CA As Threadlock into Plastic?

[Pariah Zero]

I come from an R/C Helicopter background, and I started back when there were a lot of plastic fantastic machines - the plastic was a lot like the stuff used in the TRX-4 I just bought.

It was pretty common back then was to use CA to threadlock bolts into plastic, since the last thing you wanted was a bolt backing out mid-flight. (A wise man said a helicopter is a few thousand parts trying desperately to get away from each other.)

There's even Loctite 425, which is a low strength threadloc for metal bolts into plastic, and (no surprise) it's a cyanoacrylate.

Is using CA to threadlock into plastic a common thing in RC crawlers (or surface vehicles in general?)

 

[Gula]

No, not at all. I actually use grease to make the bolt go in the hole easier. These bolts do not vibrate out the bolts if screwed into plastic. Now metal to metal, is threadlock

 

[indybama]

No need for ca on the screws, like gula said, they wont back out. Youre not causing enuf vibration with the motor spinning or bouncing around to cause that. Now i have used CA if ive stripped the threads in the plastic enuf that the screw goes in, but doesnt tighten down. Just enuf to keep it from movin, but thats only if the hole is stripped.

 

[OSRC]

There's a lot more vibration in a helicopter. Not a problem with land based vehicles, even nitro. Especially if they are machine screws, they aren't going anywhere.

I've had a few coarse thread Traxxas and Tamiya hingepins start working their way out of the suspension arms, but that's about it. In that case, a bit of CA can help.

 

[Sweetride95]

first time installing screws shouldn't need glued. The screw more or less squeezes it's way in. The plastic will more or less press fit itself to the screw. If you pre-tapped them or had a screw in and out 10x, then maybe.

 

[Pariah Zero]

There's a lot more vibration in a helicopter.

That's a fact! And that's after spending a gratuitous amount of time and effort scrutinizing, measuring, aligning, balancing, shimming, and dial-indicating, everything until it's perfect. It's a beautiful thing when it'll just hover with only the sound of the resonance hum between the main and tail rotor blades.

One touch of the sticks and it's vibration city again. :twisted: RC Heli pilots aren't known for flying gently either.

If you pre-tapped them or had a screw in and out 10x, then maybe.

I always pre-tap plastic if the bolt isn't self-tapping. I'll take the threads a tap cuts over the garbage that gets crushed in by a bolt. I seem to remember a demonstration that it's stronger too (though I don't recall how much stronger). It's also nice to just finger spin the bolt most of the way in, just like with metal-on-metal.

Either way, it answers my question.

I'll keep an eye on whether they back our or not... I can always go back and lock down bolts again.

 

[indybama]

No need to pre-tap the plastic holes on a crawler. The screws will cut their own threads if need be. If u can thread them in easily by finger, they wont hold tight much of nothin

 

[CODYBOY]

I use E6000 when putting metal into plastic. (Yes, I'm still on here once in a while).;-)
Ernie

 

[MAGNUMB]

This might be a good option if you let it cure prior to install

https://www.vibra-tite.com/products...MIotbVseHK_QIVBsmUCR2exgK9EAAYASAAEgI6fPD_BwE

hake well before each use. Apply VC-3 a length of 1 to 1 ½ times the fastener diameter, filling threads 30-50%. Although material will be dry to touch within minutes, allow VC-3 to dry for at least 30 minutes (the longer the better), depending on part size. Fasteners are then ready for assembly or to be stored for later use.

From tiny eyeglass screws to huge construction bolts, Vibra-Tite VC-3 is ideal for use on fasteners of any size.
Mounting ski / snowboard bindings, plates and inserts.
RC models (Drones, Airplanes, Helicopters).
Bolts on motorcycles.
In addition to supplying user-applied bottles and cans of Vibra-Tite VC-3 for on-the-job application, ND Industries can apply Vibra-Tite VC-3 at any of our regional service centers.

 

[Col_Sanders]

Thats not really a problem on crawlers unless you're a meathead like me and strip the hole out.

 

[ussprinceton2004]

placed CA on parts AX80005 and AXA1632

 

[godwnlo]

Blue works well to help restore stripped threads in plastic. Ill put a drop or 2 in the hole and put the screw in and let dry

 

[surfishjoe]

While wheeling my vs410 the panhard screw ripped out of the plastic housing after getting a little too sendy climbing a rock ledge, and it had the threads still attached to the screw :x. I put it back in and sure enough it popped out again. I am going to try a longer mounting screw and one of the suggested methods above. I have CA glue or I can use shoe go. Also, the above poster referenced blue lock tight is that acceptable? What would you guys use besides a new axle housing?

 

[surfishjoe]

I ended up sending in a 16mm with some ca glue. If it pulls out again I’ll have to get a new housing.

 

[HumboldtEF]

Also, the above poster referenced blue lock tight is that acceptable? What would you guys use besides a new axle housing?

loctite made for metal is not intended to be used on plastic, it will melt the plastic. It sounds like godwnlo is using it to melt bad threads, lets it dry then runs the screw back in. I have no experience doing that but it might work.

Do you have space to use a longer screw and add a locknut on the back side?

 

[MAGNUMB]

https://www.vibra-tite.com/threadlo...MIy-yBwbnI_gIVYhCzAB1FAwIpEAAYASAAEgJkJ_D_BwE