Radiator soldering
 

Someone must have some good advice for me. The side of my old radiator has come loose and I want to get it back together. Can I use regular solder and a propane torch? Look at the attached photo and tell me what you would do. Thanks.

Re: Radiator soldering
 

You should take the radiator to a radiator shop and let them do the soldering in a water tank so the heat will not affect the solder joint at the bottom of the tank and the tube sheet.

Re: Radiator soldering
 

Yes, " Can I use regular solder and a propane torch" Clamp it back together clean where you are going to apply the solder, flux it and try to copy the pattern of the other side. Don't use too much heat so as to melt the area around it. If you have never done this type of soldering, money well spent might be to take it to a radiator shop

Re: Radiator soldering
 

I have had good success in soldering up radiators using the old heavy duty copper soldering irons like the radiator shops use. The heavy soldering iron gives the penetrating heat exactly where one needs it. More importantly than the soldering iron is preparation. Cleaning out the old solder and then tinning the surfaces so that they can take the new solder. For a huge success, the surfaces have to be hospital clean and tinned before you start the soldering reassembly.

Re: Radiator soldering
 

What sssteamer said. A torch is much more difficult than an iron. If the flame touches the area to be soldered, the joint will be compromised. Also very difficult to contain the heat to only the area you want heated. Find a BIG soldering iron or a good radiator shop.

Re: Radiator soldering
 

If you have a driver and not a point show car, and you are not familiar with the solder process, clean each surface really good and use epoxy such as JB weld, PC 7 or something similar. Clamp it unitl the epoxy has set and you should be good.

Re: Radiator soldering
 

Good suggestions above about soldering.
If I was doing it I would fill the radiator w/water to just below where you're going to solder it.

Re: Radiator soldering
 

If you are going to try it yourself do not use the "Lead free" solder it melts at a much higher temp and makes it much harder because you must use more heat and existing joints come loose as regular solder melts at lower temperature ... etc etc ...

Re: Radiator soldering
 

I would investigate first why it came apart! Next,Just a question or two? Have you done this kind of soldering before?
There is an art to applying the right amount of heat, to get 60/40 acid solder with some acid flux to flow and bond without affecting surrounding areas that are soldered. Best to put a wet rag on areas you do not want solder to melt. Do you believe you can do that? If so, go for it! What is the worst that can happen? You might eventually have to take the radiator in to a radiator guy! But, the upside of doing it yourself, is if you are successful, you have some pride in your ability, and if the radiator guy has to fix it, you wallet is a little thinner. Go for it!

Re: Radiator soldering
 

I would like to hear more on the type of solder and flux to use. Acid core/flux, or rosin core/flux. What are tohe down sides to them? The non lead solder has been discussed and the higher heat required seems reason enough to stay away from it. Jack

Re: Radiator soldering
 

Well, I opted to give JB Weld a try, since this is just my old radiator that I am keeping for "whatever". I use JB Weld for all sorts of things around the shop. About 20 years ago I used it to fix a chunk that was broken out of my bell housing when I removed my engine the first time. This time, I removed and replaced my engine with no problems and the JB Weld seems just fine. Always glad to learn tips about everything in here. Thanks.

Re: Radiator soldering
 

The old electric soldering irons are really great to use. I picked up several at flea markets, for about $20

Re: Radiator soldering
 

Be very careful. The whole thing can ,come apart if you get things too hot.

Re: Radiator soldering
 

Ummmm, this really has not been my experiences with this. When you look at the construction of an A radiator, you have a core that has an upper and lower header attached. The headers are attached to the core tubes by "rolling" them in, -or swaging. You then have an upper and lower tank that is soldered to the header, and there are outlets/inlets soldered onto those tanks.

