anyone here ever solder a radiator? I found an aftermarket modine rad with the correct diemensions for my gremlin, it fits an eagle...everythings the same and the pics looked the same also but were diff numbers. well I got it short so im happy but the mounts are on the wrong side...mine mounts to the rear and the new onemounts to the front...so I need to swap the straps. ive sweat pipe but do you need a special solder? which flux? im not a plumber so this is kinda foreign to me...any helps appreciated

I was gonna say scuff it/clean w acid flux/solder w acid or solid core solder but this Modine unit is alum right? Not sure what to do w that

no its copper

In that case the above will work

The radiator shop may use a solder with a different tin/lead ratio than plumbing but either will work. A tin of (plumbing) flux is fine. Pick up a couple of acid brushes too.

Go to an Art Supply store and get some solder that is used in Stained Glass work. It is mostly lead with very little silver.
Use the paint-on type of flux and heat it first, then do the soldering joint.
Finally, wash everything down with a solution of baking soda and water to neutralize the acid from the flux. Or it will slowly eat a hole in the brass.

It's not hard. Just be patient.

CC.