Grand Design - What is the correct way to repair stripped screws on exterior?

[Yoda]

I thought I would start a separate thread on this as folks can have stripped screws other than the awning screws into the side of the trailer.

I have several #14 screws that have zero grip into the side of the trailer. A 5/16" will not fit without drilling out a bracket, and I would rather repair the existing holes. From what I can tell I have the exterior fiberglass, a very thin steel sheet, and foam as far as structure through the hole. Total debt is 1-1/4" to 1-1/2". I have good epoxy and epoxy fillers available. The worst hole a 1/4 dowel will fit loosely in, the others 1/4" will fit snugly in. A #14 screw is 1/4" so this gives a picture of how badly striped they are. I believe the holes are to big for the molly rivets. Besides I do not have the big rivet tool.

So how would GD repair these holes at the factory???

BTW - Dealer technician was going to use exterior glue and toothpicks. Toothpicks and glue are for wood, not a composite structure, so please don't advise taking it to them.

Thanks
Keith

[orbiker]

Grand Design and probably everyone else is using self tapping screws. That's the problem. A self tapping screw drills a whole that is already too big for the screw.
I fix and install washers and dryers. We use self piercing screws on the metal venting.

Just food for thought. KEN

[TucsonJim]

GDRV-Emily, GDRV-Megan
in case you haven't seen this post.

[Yoda]

Thanks Jim

[GDRV-Megan]

Thanks for the tag!!

[Yoda]

Grand Design and probably everyone else is using self tapping screws. That's the problem. A self tapping screw drills a whole that is already too big for the screw.
I fix and install washers and dryers. We use self piercing screws on the metal venting.

Just food for thought. KEN

orbiker your correct every screw I have taken out of the unit has been self drilling/taping.

They have their uses. When I extended my hay barn 36' (36 by 36 ) I used a whole lot of them. I had to learn quickly about the correct setting on my drill driver depending what I was doing. I stripped and broke a lot. Two sheets of metal siding took a light touch, sheet to the I-beams took more effort, but too much they broke. If they wobbled going it the hole usually striped. My solution was to have two sizes on hand, or just drive another screw. I have also used the self piercing (several wood stove installs)- a different animal. Usually pierced me more than the metal .

[colan]

The OP is looking for input from Grand Design, their take will be educational.

My two cents worth starts with a couple of questions. Would you mind providing a little more detail? Where are the screws located and what is being retained?

Since thin steal sheet was mentioned any chance the screw hole is into one of the aluminum “studs?”

If the screw hole is into metal I would consider using a rivet nut or a Plusnut. https://www.rivetnutusa.com/plusnut-rivet-nut-rivnut/

if the screw hole has no metal backing the plusnuts would work with the caveat of being careful about loading.

[GDRV-Megan]

Hello Yoda ! I'm double checking with the service manager on how he would make this type of fix. I'll reply as soon as i get an answer. Thanks!

[Cate&Rob]

How I would fix this type of problem . . . in a boat deck (I have no experience that this will work in an RV wall)

For discussion purposes, lets assume that we are talking about a 1/4" diameter fastener.
1) The first step is to drill a 1/2" hole around the pulled out 1/4" hole in the outer skin only (yikes!)
2) Then, we need to cut away some of the foam behind the exterior wall. I use an allen key chucked in a drill with the short end inserted into the hole and spun to clear out the foam around the hole.
3) Now, mix up a thick batch of epoxy and high density bonding filler ( West System & 404 filler is what I use) and pack this into the space where the foam was.
4) After the epoxy sets, drill and tap a hole for a 1/4-20 machine screw. The epoxy is strong and dense enough to hold the threads of a coarse thread machine screw.

You now have a molded in place "T nut" in the space behind the outer wall surface. The epoxy plug will spread the load across the back of the outer skin and an inch or more of threads in the hardened epoxy will be much stronger than the single thread of the self tapping screw that was originally held by the sheet metal backer plate.

Again . . . no promises on this . . . but, I have used this method to reinstall hardware pulled out of a foam cored fibreglass boat deck.

