removing air bubbles from epoxy

I just saw this youtube video where the guy sprays acetone out of a mister bottle and the bubbles seem to diappear.  It happens around 6:20.  Whoa! Can this be done with something less toxic, like DNA?  What’s everyone’s thought on this?  I might do some test panels with different sprays (add F, DNA, acetone, ?)

Here’s the video

http://www.youtube.com/watch?v=2PKn-59pHNM

 

embedded. that’s neato if it does work.

I just found this on a different site:

“Denatured alcohol may also be used. Test it on a small area first because the denatured alcohol can blush (whiten) the resin system. Spraying a fine mist over the surface will pop air bubbles as well as lower the viscosity of the surface and flatten it out. The denatured alcohol evaporates fairly quickly and does not cause air bubbles to spread.”

Link is here:

http://www.acpsales.com/upload/Preventing-Bubbles.pdf

can’t wait to test this stuff out :slight_smile:

Try getting a heat gun, putting it on low and just barely touch the area with the bubble, not aiming straight down but nearly parallel with the surface, hitting the bubble at a very obtuse angle.

  If the lighting is right, you will see micro bubbles, that you were noteven  aware of popping and levelling out. Bigger bubbles might take a few more passes. 

I’m not keen on the DNA for this task

Gotta remember that this is not surfboard epoxy. It is the stuff that you pour on and wait overnight to cure. This stuff is great for making tables.

I used a similar type once and it made a nice shiny finish. I don’t recall having bubbles, but you need a room that is clean and still or dust will fall on the resin.

Acetone and Epoxy…

never the two shall meet!

at least, not in my shop

So I’ll do some test panels with

  1. Heat gun

  2. Acetone

  3. DNA

  4. add F

  5. white vinegar

 

I’m very aware that the acetone is a big hazard but for the purpose of the panels it will be the benchmark.  Even if the results of the acetone are the best, I’ll never use it in my shop.  What are the health concerns of airborne DNA, add F and vinegar?  I’m always wearing my respirator but if that stuff lands on my skin or worse…

My ultimate goal is the reduction of sanding to the absolute minimum. I might try roller tests versus brush versus squeegee after the intial chemical tests. We’ll see how crazy I get with this.

we just did an A/B test in our shop on a thick ~(1/2"), viscous layer of fiber reinforced epoxy putty we make in house that has had issues with off gassing bubbles when it sets up. Acetone misting worked quite well. Heat gun on low, not so much (but I think this is likely because the amount of resin we use is already building up a lot of heat).

You are blowing an acetone coat with a heat gun? Are you f#@king nuts?

Flash fire anyone?

No, he hit one sample with an acetone mist and a separate sample with a heat gun.
(Please tell me I’m right, jsilver.)
In my experience, misting with just about any solvent will improve bubbles, so long as it’s not completely incompatible. Mind you, I"m not talking about surfboards at this point. When you deal with potting/casting resins this is often part of the process.

A very light touch with a torch set real low. Flame never touches surface.

The acetone spray work really well with resin and thermoplastics too but it’s nasty and dangerous. DNA may work too because it’s a fast solvent, i don’t think vinegra work well because it’s not a fast solvent. thick resin coat need high viscosity resin where bubble traps easily. Several thin coat of low viscosity resin is better for avoid bubbles. Vaccum resin before application and perfect cleaning of surface too.

Yeah he did one with acetone mist and the other with the heat gun (I work with him). Not nearly as many bubbles with the acetone, but when I tried to sand it the surface was still tacky (even though it felt totally cured) and I had to wait longer untill it could be sanded without gumming up the paper like poly lam resin

With liquids sprays and solvents I would worry about turning it milky.

Yep, this. It’s the cleanest method, unless your heat gun is hot enough.