How to fix this blister

[newsailor72]

New to me 84 macgregor 22, been sitting for 10 years. Giving it a more thorough look today, found a dime size blister , poked at it with a screwdriver and the top layer just popped like crackers, kept peeling away and now it's about two inch long. It won't go any bigger, it seems, and I pressed hard around the perimeter with the handle of the screwdriver, feels solid, not soft spot. The exposed fiberglass feels hard too.

What is the fix?
1. Grind, sand it down
2. Clean with acetone
3. the put alternating glass mat and glass cloth
4.Sand glass
5. Gel coat
6. Paint
Haven't done this before, just from research on YT

 

[Foswick]

With a repair this small, there is no point in adding glass. From the looks of it, you would actually have to remove a fair amount of good glass to widen/deepen the area enough to lay new glass in. It appears that your blister developed between the gel coat and the glass - very common. The underlying glass (the only thing with any structural role) appears intact.

So, the repair is all about removing loose material, ensure the area is bone dry, filling the damaged area, and then just painting over it as if nothing had happened. Super simple repair that should last forever. The steps you listed are basically correct, but you don't need glass or gel coat. Just prep, fill with thickened epoxy resin, sand smooth, and bottom paint.

I think this guy shows it pretty well:

. He does add glass, but correctly points out that he probably didn't need to. (For a small blister, there is really no benefit.)

 

[jssailem]

@Foswick has identified the solution I would use. You can speak with the support team for Total Boat products from Jamestown Distributors. They have seen and resolved this issue. I find their products are quality at a fair price.

Once you have filled the area and sanded I smooth, you might want to cover the area with a barrier coat. Then apply your bottom paint.

 

[newsailor72]

@Foswick has identified the solution I would use. You can speak with the support team for Total Boat products from Jamestown Distributors. They have seen and resolved this issue. I find their products are quality at a fair price.

Once you have filled the area and sanded I smooth, you might want to cover the area with a barrier coat. Then apply your bottom paint.

is this the right filler to use "TotalBoat Polyester Structural Repair Putty", https://www.amazon.com/TotalBoat-Po...air-Putty/dp/B07C9D2GFJ/ref=asc_df_B07C9D2GFJ

 

[Davidasailor26]

For something underwater where it’s going to be painted I’d use an epoxy rather than a polyester. Assuming the fiberglass laminate is still fine and doesn’t need structural reinforcement you could use Total Fair, then an epoxy barrier coat/primer, and antifouling.

 

[BigEasy]

After filling & fairing with fairing compond, I would apply 3 coats of interluxe 2000 (epoxy) as a barrier coat, then apply ant-fouling paint.

 

[Richard19068]

Total Boat is good stuff and has good help.

I also like the instruction manuals available from West System.

Gelcoat Blister Repair | WEST SYSTEM Epoxy

The WEST SYSTEM guide for repairing and preventing gelcoat blisters in fiberglass boats also teaches How to use our products safely.

www.westsystem.com

 

[jssailem]

I would use Total Fair.

TotalBoat TotalFair Epoxy Marine Fairing Compound

Lightweight 2-part marine epoxy fairing compound perfect for reshaping, filling, and fairing. Use above and below the waterline on fiberglass, wood, aluminum, and steel.

www.totalboat.com

“This lightweight 2-part marine epoxy fairing compound is perfect for reshaping, filling, and fairing. With an improved formula for less sagging and easier sanding, TotalFair fairing putty is ideal for boat building and repairs above and below the waterline on fiberglass, wood, aluminum, and steel. TotalFair dries fast and sands smooth. Color coded components for easy 1:1 mix ratio.”

 

[Jan11]

I don't see any barrier coat in the picture so putting a barrier coat on the patch is a serious waste of money. Why would anyone want 10 square inches of a bottom protected when it is already covered with epoxy?

Are we trying to make a silk purse out of a sow's ear?

 

[newsailor72]

Leaning towards patch it up with white marine texfor now, making the repair one inch wider all around. I'm not too concerned with aththetics right now, only paid $800 for it. Will do a more thorough bottom job in the winter (sand, barrier coat, then paint)
Will that work?

 

[BigEasy]

Leaning towards patch it up with white marine texfor now, making the repair one inch wider all around. I'm not too concerned with aththetics right now, only paid $800 for it. Will do a more thorough bottom job in the winter (sand, barrier coat, then paint)
Will that work?

No problem with that approach!

 

[newsailor72]

No problem with that approach!

Forgot to say boat will be in a slip before winter haul out

 

[Arctic Pro]

Not to rain on a parade - is it an optical illusion or does the photo show a sagged-in hull above the wood plank that's been poorly supporting the boat for 10 years?

 

[newsailor72]

Not to rain on a parade - is it an optical illusion or does the photo show a sagged-in hull above the wood plank that's been poorly supporting the boat for 10 years?

Probably illusion, seems pretty uniform to me.

 

[shemandr]

Not to rain on a parade - is it an optical illusion or does the photo show a sagged-in hull above the wood plank that's been poorly supporting the boat for 10 years?

I think it does.