I have found that radiator repair really is NOT that difficult, ...even by a novice. I know someone above recommended using a propane torch however only in rare (-emergency) situations have I found the integrated bottle-type hobbyist torches to work well in this application. The issue is most hand-held propane torches do not like to be inverted or put into positions that causes the liquid to rush to the burner as this causes the flame to vary or extinguish. My radiator torch is a handheld that uses a remote tank, and uses compressed air at 5lbs to diffuse/soften the flame. The tip of the flame is still much smaller (concentrated) than what you would find with a bottle-type propane torch. I have found the biggest thing for failure or success is how clean you get the two surfaces. Liberal use of Flux & warming heat, along with constant brushing is your friend. When you think you have it clean, do it again.

One other thought. I would strongly discourage using any type of epoxies like JB Weld as you risk failure, and to ensure all of the epoxy is gone when someone is going to make the proper repair will likely mean the tank will need to come off for thorough cleaning. I do realize there might be emergency situations where JB Weld is suitable but I would discourage the use of it in this scenario.

Re: Radiator soldering
 

Brent; I noticed that you did not address the type of solder and flux. I have been told that rosin flux/core solder is only good for water pipes and electrical connections and acid flux must be used in this application. Jack

Re: Radiator soldering
 

Rosin core for electrical repairs, Acid core for water pipes or radiators is what I have used in the past. The large electric soldering iron, or the older large copper used with a gas torch to heat it prior to use.

Cleaning and fluxing is the key to all solder work, including lead body repairs.
Heat blocking is also important, wet rag or something like that

Re: Radiator soldering
 

I've done a few radiator repairs and tank strap soldering jobs. I never had good luck with acid flux or acid core solder. I always use rosin core solder and rosin flux, and it works great.
I usually find the reason for the strap coming loose in the first place was because it never had full contact solder in the first place. Clean the entire surface on the tank area and strap area to receive solder, then tin both areas, then pull the strap to the tank and melt the solder. Add a bit more solder if needed.

Re: Radiator soldering
 

Use ACID core solder whenever soldering dis-similar metals, which is what you are doing when re-soldering the radiator frame (steel) to the top tank (brass). Clean off any remaining flux when finished soldering to avoid any future corrosion. Clean up with Baking Soda.

Use ACID core solder when plumbing or radiator repair. It is more aggressive than rosin core solder.

Use only ROSIN core solder when doing electrical work, as the acid core solder is corrosive and can degrade the electrical connection.

Whatever you do, don't use JB Weld or any epoxy type repair. By doing so, you will make it more difficult if not impossible to do a proper repair, as it will all need to be removed in order for the solder to bond with the base metal. If you don't have the experience or feel unsure please bring to a radiator shop.

Another note - As these parts were previously soldered together, there should be a coat of solder on both the tank and the steel frame where the parts attach. It will take very low heat and a minimal amount of additional solder to re-melt / re-flow the solder between these previously soldered parts.

Good luck with your repair

Re: Radiator soldering
 

Go for it! "For a huge success, the surfaces have to be hospital clean and tinned before you start the soldering reassembly." You do not need to remove the old solder completely. Hit the strap with the majority of the flame, not the brass tank too much heat will cause the solder to flow right out of the joint leaving a weak joint, too little head will leave blobs. I too use the rosin core lead solder. You will see the lead flow into the joints if done correctly.


If you screw up take it to a radiator shop, deny trying to do it yourself and brag on how cheap you got it do to the DIY repair. Just kidding, you will be fine. Cleanliness, alignment, not too much heat.

Re: Radiator soldering
 

60/40 solder has about the lowest melting point, around 370 Deg F. Plumbers soldering acid flux will work just fine. After you do the soldering with Acid core solder and/or Flux soldering, wash all soldered areas with baking soda, and flush with lots of water! And then do it again and again! Make sure once you have done this a few times you can pour baking soda mixed with water over the area and there is no bubbling or any reaction to the mix! if there is, keep cleaning and cleaning until the baking soda mix no longer shows any reaction. Acid core can and will cause corrosion if not properly cleaned up! Once dry and you are sure you have not created any leaks, get a can of Black paint and spray over your work, as needed. Let us know how it works out!