exposed to air and wind will assist drying.. Then roll on epoxy resin layers and go sailing. It should last 2-5 years or more on many boats.

[boden36]

Crushed glass is just another abrasive blasting media. Choose whichever media will give you the surface profile required.
Have you considered wet abrasive blasting? - less dust and the water will tend to wash away contaminants.


Regards,
Richard.

[a64pilot]

One assumes that if aggressive enough to chew through Gel coat, you want someone who is talented, I can see how maybe that could get out of hand fast.
I think I would want to be there

[Bdozz]

I used crushed glass and a harbor freight sandblaster to remove my bottom paint, it will remove barrier coat but not easily, I wanted to strip my bottom to see if the small bumps I was seeing were blisters , it turns out they were just in the barrier coat, it opened them up nicely. A pro probably has better equipment then I have though.

[cburger]

Originally Posted by a64pilot

One assumes that if aggressive enough to chew through Gel coat, you want someone who is talented, I can see how maybe that could get out of hand fast.
I think I would want to be there

The gentleman who will be doing the work does this for a living
And indicates even with glass barrier coat removal will be difficult and require the better part of two days. He is encouraging me to be at vessel to inspect result as the get equipment tuned up for production.

Wondering what anyone thinks about his claim that barrier coat only good for about ten years?

[svJasmine]

I have a westsail that has never had blisters until a few in the last few years. I barrier coated the boat in 1996. So it worked for 20 years for me. I have not been out of the water in 10 years and it's time. I wouldn't go crazy with any expensive blister repair. Let them dry out and Fill them and scuff the nearby barrier coat and re-barrier coat that area.

The westsails are an inch thick where they blister and it's only cosmetic.

[thruska]

Originally Posted by cburger

The gentleman who will be doing the work does this for a living
And indicates even with glass barrier coat removal will be difficult and require the better part of two days. He is encouraging me to be at vessel to inspect result as the get equipment tuned up for production.

Wondering what anyone thinks about his claim that barrier coat only good for about ten years?

If he’s a professional, he should have some good references and pictures to prove it .
Any blasting job requires proper equipment or you’re just wizzing into the wind.
I would never ever hire someone to do anything on my boat without being present. You can always shoo him off if it looks sketchy!
Too many fly by night “pros” out there.