Nylon/ plastics glue

Harry Bloomfield a écrit :

There is a photo of the parts here -

It is a clutch master cylinder piston, a design failure. The two parts, tend to part company. The black plastic on the left of the nylon, contains a fluid seal and a ball joint on the end of the push rod.

Link not working for me. I would think about cyanoacrylate for a start, but it also depends on the other plastic.

The other strategy for problems like this is to look for something which makes a mechanical bond other than in the push fit region, e.g. either a mechanical clamp or a fillet of something like epoxy around the outside. You might be able to use Sugru for this, I have a pack but have only used it once (and I forget what for, for the moment).

I think I would just drill a hole through both pieces and use a pin - or does the design of the ball joint seat prevent that?

Heatshrink?

spirit based contact adhesive

Photobucket never works for me at all

It is very difficult to glue dis similar plastics as solvent based ones might only melt one of them. Also the pliability will be different if the joint is under any mechanical loading. This is where you need a 3D printer to make it all in one lump. Brian

There is insufficient 'meat' on the black part, where it enters the nylon section.

It is a piston sized to fit a bore, nothing can be added to the outer diameter and heatshrink would pull straight off anyway.

Brian Gaff a écrit :

Normally the joint would be under compression with fluid in the system and connected to the clutch release system. With no pressure coming from the clutch, there can be some tension involved in pulling the nylon piston and seal back (to the left).

A further issue is fluid leakage through and between the nylon to black plastic part joint. There is almost zero pressure of fluid across the joint, but if the joint parts company all of the fluid is lost.

So I am looking for a specialised nylon/ plastic adhesive or epoxy glue to solve the issue.

One of the benefits of making model aeroplanes, is you get to play with just about every glue it is possible to buy.

I can tell you right away that NOTHING really sticks to nylon well, and only two options exist here to the best of my knowledge

One I have already stated is petroleum spirit based contact adhesive like the original Evostik. This can be peeled off nylon, but its pretty strong in shear

The other possibility is a Loctite style thread-locker.

You might try superglue, but I have my doubts.

I was going to suggest flaming the surfaces to enable gluing, but not for cylinder components.

NT

Ah, oops ...

Actually little research reveals that you can rough up NYLON with acetone, I was thinking of polythene