I need to solder a couple of radiator cracks.
How hot do I want this? I'll lay wet towels around the work to prevent melting nearby joints, but I'm wondering what heat source I should use for the iron and how hot it should be.
Hi, Steve. The old way would be to heat it with a gasoline blow torch and made hot enough that solder will stick to or "tin" the copper and not run off. I don't know if an acetylene torch will work or not. Might be too smutty. Mapp gas might be okay. If the solder just sizzles and runs right off the copper is too hot. Bob
I don't think you really want to use that iron.
You want to use eutectic solder: 63/37
That will flow instantly from solid to liquid at 361 degrees F. All other solders will go from solid to plastic to liquid over a fairly large range of heat.
Your iron must be tinned. There can be NO bare spots on the surface that intersects the actual solder joint. The key is heat transfer and that is met by virtue of a solder bridge between the iron and the work. You can lay an iron on a joint seemingly all day with no bridge, but the joint will flow instantly with a bridge between the two.
Overheating can damage the solder.
Best bet is to borrow an American Beauty iron at or in excess of 250W and control the temperature via common household rheostat.
Chapter XXVI of the Ford Service Manual contains a good discussion of radiator repair technique. Unfortunately, it does not discuss how hot to get the iron, other than to say that the iron should never be allowed to get "red" hot.
File the flats nice and smooth before you tin it will help a lot.
I use a plumbers torch.
My father used these soldering irons to repair both radiators and gas tanks. He always heated his with an oxy / acetylene torch. I don't know what type of solder he used though.
Propane is a clean source of heat. Don't use your "campfire" as you might get soot contamination. It's been twenty years since I last repaired a radiator and used propane and 90% tin solder directly to the core.
I would just heat it up on a gas stove. (Assuming you have a gas stove handy) Try rubbing solder on it every so often to test if it melts and how fast. Once you can quickly melt your solder, I would say it's ready to go.
Old fashion tools for an old fashion car. Good for you!
Hmm, everytime I hear the suggestion of "use a gas stove" for something or another (never for cooking food!) I think of this story:
Guy decides to try Skydiving, so he has the parachute on and they're over the drop zone; "What do I do???" he asks in a panic. "Follow your training, jump out, count to ten and then pull this cord." "Ho-Kay--but what if nothing happens?" "Then you pull this cord, you emergency chute."
"Uh, what if that doesn't work??" "You worry too much now out you go!"
"OMG, what do I do, what do I do?" he thinks to himself, "Oh yeah, 1-10, pull this cord. . . .NOTHING HAPPENED!!! Now what do I do??? Oh yeah, pull this cord!" AAAUGH!!! Nothing happened, what'll I do??" Just then he sees a guy flying up towards him, so he hollers, "Hey buddy, you know anything about parachutes?"
"NO!! Do you know anything about gas stoves?"
Eutectic tin lead solder melts at 183 C and you need to use flux otherwise it oxidizes the base metal and solder and will not stick.
Cold solder joints happen when the solder melts but the base material is still cold and it dosen't stick.
Therefore clean the area, use flux, get the metal hot, and melt the solder.
Treat it like your sweating copper pipes. Clean, flux, heat, apply solder while maintaining the heat.
I can't say for sure what size iron you would need. You may be able to put the iron on a "gas stove" and get the iron hot enough to melt solder on the iron but that is not what you are after. It is a different thing to have enough heat to heat your part hot enough to solder. That is why I would recommend a plumbers torch. Something like a Uniweld #G2002262 by Zorro. With it, you will be able to add or subtract heat quickly by playing the flame in or out. If you need to add heat with an iron, the reaction time is too slow...to the point you will have to wait on the iron to heat up again. You might be able to use MAPP gas instead of acetylene. I believe it is a little hotter than propane.
This is from the 'whatever it's worth' dept.
ALWAYS get whatever you're soldering as clean (buff w/'OOO' steel wool?) and as dry as possible BEFORE doing anything else. As Scott previously stated, any 'iron' heating device will need to be fluxed & tinned first.
