the trick ( and you still get bubbles ) is to use it in small amounts ( small thin fillet ). the bubbles come from the shrinkage and gassing off. it is normal but still works pretty darn good and i haven't had a leak in 3 years. i did solvent weld it with #4 first, the #16 was insurance.

never use silicon for sealing acrylic, unless it is specifically designed for this purpose. it may hold now but will let go later and cause major problems.


i haven't heard of the weld on #5??