Rob

[Yoda]

MidwestCamper Jim, put me on the the West systems stuff, so I cant blame you this time for my wallet getting thinner - too bad it does not make me any thinner.

[bradnailer]

Another possible solution would be to epoxy a plastic anchor in the hole that will accept the original screw. In my view, better than the toothpick method.

[Yoda]

The OP is looking for input from Grand Design, their take will be educational.

My two cents worth starts with a couple of questions. Would you mind providing a little more detail? Where are the screws located and what is being retained?

Since thin steal sheet was mentioned any chance the screw hole is into one of the aluminum “studs?”

If the screw hole is into metal I would consider using a rivet nut or a Plusnut. https://www.rivetnutusa.com/plusnut-rivet-nut-rivnut/

if the screw hole has no metal backing the plusnuts would work with the caveat of being careful about loading.

This may be the solution. I did find a more reasonably priced source https://www.libertyeng.com The tool is expensive though - but I always need a new tool
Now to see if GD can tell me the grip length needed - distance from trailer skin to the back of the metal sheet.

[GDRV-Megan]

Good morning all!! Per JD, we use #8 screws. If the holes are stripped we would simply replace them with #10 screws. I asked him about the rivet nut fasteners. He said they would work but it would be an under taking. Removing the existing screws and replacing them with # 10’s would be easier and less time consuming. I hope this answers your questions!!

[Cate&Rob]

Good morning all!! Per JD, we use #8 screws. If the holes are stripped we would simply replace them with #10 screws. I asked him about the rivet nut fasteners. He said they would work but it would be an under taking. Removing the existing screws and replacing them with # 10’s would be easier and less time consuming. I hope this answers your questions!!

Hi Megan,

With reference to the first post in this thread, the holes are already stripped out to larger than #10 (3/16") screws. The OP is asking what to do now.

Rob

[TucsonJim]

Good morning all!! Per JD, we use #8 screws. If the holes are stripped we would simply replace them with #10 screws. I asked him about the rivet nut fasteners. He said they would work but it would be an under taking. Removing the existing screws and replacing them with # 10’s would be easier and less time consuming. I hope this answers your questions!!

GDRV-Megan Please let JD know that the awnings on our units are attached with #14 screws, not #8. And the backing plate is stripped out with the #14 screws. Since there aren't many options for larger screws that are also short enough to penetrate the wall, we need to know how to repair this issue when the backing plate is stripped out.

Thanks,

Jim

[GDRV-Megan]

I'm checking. Thanks!!

[GDRV-Megan]

Sorry everyone! That was my misunderstanding. I didn't realize that you were referring to where the awning hardware is located. I just read that you were asking about stripped screws on the exterior. Typically we use the spider rivet if we have one that is stripped out. So the fix, using these rivet nuts (https://www.rivetnutusa.com/plusnut-rivet-nut-rivnut/), that was previously mentioned by Yoda would be acceptable if you don't have access to a rivet gun. The rivets that we use are GD part #960736, RIVET - #625 TRI-FOLD LG FLG ALUM .039-.354 GRIP RANGE, BLAC. The wall thickness with the EGS backer is 1/4" thick.

[Yoda]

GDRV-Megan
OK
Just to verify I have everything understood. The PLUSNUT Part Number S10P320 will work. Its a 10-32 thread and a .273 min hole size (very close to the 1/4" stripped screw). It has a grip range of 0.175 to 0.320 so should work with the .25 wall thickness to the foam. With an overall length of less than an inch when inserted should not interfere with the back wall material (my probe depth is 1.25"). https://www.rivetnutusa.com/wp-conte...ut-page-12.pdf
Thoughts? Cate&Rob , TucsonJim

If this is correct I will be ordering the tool and PLUSNUTS tomorrow depending on feedback. Should run about $60 to $70 if I priced it correctly. I plan to have a few spares too in my tool box.

Last question would 10-32 hex head (or washer hex head) stainless steel. 1" in length be the way to go on the bolts or should I go to grade 8?

Thanks - Keith