epoxy

[starmac]

What would be the best epoxy/glue to fill a hole in plastic then redrill and thread.
I have a hole that holds my headlight adjusting screw stripped out. What I have in mind is drilling and tapping it a little large then filling it with jbweld or similar, then drilling and tapping to the accept a new screw.
Any better suggestions??

[docone31]

Marine Tex.

[MtGun44]

Unless you have a reverse taper hole, it won't hold. Epoxies do not stick to most
plastics well at all. Certainly worth a try, but try to use a dremel to make the hole
reverse tapered and rough before you try. Marine tex is pretty hard stuff, never tried
to drill and tap, it have seen it used as an action bedding compound.

Bill

[uscra112]

Threaded inserts are just made for this kind of thing. Look up on McMaster.com Lots of times manufacturers use 'em as an OEM installation in plastics and even aluminimum. Keensert is one that I've used in that capacity.

On a car, I wouldn't expect any kind of epoxy to hold for long.

'Course, there's also plastic welding.

[starmac]

I have used heliocoils many times, but never on plastic. Jb weld held it for over a year (on the haul road) but I just glued the screw in. It actually held until I changed the headlights the other day and needed to adjust it, I forgot about gluing the screw in. I should have got a cleu when I had to use channel locks to turn it. lol

[fecmech]

You can probably buy a replacement part from the dealer.

[starmac]

For sure I can buy a replacement part from the dealer, for no probably around 2 hundred bucks. Then drill out all the rivets, either cut my inner fender up or just trash it and build another one. Body panels, including doors are glued on vehicles these days, I'm pretty sure there is some product that will hold a headlight screw. lol

[375RUGER]

Devcon Plastic Welder is what I'd use. I can get it at my local Lowes. It's good stuff on plastic. I think you have the right idea on how to tap large fill and tap again.

[Blacksmith]

Loctite has some products that may work depending on the type of plastic it is:
http://www.loctite.com/

Could you glue or rivet a piece of metal in place and drill and tap that instead of the plastic?

[nhrifle]

Any chance of fabricating a press fit steel or aluminum cylinder that could then be drilled and tapped?

[starmac]

LOL, I just picked up some devcon plastic welder to try, now I'm having trouble trying to come up with the exact thread pitch to tap it. lol Nothing is ever easy.

[waynem34]

jb weld.

[Beone]

West marine makes an epoxy for plastic

[Gliden07]

These work good! Harbor Frieght sells a kit with the installation tool and an assortment of the inserts. I'm sure its not as nice a tool as McMasters sells but they work good! I made some access panels for a friends race car,another friend of mine builds custom Harleys we used them to hold down a battery cover that was under and old school bicycle seat with the exposed springs.


Threaded inserts are just made for this kind of thing. Look up on McMaster.com Lots of times manufacturers use 'em as an OEM installation in plastics and even aluminimum. Keensert is one that I've used in that capacity.

On a car, I wouldn't expect any kind of epoxy to hold for long.

'Course, there's also plastic welding.

[Blacksmith]

LOL, I just picked up some devcon plastic welder to try, now I'm having trouble trying to come up with the exact thread pitch to tap it. lol Nothing is ever easy.

Probably metric!

[Calamity Jake]

LOL, I just picked up some devcon plastic welder to try, now I'm having trouble trying to come up with the exact thread pitch to tap it. lol Nothing is ever easy.

Use a self drilling screw. Getem from the local hardware store or auto supply.

[monadnock#5]

Use a self drilling screw. Getem from the local hardware store or auto supply.

I've used Devcon to repair bearing housings in electric motors. Chuck the endbell in a lathe. Rough out the housing with a boring bar to give the Devcon something to stick to. Lay the epoxy in and let it cure. Then the tricky part, boring to size. The final cut was the make or break nerve racker. Too small a cut, and the devcon just rolled under the cutter. Too much of a cut, and start all over again.
You can try to tap the hole, but I'd go with a pilot hole and Jake's self tapping screw.

[Down South]

The self tapping oversized screw was my suggestion too.

[starmac]

Where would I find a self tapping screw with the head shaped to hold the headlight bucket.

[popper]

Try one of the spring clip nuts or just the flat ones ( flat spring plate with prongs for the threads ) & use the devcon, plastic steel or JB to hold in place. Had an old Merc, everything behind the dash was repaired and held together with that cheap duco plastic alum or steel. JB is epoxy & ground granite. The older parts were nylon, glue & epoxy won't stick so you have to encapsulate it to fix.

[mroliver77]

I have epoxied about everything. Even if it will not bond you idea of threads gives it something to hold on to. You are in essence making a epoxy helicoil. You could put some release agent on the crew when you set everything. No need to cut threads in the epoxy as you have "cast" them.
Jay

[Ehaver]

If you can drill and tap it larger, why not just use a larger screw/bolt?

[montana_charlie]

Find a screw with the right thread to match the headlight screw (or use the headlight screw).
Lay in your Devcon, epoxy, or 'whatever' with the screw already in position.

If the screrw is coated with two layers of JPW, it will 'release' from the hardened material ... and screw right out ... leaving a 'tapped hole'.

CM

[Jammersix]

The correct epoxy for the material will hold.

[David2011]

Can you get a Tinnerman plate in there? They're very tough and unlikely to strip out. Failing that, some WEST Epoxy with a couple of small patches of 4 to 6 ounce glass cloth on each side of the hole and milled glass fibers in the epoxy will trap the repair so it doesn't much matter if it sticks to the plastic or not. Having used WEST by the gallon, I suspect it will stick if you rough it up a little. The milled glass fibers make the cured epoxy very strong and it can be drillled and tapped.

David

[starmac]

I am not sure what a tinnerman plate is, but this hole is extruded. the extruded part where the hole is is probably 1/2 in outside diameter.
I have new adjusting screws, and do believe the release agent will do the job, with epoxy.