When super glue just won't
 

Broken parts are always a nightmare. I have a BH commander optimus where one wheel, the clip-on type, fell off as one of the pegs broke. I try to super glue the peg back, but it breaks as soon as I try to put the wheel back on. Two attempts later, same result. The super glue just isn't strong enough to bear the bending stress when putting the wheel back.

My question: what can be done in that situation, or when super glue just won't work in general? Another example is when a part breaks around a pin joint. This becomes pretty much impossible to repair with super glue without causing additional problems.

Re: When super glue just won't
 

Usually at that point you just need to concede that the part that broke is no longer a moving part and just use some stronger glue.

Re: When super glue just won't
 

For any stress parts, Super glue isn't going to work much, at least not on it's own.

There's different ways to do a fix, but the more you try and doesn't work, the less your odds are going to be that the next fix will work if you degrade the parts.

1) use a good plastic cement, which actually melts a bit of the surface and re-bonds it.
2) acetone can be used at your own risk but does similar with most plastic as it will melt it, but again... it's risky.
3) adding a metal pin to reinforce the connection, either drill or melt a small pin/wire then add the glue that you decided to go with.
4) a good epoxy, ensuring that you manage to get the parts covered properly with extra to reinforce the stressed parts, using a pin does increase your chances to success.
5) if you go with a metal pin, and still want to go with super glue, mix it with corn starch or talcum powder to make it a paste, but you have to work very fast as it will set very fast.


Both the epoxy or the super glue "paste" can be great to fix broken parts with missing chips, basically as fillers that are going to be quite solid, as long as the bond with the plastic happens.

Note that you might want to "rough" the parts to help get the glue to bond better.

I've also had good success with a mix of super glue (Gorilla) that was quite thick, and mixed in some acetone, which I believe would be a two-tier reaction where the acetone would melt the plastic a bit and the super glue would then re-bond the parts.

These are my usual approaches and my rate of success has been fairly high, but success is usually due to the type of part, it's location and the size, and also the type of plastic.

Note: do not consider that all super glues are equal, there's a fairly huge difference from brand to brand. So get some quality stuff. I go with Gorilla now and been quite satisfied with the results.

Re: When super glue just won't
 

Better show us some pics before we can offer advices.

Personally I found glue didn't work well for small piece, sometime need to drill and screw it to secure.

Re: When super glue just won't
 

I use a automotive industrial grade2 part epoxy that melts/bonds plastic as well as putting a brass pin or screw in....your local napa or auto parts supplier should be able to help....

Re: When super glue just won't
 

You want Gorilla Glue, absolutely not Krazy Glue. Polyurethane adhesives are best for plastics. I use it for all my repairs and it's never failed me.

Krazy glue is very brittle on plastics and generally melts away the repair area. Gorilla glue "welds" the repair.

Re: When super glue just won't
 

Thanks for the replies! I somehow didn't expect super glues to be of different quality. Looks like I've been using the Krazy glue brand for a while now. I think I'll try the gorilla brand before attempting other suggestions from this thread. Regarding the specific peg I mentionned, it's about 2mm thick so I would be surprised if drilling actually worked.