3M Windo-Weld as Undercoating Patch? - PeachParts Mercedes-Benz Forum

aaronkobi · #1 05-03-2008, 09:11 AM

A couple of days ago I was sealing up my windows with 3M window weld and the bottom of the cartridge exploded and the stuff got all over my caulk gun. Since the stuff is a complete mess when wet, I decided to wait until it dried and just peel it off...

Wow, once it dried, it's about the toughest sealant that I've ever experienced. Was basically the consistency of a rubber tire. I had to use pliers to get it off of the caulk gun, and even then it wouldn't come off.

I was thinking this would be a PERFECT patch for the undercoating on my 300TD after my floor pan repairs are complete (and it's black, which is also a plus). Just goop it on a spreader and smooth it into the gaps. Anybody have any long-term experience with the durability of this stuff?

C Sean Watts · #2 05-03-2008, 09:28 AM

BUT, from first hand experience I can tell you what's good.

Herculiner brand multi purpose bed liner. You do have to do some cleaning and xylene wash prep but that is like armor. It's polyurethane based.

aaronkobi · #3 05-03-2008, 09:41 AM

Quote:

Originally Posted by C Sean Watts

Herculiner brand multi purpose bed liner. You do have to do some cleaning and xylene wash prep but that is like armor. It's polyurethane based.

Hey Sean, I was thinking about coating the entire inside with Herculiner when I'm done with all the repairs. I hear that it sticks really well to POR paint as well (can anybody attest to that?). Just seal the entire thing and be done with it... (leaving the drain plugs open of course). Never thought about doing that on the underside though... humm...

babymog · #4 05-03-2008, 10:13 AM

Most windshield sealers are polyurethene ("urethene").

Sticky and tough stuff, provided the area is cleaned well enough for a good seal. What you don't want to do is allow water to get in and be trapped.

C Sean Watts · #5 05-03-2008, 11:42 AM

Quote:

Originally Posted by aaronkobi

Hey Sean, I was thinking about coating the entire inside with Herculiner when I'm done with all the repairs. I hear that it sticks really well to POR paint as well (can anybody attest to that?). Just seal the entire thing and be done with it... (leaving the drain plugs open of course). Never thought about doing that on the underside though... humm...

It sticks to about anything as long as it's clean. If you pain over it make sure you use urethane paint.

TheDon · #6 05-03-2008, 12:12 PM

I'd rhino line the underside and interior. which is something I want to do after removing all of that stupid factory sound deadening material and putting down dynamat stuff

Knightrider966 · #7 05-03-2008, 12:27 PM

I will definitely Herculiner or Rhinoliner the bottom of my cars if I move from here. Both my 240D and my 300D are excellent examples of an Arizona rust free body! My next location to move to would be Idaho!

bgkast · #8 05-03-2008, 02:25 PM

I used some rubberized undercoating from a can over POR-15 to patch the undercoating from my repairs. It's not as good as the factory stuff, that's for sure.

aaronkobi · #9 05-05-2008, 11:32 AM

So obviously I'll need to thoroughly degrease the underside of the car before applying herculiner. Any recommendations on how to do this? Lots of gunk under there.

Also, I'm not going to scrape every bit of factory rubberized undercoating off of the car... that would take forever. Will the herculiner stick to the old stuff that remains, assuming it's degreased? Not sure how hard herculiner is... my assumption is that it's a bit rubbery and has some flex.