Brazing in aluminum radiator sensor bung
 

I have a water temp gauge lying around, and I’d like to put it to good use. I used to have the sensor tee’d into a heater core line, but since the turbo install, things had to be moved.

I’m looking to add a bung into my generic aluminum rad. How feasible would it be to drill and braze a sensor bung into the rad?
I’ve brazed steel before, and it was a PITA because of the heat required.

You wouldn't be able to braze it unless you had some sort of cavity to accept the filler metal. Unless you're talking about braze welding.

Any reason you can't just weld it?

PosCat for "lying", as opposed to the oft seen "laying".

No tig welder, only flux core.
Couldn’t I fit the fitting in, and then filet braze along the edge?

That's what I mean by braze welding. I'm sure it would work, but TIG would be a safer bet.

If you have a tight fit, it will work fine with a high silver content brazing rod. Alcor from Harris works great.

Tig weld it. Aluminum gets contaminated very easily especially if youre using oxyacetylene to braze with. It also soaks up a ton of heat, so you run a small risk of deforming or warping if youre not careful.
In the end its your desicion. But I personally would hunt down a tig welder to be safe.

Having used alumiweld brazing rods before - the problem is enough heat. Aluminum will sink the heat pretty well and you won't be able to get a massive part like a radiator up to temp. Hell, I was struggling with putting a hose barb on a water pump outlet - I had to bury the non-brazing part in sand to insulate and try to keep the heat in. Propane wasn't enough, MAPP wasn't enough, Oxy was - but you're teetering on the edge of brazing and melting. Now I have a TIG machine and won't bother with alumiweld ever again. Not saying it's impossible, but you've either got to be very good or very lucky.

Alumiweld (and like rods) are garbage. The Harris Alcor brazes at 800f (propane/butane torch). It's flux cored. This is the stuff HVAC techs use. I am by no means arguing this as superior to TIG, but IF you braze aluminum or unlike metals, Alcor is the stuff to use. I have brazed alu/alu, brass/alu, brass/steel, brass/brass and steel/alu with it. All this stuff has over 2k miles on it w/o issue. Ran the AC the entire drive back from FL last weekend (400+ miles) and also used the heater.

Alu AC fitting
https://cimg5.ibsrv.net/gimg/www.mia...4d019913f3.jpg

brass/steel
https://cimg5.ibsrv.net/gimg/www.mia...0d909c7a39.jpg

steel/steel
https://cimg7.ibsrv.net/gimg/www.mia...7022a10b6b.jpg
https://cimg8.ibsrv.net/gimg/www.mia...3c60657683.jpg



https://cimg9.ibsrv.net/gimg/www.mia...0f7d75d3c2.jpg

That looks like awesome stuff. I'll definitely look into using it. Thanks!