Stripped threads in plastic parts .....
 

I would be interested to hear your fixes for dealing with stripped threads in plastic parts (when the metal screw is overtightened in the plastic part or just through general wear) other than replacing the plastic part.

Not had to do this myself on plastic as yet but used helicoil/recoil kits many times with metal parts.

http://www.recoilshop.net/metric-m3-0-5-kit.html

depends how critical the part is (i.e. how much stress is it under?)

There are a few fixes I have used: -

a thin rubber band fed into the hole and then the screw retightened - the rubber allows the screw to bite and gives friction.
Likewise, sometimes a match or sliver of a match can do the same.
I've tried a small cable tie fed into the hole, but often the nylon doesn't "lock" as well when screwed against.

or superglue...

I have used araldite or a similar epoxy in the past. If you set the screw in araldite, let it go off then back the screw out it leaves a new thread. What was left of the old thread is usually a good enough key for araldite to key to.

Nothing if it's a non stress part.

Replace plastic part. Take care next time.
Use hand tools, and don't overtighten.

Tried a longer screw? depends on part of course.

:thumbsup:

I was thinking back to my early days of RC (early 80s). I remember my old frog and hornet where most screws went into the plastic chassis and if I damaged something then my £1.25 a week paper-round often prevented my replacing it. Fixing things with matches, araldite, longer screws etc all came into play.
One of my proudest moments came when I broke the tub chassis on my Hotshot and discovered that the overall dimensions matched the 90mm square section drainpipes we were having replaced at the time. 1 * junior hacksaw later and I had a new chassis (that was easier to work on than the old Tamiya one).
Nowadays I can replace the part, but couldn't always...

I carry a M3 helicoil kit in my hauler for just in case, it works a treat and makes for a stronger thread than the original but putting them in in the first place can be a little awkward.

One thing I did, when I was tight on funds, and depending on application, was to plug the hole with new plastic. Get the old part spru, shave of thin slices of the plastic, cut them up so they were very small, put some inside the hole, heated up a piece of 3mm steel rod (which I think was an old 2.5mm Allen driver tip that had the tip ground off), and inserted the rod to fuse the plastic shavings and plastic part together and repeat untill the hole is plugged. Once plugged, drill with a 2.5mm bit and re thread with a new screw. I know it's not great but it worked for me, hope that helps.

Great tips guys, thank you. Haven't seen the Helicoil kits before will give that a try.

Keep 'em coming.

Take the middle layer of a paper towel ( AKA shock paper)
Rip off a small piece and stuff it in the hole using a 2mm allen key so it forms a layer of paper around the hole.
A small dab of Superglue followed by a very lightly oiled screw.
Keep the screw turning.

Actually if done proper you get very strong threads.

Cruise

used to put a bit of paper in the hole, and if it was a machine screw i would wind the screw in then back out, and wick the paper with thin cyano afterwards, always worked well, self tappers, just push the paper in place around the hole with an allen key then cyano it. now use a soldering iron with a 2mm piano wire tip and feed in 1.75mm 3d printer filament... also if you are re doing holes like this, keep a tap or a screw with a notch filed in one side handy, makes new threads much easier to cut and stronger

What is Cyano?

SuPer glue
A shortened term for its chemical name Cyanoacrylate

Ptex
 

You can try a bit of P Tex , it's used for filling scrapes in the bottom of skis and snowboards... You light the end of the stick and it slowly melts , as it does drip a bit in the screw hole and then quickly put the screw in , after a couple minutes when it's cooled just undo the screw and you should be fine. Just do it outside as it gives off a bit of smoke!

Presume that is like the hot melt glue sticks?

Sticks
 

A bit like it but it's black and plastic , and you actually light the end of the stick and as it burns the plastic melts and drips , on a snow board you drip the plastic into the grooves of the base and then rub it down flat , I found it works great on stripped threads.