aggravation

I've considered buying some kind of plastic welding gear just to try it out, seems I'm always imagining some little thing I wish someone would have made from ABS or some form of plastic (I'm not really up to speed on the different types) and now I find my radiator end tank with the smallest of small pin holes at the top of the driver side just outboard of one of the tabs that bend down to hold the tank in place.
You can't see it unless you pressurize the radiator with about 20psi of air and then spray water on the area and then the smallest little bubbles start to show them selves.

I wonder, could this be repaired by way of plastic welding? Anyone know about it?

I know I can buy the end tank and O ring but there isn't anyone around here who says they can make the repair and I don't think I'd be able to bend all those tabs down evenly without creating some kind of jig to hold the whole apparatus to apply the pressure which would cost more than the replacement radiator....

Angel84-928

I was looking at plastic welding some time back and a buddy of mine bought this unit from Harbor Freight. He bought it because it looked neat and offered me to try it out.


I works by heating air and using plastic stick that look like welding rods. Honestly, I couldn't get it to melt the rods properly. Way too much work to figure it out. So I wouldn't recommend it. Maybe someone else had better luck with it.

How about using some epoxy, covering up the opening and placing a light vacuum to the radiator. This would draw the epoxy into the hole and sealing it. It would avoid the epoxy from just adhering superficially and being launched after the unit is pressurized.

Just a quick theory. Don't know if it would even work.

JEC_31

The thing about welding plastic is that heating (most types) past their melting point and then letting them cool and re-soldify in a new shape is that along the way they lose a certain amount of their original desireable properties.. such as tensile stength.

Take a plastic spoon, see how far it bends.

Heat it, sculpt it, let it cool. Now bend it - snap! It's much more brittle.

I work in a company that does a ton of injection molding, they grind and re-use scrap parts but they have to blend the recycled "regrind" with new virgin plastic to maintain the minimum properties they need. You can't do that with welding chunks of plastic, once it's gone it's gone.

Personally, I would NOT trust a repaired-but-still-AGED plastic component to hold the heat and pressure of a supercharged 928 cooling system.

I would recommend thinking of this damaged junk plastic radiator as an absolutely non-negotiable reason to get a new high-performance aluminum radiator.

Now there are a ton of things that a nifty plastic welder would be a godsend for. For example, I fabbed up a reinforcement for the broken under-wiper-tray on my ex-86 with a sheet of acrylic and some glue - but I really wanted to heat and bend the sheet into a whole new tray.

So if you get one, use it for non-load-bearing (and non-heat-and-pressure-bearing) projects.

- Josh

mark kibort

the only plastics that can be welded successfully (without the problems listed here) is the themal plastics. the best way to do a weld, is to find more of the same material, heat both the target and the extra material made of the same thermal plastic. they should start to melt and fuse together. Use a soldering iron, a large one, like a 100watt stick type to rub over the area with the extra material as they fuse together. It takes some technique, but thats the only way i know of welding these types of plastics. the hard plastics, that are not as soft and have more nylon or styrine, generally can be welded with a good epoxy like dubro plastic welder.

mk

928ntslow

I have the plastic welder from Harbor Freight...wanna buy it for half the price? Used once. I didn't have the patience. Anyone???

backnblack

Dave K had an issue with his radiator leaking and I made some clips, he bought a new end cap and rubber o ring and we clipped it back on.
check out the link.

https://rennlist.com/forums/928-forum/381548-radiator-side-tank-repair-o-with-no-tabs.html

Regards
Matt

Oh and IMO the welder isn't going to work

AND ANGEL84 RIGHT ON LOVE THAT AVITAR!!!!!!!!!!!!!! NOW I JUST HOPE YOUR NOT A CLINTON LOVER

Larry Velk

I searched for an end tank repair system as our XR4's have a chronic problem due to the fan shroud fretting the tank/gasket interface. Loc-Tite makes an epoxy made for the end tanks - I haven't tried it but it is listed as a specific fix for this problem. If I rem. Volkswagen sort of started this plastic tank deal so I would hope the German plastic is compatible with the loc-tite.

V2Rocket

hotglue that ****..lol

Angel84-928

I'm a conservative. I already have someone I give my hard earned money to that thinks they can spend it better that me. Its called a wife. The more you let government "help" you, the less freedom you have.

Honestly, I won't hit any of them in the *** with a wet dog.