Barrier coat now or later?

[Cthoops]

While the boat doesn't have any blisters now, it's also been in the northeast it's entire life - exposed for a maximum of six months to cool/cold water each year. It's going to end up in warm water, 24/7/365.

Since we're going to have to scrape off the bottom paint anyway given that it's not adhering in large sections, we may as well put on a barrier coat while we're at it. After all, the worst part of the job is going to be done already. The cost to us will be our (substantial) time plus materials.

I'd rather do this now than have to scrape everything down in the future plus fix blisters - blisters that I could have prevented by putting in the work now - while cruising.

Thanks again.

[HappyMdRSailor]

Originally Posted by minaret

Be sure the substrate is sufficiently dry before application, and it should last your lifetime.

Pretty encouraging ain't it?

Originally Posted by ramblinrod

If the boats estimate value is over $100K, a barrier coat is a worthwhile investment.

ramblin'.... a really great post, but I don't understand the logic of this one particular point ???

So if a boat isn't worth 100k+, it isn't prudent to prevent possible blistering and all of the time, expense, and work to repair a sub 100k boat after it does develop major problems?

I counter that with.... The person owning a sub 100k boat takes a harder hit on the wallet and back (arms) because he's the one that's got to perform the "un-affordable"... nightmare...

Originally Posted by Guy

No problem pulling that off during a 30 day haul out in Panama. This is why adding a barrier coat, willy nilly is not always such a great idea. You might be better off with gel coat.

Can you dry out a saturated boat in 30 days in Panama???
Methinks not...

Originally Posted by brantleychuck

Your going to spend a lot of money and time solving a problem that does not exist. Survey the bottom every few years when you apply anti foul. If the blister problem comes up solve it then

Just like condoms when you were a kid...
1. No fun...
2. Considerable portion of a teen budget...
3. Preventing blisters... Prudently Priceless...

Originally Posted by Cthoops

While the boat doesn't have any blisters now, it's also been in the northeast it's entire life - exposed for a maximum of six months to cool/cold water each year. It's going to end up in warm water, 24/7/365.

Since we're going to have to scrape off the bottom paint anyway given that it's not adhering in large sections, we may as well put on a barrier coat while we're at it. After all, the worst part of the job is going to be done already. The cost to us will be our (substantial) time plus materials.

I'd rather do this now than have to scrape everything down in the future plus fix blisters - blisters that I could have prevented by putting in the work now - while cruising.

Thanks again.

I guarantee you many things...
1. You will be miserable and sore...
2. You will be out a couple hundred extra dollars
3. You will be elated with the results
4. You will sleep better knowing you have likely avoided any blister problem

EVER....

[UNCIVILIZED]

Just remember to add in the following to the budget when re-coating the hull, be it with bottom paint, or barrier coat:
- Consumables like; sand paper, sanders, shop vacs, rags/paper towels, power cords, etc.
- Protective Gear
- Beer

With all of the above, it's easy to almost match, or even exceed the cost of the coatings, depending on what you use, & how many gallons. Assuming you're fully stripping the hull down to gelcoat that is.

[HappyMdRSailor]

Originally Posted by UNCIVILIZED

Just remember to add in the following to the budget when re-coating the hull, be it with bottom paint, or barrier coat:
- Consumables like; sand paper, sanders, shop vacs, rags/paper towels, power cords, etc.
- Protective Gear
- Beer

With all of the above, it's easy to almost match, or even exceed the cost of the coatings, depending on what you use, & how many gallons. Assuming you're fully stripping the hull down to gelcoat that is.

Massage parlors...

[Tetepare]

I did my bottom about 15 years ago with Interlux, and it's just as good as the day (after) I finished. No blisters anywhere.

But do yourself a favor, don't do it the way I did. I did the whole thing with a belt sander which was the most dirty, painful job ever. Now they have these paint removing strips that cling to the hull and when you pull them away, so comes the paint. Do that, not the belt sander. Then you can finish up the paint removal with whatever works best for you.

[antoha]

An alternative to sand blasting is soda blasting (same process, but a little less destructive). Unless your old bottom paint literally flakes all off with a putty knife, sanding off bottom paint is a very toxic job, best left to professionals (not because they do it better, but because chances are you'll spend more money on doctors repairing your lungs later).

Our MA domiciled boat had not been sanded down before applying bottom paint (ever?), so we stripped it down (hired a soda blasting company; make sure they have a good reputation: it's easy to cut through gel coat if not careful), the rest we did ourselves (except also had a professional do a thorough inspection of the bottom and fix what had to be fixed, you really don't know what's hiding under 15 layers of bottom paint).

Good luck! It's nice to know you begin with a solid foundation.

Also: one thing about this blasting business is that soda (or sand) ends up everywhere inside unless you are pedantic about triple covering every sink and what not; they did stuff rags in all through hulls but a little still got in).

[antoha]

just to add to ramblinrod's great writeup: interprotect 2000 comes in 2 colors, grey and white. alternate them, so it's easy to see what you already covered.

same idea works for bottom paint as well: do a layer of say red, and top layer of say blue (or any other contrasting color combination). on haulouts, when the undercolor shows up - touch up; if it doesn't - you're still good to go for another season.

