So the firewall has seperated from he fuse on one side on my A/C. I think it was caused by the pressure i apply with my eletric starter and the ensuing vibrations. Any tips on repairs? Someone recommended 30 minuted epoxy since its more flexible.

Yes, use 30-minute epoxy to attach the firewall to the fuselage. There are a couple of other things you can do to help make it stronger. First you can epoxy tri-stock in where the firewall joins the fuselage. This will create more surface area for the two parts to attach to each other. The other thing you can do is pin the firewall to the fuselage. Drill holes through the fuselage into the firewall, put 30-minute epoxy in the hole, and drive in wooden dowels (wood toothpicks work on smaller planes) into those holes. These will keep your firewall from pulling out.

Hope this helps

Ken

I'm wondering if the bond or the wood was weakened by fuel collecting on it? I don't think a firewall should seperate from the fuselage for the reasons you mentioned, but I could be wrong. How much pressure are you using on the starter? If you suspect vibration, check the balance of your prop.

Don't forget to fuel proof your repair when you are done !!! ENJOY !!! RED

Besides what RCKen said, it also doesn't hurt to line the corners of the firewall inside the fuel compartment with small pieces of fiberglass to reinforce everything.

Hogflyer

RCKen is right on with his suggestions.......try one of 'em, they will all work.













Flyin' is like breathing.......everybody should do it.

I don’t think a starter could cause a firewall to seperate,but worse things have happened but not likley.Hard landings vibration poor glue joints fuel soaked would sound more like a cause. I read here about pinning the firewall and since then have done that to all the models I build. Your fix is simple and shouldn’t be much of a problem.

Make sure to check your CG when your repair is done. A little extra nose weight might not hurt, but not knowing how much extra weight your going to put into the repair, it's always a good bet to check that CG before the next flight.

Repairs in the nose are usually OK, but check anyway.
Repairs in the tail ALWAYS CHECK.