I prefer to use flux paste (looks like vaseline in a tin can) around the cleaned seams before applying heat. I've then used an electric 'blade' soldering iron with rheostat control (leaded stained glass), or propane torch for copper plumbing.
As the heat source is applied, continue to 'dab' your solder to the base metal near that heat. You'll observe the melt point when solder flows, then a quick wipe, and it's time to move on. The wipe of the fresh joint is done with a soft cloth or leather glove. You'll see any gaps you need to re-address. (Don't be afraid to use more flux!)
The higher the tin (the 1st #) to lead (/2nd #) solder ratio affects the flow and work-ability of the solder. Unless you plan on drinking the radiator water, I wouldn't worry too much about the lead. "Git 'er done!" (and on the road!)
Assuming you want to solder copper fins on the radiator you could be in for a very frustrating experience. Soldering copper is not easy. I was a sheet metal worker for 30 years. To include a few years at a roofing company. Although 99% of the world calls what is in your hand an iron, to an old tinner it is called a soldering copper by that trade. Because it (the head) is made of solid copper. As you can see it doesn't look like copper because it is totally dirty. As this point it just a hammer of sorts. It has to cleaned and tinned to do any soldering. You will need to file the working part of the copper. That is the 4 beveled edges at the end that come down to a point. As you do you will see it is in fact copper. To tin the copper it is best to use a sal ammoniac block. Heat the copper to about 800 or 900 degrees and rub the copper on the block while melting solder to coat the cleaned parts. If the copper is hot enough to melt solder, the most ungodly smelling smoke with roll off the copper and tin it. Propane is not a hot enough gas. I am not certain if mapp gas is either. Acetylene is best.
Copper is very difficult because it has to be 100% clean. 99% will not due. Copper oxidation does not just lay on the surface it penetrates into the copper pitting it and making it very hard to clean. Generally, ruby fluid is the best flux to use. But it is not a clean agent as per se, it is used to tin the copper so solder it will stick it. You could try plumbers paste but I am not certain if it will work. I used to dread repairing old copper flashings etc. that was oxidized green as well as many others in the trade. Believe me I have seen soldering coppers fly off of roofs by fellow workers. It is both an ugly and pretty site as they tumble end for end to the ground. I do not miss that part of the trade. Good luck with your effort and hope this helps.
No, not copper fins.
Cracked brass shell.
Gas stove or propane torch will work. You'll need to tin the iron too. Clean/file the tip. As you know the cleaner the better. Both the iron and the work. When it melts the solder reasonably quickly you're ready. Is that the frame or the tank? Looks like a stress/vibration crack. If it's the frame perhaps an over lapping piece of copper bent to fit will prevent a return of the problem.
This may not help you in your current project, but keep it in mind at your next auction or swap meet. New ones are pricey, but old ones are usually cheap, except on eBay maybe.
This is the biggest they make. A 300W one would probably be o.k. too for what you're doing.
For heat you can use an acetylene torch. Or you can use a venture burner and propane. A bit of engineering initially for lines etc, but it offers quick and reliable heat source. Or for convenience a 100,000 btu weed burner.
Steve, you need to clean your "copper" with a file. Then heat it and tin it on a block of Sal Ammoniac. The proper heat is enough heat to keep the copper tinned without burning the solder. When working on the job, you need enough heat to allow the solder to flow from the copper to the part as described, forming a puddle as the workpiece reaches the proper tinning temperature. Oxidation is the enemy of any soldering operation. The work piece must be clean to start and kept clean during the process. Tinning is accomplished by brushing flux across the workpiece, allowing the solder to flow. When you achieve flow, the temperature is right!
Steve, from the picture it looks like some material like epoxy was smeared over the crack. It has to come completely off, down to perfectly clean brass, before you do anything.
That holds true even if that is solder.
But your main problem is that solder (or epoxy for that matter) can't hold two thin metal edges together. Both are great at holding the flats of two pieces together, or for sealing the crack in an otherwise structurally sound joint, like in a fuel tank, or filling a valley in a joint like they used to do on body and fender repairs, before Bondo.
