.dsaavedra.

Thinning Epoxy with Fingernail Polish Remover

48 posts in this topic

To the best of my knowledge, you can thin any 2-part epoxy. The amount of solvent used to thin epoxies can vary from brand or type. Glue-types are generally pretty high in viscosity and will probably need reducing. 100% solids epoxies made for coatings applications are thinner by nature and would flow right over that foil beautifully. Even beyond viscosity, cure time is a major factor for flowing over surfaces. It needs to stay fluid long enough to wet out all the surfaces properly. That's why I preach slow-cure.

As for your acetone problem, it's not just that it dries too fast. Epoxies have limited solubility in acetone. You need a blend of a ketone(s) and toluene. 75:25

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Downriver,

Why does D2T stay tacky if you mix in a thinner before the two part mix is thoroughly mixed?

I'm guessing the thinner bonds to one part better than the other, and screws up the mix if they're not already mixed before it's added.

But I'm certainly no chemist, or epoxy solvent expert, although I have tested my share of alcohol "solvents".

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Downriver,

Why does D2T stay tacky if you mix in a thinner before the two part mix is thoroughly mixed?

I'm guessing the thinner bonds to one part better than the other, and screws up the mix if they're not already mixed before it's added.

But I'm certainly no chemist, or epoxy solvent expert, although I have tested my share of alcohol "solvents".

Some epoxies react with hydrogen and/or oxygen as part of their curing process. Alcohol contains hydrogen and oxygen molecules that will react with the epoxy before it can react with the hardener. Alcohol is low viscosity, so those molecules are flowing around linking with the resin faster than the hardener can. I'm about positive that even if you used it after the mix, you're still not getting a full cure. If you thin it with DNA, I'd bump the hardener up 10% or so and see what happens. Should get a much better cure and ALOT less yellowing. Remember that an improperly cured film will yellow very fast, no matter what quality epoxy you use.

Edited by Downriver Tackle

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Down River that mix ratio of keytone and toluene isn't that close to lacquer retarder?

Pretty close. Old-school lacquer thinner. Component systems vinyl thinner is the closest out there. Available at Cabelas, Gander, etc. Gotta watch "lacquer thinners" out there. Most contain alcohols aren't good for 2-component paints.

I hope I didn't open up a can of worms. LOL One thing to remember if you're brushing your epoxy and thinning with strong solvents. Use the thinner sparingly. Some underlying paint systems may wrinkle if you use too much.

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I now see it all. Thank you Downriver Tackle for sharing your knowledge. Nice site to!

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Downriver,

Do you have any experience with Minwax Wood Hardener? I used it for the first time as a sealer on a wooden lure, and the lure cracked when I left it in the heat.

I used Krylon white primer over it, then Auto Aire water based aluminum, opaque water based Createx, water based Wildlife Colors iridescent violet, Krylon spray glitter, Krylon spray clear with UV inhibiters, and then two coats of Etex.

The top of the head split and peeled, down to the primer, which seems tacky.

I wonder if the sealer and primer didn't bond, or if the sealer still had solvents left in it.

The Wood Hardener is some kind of a polymer that restores rotten wood to structurally sound.

Looks like I'll be stripping and redoing at least the head of that lure.

And I guess I'll have to put the rest of them in the garage between trips, to keep them from getting too hot.

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No, I haven't used that before.

That aluminum would be my first suspect. I t takes a long time to dry and properly cure. That's happened to me. Something in that combo didn't cure correctly or you had a really hard paint up against a softer paint. I try to use Autoair all the way through the colors. They've already done all the r&d work and know they're paint works together in a system. When I'm using that many layers also, I make absolutely x-tra sure everything is fully cured before I clear it.

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Downriver,

I examined the lure under sunlight, and it really looks like something in the paint scheme bubbled on the top of the head under the 110+ degree heat under my boat cover, and caused the epoxy to bubble and crack.

The white Krylon primer is what's left under the peeled section, so I think either it was too thick, and not fully cured, or the opaque black that went over it wasn't fully dried, so water vapor developed, causing a bubble and cracking. The Auto Aire alum was put on the belly and lower sides, and then the black went over the middle and upper sides and back. Then I put the auto air over the sides and shoulders as a scale pattern. The paint scheme come off with the Etex Lite epoxy, all the way down to the primer which is still on the lure.

Anyway, I'm going to redo the front section (gotta love removable pin hinges) and repaint it the same way, only drying it better between coats.

And I'm taking my lures off after I fish them, and putting them in the garage, instead of baking them under my boat cover.

Live and learn.

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Mark,

Your problem may have nothing to do with chemistry, but with physics.

If you sealed the wood at low temperature, heat would expand anything which is left in the wood (air, acetone, water, etc) and so such problems will certainly appear if the difference in temperature is very high. To diminish the possibility of physics cracking your lures, you simply have to seal your lures at a higher temperature (preheat them before sealing). And you will do nothing wrong if you preheat them before any other layer you add to them. That's because the clearcoat will always crack from inside out, not from the pressure from the outside the lure. The lure can stand a high pressure from the outside.

If, in the case you described, you saw that the primer was not cracked, that doesn't mean a thing. The situation may be that air escaped from the lure, but did nor crack the primer, it just went through it, causing the problems to other layers.

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rofish,

I wonder if it was the Minwax Wood Hardner that I used as a sealer this time. Maybe it off gasses for a longer time than their Polyacrylic Sealer that I had been using.

Or maybe I put the primer on too thick, and it still had some solvents buried in it.

