Repair stripped screw holes in fiberglass

[bkenobi]

A couple of the mounting screws for the ingress handle on my NL are stripped. If this were wood, I'd glue a toothpick in there and move on. What is the best approach for stripped fiberglass?

[SidecarFlip]

I'll remember the glued in golf tee trick.

[errante]

As mentioned, if you can get to the backside that would be best, but that is usually not possible. There are many ways to deal with this depending on the situation but I have always had the best luck with the following. Remove the fastener and roughen the hole. This may involve taking a drill bit and going through the fastener hole and drilling off in 2-3 directions a short distance, always being aware of where you are headed. Thoroughly dry the hole. Tape off around the hole. I use an epoxy with a high strength filler. I personally prefer west system but there are many other brands available. West system has a small repair kit for such things(or at least they use to). You will need to purchase either denatured alcohol or acetone for clean up. Fill a small plastic syringe with mix of epoxy and filler. These plastic syringes can be purchased at west marine or similar store. Check it out online. Lubricate the appropriate fastener with wd-40 or similar. Squeeze the epoxy mix into the hole and screw the fastener, without the handle, about the right distance into the hole. Remove tape and clean up immediately. Let cure for 24 hours. Remove the fastener add a little bit of chalk, just because, and reattach handle.

[covered_wagon]

username taken wrote:
This stuff is great for fiberglass. It's an epoxy putty you knead together and jam in the hole - makes for a much better screw mount than the original fiberglass. In all truth, the bigger and more ragged the hole, the better this stuff works.

https://www.westmarine.com/buy/west-marine--marine-rx-epoxy-repair-kit-2-oz--13967443?recordNum=11

NL uses UHMW polyurethane behind the fiberglass for any kind of load bearing screw. You can get 2x2x 1/2 blocks of it at a good industrial hardware store. Screws will not strip that kind of thing out.

I'm the guy that first told Northern Lite about how to do that to hold their lower awning hardware and fix stripped screws and leaks. I removed the tailites and was able to get it up in there with my arm. Other areas of striped screws I removed the door frame to batteries or compartment, water fill door, whatever, exposing the fiberglass cut out edge and shoving a half inch thick piece between the shell and bead board with a knife edge or bevel cut on the uhmw so it allows you to force it into the bead board and hold it in there. I had many leaks with a new camper and fixed them all by holding firm like supposed to be.

[username_taken]

This stuff is great for fiberglass. It's an epoxy putty you knead together and jam in the hole - makes for a much better screw mount than the original fiberglass. In all truth, the bigger and more ragged the hole, the better this stuff works.

https://www.westmarine.com/buy/west-marine--marine-rx-epoxy-repair-kit-2-oz--13967443?recordNum=11

NL uses UHMW polyurethane behind the fiberglass for any kind of load bearing screw. You can get 2x2x 1/2 blocks of it at a good industrial hardware store. Screws will not strip that kind of thing out.

[Ste7of1]

If you are only dealing with fiberglass (no wood backer to grab) another option would be to install a small rivetnut through the hole. This would grab on both sides then you can use a machine screw into the rivet Nut (sized to match) to secure. This approach does require a rivet tool for the rivet Nut installation. For example: https://www.amazon.com/eBoot-Plated-Carbon-Insert-Nutsert/dp/B01NAHXLJM/ref=sr_1_2?ie=UTF8&qid=1502663312&sr=8-2-spons&keywords=Rivet+Nut&psc=1
If you have access to the backside of the panel you can use a weld Nut instead of the rivet Nut eliminating the need for the rivet tool. https://www.mcmaster.com/#90860A100

[bkenobi]

Link?

[umpqua]

Battling the same problem with my Bigfoot.
I used epoxy to set 2-3 tooth picks into each hole. The holes are in a stud, so I have something to grab into. I did upgrade to longer 1/4 x 2" SS lag bolts. The epoxy I used was 12 hr cure, so I'll finish tomorrow.

Tomorrow I will drill a pilot and reinstall the handle. There is another website/forum where this issue was addressed. I used suggestions from that site with some advisory from here.

[theoldwizard1]

Use a cheap plastic hollow wall anchor.

[tattoobob]

I would try a screw one size bigger first, 99% of the time that has worked for me

[jesseannie]

I think finding out what is behind the glas is the first step. Then perhaps a nice looking stainless steel sheet bigger than needed glued and screwed to the glas then screw the handle through that into a fresh spot an inch or so away from the original. Reinforced with the stainless and in a new location I think you would golden.
Jesseannie

[bkenobi]

I temporarily used a could toothpicks and reinstalled in the same spot. I want to put it in the same location with a permanent fix.

[jesseannie]

Are you going to reattach the handle in the same place? It seems like making a structural repair or an aesthetic one would be different.
Jesseannie

[bb_94401]

Fiberglass construction usually makes use of backing plates when they want to attach something with screws or bolts that will have a lot of pull out force on it. Foam core construction uses epoxy plugs between the two fiberglass layers for attaching things where the force is more in shear.

If there is no access behind where the screws goes just through fiberglass and there is no backing material, then the most common approach is to use the screws to hold and locate the part until a high strength polyurethane adhesive cures (SikaFlex or 3M). Tensile strengths are in the range of 170 to 500 psi. It is what attaches the access ladder to the roof on my TC, the screws aren't really doing anything.

[JoeChiOhki]

bb_94401 wrote:


Easiest way to get what you need is to go to your local marine store:

Fisheries Supply
1900 N Northlake Way
Seattle, WA 98103

and talk to someone in the resin / fillers / fiberglass section. Explain what you are trying to do and they will point you in the right direction and explain how to do it.

Wish they were closer, I'd love some of their help for my up coming fiberglass work.