Adhesive/Sealant Instead of Silicone

[edwardb]

Well, informally, the Sikaflex 252 cures with moderately more hardness than silicone, but not nearly as much as I would have thought. I'll do more thorough testing today. The panel bonding adhesive is much more what I had in mind. I would definitely NOT think to use the Sikaflex product without riveting also...it has a lot of squirm. I would, however do that with panel bonding adhesive. I think a combination of pba and riveting would make for an incredibly strong and stiff structure. I feel that while silicone gets the job done just fine, one of the above methods may just provide another nth degree of margin for close encounters with both moving and inanimate objects.

For those who are multiple builders, a question:
Roughly how many tubes of silicone does a typical build require?

Personally, I wouldn't omit the rivets no matter what adhesive is used. When you dry fit everything and match drill all the holes, that establishes your alignments. You will need to tweak some bends, occasionally do a little trimming, create some clearance for weld beads (just did that last week with some trunk panels), and you don't find all that out until you get everything properly pulled into place. Clecos and riveting gets everything back where it belongs, plus creates a tight joint allowing the adhesive to do its job. I think it would be very difficult and of questionable value to try the same thing with clamps, contact tape, whatever. Just my opinion.

2-3 of the large caulking gun tubes should be plenty, although I sometimes have trouble with it setting up in the tube once its opened because there can be some time between when you initially open and then use it all. And I've tried everything to seal them properly. I've had to buy another tube because a half full one wouldn't dispense any more.