Hey yall,

Any suggestions for sealing two mating surfaces (~2"x2") from water nudging its way in between? I was thinking an RTV gasket but I'm not sure if that'd be a good idea.

I'm replacing my rear bumper, and it's secured to the chassis with a couple steel brackets. I want to keep water out when I bolt it all back together. It looks like the factory used wax undercoating to seal the contact surfaces, which held up decently for 20 years...

 

What we use on boats is the adhesive sealant 3M-4200 and 3M-5200. They are sticky and can take some stretching. I used the 5200 a gap in the seam between two body panels at the top left corner of the rear window hatch. The 4200 is considered removable (with efforts) whereas the 5200 is considered permanent.

 

Cool, if it works for boats it should work for me. I'll try one of those.

Thank you!

 

Part of the reason I used the 3M adhesive sealant is that I had some left over from previous jobs on my boat. I don't think they are paintable. You should look at their product descriptions to make sure it will work for you.

If you do get either of the 3M adhesive/sealants and have some left-over, what we boat people do is put some cling-wrap over the the tube opening before putting the cap back on. We then put the tube in a zip-lock bag with as much air squeezed out of it as possible and then store it in a freezer. (Really!)

 

Another thing you can do Christine is use a vacuum with a small hose to suck the air out of the bag. That 5200 is some wicked stuff!

 

Butyl window ribbon sealant would would probably work pretty well in that situation. I use the stuff to seal up my headlight retrofits. It's meant to watertight seal windshield glass to the body of a vehicle, so I would image it should keep water from getting into the body there at the back too lol

Comes in several forms, but I buy in in the ribbon form, comes in a roll in a box. You pull it out in the length you need, cut it off, and just stretch/squish/work it into the shape you need and lay it into place where you need it to be. It doesn't set and harden or cure, it stays pliable. It isn't a glue or adhesive, but it's dang sure sticky. Don't get it on any clothes you like, because it will NOT come out...