WonkoTheSane GRM+ Memberand SuperDork
1/13/20 9:13 p.m.

So I'm trying to resurrect this old hardtop I got years ago that was obviously dropped.. I got it all repaired using West Systems epoxy & fiberglass mat, it's looking pretty good now and nice and strong!


I'm just trying to figure out what glue they used to hold these things together.  It's grey seems like an expoxy of some sort.  Anyone have any idea?

Here's a close-up of what it looks like:


This is an early hard top, no defroster or headliner, and it doesn't look like the bonding agent was applied by robot.  The line is fairly wavy and the thickness is fairly inconsistent, so I think I'm looking for a caulking tube dispensed material..


Maybe construction adhesive?

MrChaos GRM+ Memberand SuperDork
1/13/20 9:16 p.m.

3m Panel bond?

Patrick MegaDork
1/13/20 9:17 p.m.

You can get a 2 part grey epoxy in caulk tube at the home stores.  It's called anchoring epoxy for putting bolts into concrete, and that's kinda what your stuff looks like

Don49 Dork
1/13/20 9:24 p.m.

Various  companies make 2 component panel bonders. Check with your local auto body supply house.

WonkoTheSane GRM+ Memberand SuperDork
1/13/20 9:29 p.m.

It looks like 3m panel bond is clear, although I'm sure it would work, I'd have to gamble the $125 it would take to find out.


Thanks Patrick, I think that's what I was thinking of.  I kept coming back to window adhesive, but that seemed a lot more rubbery than what this stuff solidified to.  I'll check out the anchoring epoxy tomorrow!

Nate90LX Reader
1/14/20 5:23 a.m.

The urethane windshield adhesive should work. It is flexible, but has good strength. It's intended to hold to a painted panel. It sounds like it might be cheaper than panel bond. It also has a long time (usually 30 minutes) before it sets up, so no rush to work quickly. It will probably take 24 hours or more to dry. Some epoxy adhesives set up in 5 minutes or less. 

triumph7 Reader
1/14/20 7:38 a.m.

IIRC, the top is made from what is called sheet molded composite, SMC.  The only thing I know that will definitely bond it is an epoxy resin.

Adrian_Thompson MegaDork
1/14/20 11:02 a.m.

I'd contact 3M and ask what they recomend.

buzzboy HalfDork
1/14/20 11:21 a.m.

It's the same stuff they use on Corvettes, isn't it? SMC, I believe it's called. 

CAinCA GRM+ Memberand New Reader
1/14/20 11:25 a.m.

It looks like JB weld.


I build high power rockets (up to M power) and use epoxy to bond structures on a regular basis. If you already have West Systems that's what I'd use. It's a decent epoxy. I'd thicken it up with colloidal silica, or high density filler (West Systems 406 or 404). They are both available at West Marine if you have one local to you.

WonkoTheSane GRM+ Memberand SuperDork
1/14/20 12:26 p.m.

Yes, the hard tops are made out of SMC, and you have to be careful about which epoxies you use as some won't adhere.  This west systems stuff has been proven to work well.


CAinCA - That's really cool about the colloidal silica!  I'll have to see if the local shop has some.  Unfortunately, the closest West Marine is about an hour and a half away, so Amazon is closer :)

therieldeal Reader
1/14/20 12:36 p.m.

We use Loctite E-120HP at work to bond aluminum parts.  Pretty impressive stuff, not sure if it will bond with your particular plastic though.

WonkoTheSane GRM+ Memberand SuperDork
1/14/20 7:45 p.m.

So looking around, I believe this would be the proper product to use:


However, it's $49 dollaroos, plus a gun, so a quick Google for "glue smc permatex" yields:


Which says it's for SMC and was in stock at advance for ~8 a package.  So I'm going to try that I think.

cmcgregor Dork
1/14/20 8:44 p.m.

It's probably not helpful for this particular use, but I recently discovered https://www.thistothat.com/

WonkoTheSane GRM+ Memberand SuperDork
1/15/20 9:49 a.m.
cmcgregor said:

It's probably not helpful for this particular use, but I recently discovered https://www.thistothat.com/

That's a really cool resource!

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