Whichever it is, I sanded the damaged section down to the primer, reprimed it with two light coats, hit it with the hair dryer, and am letting it hang in my garage which is up to 75+ degrees al;ready, and it's only 10:45 in the morning.

I will hair dry it again before I start my painting, and really well between coats, and let it sit for a day before I put on the glitter and topcoat.

Mostly, I'll keep the lures out from under the black boat cover in the summer, where temps get up over 100 degrees every day.

Fingers crossed.

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There's an easy way to tell if a layer wasn't fully cured. Too late because you already repainted. Next time, take a piece of very sticky tape, nylon tape prefered. If not, duct tape. Lay it across the crack, press down real well, then rip it off perpendicular to the crack. You''ll have some paint on the tape. Look to see which layer failed. If that layer is on both the chip and the lure still, it was too soft or under cured. If it was a clean delamination of a layer, it was and adhesion issue of some sorts.

If that wood hardener, or any of the paints, had mineral spirits in it, that stuff is a pain to get out of the film! Even after heat-curing, I'd wait 24 hours before putting anything else over it, especially something waterbased.

Edited by Downriver Tackle

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That's a slick idea! I found that the white primer had stuck both to the epoxy/paint section, and to the lure, so it had to be the weak link. I think I just put it on too thick, and didn't give it a chance to really cure. Operator error.

Man, I hate when there's no one to blame but me!

I will be keeping the lures out of the heat. Direct sunlight heat seems to be okay, but baking under the boat cover just cooks the lures.

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Yes, Downriver T. is right. That space under the black cover could be an excellent dryer for your lures:lol:

I was thinking to suggest that you paint that black cover in white, so if you forget your lures there, you will not have such problems anymore. And you could make a drying box at home, painted in black:)

But what I wanted to say earlier is that physics will take it's toll on every chemical you may find on the market, regardless of quality. So you do not have to think that a stuff like Minwax may be the culprit.

What you have to think of in the first place is how to reduce the difference between the 2 temperatures: the one at which you have sealed your lures, and the one under the cover of your boat.

Everything you say about thin layers of paint which have to dry perfectly before applying another coat is right, but this hobby requires a physics orientated mind as well.

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rofish,

I think it will be a lot less work moving my lures that painting my boat cover. :lol:

Seriously, I paint and coat my lures in my garage, with the large overhead door open. In the summer here in Los Angeles, the temps. have been in the 80's, and my garage has a black roof, open framing, and no insulation, so it's hot in there when I'm painting.

I have a fan going, but that just moves some air. It's still hot. :flame:

And the temps on the lakes have been in the 90's, so there's not a big temp. swing there.

Since I can't heat the lures to the 120+ boat cover degree temps. while I'm paint and top coating, I think I'll just have to learn to remember to cut off my lures and move then after every trip.

It's easier than repainting them all the time. :wink:

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Mark, I put the denatured A. in prior to mixing the D2T and have never had a problem with it not curing properly. Now I mix the batch for about 2 min for I start applying to the baits.

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Just a small related side issue.

It made sense to me, to mix the solvent with one epoxy component first. This would buy extra time, allowing a thorough mix. Then introduce the second component of the epoxy and mix. But I remember someone mentioning that this was a bad idea.

Any thoughts?

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Some epoxies react with hydrogen and/or oxygen as part of their curing process. Alcohol contains hydrogen and oxygen molecules that will react with the epoxy before it can react with the hardener. Alcohol is low viscosity, so those molecules are flowing around linking with the resin faster than the hardener can. I'm about positive that even if you used it after the mix, you're still not getting a full cure. If you thin it with DNA, I'd bump the hardener up 10% or so and see what happens. Should get a much better cure and ALOT less yellowing. Remember that an improperly cured film will yellow very fast, no matter what quality epoxy you use.

Benton,

I'm only going by what Downriver said.

Sounds like maybe you're not experiencing problems because you may be going heavier on the hardner, or you're just magic!:worship:

I've found that any DN in my initial mix of D2T screws things up.

Maybe it's just me. :eek:

Interesting what he said about increasing the hardner decreasing the yellowing. I may try that just to try to keep it clearer.

Downriver,

It's really great to have someone who actually works with these chemical, and unstands the processes involved, here to comment and teach. Understanding why stuff works the way it does is priceless.

If you do a search for "epoxy" on this site, you'll see there are endless questions concerning why and how.

Thanks for sharing your knowledge.

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No problem. Just here to try and help and get a little info off you guys also. ;)

Interesting about how the two paths intersected for me with custom painting and fishing. About 10 years ago, I worked for bass pro Kim Strickers cousin and nephew who owned a paint manufacturing company. Kim also owns a paint manufacturer here in Michigan. That sparked the interest again in fishing and started the r&d process of making my own lure coatings and techniques. I dabbled with it for a few years, then painted a few lures for walleye pro Pat Cavins. The rest is history. Now I enjoy kicking back on Sundays and watching people on TV fish with my lures. :)

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I do, but don't really advertize them. Large volume, easy to paint walleye baits is what I like to do. I'd rather paint 50 $4 lures at a time then 2 or 3 $10 bass lures per order. It's such a contrasting market also. Try to sell a walleye pro a $10 custom and they'll laugh at you, no matter how detailed. On the other hand, a bass pro won't touch a $4-5 paint job, even if it's the exact same thing they're getting elsewhere for $15. Low price paint jobs in the bass world are perceived as junk right off the bat and most guys won't even take the time to find out otherwise.

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Kinda like some of the people I do work for. They'd rather be hit by a Rolls Royce than missed by a Volkswagen.

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