Epoxy for pop off valve

SpeedracerIndy · 07-28-2003, 10:24 AM

Can anyone suggest an epoxy, cement, or sealant that works well for installing the pop off valve? I have tried two things from AutoZone that say are high temp and high pressure resistant, but both would not seal to the plastic air box. I need something that is going to seal up the less than perfect hole in the box also. Thank you.

1fastredsc · 03:07 PM

Gotta make sure that it can bond to plastic, and also put small scars or ridges in the plastic that comes in contact with the epoxy this way it has something to bite on to.

john walker's workshop · 07-28-2003, 10:42 AM

gravity takes it's toll if you have a big gap unfortunately.
i use a Hardman product which comes in a little double pouch. lable says: machineable, fast set epoxy tooling and body patch. hardman, a division of harcros chemicals, belleville nj, 07109, 210-751-3000. adheres to metal, wood, and hard plastic tooling can be machined, sanded, drilled and tapped. reorder # 04002. try a marine supply store. then there's marine-tex.

ruf-porsche · ruf-porsche's Garage

Let the epoxy set before starting the engine or else the engine vacuum is just gonna suck that epoxy down into the engine.

UTKarmann_Ghia · 07-28-2003, 11:25 AM

I used the plastic epoxy from Autozone about 3 months ago and it's holding famously. It has a high pressure seal and is made just for plastics. Is this the one you tried? I also scored my plastic so that it would adhere well (basic adhering principals). Good luck!

Randy Webb · 07-28-2003, 11:38 AM

Try an adhesive silicone seal product (RTV). It will flex when the airbox does, and epoxy won't.

SpeedracerIndy · 07-28-2003, 11:40 AM

The first one i tried from autozone was just a high temp silicone. I suspected it wouldn't work from the start but had it laying around so I just tried it. Started the car and pop, it was gone. So then I got some brown gunk that said it was high temp, and high pressure resistant. I suspect that it is not supposed to stick to plastic even though it does not specifically say what materials it works on. I almost bought that Hardman product but it didn't say that it was high temp resistant. Does this area not get that hot? I think I'll pick some up on my way home from work. Thanks for the replies.

RoninLB · 07-28-2003, 12:22 PM

Hey Casey.. silicone and RTV isn't the greatest idea for plastic.. the Hardman product sounds good.. and the Marine Tex is definately heavy duty. it's also great for skimming the inside case of sludge and centrifical water pumps.. and Marine Tex has a flexable sister product called Calk Tex .. I think if you tried to remove Calk Tex with a hammer and chisel the hammer would bounce back off the chisel and crack your skull.. it's also supposed to be good for emergency golf balls......

Randy Webb · 07-28-2003, 12:36 PM

Ron -- Why do you say the silicone products aren't good for plastic?
They've worked fine for me, and the manf.s tech sheets are online.

Maybe you didn't get the surface completely prepped?

RoninLB · 07-28-2003, 12:53 PM

Quote:

Originally posted by Randy Webb
Ron -- Why do you say the silicone products aren't good for plastic?
They've worked fine for me, and the manf.s tech sheets are online.

Maybe you didn't get the surface completely prepped?

I'm definately biased.. silicone is not vapor proof.. like some guys put silicone over coil terminals to prevent water intrusion/ NG.. I've seen many aplications of silicone where another product would be better suited.. maybe in a desert climate you can get away with it.. but the NW is Wet and Wild.. look at the silicone edges after a while.. you can see it delaminating.. I bet if you get a marine supply catalog you'll find plenty of interesting sealing products.. if you see that a product is effective for below water line thru hull fittings.. you definately have a good sealing product. many of them are Not 2 part epoxys.. they will be sized to a caulking gun. and many are available in small tubes for $5..
party hearty............Ron

Rot 911 · 07-28-2003, 02:14 PM

Before you do anything make sure you get all the silicon off the plastic. I'm not just talking about what you can see either. Silicon will leave a film behind that makes it very hard for anything to stick to the plastic. First wipe down the plastice with some paint thinner then rough it up with some sand paper. Then try the epoxy.

SpeedracerIndy · 07-28-2003, 02:44 PM

Thanks for all of the advice. I have cleaned the air box and the pop off valve with pvc primer. That is about the most caustic solvent I have that will not dissolve the plastic. Being a chemist, I have access to plenty of fun stuff too. I am going to try the two part plastic epoxy mentioned above. The only reason I did not start with that was the heat issue. It sounds like others have used it with success, so I'll give it a shot.

Doug Zielke · 07-28-2003, 03:10 PM

1.) Rough up the surfaces of both the airbox *and* the pop-off valve with coarse sandpaper.

2.) Clean, and clean again with brake cleaner.

3.) Use JB Weld epoxy per instructions.

4.) Allow to cure for at least 24 hours.

UTKarmann_Ghia · 07-28-2003, 03:10 PM

Good idea Casey and good luck!

1fastredsc · 07-28-2003, 03:11 PM

In that specific area heat resistence isn't all that big of a deal since cool air is being induced on both sides of the valve. And even if it got a little heat from the motor, it wouldn't be more the like 200 degrees so even then high temp isn't a big deal.

Jared at Pelican Parts · 07-28-2003, 03:21 PM

You do not want to use RTV to seal it. RTV reacts to gasoline and vapors, causing it to melt and gum up. I reliaze it is in the airbox, and the chances of the vapors getting to the RTV is small, howeer I wouldnt chance it. I've pulled apart carburetors where they used RTV to seal the float bowls, and the insides were all full of blue glop, choking the jets.