What causes epoxy to do this?

Bingo, Jeff.

I don't know why I didn't notice it earlier, but the fisheye/voids are exactly clustered above the summer/loose grain of the wood. Anyplace where the grain opens up, or where there are swirls in the ply, there it is.

The drawings & instructions for the boat were released in a magazine in '58. I figure it was built within a couple years of that, so it's as old as I am. Goodness knows what glues, etc., were used then. Maybe they sprayed it with some proprietary preservative at the mill? It's ACX, for sure, and not marine ply, so...it could be anyone's guess as to where the contamination came from, but I'm a little thankful that it's not me.

Now, the question is, providing I allow it to cure, sand down the layer and proceed with glass & filler, does it matter...? It's a fair-weather little daysailer, nothing that is going to get stressed or tossed about.

 

Look closely at the fisheye areas and see if they have epoxy over them. If they do, scuff, putty and paint, as the epoxy should have sealed the surface. If these areas appear to be epoxy shy, damn, it's a tough call with a relatively unknown quality of goo, possible contamination, etc.

When you put down the sealing coat, did it fisheye too?

 

Given it's a daysailer, I think I'd sand the lot, use a scotch brite pad into the divots & give it a screed of gluemix into the divots & lay your fabric straight on & wet out, maybe peelply or just do a screed of lightweight sanding filler while it's still green, the poly hung on there for years apparently, your epoxy will do better.
If you're worried about adhesion in those divots- do the prep but set up a test or two on the biggest you can find- basically mask across the middle & along the sides of a "flaw" lay a strip of fabric with an end to pull & once it's cured(fully) do a pull/peel test to satisfy curiosity.......... do some on an unaffected area too as a control/comparison........

Jeff

 

Thanks, guys, for the input.

Paul, I didn't notice fisheye on the seal coat as I pressed it in pretty hard and scraped down the excess. It looked to me that I had a consistent coat. As for the voids now, they DO have epoxy on the wood surface and have just repelled the majority of it. This morning, after curing overnight, the voids aren't as deep and it is, overall, a little more leveled out. I am going forward with the assumption that the wood, is, in fact, sealed.

The perfectionist in me wants a nice, smooth coat, the engineer wants to find a solution to this, but the realist needs to move on - I have more challenges to go before this little boat gets splashed.

Jeff, honestly I'm not terribly concerned with adhesion. I think at this point it's more of an aesthetics & pride in workmanship issue and keeping the rough nature of the coat from telegraphing through the glass.

So, guys, do you feel I need a treated fill coat before the glass? My concern with that is what happens if it just fisheyes again? I would have used 16 oz of precious (to me) goo to no avail. Would a lightweight sanding filler mix on top of the glass take care of any roughness that telegraphs through with a little more assurance of success and less materials used? I feel like that is my most effective option right now unless there might be serious issues with that approach.

If necessary, I would rather apply another coat of epoxy over the glass and before the filler, rather than under the glass.

You guys are great; thanks for your time & input!

Curtis

 

If you do have goo in the divots, then smear some fairing compound over the surface, sand it flat and move onto paint.

 

I wouldn't be too worried either..........
Best get on with it, if you're going to glass it, as I mentioned screed some high density glue mix into the divots to finish flush then glass. I try to do most epoxy sheathing all in one session, a pre coat, push some glue mix around into ply end grain & any thing similar, lay & wet out glass or dynel.... all on a falling temp.
I never trust any "shiny" surface for adhesion.

My guess(speculative forensic shipwrighting) is on the existing surface is that back in the day some waxed, half mixed super goop poly was brushed on as a hot coat, then glass to follow........ or something along those lines..
See below one of my favourite boatbuilding videos......


https://www.youtube.com/watch?v=xxzkUNUI0HM

Jeff.

 

Well, THERE'S my problem: I'm lacking the proper assistants! LOL

 

Gotta get some glycol oxonic phosphate & some some groovin stripy pants as well.....

 

That's probably what screwed up the wood in my boat. Well, that AND the glycol oxonic phosphate!

 

@#$%!!

Postscript - It was the epoxy the whole time.

After all that gnashing of teeth and beating of breasts, it was the epoxy batch that was bad.

I had 1.3 qt. kit from Fiberglasssupply.com that I purchased last year. I finally finished it (with the results well documented in this thread) and broke into the newer 1.3 gal kit that I purchased this Fall. The difference was immediately noticeable - the smell was the first thing: The hardener was much stronger and with a noticeable ammonia-like smell completely missing from the 1.3 qt. hardener batch, though it was all supposedly the same type & description.

Upon mixing you could see the new batch immediately starting to react - the mix turned milky for a while before becoming clear again and started to warm immediately. The 1.3 qt. kit did not do this, merely turning a little blurry before becoming clear after a minute or two of mixing, and it only warmed when it was about to kick en masse.

The newest batch of fiberglasssupply.com epoxy is behaving as it should and as advertised. I cannot believe my poor luck at having my first major experience with epoxy being a bad batch. If I had at least one previous experience I would have known better.

I guess that explains why the 1.3 gal. kit is on sale, as they are probably attempting to recapture customers lost to bad hardener batch last year and gain new ones.

Needless to say I won't be buying from them in the future.

Thanks to everyone who offered assistance & advice - it's just a shame it was misdirected.

 

I'd be inclined to write a suitably worded letter to the vendor - At the very least you are entitled to a refund for the faulty product. And while there is usually a clause excluding 'rectification costs' you may find including a breakdown of reasonable costs you have incurred may result in a one off 'ex gratia' payment without any admission of liability or fault.

Do not make threats - either specific or implied - that will weaken your case (in some jurisdictions an ill considered letter of complaint may actually be considered in the same light as extortion, much more serious than selling duff products), no, you are appealing to their sense of fair play and integrity and offering them an opportunity to make things right - these days there is so much competition that good customer service can make the decision.

 

Yes to those who suggested some woods will do this by release of lignins and tannins and you can add oils and waxes to that --- Solution is to thin your first epoxy coat with up to 30% methyl alcohol (we just refer to it as "metho" in Aust) -- It acts as a carrier molecule and facilitates for deeper penetration into the wood surface --- It will take a full 48 hours to be sand-able and you may even need a 2nd thinned coat . -- eventually once set , this first "lock coat' prevents the dispersing of lignins waxes and oils from the wood for subsequent finishing coats -- Cheers

 

over time the part b of any epoxy will get darker and develop that ammonia smell. That's OK - nothing wrong with it.

probably not a bad batch. Your small kit was obviously part of a much bigger batch - dozens or a hundred or more gallon batch. Issues would have been pouring in from many different users. everyone would have had the same issues as you.

epoxies don't warm until they are about to kick.

sounds like a problem but don't think your explanation is correct.

paul oman
progressive epoxy polymers inc

 

Yeah, Paul, I understand. I used to do a lot of production issue troubleshooting for a major aerospace firm, so I know there can be a lot of causes for issues with the product, so I don't want to beat up on the vendor too much - it could have been things beyond their control; sometimes things just happen - maybe the dispensing or mixing equipment had an issue, it could have been an old batch of part b that had escaped inventory and became unstable - who can possibly know?

But, the good news is that the current batch is working as advertised and I am moving forward