Recommendation for repairing plastic?

[David B]

Got a saw with a hole in the bar oil tank. I'm thinking JB weld. Good, bad, other ideas? Epoxy better?

[Timburr]

As a quick fix, I used epoxy about 1½ year ago to repair a bar-oil tank. Still going strong. Just make sure the surface to bond is absolutely oil-free if you want to go with this method.

[David B]

Thanks. Wonder if plastic-specific epoxy is better than JB?

[Don_N6CRV]

Hello you might try some Auto body filler. It will stick to just about anything.  I have used JB weld and it also works good.
Don

[David B]

Thanks...tried the JB if it doesn't work I have some small chips off another part I may try to "weld" in, can't be too much harder than welding metal.  8)

[Frickman]

NAPA sells a two-part epoxy for welding plastic, it's called "Plastic Weld" or something like that. It comes in the side-by-side tubes with a plunger. I have used it with great success in patching plastic gas and oil tanks.

[rickk]

I'm not sure how oil-resistant it is, but "Gorilla Glue" (urethane based gook) sticks to just about anything I have ever needed to stick something to. I just fixed up a Husqvarna air filter cover with the stuff. Maybe try drying a blob of it and soaking it in oil to see if it deteriorates before you try it for real.

"Welding" plastic is not that simple, as there are lots of different types of "plastic". Some melt with heat and can be fused together (if you don't manage to destroy the object). Some will burn before they melt.

I would think that most chainsaw plastic would be both solvent and heat resistant (thermoset), so be careful about trying too hard to fuse it together by melting it.

[Coon]

DO NOT USE autobody filler as it will absorb oil or gas, which ever tank you are fixing.  The body filler will definately stick but you'll be sorry that you used it.  You can purchase a variety of different two part epoxies at your local autobody shop or maybe even your local hardware store.  Two part epoxy comes in a few differeent strength's ranging from 5 minute epoxy, 10 minute epoxy and, 20 minute epoxy.  Use a coarse sandpaper and roughen up the surface to be fixed.  Depending on which epoxy you use you will only have a set time to apply because it hardens quickly.  Once the epoxy is applied you must sand your finish when you can touch the epoxy with your finger and it doesn't stick.  At this point you must finish your sanding immediately before it hardens too much.  It can then be primed and painted.

3 years of autobody repairing experience sure does pay off  8) 8)

[Don_N6CRV]

Hello Coon, you now have me wondering about the Auto body filler. I used it to fix a gas tank on a lawn tractor and it seems to be working fine. What should I watch for? I did paint the tank after it sat up and the paint is still sticking. Don't have any leaks but if it is going let loose all at once I sure don't want a tank of gas on the floor. Thanks
Don

[David B]

The JB seems to be holding. I blew in the tank as hard as i could and it held. Ran/tuned the saw, ok. Just need to take it out and cut.

[Coon]

Hello Coon, you now have me wondering about the Auto body filler. I used it to fix a gas tank on a lawn tractor and it seems to be working fine. What should I watch for? I did paint the tank after it sat up and the paint is still sticking. Don't have any leaks but if it is going let loose all at once I sure don't want a tank of gas on the floor. Thanks
Don

That is exactly what will happen... all of the autobody filler will let loose all at once.  A chemical reaction actually occurs changing the composition of the filler.  It will absorb as much gas as it can hold and then in time as the gas and filler are exposed to air it actually will change the filler to a kinda gummy putty which will fall off.  It will though help by having the repaired area painted but once the paint is chipped or scratched it will expose the filler to the air and thus the chemical reaction.

JB WELD will also work for a short period of time.  I have used it on a variety of surfaces  and some will work and some won't.  It all depends on What comes in contact with the JB.  JB   DOES NOT work well with brake fluid, gear oil, gasoline, deisel, Alcohols, thinners, and things that have a higher acidity lever.

Brad.

[David B]

  JB   DOES NOT work well with brake fluid, gear oil, gasoline, deisel, Alcohols, thinners, and things that have a higher acidity lever.

Brad.

So you think it'll hold my bar oil?

[Modat22]

NAPA sells a two-part epoxy for welding plastic, it's called "Plastic Weld" or something like that. It comes in the side-by-side tubes with a plunger. I have used it with great success in patching plastic gas and oil tanks.

This stuff works with oil very well. If fuses with the plastic itself and make a very good patch.

I used it to fix a gas filler neck on a honda recon that got broke off a couple years ago.

[Frickman]

I can't recall off-hand what the name of the NAPA plastic weld is, so I always look for the package. It comes in a cardboard blister pack, and the cardboard is printed pink and black.

[Modat22]

this is the stuff I was talking about, I try to keep some in the shop.



its called plastic weld made by permatex

[David B]

Excellente..we carry permatex at work, maybe I'll have Mike keep some around.  8)

[Coon]

So you think it'll hold my bar oil?

Yes it'll definately hold on your chain oil tank.  Make sure that you clean the area to be repaired so that it is free from oils.  Use some kind of alcohol to clean the surface as it will remove all traces of oils on the surface.  Next use a coarse sandpaper and roughen up the surface to be repaired.  Blow all of the dust away and use the alcohol again.  This will ensure the surface is clean and free of all oils even the ones that you leave when you touch something with your skin.  Apply your JB or Epoxy and sand if needed when it will no longer stick to your finger.  With the epoxy do not wait too long for it tends to harden quickly and gets hard to sand.  Once finished sanding you can now prime and paint.