Technical Soldering heater core tubes??

I'm in the middle of resurrecting a stock heater for my 40 coupe and hit a snag.

The core has a minuscule leak in the middle of the core. Two radiator shops can't fix it.

I've found a Chrysler core at my local parts house that is close in dimension, but the two tubes only extend about two inches from the tanks. I need to add elbows and extensions.

What is the best way to sweat on the new plumbing that close to the tanks without heating the tanks enough to loosen their bond to the core? Don't want to go through that. Closest radiator shop is 40 miles, other is 75.

Some of you guys have posted pics where you did this. Got any tips?
(Fill with water to bottom of tubes?)
(Use preformed hose elbow and go through firewall?)

Thanks!

 

You might try setting the heater core on it's back and filling the
core with water up to the base of the tubes so they don't overheat.
Best of luck.

 

A water saturated shop towel draped on the tank should easily pull away excess heat. Although I really think careful use of a propane torch would not damage the other joints/seams. But better safe than sorry.

Ray

 

Thanks! That was one thing I had thought off. Great minds think alike.

 

Man , I have been into this before . It’s a real live BITCH ! Once it gets to hot you will be chasing the leak for about 3 weeks ! I pressure tested my last attempt , at 30 psi for 5 mins in a bucket of water , no leaks . Installed it in my truck , it’s leakin now , 2 months later .

 

What about using an old soldering iron? Heat it up and then heat up the tubes. On th either hand JB Weld would do the job.

 

You would be better off having a radiator shop extend the tubes. A good radiator man knows just how much heat he can get by with. They also have a paste with solder in it for tinning the tubes first.

 

Fortunateson is right. A large soldering iron will direct the heat where you want it. Unlike a propane flame which is more spread out.

 

For precise heat, use a smaller butane torch. They make them in all sizes. I use different things to solder with, just like I use different wrenches to fit different bolts. Soldering is an art, and it can be learned. If it isn’t working easily, you are doing something wrong. Soldering should be quick, if you have to linger with the heat or solder.....som ting Wong !






Bones

 

Put it in a bucket of water

 

No need to put it in water etc use a small flame and start away from the job at a distance, just enough heat to melt your solder. Tin all surfaces first.

 

I would not "butt" connect the tubing than solder, better to flare extension, tin inside & out, sweat solder like you would copper lines in house pluming.................
If not comfortable using heat use some MarineTex epoxy..............................................

 

Old style “soldering coppers” or “irons” have their place, but this ain’t one of them. Too large and too slow to keep the applied heat localized. @Boneyard51 has it right. The right tool for the job........a “pencil tip” style keeps the gas flame localized. Also, I definitely agree with @brigrat , no butt joint.

Ray

 

Epoxy I don’t think will ever fix your repair . Butt solder joint is never ever going to fix you either . I use the very smallest tip I could find available for oxy / acet torch and 50/50 solder . Tin the swedged fittings first , use a good paste and creep up on the heat . You will know when the heat is correct , the solder will FLOW to the paste in the fittings , when it flows back off the heat and allow it to cool . That seam where the tank is attached to the core is not for a first time at soldering to attack . Once its unattached you will chase the leak around and around the tank . Take your time and clean , clean and flux the joint area it should work well . When you buy new fittings , shiny copper from the store is not clean ready for solder , brush and sand the areas to be soldered very well and don’t touch them with your fingers , apply paste with a brush . Everyone probably knows everything I just repeated , just use your head and remember solder melts at low temp , unlike gas welding . Be careful , cover the eyes , fittings get hot and don’t look hot to the eye , a burn with acid and lead in it is never a good one to deal with .

 

I have done it with a soldering gun. You need a very small snips to clear away enough of the "fins" ( I don't know the technical term), to get to the leak. The amount of fins I had to cut away didn't seem to affect the heat in my car. You say that your leak is in the middle of the core, so that might be a good thing. Hopefully yours is exposed enough to get the soldering gun to. It must be very clean with no anti freeze residue and I used plumbers flux with 50-50 solder. So far the repair has held for about 40 years. I suppose if you have a micro torch it would work also, but you need to be aware that the tubes could be very fragile from age.

 

Find some heat sink paste. I used it alot when I was doing commercial refrigeration and cryogenic refrigeration. It works much better than a water soaked shop towel. Also remember, when sweating pipe, cleanliness is next to Godliness. Get everything perfectly clean and you can make the solder joints a lot easier.

 

The heater was the first thing I threw away cause some old guy told me real hot rods don't have heaters !

 

Take it to the rad shop. That is an easy fix.

Sent from my SM-T350 using The H.A.M.B. mobile app

 

Outlier here. Unless you go absolutely bat shit crazy with it, the core connections to the tank are plenty far enough away from the nipples to use a propane torch. I wouldn't think twice about doing it. My only concern would be if the nipples are also soldered to the tank. Are they? If so, then set it nipples up and fill it to the base of the nipples with water. A soldering iron will more likely than not result in a cold solder joint, ie a leaking one.

I love it when I can write something that contains the phrase "nipples up".

 

Thanks for all the suggestions. I've been soldering plumbing joints for probably 40 years, but this has me paranoid, due to the closeness of the tanks. Maybe the 45 mile radiator shop trip isn't so bad.

"Nipples up"!

 

If you have been soldering plumbing joints for that long, this should be a walk in the park. Just do it. Forget about the immersing the heater core it water idea. That just sucks up all the heat and makes it impossible to do. Test it after you are done like you would a bicycle inner tube. Worst that can happen is that you make a 45 minute drive.

 

If you can sweat in plumbing,,,you can do this .
If you are still worried,,,use the heat sink paste like the man recommended.
The pros use that as well sometimes,,,it will keep the heat localized.

Tommy

 

Thanks, guys!

 

Back up for another question: What about JB weld?

 

That’s some great stuff, works miracles, sometimes, but in this case I would solder. But if you do use JB, make sure it’s squeaky clean and a somewhat rough surface, think sand paper rough.








Bones

 

Looking at your earlier post " How to Tech etc " could you not use hose elbows between the copper tube and the core.

 

The trick to soldering is clean the parts with sandpaper or a wire brush so they are shiny, then use soldering paste first. Don't overheat the part, stop the heat when the solder starts to melt and gets drawn into the joint.

 

Yes. In fact I considered that at first, but that, of course, required a clamped joint inside the car. That seemed to be a leak potential so I passed on it, reasoning that the soldered joint would be more secure in that area.
I think that I will entrust those two elbows to a shop. They can pressure check it also.

 

Anybody have any experience with "SharkBite" solderless fittings?
That would solve any of the concerns I've had.
They push on and seal with an o-ring.
90° Elbow is available
For use with copper, Pex and other types..

 

They work great and are removable , but I still like a rubber connection for vibration and ease .