I finally found an epoxy that works with E85 and can still stay in a cylinder head. It’s a Hysol Loctite product for aerospace use. Most of the true aerospace grade epoxies that did work in alcohol were hundreds per ounce. This stuff is about 70 per tube, and there’s almost 7 ounces in these tubes.
I mixed a sample, along with some others and put them in E85 for a few days and this one was completely unaffected. The others weren’t so lucky. Most turned to mud or delaminated from the substrate. I was surprised at how flexible it is given it was the hardest setting of the 3 I was trying. It’s hard to even scratch the stuff, but I could flex the aluminum it was on all around without even discoloring the epoxy. Like the way plastic turns white when you bend it. It takes some time to work with it because it's about like honey at first, so I do a base smear to start, then as it thickens I'll add more to build it up.
The Loctite guy said it was made for jet aircraft nose cone repair.
