3M Scotch-Weld Instant Adhesive Primer AC79, Clear, 2 fl oz Bottle

I repair things as a career. Like huge industrial stuff,1000ft long lake freighters, steel mills etc. I have access to so many expensive industrial chemicals and adhesives. None I had found were up to the task on a home project I was doing in my shop. I needed to bond a rubber boot to a part made from POM (Acetal) Both are difficult to adhere to. Nothing sticks to POM and anything strong does not flex with the rubber. LOTS of inter-web research and LOTS of claims and hype. I found that both materials were on an extensive list 3M had of materials P40 is comparable with. They were NOT kidding! It worked even without the primer! Like my first try I mis-located the boot a bit..... Too late! It is still stuck right where I put it. This stuff is ultra thin! Some part in the description says gel. NO! BUT! the way this stuff wicks into the gaps and stuff makes this all the better for me. I assemble the parts exactly where I want, a single drop at the joint......and it's capillary action pulls this stuff right where it needs to be! I've used it on a few more things playing around. THIS STUFF WORKS! HIGHLY RECOMMEND! The primer is a must have IMO. It gives the best chance at a successful bond, especially for difficult plastics. YOU PRETTY MUCH GET 1 SHOT AT IT! Ray the Maker

I am gluing silicon rubber to a stainless steel washer; a very difficult task. I first used just Scotch Weld PR40, plastic and rubber adhesive. I abraded the washer and rubber with 150 grit sandpaper. After 24 hours the rubber peeled off fairly easily. I repeated the experiment but used the Scotch Weld AC70 brushed on the abraded rubber. After 24 hours the rubber stuck very well even while pulling with considerable force! The primer and abrading are essential!

It's plain acetone. Don't waste your money! It does have a cute little brush attachment tho.

This is *not* just acetone like you can buy in a can or nail polish remover. Acetone is simply what is used to dissolve the ingredients that are actually important. These compounds aren't hazardous so they don't need to appear on the SDS. This stuff works. If you try using just acetone you'll find that it doesn't. 3M makes great stuff. Use this primer with their instant adhesive for plastic and rubber.

I know propylene is hard to stick. That is why I bought this primer to go with an adhesive that specifically requires a primer. Unfortunately, even though I applied it to a cleaned surface multiple times, the adhesive kept flaking off. It smelled like acetone, so I am very pissed that I bought 20ml acetone for 50$. I will try to return it.