I have a continuing problem with the bay doors on my Motorhome.
The mechanical metal brackets that hold the doors closed keep pulling out of the fiberglass mounting points.
The doors are fiberglass and have rivets (4) on each bracket on each side of the door. The rivets pull out.
I have used many different brands of 2 part epoxy over the years and they all have eventually failed.

Any suggestions for an adhesive that will hold.

JB weld?

Maybe some of that stuff that comes in a roll and cut off a piece and need it in your hand and then apply it. It is like a soft putty?

quote:

Originally posted by old rugged cross:
JB weld?

This. I’ve used it to seal a quarter sized hole in the cclutch cover of a dirt bike 40 mile from home.

Have you tried re-rivoting plus JB weld?

Scotchweld 2216 is what you need, and a little bit of cotton flox. Clean everything with 36 grit, then acetone. Coat both the metal and fiberglas doors with a thin coat of pure well-mixed A+B Scotchweld, then add a little bit of cotton flox to the remaining Scotchweld and mix it in thoroughly with a popsicle stick. Apply a thin coat of the flox impregnated epoxy to the door and metal, then join the parts & rivet them while wet, or use a Cleco in the rivet holes until set...and then rivet after cure.

If you don't have or can't find flox, send me your address and I'll mail you enough to do the bonding.

I work with Fiberglass all day long, in the yachting industry. Is there a way to glue an aluminum backing plate behind the fiberglass and thru bolt the doors? Or drill and tap the aluminum plate and use machine screws into that? Do you have any pictures? There are also special collets you can use to go in the holes for the machine screw to thread into that expand. Something like this can work well if you have access to the back side as well? Otherwise best to mix a mixture of west system with Cabosil into a thick paste, fill holes, let dry and re-drill.

https://boltdepot.com/Product-...14d5eb766383a9d4a8aa

3m 5200?

quote:

Originally posted by trapper189:
3m 5200?

Not familiar with 5200, but 3M 08115 panel bonding adhesive would be a good alternative to Scotchweld + flox

quote:

Originally posted by trapper189:
3m 5200?

I used this to bond my solar panel brackets to the fiberglass roof of my truck camper. There hasn’t been any issues in three years.

E-6000 adhesive ,

Has never failed me

Plexus bonding adhesive.

We use it for bonding metals together where welding can't be done. We even use it to bond fiberglass or acrylic to metal frames.

5200 would work. Takes 3 days to dry and 7 to cure. The parts have to be clean, from oil and dirt. Plexus would also be good.

Some photos of the application would help us envision this so these aren't all just WAG's and no help.
If there's any way to enlarge the contact area between the fiberglass and bracket that sure would help.
Also, which part, the fiberglass or metal, is losing the bond? Have you scuffed both parts and cleaned with acetone first?

I do have 5200 adhesive on hand and have used it many times. My first thought was the 5200 but because it stays somewhat pliable I did not think it would be good to anchor the metal brackets to the fiberglass, that's why I was seeking an epoxy.

In the past I did re-rivet and glue.
The rivets go into a fiberglass hole and there is really no area for the rivet to spread out inside that hole.
Gluing a metal plate to rivet to would be a possibility but I would need to hog out the fiberglass under it so the rivet could spread.
If that did not work I would have a lot of repair work to fix the fiberglass. I would also be back at square one looking for an epoxy that I can use to glue the metal plate to the fiberglass.

How about using fiberglass resin inside the hole?
Would the resin bond strongly to the old fiberglass and the metal?

I will try and take some pictures today.

Is there any chance of putting a T-nut or backer plate on the outside?
Something along the lines of this:
https://www.mscdirect.com/prod...py63DsMaApuJEALw_wcB

Using rivets in tension like that in a soft material is just asking for it to fail, as you found out.

3M used to make a product Structural Adhesive. Two part product, correctly,mixed looked like coffee with cream.

3M 5200.
We used it aboard ship for lots of stuff and I never once saw it fail to hold.
Aluminum bracket to steel hull.
Al to AL
steel to Steel
AL to Wood

quote:

Originally posted by jimmy123x:
I work with Fiberglass all day long, in the yachting industry. Is there a way to glue an aluminum backing plate behind the fiberglass and thru bolt the doors? Or drill and tap the aluminum plate and use machine screws into that? Do you have any pictures? There are also special collets you can use to go in the holes for the machine screw to thread into that expand. Something like this can work well if you have access to the back side as well? Otherwise best to mix a mixture of west system with Cabosil into a thick paste, fill holes, let dry and re-drill.

https://boltdepot.com/Product-...14d5eb766383a9d4a8aa

Here's your answer on a silver platter. No lack of expertise on the SF... I'm no expert but I've done lots of successful jury rigging and jimmy's recommendation looks solid and economical, esp considering his profession.

quote:

Originally posted by jimmy123x:
I work with Fiberglass all day long, in the yachting industry. Is there a way to glue an aluminum backing plate behind the fiberglass and thru bolt the doors? Or drill and tap the aluminum plate and use machine screws into that? Do you have any pictures? There are also special collets you can use to go in the holes for the machine screw to thread into that expand. Something like this can work well if you have access to the back side as well? Otherwise best to mix a mixture of west system with Cabosil into a thick paste, fill holes, let dry and re-drill.

https://boltdepot.com/Product-...14d5eb766383a9d4a8aa

This!

3M 5200. That ain't goin' nowhere!