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Building Tips and technical articles. => Building techniques => Topic started by: P Maset on October 11, 2021, 05:35:21 PM

Title: Thinning epoxy with acetone
Post by: P Maset on October 11, 2021, 05:35:21 PM
Hi all, I have a question I looked for the answer, but found nothing here(probably searched wrong). Anyway, my wife has a project that requires clear epoxy to cover some art, and what she has is super thick. I have heard you can thin epoxy with acetone to make it flow out, but have no idea what kind of ratios to look at. can anyone provide any insight? Thanks in advance.

Pat
Title: Re: Thinning epoxy with acetone
Post by: Avaiojet on October 11, 2021, 05:49:29 PM
If she's doing "collage," there's stuff available just for this "art technique." I have no idea what they use?

Art store or on line could be a start.

Charles

Title: Re: Thinning epoxy with acetone
Post by: Tim Wescott on October 11, 2021, 05:52:07 PM
I think acetone will work, but denatured alcohol, or low-water content isopropyl alcohol (90% or 99% isopropyl).

You only want to do this if the epoxy is going to be in a thin layer, like paint.  If she wants to encase something in epoxy, she wants to get the stuff that's made for that.  If the layer of epoxy is not thin enough, then solvent is left in the mix and gets trapped, weakening the epoxy.

Note that over time, epoxy glue will yellow in sunlight.  If this is going to be the outer coat, and if the colors are important, then she wants to get something that's specifically meant to be a top coat.
Title: Re: Thinning epoxy with acetone
Post by: Mark wood on October 11, 2021, 05:54:17 PM
Thinning with acetone or alcohol can be done but the result is often not good. My experience is that thinned epoxy comes out gummy and never fully cures correctly. Thin casting epoxy is not that expensive even if the price is high in dollars. Personally I'd shell out the money for the right material. I have many other ways I screw sit up without challenging my materials with methodology that doesn't have instructions included on the package or I have been messing with for years.
Title: Re: Thinning epoxy with acetone
Post by: Tim Wescott on October 12, 2021, 09:01:27 AM
Mr. Maset:

As you can see, we're trying to guess what your wife intends, and giving you advise based on supposition.  Can you say, in detail what her plans are, so that we can give you some useful suggestions?

... My experience is that thinned epoxy comes out gummy and never fully cures correctly....

That is interestingly contrary to my experiences at least when I've used the epoxy as paint, and made sure the film is thin enough to flash off the solvents before the epoxy cures.  But it's absolutely routine for the epoxy left in the paint-pot, that has to try to cure when there's still solvent present.
Title: Re: Thinning epoxy with acetone
Post by: P Maset on October 12, 2021, 09:25:37 AM
Mr. Wescott,

You are absolutely right, I SHOULD have said what she is doing. the epoxy will be used as a top coat over acrylic paint poured over 4 inch tiles in an abstract pattern. And thanks to all for the input!
Title: Re: Thinning epoxy with acetone
Post by: Mark wood on October 12, 2021, 10:08:06 AM

That is interestingly contrary to my experiences at least when I've used the epoxy as paint, and made sure the film is thin enough to flash off the solvents before the epoxy cures.  But it's absolutely routine for the epoxy left in the paint-pot, that has to try to cure when there's still solvent present.

Thin films behave differently than casting and bonding applications. I wouldn't use an epoxy formulated for painting for bonding nor an epoxy formulated for bonding for casting. Each application has different requirements. Thin films such as painting have a thin enough layer as to allow the solvents to precipitate out of solution. Not so much with a heavy bond or cast scenario and the solvent stays trapped with the mixed resin inhibiting its ability to cure correctly. The manufacturer uses various dopants in the epoxy to facilitate the thickness and quality of the epoxy. Some of these dopants are paraffins which allow the hardening agent and resin molecules to move around in order to properly cure. Think of localized pockets of cured resin separating from the hardening agent. The paraffins help prevent this from occurring and eventually migrate to the surface of the cured epoxy which is why we need a peal ply or to sand the surface of the epoxy before painting.  For making cast parts such as propellers the EPON resins work well while bonding and fiberglass applications West systems works well and of course the two part paint systems and our general purpose epoxies like Bob Smith and Devcon. 

For the application here, there are casting resins specifically made for the shiny table top look which is what the OP is looking for. I'm not specifically familiar with these resins and I'd simply look for a one with a good reputation. The cost of a gallon unit is around $100 and would be enough to do tons of 4" tiles or a large mosaic. What I wouldn't use is West Systems or other epoxy we commonly use for model building. EPON could be used but it would be prohibitively expensive.
Title: Re: Thinning epoxy with acetone
Post by: John Craig on October 29, 2021, 01:07:15 PM
Eval & consider:https://www.bing.com/videos/search?q=West+System+Epoxy+Products&FORM=VARSQP

I believe they have a help line or email.  I have seen some very beautiful artwork protected by their epoxy.
Title: Re: Thinning epoxy with acetone
Post by: Larry Wong on October 30, 2021, 03:29:59 PM
How about just apply and use a heat gun to thin it to flow? S?P
Title: Re: Thinning epoxy with acetone
Post by: Steve Helmick on November 17, 2021, 06:41:37 PM
Z-Poxy finishing epoxy would be my first choice IF I insisted on using stuff from the hobby shop, because it's already quite thin, so little other stuff need be added, if any. I'm not real sure how CLEAR it is, and you'd definitely want something that wouldn't turn amber, for instance. Perhaps somebody knows about that? I have thinned the old Hobby Poxy Formula 2 with lacquer thinner, acetone, or dope thinner...many decades ago...and it hardened fine but was VERY brittle and not what I desired.

I'm sure there's something out there made specifically for your task, but I'd look at a good crafts store and not what we refer to as a "hobby shop". I'd suggest using what they suggest...after testing it to be certain it'll harden as CLEAR as you want.   y1 Steve