Getting rid of amine blush

[DayTripper]

Remind me again, what sort of boat is this? It doesn't really matter, pro or beginner, the idea of pre-coating, waiting a week and then sanding before finishing the job makes no sense at all. If you really want to pre-coat, then go for it.

Just understand that it can make sliding the cloth around somewhat more difficult - but it is hardly a deal-breaker. There simply isn't all that much cloth sliding needed during the initial draping part of the job.
Applying and saturating the cloth as soon as your pre-coat has hardened enough that you won't disturb it makes drastically more sense - and will likely make a better boat with less work and no mid-job sanding.

I still think the peel-ply may be your biggest danger. As you have already seen, problems which hide under that stuff until the resin hardens and it is too late to correct them is not a formula for good glass work.

Thank you for your perspectives.
I think sanding the pre-coat will make the cloth easier to slide around than on bare plywood. But that's just a side benefit. Main reasons for me to pre-coat are to minimize chances of lifting cloth by outgassing and to prevent epoxy starvation by wood absorption. Not issues for pros but issues for a novice like me.

I will only use the PeelPly if my testing on scrap plywood turns out 100% good. Otherwise, I agree that it could be a bad thing.

Thanks.

[DayTripper]

If using WEST System epoxies, consider using the 207 hardener, less amine blush to begin with. No harm in precoating then removing blush from cured layer and applying fiberglass later. You end up with a mechanical rather than chemical bond to the first layer and you need a well sanded surface to bond to. Overall more time, effort, and epoxy. Precoating helps pre cutting or pre assembling when you can take advantage of a horizontal surface.

Yes, in the "Epoxy Basics" book by Russel Brown that I just purchased, he mentions that 207 hardener does not have amine blush issues. West Systems also mentions the same thing in their 207 ads. I may bite the bullet and buy the 207 hardener which will cost $109.99, though I already bought the 206 slow hardener.

But from what folks are responding with is that it's easy to remove amine blush using a scrubber, warm water and drying with paper towels or clean towels. I'm deciding. More time and effort are non issues for me as I don't mind doing it. I don't think additional epoxy will be much of an issue since less epoxy will be needed when applying the cloth. Also, in Russel Brown's youtube video he mentions applying a thin pre-coat of epoxy by using a squeegee which also helps force epoxy into the pores of the plywood.

[DayTripper]

One can talk and debate the idea of pre-coating all day long and never really know what the result will feel like. But if a simple test is done on a scrap of similar material, then the conjecture gives way to real knowledge. Sure, it's just one test, one example. But it's also real personal experience gained for little time and material expense.
Jeff

Agree. Testing on scrap plywood is exactly what I'm doing prior to glassing my boat.
Thanks.

[wizbang 13]

If the ply is old and banged up, a pre coat can be a good idea, cuz yer gonna be dealing with epoxy with a putty knife to fair the surface of dings and scratches before glassing anyway. Yes , a pulled out and pushed in squeegee pass.
If the surface is new and clean a pre coat is pointless .
bruce

[Autonomous]

If you are a subscriber to offcenterharbor.com, Russel Brown has some good videos there too. They are the main reason I subscribed.

[Larks]

Nothing wrong with precoating and letting it dry prior to glassing, I did it on my H28 and it alleviates any somewhat dry (or drier) spots in the glass that can be caused by the ply wicking up the epoxy after you’ve walked away (as has happened to me).

But it doesn’t need to be a thick heavy coat that would cause amine blush anyway: apply it with a roller and then go back over it with a squeegee after a minute or so and scrape off the excess.

You can let it dry and then give it a rough sand with 80 grit to key it and knock down any edges from the squeegee.

If you do use Peel ply (after glassing) that will remove any amine blush.

Make a false floor of MDF or something on your floor under the boat to catch any epoxy drips (which you will inevitably get) and other mess that you are concerned about.

[Todd Bradshaw]

Sorry, but the thickness of the coat is not what causes amine blush, and putting on thin coats won't prevent it.

[Autonomous]

Kids...

[Larks]

Sorry, but the thickness of the coat is not what causes amine blush, and putting on thin coats won't prevent it.

Agreed Todd and perhaps I could have said “contributes” rather than “causes” but even then I’m sure that you’d correct me and I guess rightly so: However I’ve not had any amine blush issues after removing excess epoxy from bare timber with the squeegee (using slow curing epoxy) whereas I have had amine blush occur in roughly the same warm temperatures, higher than normal humidity and general conditions on thicker applications of epoxy........ I can’t claim any expertise or science on the subject, just talking from my own experience.

I’ve also not had any amine blush issues where I’ve used peel ply over epoxy impregnated glass.

[Todd Bradshaw]

On a peel-ply surface the blush is still there - but it still floats to the top, which now is on the top of the peel-ply. Thus peeling the fabric off takes the blush with it, leaving a blush-free surface.

High humidity has always seemed to generate more blush on my projects. However, the fear of having to deal with amine blush tends to get a lot more publicity than it deserves, and much of it being spread by folks who actually have little or no experience actually dealing with it.

Glassing does create some blush issues worth noting though. A properly applied layer of fiberglass should have a clear and very even cloth texture - no pools, no flooding, no starved areas or voids. You really don't want to be trying to wash blush out of that texture, so getting at least one good filler coat on before ending that session to help hide the weave is a really good idea. That is one place that peel-ply can help as long as you can work without actually seeing through it.

