HOW DO I MAKE BALSA FILLER HARDER?
 

I have filled a hole in my firewall with balsa filler and I am concerned that I will chip out the filler with inadvertently knocking the plane around. How do I harden the filler beyond the normal dried state? I have considered soaking it with thin CA. This plane is still in the building stage and I will cover the firewall with thinned epoxy before I am finished. Is this all I need to do or is there a proven method of making filler harder?

Also, since this is on the firewall and very close to my muffler, will it melt with engine heat?

RE: HOW DO I MAKE BALSA FILLER HARDER?
 

HI KELLEY! The thinned epoxy should work. If I have a hole that I am plugging, I drill it to the next dowel size and plug it that way.

RE: HOW DO I MAKE BALSA FILLER HARDER?
 

You don't have to worry about heat an epoxy. Unless the muffler or cylinder head is in direct contact with it, epoxy is no problem.

Some epoxies are specially formulated for high temperature applications (Circuit boards are made with a high temp resin). Even "standard" epoxies are rated for temperatures higher than what a model engine puts out. It will burn before it melts.

RE: HOW DO I MAKE BALSA FILLER HARDER?
 

CA works great for making it harder, just soak it and wait a minute, then whipe it off and it will be rock solid, I've done this many times

ryan d.