ORIGINAL: brit
I had the same problem with ply spacers but realised it before flying I changed to aluminum used blue locktite, flat washers and lock washers, no trouble with loosening in 31 flights so far, also I did apply a thinned epoxy to the firewall several light coats before I mounted anything it seems to tighten up the wood pretty good.Just make sure to spread the load on each bolt with a flat washer first then lock washer and locktite. Good luck
So you're saying you use washers between the stand-offs and the hardwood? Might just buy something hard like silver since i'm just going to cut them into small squares. One more question on engine mounting. The standoffs I bought are bored for 10-32 oe 5 mm hardware. I couldn't find long enough 10-32 at the hardware store in my home town or online so I bought some long 10-32 bolts from Tru-Turn that are for their spinner retaining screw. Will these work as my engine mounting bolts?