WELDING STAINLESS STEEL - THE PROBLEM When welding stainless steel (or one of the high nickel alloys --- Inconel, Monel, ect.) the shielding gas or the flux in the electrode only protect the front of the weld. You must use something, usually either SOLAR FLUX or backing gas (argon purge) to float out the oxides and dissipate the heat on the back of the weld. Failure to protect the back of the weld will result in a sugary, porous weld, and burn-through. The front of the weld may look good, but you'll see the difference when you look at the back.

WELDING STAINLESS STEEL - THE SOLUTION SOLAR FLUX, applied to the back of the joint, works chemically to dissipate heat and float out unwanted oxides, SOLAR FLUX has been producing x-ray quality welds in stainless steel for over 50 years. It is often preferred over backing gas for it ease, speed simplicity and low cost. Other variables being the same, either SOLAR FLUX or backing gas will produce the same quality weld.

WHAT IS SOLAR FLUX ? SOLAR FLUX is very fine powder packaged in One-pound can. It can be used with any welding method. There are two types: Type B for stainless steel and alloy steel, and Type I for high nickel alloys.


1. Mix with alcohol. Methanol preferred for best results. Mix to the consistency of thick cream. Mix only what you're going to need for a day's work.

2. Let mixture stand for a few minutes while a chemical reaction takes place.

3. Brush the mixture on the back of the joint. Use it sparingly, just enough to get complete coverage. Try to stay within ¼" of either side of the joint.

4. Allow a few minutes for the alcohol to evaporate.

5. Weld using the same procedure that you would use if you were using a backing gas. Note: good practice dictates that you always run and test a sample coupon when changing anything in your procedure.

DOES SOLAR FLUX LEAVE A RESIDUE AFTER WELDING ? Yes. It leaves a very thin, chemically inert, glass-like residue that adheres tenaciously to the base metal. This usually need not be removed except in three cases:

(a) inside a pipeline carrying food or beverage where it could act as a bacteria trap, or

(b) inside a pipeline operating at service temperatures above 1,000 degree F in an oxidizing atmosphere, or

(c) where appearance or fit-up with mating parts require a polished surface.

HOW DO I REMOVE THE RESIDUE WHEN NECESSARY ? Use standard stainless steel post weld cleaning methods such as a stainless steel wheel or wire brush or by pickling in acid solutions such as nitric/hydrofluoric. Caution: acid cleaning should be done only by qualified and experienced industrial cleaning personnel. Spec No. Material Method Solar Flux Type MIL-F-7516B Class 2 & 4 Stainless Steel Gas & Arc B, I MIL-F-7516B Class 1 - 4 incl. Stainless Steel & high nickel alloys Gas & Arc I Certificates of conformance available by request on purchase order.



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