What type of metal is suitable?

[malG]

I'm trying to fix a car with a broken inlet neck on a plastic radiator tank. The car is very old so I don't want to spend much, please don't bother telling me otherwise.

I found a high heat resistant epoxy putty that's good for radiators: http://www.hemmingsdiy.co.uk/quickste.htm

Now I need a metal stem to insert in to the broken inlet neck. I found someone who sells locally: http://www.performancemetalsaustralia.com.au/

From the above site there are many choices. Which steel tube is suitable for a high temp plastic radiator and rubber hose? Please tell me your reasoning.

 

[PottedMeat]

Any reason you can't use a tube of the same plastic as the inlet neck?

Why does it have to be metal? Would heating/cooling cycles cause the metal to contract/expand and possibly crack the epoxy?

Is the tank under pressure?

 

[malG]

Why does it have to be metal? Would heating/cooling cycles cause the metal to contract/expand and possibly crack the epoxy?

Is the tank under pressure?

I don't mind using plastic but I can't seem to find anyone selling a short 1 3/8" (35mm) plastic tube locally in Australia.

The tank is under pressure but not extreme high pressure. Not sure what you mean by heating/cooling cycles as the top of the radiator is always hot and we have mild winters here.

 

[herm0016]

the top is hot when you are driving, not when you are not running the car.

 

[Modelworks]

Make sure you roughen the surface on the radiator when applying the epoxy to make sure it gets a good bond.
Any metal will work that has a thick enough wall to withstand whatever pressure you are dealing with. Pressure is around 16-20psi so just about anything with a 1/8" wall or thicker will work.

 

[malG]

Make sure you roughen the surface on the radiator when applying the epoxy to make sure it gets a good bond.

Good advice, thanks.

 

[Colt45]

It's only going to last 3 days, so it doesn't matter much what metal you use. You don't need much more than tinfoil to hold up to 15 psi. But the bond will fail, guaranteed. Get a new rad, don't waste your time.

 

[malG]

It's only going to last 3 days

Dead wrong, the broken inlet neck has already lasted 4 months without a leak.

We just need a little extra insurance.

 

[uclabachelor]

Dead wrong, the broken inlet neck has already lasted 4 months without a leak.

We just need a little extra insurance.

Oh the irony in that statement.

I'd just pay $200 for a new radiator instead of having to worry about when the crack will leak and cause a head gasket to blow.

But that's my route. If you want to "epoxy" it, find an epoxy that can withstand 250F temperatures and chemical/oil corrosion.