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View Full Version : Welding Help needed soldering alluminum.



Pete Lamberty
06-25-2015, 3:02 PM
Hi, I am trying to solder aluminum with a propane torch. I am unable to do it. I am using .063" 6061 aluminum. I have tried silver solder, Al-3, and Muggyweld Super Alloy 5. I have only gotten Al-3 to work one time. The others don't work at all. I am using a propane torch, I don't have an oxy/acetylene set up. I have the Bernzomatic TS 3000 torch tip on a propane tank. The people at Muggyweld told me that this should work. It doesn't. They make it look easy, See the video here.
http://muggyweld.com/aluminum-plate-solder
I have taken seven welding classes at the local community college so it's not like I am a total amateur at this. But I still can't do it.
Thanks for any help that you can give me.
Pete

Charles Wiggins
06-25-2015, 3:38 PM
Never done it. I always resorted to welding. BUT...

American Welding Society: Tips for Soldering Aluminum (https://app.aws.org/wj/2004/02/046/)

Dan Hintz
06-26-2015, 10:49 AM
Flux flux flux... if those surfaces aren't clean, that stuff won't flow worth a darn.

David Ragan
07-07-2015, 7:24 PM
I have to ask, is the reason why some metals won't solder for me is that they simply weren't clean/fluxed enough?

I thought is was cause some metals just can't be soldered.

What's the deal?

Pete Lamberty
07-08-2015, 12:59 AM
Hi David,
All metals, except gold, oxidize. This oxidation must be removed before you can get a good weld, brazed, or soldered joint. All you have to do is to use a stainless steel brush and brush the metal a lot. Also when soldering, the flux will clean the metal. But I don't think you would normally use the flux with out brushing first. I am doing an art piece. I don't want a bunch of scratches on the surface. Muggyweld says that their flux will clean the surface without the need to brush it first.
I tried to solder the aluminum for several hours on Sunday and only got very poor results.
Pete

Mike Lassiter
07-09-2015, 8:24 PM
another issue is getting the base metal hot enough to melt the solder. Not pushing the solder against a hot iron to melt it on a too cold metal for the flux to properly clean and the solder to bond. If you don't have enough heat to raise the metal temperature for the solder to melt when it contacts the metal you might get a cold joint ( solder is melted ON the metal, but is NOT bonded to it.)

Bill George
07-11-2015, 10:30 PM
Hi David,
All metals, except gold, oxidize. This oxidation must be removed before you can get a good weld, brazed, or soldered joint. All you have to do is to use a stainless steel brush and brush the metal a lot. Also when soldering, the flux will clean the metal. But I don't think you would normally use the flux with out brushing first. I am doing an art piece. I don't want a bunch of scratches on the surface. Muggyweld says that their flux will clean the surface without the need to brush it first.
I tried to solder the aluminum for several hours on Sunday and only got very poor results.
Pete

Its darn hard to do, I have done it in the past but I can not recall what I used. It was special solder and flux, never heard of what your using. When doing aluminum the problem is it oxides almost right away. When TIG welding aluminum I use a stainless steel brush used only for aluminum, pre-clean in some cases with acetone. The problem with heat on aluminum isn't that you don't have enough in most cases you have too much. You can not see the metal change color like you can with steel or stainless, one minute its good next its melted!

I have used Harris products for years > http://www.harrisproductsgroup.com/en/Products/Alloys/Soldering/Lead-Free-Solders/Al-Solder-500.aspx Do some reading on there website first.

Chris Parks
07-11-2015, 11:00 PM
I am old enough that we used to oxy weld aluminium and back then we were taught how to braze aluminium and it was like water as there was no build up as such from memory. I only did it a few times and have no idea of what was used in the way of filler rod, flux etc but there are Youtube videos showing it.

Pete Lamberty
07-12-2015, 12:52 AM
Yes, I have watched a lot of the you tube videos. The product I have been trying to use is Muggyweld. See the video here if you want. http://muggyweld.com/welding-3003-aluminum The only difference is that I have been using type 6061 aluminum. I will have to get some 3000 series aluminum. I do not have any welding equipment. That is why I am trying to do it with a propane torch.

Tom M King
07-15-2015, 11:01 PM
I wish my old friend Chuck Hughes was still alive so I could ask him about this. There's stuff sitting on the Moon made out of lightweight thin metals that he not only welded, but figured out how to weld. He was also pretty good at cussing, and would have had some choice words about anyone trying to solder aluminum with a propane torch.

Brian Ashton
09-22-2015, 8:14 AM
It's a bit old to be replying to but it may still be worthwhile. Been doing a fair bit of aluminum soldering lately on a big modelling project I've got going. Depending on what you're trying to achieve it may not be the best choice. I'm finding that for all but a few instances I'm going back to adhesives and mechanical fasteners. Even though the heat needed to do the soldering isn't very high it still changes the structure of the aluminum too much to be much good. The molecular structure is really course which leads to: It no longer files well, is very soft yet brittle (it bends real easy but also break after one or two bends) and often it warps. I definitely wouldn't trust soldered aluminum in anything where there was stress on the member. The joint itself seems good but the actually aluminum member is real suspect. YMMV