[UNCIVILIZED]

Guys, come on. Stripping the bottom on a boat with a sander's not that big a deal.
Well, unless the amount of time that you have before entering a retirement home is measureable in months, counted on your fingers.

I mean, I far prefer it to revarnishing a boat's interior, & all of the sanding that that entails. AKA, weeks. In a confined space, with little to no breeze. Lest you muck up a coat, & have to sand it & the one under it, fully off, again.

I've stripped the bottom of all 3 hulls on a 37' Searunner in 2 1/2 days, solo. And that wasn't down to gelcoat, but bare glass. So, mucho more paint than a regular bottom job.

Plus more racing boats than I can even begin to remember. Call it a LOT more beers than you find in 3 cases, & we'll call it close. NOT counting fairing jobs, to put a slick finish on'em, in said figures (either, BTW).

Just wear a reasonable level of protection, & have at it with your 9" grinder/sander. That, & a dust muzzle helps.
Ah, & I'd suggest not doing it during Summer's hotter months, or more protection's needed due to open pores from the heat, thanks.

[antoha]

Uncivilized: recently they introduced all sorts of fines for not containing hazardous waste (and bottom paint is one of them), at least in the US northeast. so punitive, they can easily put a club or marina out of business, let alone an individual. so when grinding, you now have to completely enclose the space under the boat and make sure none of the dust escapes; we now have to filter and recirculate bottom wash water to be compliant with the new codes.

so: no breeze, enclosed space, and very toxic stuff. yes, you can wear enough protection, but i'd rather someone else did it.

[minaret]

Another point on this; if you have stripped the bottom to gel, applying at least one coat of 2000 is wise, if only to catch the bond window with the first coat of bottom paint. This means the first coat of AF has a chemical bond to it's substrate. This promotes adhesion dramatically, the AF will never flake to substrate when done this way. And if you're doing one coat, you may as well do the rest. I always recommend it.

[UNCIVILIZED]

Originally Posted by antoha

Uncivilized: recently they introduced all sorts of fines for not containing hazardous waste (and bottom paint is one of them), at least in the US northeast. so punitive, they can easily put a club or marina out of business, let alone an individual. so when grinding, you now have to completely enclose the space under the boat and make sure none of the dust escapes; we now have to filter and recirculate bottom wash water to be compliant with the new codes.

so: no breeze, enclosed space, and very toxic stuff. yes, you can wear enough protection, but i'd rather someone else did it.

I've done it both ways. I'll still take a bottom job over a varnishing gig.

[Cheechako]

With no current blistering, it should last a very long time if you do a good barrier coat. Good insurance against a problem later. If your current paint is flaking, opportune time. Why not?

[Cadence]

Originally Posted by Cthoops

Our new-to-us Bristol 29.9 has very likely spent her whole life in the northeast. She currently does not have a barrier coat, and she doesn't have any blisters.

The plan is to cut the lines and head for warmer climates in May 2021, so we'll definitely want to put on a barrier coat before we leave.

The bottom paint job by the prior owner's yard left a lot to be desired with patches that are flaking off down to the gelcoat, so it seems like a logical time for us to remove the existing bottom paint and put on a proper barrier coat before repainting.

How long can we expect a barrier coat to last? 10 years? Longer? I don't want to undertake this big DIY job too soon only to be hauled out in who-knows-where having to sand everything down to the fiberglass again.

Just my dumb opinion. I wouldn't mess with the gelcoat? I think a barrier coat would probably rely on a chemical bond? Worst case just give the gelcoat a little tooth.

[donradcliffe]

I think most posters who say to leave the gelcoat alone have never had a boat in the tropics where osmosis proceeds an order of magnitude faster. Sanding it down (RO 60 grit and shop vac to the sander) would take me about 2/3 days. Barrier coat it-as mentioned, bottom paint really sticks to a green barrier coat.

[Monepit]

Originally Posted by Cthoops

While the boat doesn't have any blisters now, it's also been in the northeast it's entire life - exposed for a maximum of six months to cool/cold water each year. It's going to end up in warm water, 24/7/365.

Since we're going to have to scrape off the bottom paint anyway given that it's not adhering in large sections, we may as well put on a barrier coat while we're at it. After all, the worst part of the job is going to be done already. The cost to us will be our (substantial) time plus materials.

I'd rather do this now than have to scrape everything down in the future plus fix blisters - blisters that I could have prevented by putting in the work now - while cruising.

Thanks again.

Been there done that. Absolutely barrier coat. I had a carver I bought at 13 years old. No blisters. Pulled it at 15 and about 50 blisters. At 16. Many more. Also if you barrier coat properly, the paint will always stick. I had the carver pulled and painted 3 times in 5 years because the paint kept pealing. The last time I had it sandblasted and it still pealed. Barrier coat is also a primer. So the paint sticks. You will regret it if you don't. When I bought my present boat, also a northern boat, it had no blisters. I had it pulled stripped and barrier coated. Absolutely no problems since.