Epoxy Won't Stick

Post questions and info about safe and unsafe materials that can be or should not be used to construct a launcher. Also post things about different universal accessories for your cannon (breech loader, muzzle break, etc.)

Postby cacophobia91 » Fri Jun 09, 2006 4:31 pm

I bought some small plastic pipe made for use in sinks for an airsoft barrel and since it is not pvc I had to glue it with epoxy. I tried to glue it so that the pipe would go through an end cap but the epoxy won't hold it together :(. I sanded the pipe and and tried it again bot it still couldnt stick. I looked at the label and the pipe wasnt made out of the type of plastic that epoxy doesnt stick to. I can't figure it out.
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Postby Drew Rowland » Fri Jun 09, 2006 4:36 pm

Clean the contact surfaces with solvent first.
Drew Rowland
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Postby GalFisk » Fri Jun 09, 2006 5:16 pm

Do you know what plastic it's made of? Polypropylene and especially HDPE (polyethylene) is almost impossible to glue, but I've heard good things about using polyurethane glue on these. And cleaning is important in any case.
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Postby cacophobia91 » Fri Jun 09, 2006 5:45 pm

It is called Pex. I just looked it up and found out that it is a type of Polypropylene. They usualy use mechanical fittings with it. Are their any ways of connecting the pipes with out glue?
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Postby Ian2accurate » Fri Jun 09, 2006 10:14 pm

I've had alot of problems with JB weld... Make sure you sand the surfaces and mix the epoxy well. You might be able to use some duct tape and just force it in. Then screw bolts in the side. It holds pretty well. It depends the type of your connection though.
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Postby TurboSuper » Fri Jun 09, 2006 10:43 pm

You may wanna consider some steel brake/fuel line tubing instead, it will save you alot of trouble.
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Postby fullmetaljacket » Sat Jun 10, 2006 10:54 am

don't just sand the contact surfaces - use a box cutter or a sharp pointed file to make deeper incisions/scratches, or use a drill bit to roughen up the surfaces better.
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Postby SpudMonster » Sat Jun 10, 2006 2:00 pm

If it isn't too much trouble, could you simply buy a PEX to NPT adapter??? If it is 1/4" I.D. PEX, then you could use a 1/4" barb or a 3/8" compression elbow for adapting the pipe to NPT.
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Postby markfh11q » Sat Jun 10, 2006 7:47 pm

That's what I was gonna say... just find a NPT x compression nut that fits and thread the (1/4") NPT side where you want to connect.
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Postby davidbowie » Sun Jun 11, 2006 8:17 pm

I use quite a bit of PEX. Either use a barb to connect to NPT threads, or bolt it into a modified PVC fitting.
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