Flyers,
I have a basic question...I'm going to coat joints and edges around a firewall on a hellcat 60 and other stress points. What do you thin 30 minute epoxy with, do I mix the hardener in...also... how much do I add to thin. Is acetone better or some type of common rubbing alcohol. Thank you in advance for your help.
Steve

The common rubbing alcohol that I have seen has 30% water; not good. Paint stores may have alcohol for cutting shellac that is 100%.

I use denatured alcohol. Works well and doesn't take much. It works good for fuel proofing firewalls, etc. However, I'm not sure I'd use it to strengthen any stress points. I don't think it would add much strength on is own, but with a little fiberglass cloth laid down first it works well. Be careful not to make your plane too heavy though. Epoxy adds up in the weight department.

Alternatively, you could use your heat gun and carefully heat the epoxy, thereby lowering its viscosity and not needing to add anything to it that may alter the curing time/consistency. I do it this way and it works great. Just be sure not to overheat the epoxy.

you can get rubbing alcohol that is 90% and above

The denatured, Acetone, Xylene, and all the rubbing alcohols all seem to work.

It doesn't take but just a little

Time 1745

To all gentleman,

Thanks for the info. I should say this is a new arf kit from H9...I guess I'm not really trying to strengthen the kit structurally...have not flown the plane yet. I was just sort of reseaming the areas to fill gaps and perhaps keep it together so it will not vibrate loose to soon. This plane is a beautiful model.

Steve

I use all different types of glues for what you're talking about. If it's a tight fitting joint, thin CA. If it's not the tightest fit I use med.CA. If it's structural, or a decent size gap, I use epoxy. For fuel proofing I use epoxy with a touch of denatured alcohol.

Walmart actually has a really good price on denatured alcohol in the paint department; I was surprised ($4.35?).

Ok fellows I understand, thanks.....is it required or ok to mix the epoxy with the hardener before adding the acetone

Yip, it is.

I've read about lacquer thinner, acetone and denatured alcohol. Great Planes recommends alcohol. I'm inclinded to go alcohol but have yet to try it. I will though as I build my new ARF.

Bill

It doesn't take much alcohol to really thin it out so add on the verge of caution until you get a feel for it.