EGADS! Epoxy coming off with masking tape!

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Locutus
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EGADS! Epoxy coming off with masking tape!

Postby Locutus » Thu Jun 25, 2015 4:06 pm

I was removing masking tape after painting and had the horrifying experience of pulling an epoxy layer off the cloth along with the masking tape.

Image

I don't imagine there is anything I can do about it at this point except wait for the paint layer to blister and fail, then sand down to bare wood and start over. Hopefully I'll get a few seasons out of it before this happens, if I'm careful.

Moral of the story, for me, is: Don't believe in a "no-blush" epoxy product. Clean and sand each layer before applying the next. In this case, I didn't sand after the initial cloth application because of the texture of the cloth, that you can see in the photo. I did sponge wash it with water and then denatured alcohol, followed by a rubdown with a dry towel. That wasn't good enough, apparently.

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Andy Garrett
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Re: EGADS! Epoxy coming off with masking tape!

Postby Andy Garrett » Fri Jun 26, 2015 10:53 am

That sucks man. :( Sorry as hell for you.

I was never tempted by the 'no blush' stuff for just that reason--I just didn't trust it. Zero calorie foods and non-alcoholic beer still have minute amounts of the things they claim to be free of. This phenomenon probably crosses many industries. It seems that perhaps you were the victim of that.

You may want to name the product and describe your exact procedure in great detail including temps, humidity, etc. This will allow other builders to make their own informed decisions about if and how they choose to use that product in the future.
Andy Garrett

Perhaps the slowest Zip build in Glen-L history...

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hoodman
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Re: EGADS! Epoxy coming off with masking tape!

Postby hoodman » Fri Jun 26, 2015 11:11 am

Hopefully its just localized in an area that didn't get cleaned as well as others.

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Locutus
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Re: EGADS! Epoxy coming off with masking tape!

Postby Locutus » Fri Jun 26, 2015 12:35 pm

Procedure:
(Mix of epoxy in all cases was done with graduated mixing cups and stir stick, stirring for over one minute, scraping sides and bottom of cup several times. Mixture was then poured into roller pan. Temperatures were variable outdoor Spring temps, usually not going below 45 F at night nor above 70 F daily high.)


Sanded bare wood, sponge cleaned with water, cloth cleaned with denatured alcohol, final clean with dry towel.

Applied System Three S-1 penetrating epoxy. Two days of cure, then sanding and cleaning as above.

Applied System Three Silver Tip epoxy. Immediately applied pre-cut 6 oz. fiberglass cloth while epoxy was still wet, applied more epoxy on top while squeegeeing the whole mess down. This layer seems to be holding up just fine.

Cleaned, but did not sand, cloth layer. I did not sand because I didn't want to cut into the cloth, since it presented a textured surface. Cleaning was the three-step process described above.

Applied the next coat of epoxy about 24 hours after cloth layer. (Quick wipe down first, to remove overnight dust.)

I don't remember if i sanded this coat before the final coat 12 hours later, but it's the layer immediately following the cloth layer that is separating.

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Roberta
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Re: EGADS! Epoxy coming off with masking tape!

Postby Roberta » Fri Jun 26, 2015 2:18 pm

Wow! That is discouraging! How long was it between the time you wetted out the cloth and then applied the next coat of resin? How long did you wait after cleaning with water and DA before applying that coat? Are you working outdoors and is the humidity high?

I know you are anxious to complete the boat, but now is the best time to resolve issues. A poorly sealed bottom will absorb water and really ruin your wood. Best to get it resolved now.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Locutus
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Re: EGADS! Epoxy coming off with masking tape!

Postby Locutus » Fri Jun 26, 2015 4:04 pm

I'm pretty confident that the wood itself is well-sealed, and that the cloth layer is not going to delaminate. It's just the next layer after that which is a problem. IIRC, I waited about 24 hours between the cloth layer and the next. I made sure it was good and dry before applying the epoxy.

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Bill Edmundson
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Re: EGADS! Epoxy coming off with masking tape!

Postby Bill Edmundson » Fri Jun 26, 2015 5:21 pm

Locutus

I'm pretty sure time is not the issue this time. I haven't seen this before. But, in general you can put the next coat on as soon as the previous coat is not tacky. This assures a good chemical bond.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build


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