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Ritchie

Screws not tightening in plastic after reuse

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Hi, i am currently restoring a chassis that was unfinished and renewing parts where i can, however, whenever i try to screw into the plastic, the screws will not tighten, has anybody got any suggestions please, thanks.

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Thanks for that, would the use of threadlock do the same job guys?

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No, anaerobic threadlock is for metal-2-metal bonding.

Plastic thread repair is best/easiest/fastest with superglue. If your hole needs more filler material, shave a sliver of wood/toothpick down the hole before applying glue.

It's also ok to use machinethread screws into plastic holes. Those selftappers are easy to overtighten until hole strips.

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I've been using UHU Plast fl├╝ssig in the past, which is essentially a glue for plastic model kit building that melts the plastic parts together. I think similar plastic model glues are available from other brands too.

I use it by placing some drops on the screw or inside the hole, then tighten the screw into the hole 2 times, and then let the screw inside the hole for at least 24 hours. Worked well for me.

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My repair method for stripped threads in plastic -

1) Superglue a piece of scrap parts tree into the screw hole, enlarge slightly if required using a drill and allow to set & trim as required.

2) Drill a new hole in the centre of the now filled hole to take the screw and cut a new thread.

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My repair method for stripped threads in plastic -

1) Superglue a piece of scrap parts tree into the screw hole, enlarge slightly if required using a drill and allow to set & trim as required.

2) Drill a new hole in the centre of the now filled hole to take the screw and cut a new thread.

you can also powder up some scrap parts tree and make a paste using Plastic weld solvent . Fill the hole , allow it to set overnight and drill a hole to suit . Works well

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Great advice, I'll try your suggestions next time I've got to struggle with threads. Many thanks!

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you can also powder up some scrap parts tree and make a paste using Plastic weld solvent . Fill the hole , allow it to set overnight and drill a hole to suit . Works well

Smart! I think I need to start saving my sprues. They've gone from trash to resource :-)

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Smart! I think I need to start saving my sprues. They've gone from trash to resource :-)

the big advantage is that your using the same material so in theory the repair will be as strong as the original part

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This probably sounds crazy, but I've actually melted a small portion of a parts tree (with a heat gun) to fill the stripped out hole, let it cool, molded it to be flat and then drilled a new hole to set the screw in. Just don't melt it to the point it is burning

Sounds silly, but going on a year and still holding =)

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That doesn't sound silly at all. Plastic welding is a recognised repair technique, used on everything from car bumpers to domestic appliances. Makes sense to use it on model cars too!

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I have once used heat shrink tube to repair a stripped screw hole. Heat shrink the thread of the screw and superglue it in the stripped hole, after drying remove screw and you have a nice threaded hole.

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great advice guys, i will try these at the weekend, work has prevented me doing my hobby for a few days, but we all have to earn a crust don't we LOL

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