Chick wants to spray epoxy resin

[KBbricker]

I'm interested in finding information on spraying epoxy resin and want to know where to start. Thus far i've been brushing, but spraying will save time. I've heard it is a more common practice in boat-building (i make furniture), so here i am!
-k

[JR-Shine]

I dont think its ever sprayed in boat building, sorry.

[KBbricker]

i use epoxy resin because i find that it doesn't offgas as long as polyester resin. i'm considering doing a topcoat with gelcoat. does gelcoat offgas and if so, for how long?

[D'ARTOIS]

Yes, it has been sprayed. But why do you want to spray? Clean epoxy doesn't work as a varnish, in clear sunlight it chalks - so you need an UV protector in way of a varnish and that is mostly a 2 component polyurthane varnish that can be sprayed quite well. So why the use of epoxy - that's at best a glue, not a varnish. For using it as a glue, you don't have to spray it.

[Pilot]

KB, where in NYC are you? We build boats on the Island. I also have on office in the Wall St area.

[John ilett]

Can't imagine spraying epoxy is common practice with boats apart from an epoxy primer into moulds. UV problems etc.

Maybe Duratec (Spray polyesters) could be what you need. Used in the marine industry but also with furniture and musical instruments etc.

Duratec coatings

[KBbricker]

i'm in brooklyn, but do my studio work in north jersey. i'm considering spraying gelcoat to finish my pieces instead of epoxy resin since i checked with my supplier and they seemed upset that i would try it. apparently their guns are for gelcoat and polyester spray only. they did not recommend i spray epoxy.

[D'ARTOIS]

Bricker,

You can spray epoxy just as you can spary poly resin. What's the deal?
What's your tech issue/problem?

The cleaning process of your gun and nozzles must be done with mek (methyl ethyle ketone) and that causes no problem.

However, do you know how to dilute epoxy till it is applicable by a spray gun?

and,

what brand of epoxy are you using and what is the formulation?

[yokebutt]

Bricker,

Sure, you can spray it, but you get a really nasty cloud of resin mist that clings to anything and everything like a heavy and drizzly fog, have you tried rolling and tipping?

Are you making your parts with epoxy or poly resin?

Yoke.

P.S. Are you clear-finishing your parts?

[jimslade]

West system makes an epoxy that can be sprayed. UV protected. I have sprayed it on cedarstrip canoes. DO NOT CLEAN YOUR GUN WITH M.E.K. THATS STUPID!!!!!! use acetone or a quality laquer thinner. I have been repairing and refinishing fiberglass for thirty years. I hope I know what I am doing.

[D'ARTOIS]

Apparently you don't. We clean everything with mek or aceton - they are of the same family. Before we apply epoxy, we clean the surfaces, even wood, for max adhesion, with mek or aceton, mek is a bit haevier and not that healthy to inhale, but for the rest there are no objections to use it. And I use epoxy since 1966- when it was even unknown in yachtbuilding.

[casavecchia]

I am with John Ilett, never needed spraying epoxy.
We all are aware that epoxy poses significant health risks.
Spraying epoxy enormously magnifies theese risks.
If you want to, please use nitrile gloves, nitrile coverall, rubber boots, full face respirator and take extra care in disposing of diluted resin.
Think health first!
Marco.

[jimslade]

I agree with Marco.Mek will kill you slowly I know of someone who destroyed their lungs. mek is NOT of the same family as acetone. MEK is only thinned out with acetone but mek is a strong oxidizer. If You have little value for your life DON'T read warning labels.

[D'ARTOIS]

I have never denied the nasty side-efect of mek; on the other hand, we use it for a long time and whatever your findings are, that's entirely up to you. For the rest, it's not my problem.

[mastcolin]

Sorry to be the one with B.Sc. chemistry degree here but acetone is in same chemical family as MEK. They are both ketones. MEK is slower evaporating so is normally better to use. (use Ask.com or google.com for more info) MEK is not 'thinned with acetone". Well, maybe it is if you buy from some 2-bit shop.

Yep, spraying epoxy is possible but as everyone has pointed out they are pretty nasty to spray H&S wise. If they were discovered today they would be made illegal before they got out the lab.

Even if you spray them I'd recommend the 1st coat to be brush. This fills the grain better. Epoxies don't wet out well. Even when you do spray them, you may have problems with pin-holes/fish-eyes/cissing/crawl - whatever term you use.

The other issue is film build. You can only apply at intrinsic thickness before it sags. For most epoxies that aren't especially thickened that will be about 100microns - you can brush this.

What are you going to gain? Any sort of conventional spraying will entail waste of up to 60%. I'd just try to apply it by brush/roller with less texture and give it good sand before finishing coat.

If you are wanting to speed up work I'd check out a) heat eg 45C b) different epoxies with faster cure profile

If you do spray them, use the recommended thinner. MEK and acetone whilst capable of thinning have side reaction with the epoxy/amine so you can get problems. ( please don't get me to draw this out. I've not been in labs for 8 years! I remember it is something to do with ketamines. It slows the cross-linking. When I worked with International Paints/Interlux we used it to extend the pot-life of epoxy paints - but it can lead to other problems you don't wanna hear about)