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Discussion Starter · #1 ·
Giddayall,

I notice that a couple of screws which hold the front bumper on my Terra Crusher down don't tighten up.

I've used loctite but obviously the plastic has lost the thread and it soon works loose again.

Any secrets as to what can be done?
I had heard that you can use loctite and put a few bits of thick fishing line in the holes first and that would help the screws to "bite" a bit better.

But I'm thinking this might make the holes prone to cracking if too much "filling" is used.

Cheers,

Steve
 

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some options for you are


replace scew witha machine fhread screw


white plumber's tape


a drop of CA glue down the how. wait till she drys and then replace screw.





one of the 3 should fix it
 

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jiggen5354 said:
some options for you are


replace scew witha machine fhread screw


white plumber's tape


a drop of CA glue down the how. wait till she drys and then replace screw.





one of the 3 should fix it

I've got the same problem on my Savage, thanks for the great idea Jiggen5354!
 

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Do not use threadlock for screws into plastic. It is only good for metal-to-metal.


Use superglue to lock screws into plastic.
 

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Discussion Starter · #5 ·
Thanks guys,


If I use superglue, will I be able to remove screws easily when I need to?


Cheers,


Steve
 

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with super glue you put a drop down the screw hole and wait till it dries. then put the screw in. that way you give the screw something to bite into and you will still be able to remove the screw if you need to
 

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Superglue doesn't stick to shiny smooth metals very well, so even if you put the screw in when its wet the screw will still come out clean later.


Thicker superglues (not gel) is useful for building up stripped holes. Use a pin to make sure it flows down the whole length of the hole but no need to "fill up the well". Just coat the sides.
 

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If anyone is interested, use "DEVCON Plastic welder", its a 2 part special epoxy. Remove screw, mix "plastic Welder" and fill hole. LET CURE, drill small pilot then refit screw, it will be as strong as the parent material.

Enjoy.
 

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Or you can use a zip tie. Cut in length to suit then drop it in the existing hole, place back the screw and it be good as new:thumb: I use the smallest zip tie and works great for me:lock1:
 

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Stevo - I think the best solution would be to get out the Baja 5b !!!
 

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Another good idea is to use a thread repair kit or helicoil kit, not only will it fix the thread but it will also be a nice and strong stainless steel thread, its a bit pricey but its worth it very reliable
 

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Another good idea is to use a thread repair kit or helicoil kit, not only will it fix the thread but it will also be a nice and strong stainless steel thread, its a bit pricey but its worth it very reliable
"Helicoil" kits are not available down to M3 or M4 (UNC4/40 equiv.), they will only range down to M6 (from memory), also, have you ever tried to remove the tangs from the insert when screwed into plastic?.
"key inserts" only available to M10.

"Devcon" I believe, have a new "thermal welding" plastic range, it uses very low heat to melt the insert which bonds to the parent plastic, you then drill and re-tap the thread or re-fit the "pk" threaded screw.
 

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Actually, you can get repair kits that go down to M5 and M4 (from experience) maybe you shouldn't rely so much on that memory of yours.
And yeah I use the kits quite a bit and the tangs are not an issue for me, they also provide me with the option to fix metal threads on my truck when the need arises so for me thay are perfect, I also get the peace of mind knowing that where a plastic thread failed once it will not fail again being metal.
 

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HeliCoil Thread Repair Kits are available in metric series from range M2 to M56 in Coarse & Fine pitches and in UNC/UNF series starting from # 2-56 , 4-40 to 1-1/2 inch.
Taken from adelaide.gumtree.com.au/adelaide/11/13840911.html
Your right, memory fading...........Where are my glasses, need to lay down for a nap...:doh:
 

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so threadlocker is bad for plastic is it?? any idea what it does to it?
 

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It doesn't bond to plastic, it was made for metal to metal mainly. I mean it does do the job, but super glue is better TBH.
 

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so threadlocker is bad for plastic is it?? any idea what it does to it?

It doesn't do anything to the plastic but it doesn't have the same binding affect on general plastics as it does on the material it was designed for. Most modern plastics are based on either
polypropylene or polyethylene and one of the unique attributes of plastic is that it creeps or changes shape under stress and no amount of thread lock is going to counteract this particular characteristic.

Threadlock is designed for material that is resilient to this behaviour. Plastics will generally fall into one of fifty families and each family can have dozen of variations so if by chance thread lock works on your particular plastic then it is indeed by chance.
 

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Ah... that explains.. i guess i should use superglue.
""with super glue you put a drop down the screw hole and wait till it dries. then put the screw in. that way you give the screw something to bite into and you will still be able to remove the screw if you need to""

method sounds alright.
 

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loctite 480, is a black retarded setting cyanoacrilate (ca) style glue that takes 30 to 120 seconds to set, it bonds well to plastics and doesnt leave that ugly white stain the normal ca glue leaves behind, a small amount on the screw and set it in place, 2 minutes later your screw is set and removable should the need arise, available from most repco and bursons, coventry in the southern states, it is also great for gluing tyres as it allows for moving tyres into best position before it goes off and sets, and being black it blends well with the tyre, or Q Bond, is a fast setting CA glue that comes with black and grey graphite powder, just a drop and sprinkle with the powder and your hole is filled, pilot drill and reset screw, it will be stronger than original material and bonds well with plastics, also available from repco
 
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