I don't think either solder or any other method I know of will make that joint strong, except for brazing, which would terribly discolor the brass - maybe permanently - because of the heat required.
What you need is a 'splint' of similar metal, that overlaps the joint by at least a half inch on each side of the joint, or better yet a full inch on each side. Then solder (or epoxy) that splint in place while holding the crack firmly together.
The 'splint' can be on the inside, for looks. Works just as well.
Once you have a structurally sound joint, the crack can be hidden by flowing in some solder and then removing all of it from the surface by sanding. Then polishing.
I think that is a lap joint. You are going to need to get both pieces hot enough to flow the solder in the joint. Hopefully you can get enough flux in so it will suck in the solder when you get it hot enough.
If you just solder up the crack it will be weak and crack again.
From the photo you posted, it looks like you are wanting to fix a cracked in the top of a side panel. I never really studied that piece too much but I think the top of the side panel has a 90 degree bend and it is soldered under the top tank. Your crank appears to be in the bend. Solder may fix that but probably won't look too good.
That joint will probably take solder. You will need to heat the material to melt the solder not just heat the solder. Again, clean and flux well. You might try heating with a mapp gas torch without even using a copper. Go for it.
Well, the old man is a happy camper. The bottom line is: Leak fixed.
Going back to how all this started, I believe it was last year when I slid off a muddy road into a pile of branches. I think that's when the radiator suffered cracks on both sides.
This is the passenger (right) side, showing the temporary repair I made a few months ago. I just soldered the crack. Yes, that's solder, not epoxy. This side was leaking, and the solder stopped the leak. But as Peter observed, soldering the crack alone didn't provide any structural support to keep the pieces together. Eventually the vibration of driving separated the pieces and the leak reappeared.
I decided to apply patches, as somebody showed in a previous discussion. The first step in that was to thoroughly wire brush the patch area. Gorilla tape marked the patch boundaries to show me where to brush.
This is where the leak was. I dug in deep enough for the solder to reach it.
This is the crack on the (right) driver's side. It completely loosened the side panel, but didn't cause a leak.
I slathered on plenty of tinning butter, and used a couple of propane bottles to heat the iron. That worked very well for filling the cracks.
I made the patches of .031" brass cut into 1" strips. About ¼" is bent to fit over the top of the tank, with the remainder soldered to the side panel. I hope that will be enough structural connection on both sides of the crack to keep the pieces together. I found that the iron didn't have enough heat to reach both the patch and the panels under it, so I used the direct flame from a propane torch.
I filled the radiator up to the neck and let it sit for several hours, and found no leaks. My next step on this project will be a trip to the HF store for a couple of buffing wheels to make it all pretty.
Very nice, hope the repairs hold!
If not, you can heat the patches and remove them, then solder on larger and/or thicker patches.
Nice job Steve, thanks for sharing your experience and methods of repair.
bridging it was the best thing you could have done. You can always put a faux piece on the other side if you don't like the look. Good job.
Take acid and put zink in it until it won't eat anymore zink use this to clean what you want to solder heat with small flame the surface you want to solder get a role of 50/50 solder and hold it to the metal and keep heating the metal when the metal is hot enough to melt the solder run the solder along the crack and your done. but it must be tinned and clean. 50/50 is more forgiving and will melt at a lower heat and don't heat the solder old zink jar lids is a good source of zink
I spent all morning with the buffing wheels.
The work took all morning because leaks had left a lot to clean up.
I think the old radiator with its hundred years of dings, pits, and dents doesn't look too bad.
The .031" patches extend down the sides about 3/4", with a 1/4" bend that "hooks" over the top of the tank.
The question now is whether the 1" brass sandwiches with their solder filling will survive the vibration of Model T driving. A short drive to pay the water bill, about six miles, went OK. We'll see how it is on longer drives.
Looks like you've given it your best shot, hope it holds over the long term!