Does anyone still remember a product from the past called SAL-MET, housed in its typical soft metal "toothpaste" tube container, plus, it was about the same viscous consistancy of our current day gel types.
Its introduction would have been dating from about the early '50's. Its use was for the occassional time when you would come against the situation of HAVING to solder aluminum, or at least get the aluminum tinned such that common copper wire interfacing could be made onto it.
This was all very dependant upon the use of a healthy WELLER gun for the required heat capacity. This was accompanied with the secondary effect of creating one acrid odor along with a strong sizzle-spatter-frying noise.
BUT.... it DID create a great tinning action for any further reworking.
Now, with a SALMET sample, and my CE background, that would just be a matter of running a Gas Chromatography Analysis to precisely differentiate its elemental composition fingerprints and then a further delving for the determination of their proportions.
With current experimentation, plus not having a S-M sample and not even finding a trace of the company's existance anymore, I am currently having an adequate result with the use of Oateys flux(no solder dust filler) that you can find at a HD or Lowes in its small tin.
A MSDS check reveals its composition to be brown petrolatum jelly and its active ingredients of Zinc cloride along with ammonium cloride.
I upped the NH4Cl content a bit with filings from my soldering stations sal ammoniac block and the resultant mix now really gets with it.
One makes an initial clean scraping of the aluminum surface with a cheap large jewelers screwdriver....pressed in and used chisel style..... and then make immediate application of a covering of the flux and a continuous scraping action with the irons tip. Once a solid tinning has been acquired, I cleaned all the working area free of any flux with a vigorous cleaning with MEK . Then, afterwards, typical rosin based flux was used on the tinned area for its further interfacing to copper/tinned wiring. The technique works great.
This had all come up due to the popping apart of an odd sized rocker switch used on some exotic medical diagnostic equipment. It seems that the frontal aluminum mounting plate was merely swaged to the aluminum housing of the switch proper and had popped apart. An inspection revealed the two side junctures would afford adequate area for the build up of a fillet of either epoxy or solder....I'll take solder any time that the soldering temp is permissible...thus....the following healthy repair result:
http://img223.imageshack.us/img223/6315/aluminumyumumsarteringiea6.png
73's de Edd
marv
:QUERSTION ?........as old Tech Sgt Terrell in my command used to say ..we all knew the diff...but he always put an R'uh sound to it....
:
:Does anyone still remember a product from the past called SAL-MET, housed in its typical soft metal "toothpaste" tube container, plus, it was about the same viscous consistancy of our current day gel types.
:Its introduction would have been dating from about the early '50's. Its use was for the occassional time when you would come against the situation of HAVING to solder aluminum, or at least get the aluminum tinned such that common copper wire interfacing could be made onto it.
:
:This was all very dependant upon the use of a healthy WELLER gun for the required heat capacity. This was accompanied with the secondary effect of creating one acrid odor along with a strong sizzle-spatter-frying noise.
:
:BUT.... it DID create a great tinning action for any further reworking.
:Now, with a SALMET sample, and my CE background, that would just be a matter of running a Gas Chromatography Analysis to precisely differentiate its elemental composition fingerprints and then a further delving for the determination of their proportions.
:
:With current experimentation, plus not having a S-M sample and not even finding a trace of the company's existance anymore, I am currently having an adequate result with the use of Oateys flux(no solder dust filler) that you can find at a HD or Lowes in its small tin.
:A MSDS check reveals its composition to be brown petrolatum jelly and its active ingredients of Zinc cloride along with ammonium cloride.
:I upped the NH4Cl content a bit with filings from my soldering stations sal ammoniac block and the resultant mix now really gets with it.
:
:One makes an initial clean scraping of the aluminum surface with a cheap large jewelers screwdriver....pressed in and used chisel style..... and then make immediate application of a covering of the flux and a continuous scraping action with the irons tip. Once a solid tinning has been acquired, I cleaned all the working area free of any flux with a vigorous cleaning with MEK . Then, afterwards, typical rosin based flux was used on the tinned area for its further interfacing to copper/tinned wiring. The technique works great.
:
:This had all come up due to the popping apart of an odd sized rocker switch used on some exotic medical diagnostic equipment. It seems that the frontal aluminum mounting plate was merely swaged to the aluminum housing of the switch proper and had popped apart. An inspection revealed the two side junctures would afford adequate area for the build up of a fillet of either epoxy or solder....I'll take solder any time that the soldering temp is permissible...thus....the following healthy repair result:
:
:http://img223.imageshack.us/img223/6315/aluminumyumumsarteringiea6.png
:
:73's de Edd
Maybe it'll work for the positive terminal, too. I'm talking about the axial lead 'lytics, where a nub is still present after the wire breaks off.
Thomas
I also intrincially discovered that my 1950's tubes of Sal-Met had synergistically expired which rendered my aluminum soldering activities static. I performed a Bolean on-line search and found a retired Boeing Aircraft engineer in California that sells proprietary fluxes. He sold me 6 oz (liquid) of aluminum soldering flux and it's wetting action and flow tension far exceed that of Sal-Met. I would heartily recommend it and wish that I could recall his identity or address. Oh, and that poster that cited that AL02 as the inhibiter of aluminum solderability is indeed correct. Aluminum is purposefully oxidized in many instances to enhance its appearance, give it color, and increase its surface hardness . . .we call it anodizing.
Yes I do remember Sal-Met, in fact I have a very small amount left. The only problem is that I have been thinning it with an liquid acid flux to keep it going. About 10 years ago I was able to contact the son of the original maker. Can't find any info from that contact in order to talk to him again. At that time I was told that his father, the originator of Sal-Met, died and took the formula to the grave. Apparently it was all in his head, nothing written down. What a shame. The son said that every now and then someone would inquire as to obtaining some. Each year these inquiries were getting less and less. I'm like everyone who knows how great Sal-Met is and wish I could get my hands on some more. Regards, Frank
Frank: Did I ever work with you in the Atlanta airport area?
Lewis L.
Delta (Retired)
The problem is that it oxidizes instantly therefore the oxidation impedes the soldering action.
The trick is to solder before it oxidizes. So I'm sure that Sal-met or its ilk prevents air contacting the surface somehow.
Once I understood this.. I was able to solder after a fashion by repeatedly scraping the hot, tinned, iron on the aluminum while applying heat and solder with flux.
You can scrape the iron on the surface quickly back and forth and this breaks the oxidation layer and if the hot solder is present as the oxidation layer breaks the solder can have a chance to adhere before the instant oxidation begins.