[DayTripper]

Nothing wrong with precoating and letting it dry prior to glassing, I did it on my H28 and it alleviates any somewhat dry (or drier) spots in the glass that can be caused by the ply wicking up the epoxy after you’ve walked away (as has happened to me).

But it doesn’t need to be a thick heavy coat that would cause amine blush anyway: apply it with a roller and then go back over it with a squeegee after a minute or so and scrape off the excess.

You can let it dry and then give it a rough sand with 80 grit to key it and knock down any edges from the squeegee.

If you do use Peel ply (after glassing) that will remove any amine blush.

Make a false floor of MDF or something on your floor under the boat to catch any epoxy drips (which you will inevitably get) and other mess that you are concerned about.

Thanks Larks.

I do intend to use PeelPly when applying the cloth but only after my tests on scrap plywood come out 100% good. If that works out, it will reduce epoxy use minimizing weight while providing a really nice, glass weave free surface minimizing sanding. My preliminary test with PeelPly had resin bumps in the center area but the smooth parts were as perfect as I could have hoped for. Plus no amine blush .

Regarding something on the floor to catch epoxy drips, I'll be using black roofing felt per a suggestion I received. I already had the roofing felt and have cut it in half lengthwise to lay under the perimeter of the boat.

Thanks.

[Edward Pearson]

MAS epoxy is designed not to blush. And it didn’t when i used it. Just had crystalization in the tubs...


Only seen blush when using Sicomin when it was raining outside and doors open (MAS got hard to get in ghe uk). Doesn’t crystalise in the tubs though...

[DayTripper]

MAS epoxy is designed not to blush. And it didn’t when i used it. Just had crystalization in the tubs...

Only seen blush when using Sicomin when it was raining outside and doors open (MAS got hard to get in ghe uk). Doesn’t crystalise in the tubs though...

West 207 hardener is also rated as not having blush.
Thanks.

[DayTripper]

If you are a subscriber to offcenterharbor.com, Russel Brown has some good videos there too. They are the main reason I subscribed.

Will check it out.
Thanks.

[willin woodworks]

Wet sanding epoxy to try to remove blush is absolutely stupid. One of the reasons you use the scotch brite pads is because blush quickly plugs up sandpaper, making it worthless. you are also wrong thinking that wet sanding green epoxy makes it non-toxic. In terms of exposure, getting it on you wet might even be worse.

I have usually found that the biggest drawback to pre-coating is that it raises the grain, making it much more difficult to move the cloth around on all those little stickers. If you are doing any sanding between the various parts of the glassing process you are doing it wrong. Any and all sanding should only take place after full cure - like 7-10 days.

Read this again. And again...

[Autonomous]

Wouldn't my beloved cabinet scraper take care of the raised grain stickers in a jiffy?

[Todd Bradshaw]

Sure, you could scrape them down, but why bother when it is not needed? There shouldn't be a lot of cloth sliding going on, and the trick when moving it over the stickers is simply to lift it, rather than drag it as you spread it out. Once you start saturating the cloth it will slide around pretty well.

[Todd Bradshaw]

It's interesting. I first started working with resins 50 years ago, when I was a sculpture major in college. I had two professors who worked in epoxy resin/fiberglass and a third one who worked with polyester resin making big polished transparent lens-like castings that sometimes weighed up to 75 pounds. On weekends I worked for him, wet-sanding them. When your profs work in resin there is a pretty good chance that you will also be using it for your own stuff.

At the time there were no boat building epoxy resins yet. The stuff we used was quite thick and semi-clear white-ish. We didn't really have much in the way of safety procedures, like gloves and masks (though luckily we hardly ever did any sanding on epoxy projects) but I don't recall ever seeing anything like blush.

[neophyte1955]

take a scotch brite pad,Dip it in denatured alcohol. Light scrub of parts. Done.

[wizbang 13]

take a scotch brite pad,Dip it in denatured alcohol. Light scrub of parts. Done.

nope. water .just warm water.

[Todd Bradshaw]

Yep, just plain water. Adding other chemicals to epoxy work is usually just asking for trouble, as well as being unnecessary in this case.

[dbp1]

... not to sound critical ... but I sort of want to channel Bruce here (hope he doesn't mind):

stop asking questions and just build the damn boat. It's a stitch and glue Jon boat, not a museum piece.

[wizbang 13]

... not to sound critical ... but I sort of want to channel Bruce here (hope he doesn't mind):

stop asking questions and just build the damn boat. It's a stitch and glue Jon boat, not a museum piece.

i doan mine
i hope folks don't get caught off guard with my directness sometimes

[DayTripper]

... not to sound critical ... but I sort of want to channel Bruce here (hope he doesn't mind):

stop asking questions and just build the damn boat. It's a stitch and glue Jon boat, not a museum piece.

OK, I'm outta here! I won't be posting in the woodenboat forum anymore.

BTW, why did you read my threads if it bothered you so much? You weren't forced to read my threads.
Thanks to the sincere folks who offered help along the way. No thanks to you or wizbang13 with his WTF and other childish comments.

Bye.