Soldering heater matrix

You're not really going to solder that. You need to braze it. Soldering only works when a core has a hole in it where you can crimp it at the split.

The job has to be VERY clean, sand blasted, use an acid flux, heavy soldering iron, 50/50 solder.

should work.

.> You're not really going to solder that. You need to braze it. Soldering only

--------------------------------- Not true. It is possible to repair but to do it properly the pipe will have to be unsweated from the unit ,the area cleaned and tinned ,stub pipe cleaned and tinned.Run solder around the hole and when cooled apply more flux,heat pipe enough to melt solder and plunge into hole .Hold for a while to allow solder to solidify.If req.d smooth out with a decent soldering iron.

Good advice. Grit blasting the area would be the ideal, but you could find that repeated applications of 'Bakers Fluid' heated with the soldering iron, and then steel brushed, will clean the area enough to allow solder to 'take'. Use plenty of Bakers Fluid.

Preferably use plain solder. Not the flux cored type. Cored solder can be used, but it tends to burn and get a bit messy if used with Bakers Fluid. Mike.

Once remember repairing a Singer Gazelle radiator by cutting out the leaking cores & sealing them up, it took a couple of hours. Put it all back together & started it up, unfortunately left a spanner on top of the radiator, which promptly fell into the fan & back through the radiator. Wasn't best pleased LOL

Alan...

If the leak is from a join of a pipe into a header tank then sorting should be straight forward, leaks from the header tank to core matrix can be more difficult to fix. What tools are you using at the moment, ie solder type, flux, torch etc. For this type of repair I prefer oxy acetylene or similar as you get great control of the molten solder but you have to know what you're doing as without care you can easily over heat the joint.

An active plumbing flux - like Everflux - is far more effective than Baker's IMHO. I've tried as an experiment soldering green pipe that was lying around in the cellar for years without any cleaning and it works just fine. Not sure if it would cope with grease, etc, though. But you must wash off any excess with water afterwards. Doubt it would do the cooling system any good. ;-)

Oxy acetylene is usually outside the scope of an amateur. But there are plenty of low cost butane blowlamps that will do just as well.

Open flames are what the professionals use.

Usually if you were to use an open flame whilst doing the repair and that hits the core it will disintegrate thus a large iron is preferred.

Indeed.

I've got a nice little jeweller's butane blowlamp with a very fine flame but plenty of heat for this. Of course like all these things it needs skill to use.