Will epoxy bond to plastic?

[rhr1956]

Specifically I'm needing to patch a 1" hole in a non-structural piece of plastic. It does need to be water tight. It's an injection molded type of plastic. Probably not straight ABS but something similar. I was thinking of using a little glass cloth and resin. Any thoughts?

[MacG]

Plastic is a generic name. You should identify the chemical composition first.
There is another type of glue that bonds as well, or even better, to metals and ceramics.
Epoxy is best used where there is room between the joints. Resorcinol-phenolformaldehyde is better where the joints are just minimal.
Epoxy does not bond to Nylon and related products. There are definitely more, like vinyl and partly pvc. Depends really on composition.

[sailorchic34]

Depends on the plastic. PVC and ABS bonds well with Fiberglass. PE which lots of tanks are made of not so well. PE or polyethylene is a wonderful plastic, but it has to be Heat fusion bonded to seal different pieces together. Standard adhesives and resins don't stick to it very well

[MacG]

Originally Posted by sailorchic34

Depends on the plastic. PVC and ABS bonds well with Fiberglass. PE which lots of tanks are made of not so well. PE or polyethylene is a wonderful plastic, but it has to be Heat fusion bonded to seal different pieces together. Standard adhesives and resins don't stick to it very well

Probably you mean to. Otherwise you should indicate the matrix material.

[minaret]

Originally Posted by sailorchic34

Depends on the plastic. PVC and ABS bonds well with Fiberglass. PE which lots of tanks are made of not so well. PE or polyethylene is a wonderful plastic, but it has to be Heat fusion bonded to seal different pieces together. Standard adhesives and resins don't stick to it very well

There are some new resins for PE tanks as well. A neighbor down the dock just repaired a large PE tank with it and it has gone well so far. I'll have to ask to get the product name, I think it was a WEST product...

[rhr1956]

It's not PE. I'm pretty sure its injection molded ABS or something similar. It's not acrylic, polycarbonate or vinyl.

[sailorchic34]

PE is used for injected molded tanks. I've a Todd Holding tank that is PE.

[tamicatana]

See whether West Systems' G-Flex will do what you want

[foggysail]

I have epoxied numerous plastics using stuff sold by Home Depot ( about $10 in the paint dept) that claims to work on plastics. So far, the stuff I glued all seems to be be holding.

[JesperWe]

Epoxy will bond a little to ABS, but if it's molded chances are it's not ABS but PA/Nylon, PE, PP or POM, which Epoxy will bond very badly with. Close to not at all, actually. You could get a little mechanical bonding if you roughen the surface before gluing.

There are primers in existence that will give you better bonding to PE, PP or PA (nothing really helps with POM). These will not be available at your local marine store though. You will need to find a specialized professional glue outfit. Devcon Flexane FL-20 or Sika 206 G+P are not so bad in my experience. 3M Primer 94 is not as good, but better than nothing. (If you get them, be careful when working with isocyanate based stuff...)

[sailvayu]

I am guessing you will not have good results but i would recommend doing a test patch and see how hard it is to peel off once fully cured. 3M does make an adhesive for most plastics. Good luck

[bobconnie]

Theres always 5200 it sticks to most anything !if ya rough it up a little !! and it's not a fuel tank it might work !! But ya cant paint it !! just a thought

[SkiprJohn]

You can also weld most plastics. Just another option to think about. Some plastic kayak dealers can put you on to what is needed and plastic patches.
kind regards,

[David M]

You can get a physical bond which might be good enough but you will not get a chemical bond. A chemical bond is always better. Roughing up the surface will get you a better physical bond but there is no guarantee that it will be good enough for the applicaton.

Welding or melting would be a type of chemical bond where you have bonds at the molecular level.

[MacG]

PE can be welded as SkiprJohn suggests. ABS you may glue with ether or chloroform or any acrylcyanide type of glue.