Stripped screw hole in plastic.

[GeneZ]

Suggestions, or know-how, please.

I have a stripped hole in a plastic composite speaker cabinet. When working with plastic how to tighten up the hole?


Thanks, Gene

 

[wrenchone]

Put in a threaded metal insert or a T-nut, available on Ebay or at a good hardware store.

 

[GeneZ]

Put in a threaded metal insert or a T-nut, available on Ebay or at a good hardware store.

Thanks.. but sorry...

This is for a self tapping type screw. Pointed tip. Metal into plastic.

 

[wrenchone]

Well, it sounds like you're going to have to adapt the hole to some other type screw, if it's stripped out. Self-tapping screws are a dodgy prospect at best, especially with soft materials.

 

[Conrad Hoffman]

Inject it full of epoxy. Cure. Drill a new pilot hole and run the self-tapping screw in. Many people drill pilot holes too small in hopes of getting a better fit. Usually a mistake as the plastic just cracks.

 

[Darkstar52]

Plastic Welding

You could weld it. It's quick and easy, but the tool is a bit pricey for a one off job. Every auto body shop has them. What could they charge for a five min. job ? Best of luck
Howie

 

[sofaspud]

First thing I'd try is a piece of flat toothpick stuck into the stripped hole. Ease the old screw in; you'll only have a bigger problem if you let the plastic crack.

 

[stratus46]

Thanks.. but sorry...

This is for a self tapping type screw. Pointed tip. Metal into plastic.

His T-nut or threaded insert idea is a good one. Of course you'd have to abandon the self tapping screw for a machine screw. Alternatively you could fill the hole with Devcon plastic welder and re-drill it the next day and continue to use the self tapper and possibly strip it out again, The machine screw IS better.

G²

 

[Cal Weldon]

What's wrong with Conrad's idea in post 5? sounds pretty achievable and easy on the execution side to me.

Just remember to put a piece of tape on the inside to prevent it from dripping out the hole.

 

[digits]

My dad used to fill any plastic holes with a mixture of superglue and bicarb of soda (I think that was the second part, should be easy to look up), it is so strong you can attach a watch strap with it when the pin hole breakes off....and it doesn't eat the plastic like the glue would do on its own.

 

[GeneZ]

My dad used to fill any plastic holes with a mixture of superglue and bicarb of soda (I think that was the second part, should be easy to look up), it is so strong you can attach a watch strap with it when the pin hole breakes off....and it doesn't eat the plastic like the glue would do on its own.

Well, look what that just led to! Excellent tip!


From:

Glueing plastic with super glue + Bicarb of Soda - Woodwork Forums

Here is my tip. Set up your joint however you can by clamping etc until you get an almost perfect fit. Dribble in some superglue and then reach for a pinch of Mum's BiCarb of Soda and sprinkle in onto the superglue. It will set like concrete (and about the same colour) in less than 1/5th of a second. It gets hot - dammed hot so don't have any superglue on your fingers when you reach for the bicarb.​

 

[digits]

awesome, play around with it on some scrap plastic first to get the hang...

 

[Cal Weldon]

Superglue won't fill a hole like epoxy.

 

[digits]

Not on its own, but whatever it turns into when mixed with the soda is incredibly tough.

 

[Cal Weldon]

That may be true but I am wondering how it will set up and why you would to go through that? It just seems like epoxy is ready made for the project.

 

[GeneZ]

That may be true but I am wondering how it will set up and why you would to go through that? It just seems like epoxy is ready made for the project.

That quickly?

"It will set like concrete (and about the same colour) in less than 1/5th of a second. "

 

[DaveG]

If the hole filler is harder than the surrounding material, any screw you put in will walk off center around the filler. The epoxy may be a least roughly similar to the plastic.

 

[GeneZ]

If the hole filler is harder than the surrounding material, any screw you put in will walk off center around the filler. The epoxy may be a least roughly similar to the plastic.

Its good to keep your mind open...

 

[DaveG]

 

[digits]

Epoxy, would be the first thing I use if I had some standing around, except where you have to build external bits, not haveing any, the superglue would be my way. You can always drill a pilot hole through it for your screw.