Lonnie-S wrote:
1) Did the Sikaflex ooze from the joint between the floor and chassis tubes under the pressure of the bricks?
2) If so, does it dry hard like epoxy, or is it flexible and there's some way to trim it (or clean it) off afterwords?
Whether steel or aluminum is used, it does seem like Sikaflex is an attractive alternative to riveting or welding the floor in place.
PU sealant/Adhesives (of which Sikaflex is just one - probably the best known - brand-name) behave kind of like super-tough, super-sticky versions of the silicone sealants you'd use in your bathroom; hence you can probably appreciate Gavin's stress on the need to keep everything clean... the slightest bit of greasy contamination on the surface, and it'll just peel off, real easy. You could argue that they behave like a half-way house between silicone sealants and epoxy, but in technical terms they are treated as and elastic (gap-filling) adhesive, rather than as a high-modulus rigid (film bonding) adhesive
They'll squeeze out of joint under pressure. They're not as hard as epoxy when set, but if you've got your bond nice and clean as recommended by Gavin, they'll still stick like the proverbial to a blanket and the excess won't trim/peel away anything like as easily as silicone (though you can trim them away with a razor blde or sharp knife, with care), so you're best off wiping away any major excess
before they go off, in my experience.
As with most adhesives, though, the manufacturers produce comprehensive guidance on handling and application, so always best to get it form the horse's mouth.
As Botbasher said way back on page 2, a belt-and-braces approach of rivets in key locations is a damned good idea, just to avoid any risk of peel, regardless, I think.