How to repair aluminum radiators

[4.3LXJ]

I think this is a subject that is now timely. Some of us on this forum have departed from brass radiators and bought aluminum aftermarket radiators. They generally cool better and can be cheaper. However, they have one drawback. If you get a leak, radiator shops will not touch them. So, you put up with the leak or you get another one. Personally, I don't like the throw away mentality, unless it is my D35 rear end :D So my son ran across some aluminum solder at a trade show and bought some. He had the idea that since he has an aluminum Mighty Mite he could fill in some holes. I however, not only have a Mighty Mite full of extra holes, but a leak in my aluminum radiator. So I did some practicing today with this stuff. I have a MIG that will weld aluminum, and I have gas welded aluminum with a flux cored aluminum rod. But even though I have welded stuff like air conditioning cores, which are a little thicker than pop cans, I can't use that stuff without deforming the aluminum a little. So I decided to try this solder.

It doesn't look like anything fancy.

http://i649.photobucket.com/albums/uu215/warriorsuspension/Build%20Stuff/IMG_1534.jpg

It is available at M&T Enterprises
Medford,OR

541-499-2644
[email protected]

Cost is $35 per pound

I first chose a piece of scrap that had a 1/8" slot cut out of it. Thought I would test the limits first, I don't know why.

http://i649.photobucket.com/albums/uu215/warriorsuspension/Build%20Stuff/IMG_1529.jpg

The instructions, who reads those anyway, says to clean the aluminum. So I buffed it with a rotary scotch brite pad on my die grinder.

http://i649.photobucket.com/albums/uu215/warriorsuspension/Build%20Stuff/IMG_1530.jpg

Filling a slot can be done, but I need a little more practice to do it well. I lost it once on the floor from too much heat. Also had too much heat in the whole thing because I am used to getting stuff to flow. Apparently, you drag your puddle with the end of the rod while applying a slight pressure to the surface. You have to have enough heat to make it stick, but not enough to deform the aluminum. I used a propane torch for this job

http://i649.photobucket.com/albums/uu215/warriorsuspension/Build%20Stuff/IMG_1533.jpg

So I got another piece of scrap and laid it on top, with a slight gap. I used the dragging the puddle trick. It works. In this application, which would be like patching a large hole, the little piece takes less heat. So I drug a thin puddle down the edge of the little piece, then directed the flame more on the large piece and drug another puddle and joined the two as I did. The soldier on top was done last. The only improvement I would make on this is to clean the surface of the rod of oxidation with a stainless steel brush. There seems to be some slag that doesn't melt. I am assuming that is the oxidation on the rod.

In a couple of days, I will pull the radiator and repair it.

[Hum Wee JR]

I see dad (4.3lxj) has been playing with the aluminum soldering rod I got. This stuff is pretty cool. The vendor I got it from was patching holes in everything from beer cans to aluminum intake manifolds. If anyone decides to try this stuff out here's a couple of tricks to help you out. Use a propane torch, map gas and oxy acetalyne burn way to hot. When patching a hole in something start your solder next to the hole then drag across, it will patch better. As for cost I paid $20 for the bigger bundle. When I asked for permission to do a write up on this forum he gave me the second bundle for free. Woo hoo!!

[cantab27]

update steve...ya fix the leak

[4.3LXJ]

update steve...ya fix the leak

In a word, no. But not the fault of the solder. I thought I had a localized leak. I took it to a radiator shop to have it cleaned up and pressure tested. It was leaking at both headers, where the tubes enter the tank. So I thought WTF is going on here. When I got it back I could see what happened. When Griffin made it they didn't solder the tubes to the header. They epoxied them. It was clear when I got it and I didn't know the difference. Now it is yellow and peeling on one side. Got it off that side and will get some good epoxy and go for it. I haven't cleaned up the other side. It seems to be sticking better.

[bluedragon436]

That is pretty cool... We were just talking about repairing/welding aluminum for such things as radiators or even intercooler cores for cars...

[BlueXJ]

I can't believe that "Griffin" the worlds best aluminum radiator company would send stuff out that is glued together instead of welded. SHAME on them.

[4.3LXJ]

I can't believe that "Griffin" the worlds best aluminum radiator company would send stuff out that is glued together instead of welded. SHAME on them.

I here ya there. After searching custom aluminum radiator companies, many of them make a point now to emphasize that they do not epoxy their radiators, but braze them fully or weld. Bad assumption on my part. I was buying a name.

[DETOURS]

When accessable, I've TIG welded a number of rad's....

'Glue'......has become very normal for aluminum these days, many of Land Rovers body panels are actually 'glued' on the body.

[4.3LXJ]

I am finding out that "glue" used to be the standard in radiators. Now many companies are moving away from that and brazing. This current radiator is my second, the first warrantied out.