Epoxy Fairing Over Interprotect 2000E

[endoftheroad]

I'm working on a hull that had a bad blister problem.
After the hull was properly dry, many many many months () and blisters repaired I applied 2 coats of 2000E for the hell of it and for ease of seeing the unfairness. I will be applying more coats of 2000E after the fairing process.
I'm thinking I'm going to use West Epoxy with 407 and 410 fillers for fairing.

2000E can be applied over itself without sanding but can I fair with West Epoxy over the 2000E without sanding?

[Ziggy]

I think the usual method is to fair it before applying Interprotect. If you are fairing with West System epoxy, you need to thoroughly wash it to remove amine blush and then let it dry. But I think if you apply West system epoxy before Interprotect is fully cured (i.e, you can leave a thumb print), it should stick. By the way, it is also best to apply successive layers of Interprotect before they are fully cured. And it's really, really important to apply the first layer of antifouling before the last layer of Interprotect is fully cured, otherwise it will keep peeling off.

[endoftheroad]

Thanks Ziggy,
Im aware about the chemical bond with the anti fouling paint.
Im aware chemical bonds are better than mechanical bonds.
I've considered chemically bonding West to the 2000e but I'm uncomfortable with the window. It's alot of work mixing West to the correct consistency and troweling with the short 2000 window all by myself. Wife wont help. .
I'm stuck with the situation and struggling for whether I should sand the 2000 with 80 grit prior to applying the West filler.
Yes it's more common to fair before the barrier coat but I let some article influence me to apply the 2000e first as well as after.
I had a bad blister problem on this boat.
I will wash the West blush properly prior to applying future layers of 2000e.

[endoftheroad]

Yacht paint forum product support (Interprotect makers) state that you can use their Watertite epoxy filler in between coats of 2000 without sanding or washing off the blush as there isn't any blush residue from these products. Of course I'd acetone wash in between their products.

So why couldn't I apply West epoxy over 2000 without sanding?

Unless someone wants to donate about 4 gallons of watertite filler?!?!? It'd cost a million bucks, that stuff is expensive and awesome as well. I love using it for minor filling.

I'm not interested in what I should have done as it is already in the past I need to know whats the next best step.

Thanks

[Badsanta]

Check with the manufacturer?

[Ziggy]

1. Yes, Watertite filler is very expensive.
2. I suspect that International's tech support might not be very helpful regarding applying West System epoxy over Interprotect, since it is not their product. But it can't hurt to ask. Instead of using West System, you might consider Epiglass--it is an International epoxy meant for fairing. At least you'll get an answer from tech support.
3. If I had to apply West System over fully cured Interprotect 2000, I would definitely sand it first.

[endoftheroad]

Thanks guys.
I'll look into epiglass.
I could sand it if I have to.

I think it's odd that I can't find any inquiries on the Internet for putting epoxies on 2000e.

Other than their own epoxy filler "watertite".

[Ziggy]

A few years ago I filled in a thru-hull hole in my Interprotect 2000 covered bottom. I faired the patch with West System epoxy mixed with the West System barrier coat filler. As far as I can tell, the fairing still holds, but the Interprotect was well sanded around my patch.

[contrail]

If I remember correctly, from the last time I did this, you are actually supposed to use a different product (Interprotect 1000?) between the fiberglass and the 2000, which will otherwise interact poorly. So said the manual and so said the tech support. As you said, you have already done what you have already done, so it will be interesting to see how it works out. The directions were 1) Interprotect 1000, 2) fairing compound, don't remember which, 3) Interprotect 2000. Not all epoxies behave alike!

[endoftheroad]

Never heard of 1000


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[Suijin]

For below the waterline repairs that require fairing I've always put down two coats of interprotect, let cure, sanded for tooth, then applied WS with 410 filler, let cure, fair and/or sand for tooth, and two more coasts of interprotect.

[Cheechako]

I wouldn't put filler over it.

[contrail]

Originally Posted by endoftheroad

Never heard of 1000


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Interprotect 1000 is used to cover and saturate bare fibers that are exposed when blisters get ground out. Subsequently, fairing is done, and then Interprotect 2000 or 3000 is applied. You can still look up 1000 to see how this works, although the current manual for 2000 substitutes Epiglass Resin for the 1000. When I did my last blister job (thankfully), there was no Epiglass and the manual and techs specified 1000, one of the stated reasons being that the 2000 should not go straight on the bare fiberglass. If, of course, you were doing a preventative barrier coat, where there was nothing ground out, you could start with the 2000 or 3000. Since the current manual specifies Epiglass, I assume that the procedure is otherwise the same, i.e. Epiglass over bare fibers, before the 2000 goes on, but this may have changed. !000 is quite a thick but very clear epoxy that left no solvents. If memory serves, Interlux didn't want the solvent from the 2000 to interact with the bare glass, but it has been a long while since I did this. Anyway, that's what Interprotect 1000 is!

[endoftheroad]

Thanks. This helps very much


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[lateral]

Not much point putting 2000 on first if you plan to fair non chemically later. If you are going to sand with anything less than 150grit as you will be sanding thru it. Waste of 2000.

If I already had done it and then wanted to fair I would cross hatch 46 grit to tooth 407/410 in, & write the interprotect off.

I only use 2000e with regular way up hull, otherwise do 100% solid flow coat upside down hull.

BTW, any body seen a water vapour permeation test done on 2000e similar to Wests test on thinned epoxy? ( Which is what interprotect essentially is)