Silver Solder Stainless Steel

[jbrandon]

I have the need to silver solder (for strength) a washer to a 1/4" stainless steel rod. I know the washer is mild off the shelf steel but the SS I and not sure what type it is.

I bought a silver solder kit with flux and tried that but only got a glob not a nice flow like with brass.

Can this be done?

[eeengineer]

When you say "silver Solder" are you talking about a tin solder containing some silver or a high silver content brazing alloy. Since you compared it to barass I am assuming the later.
SS grows a very resiliant oxide. If you are going to wet it you must get rid of it first.
Next some types of SS will grow a strong greenish oxide in the presence of wet hydrogen. If you are using a oxi-acetylene torch, resist the temptation to use a srongly reducing flame. You should adjust the flame to where it is just about neutral,

I have been using Harris 45 alloy on cast iron. Itried Harris 50 and did not like it.
Also there is a black flux which is more active than the white flux. I have tried it and it does seem to promote flowing better but it is a bi..h to get off.

Jim B.

[jbrandon]

Thanks for the reply!

Okay, I am using Hi-Sil Kit, claims 45%CF. Also says Alloy BAg-5, Heat 111145 and is 1/16: dia wire. I would guess the Ag is silver but what the B is I have no idea. The kit came from Techniweld Corp. Came with white flux (dried out) but I have found I can crumble it and it will flow okay. I have purchased some new silver flux.

I guess I am not answering your question about the content of the solder but I see no indication that it contains tin or other alloys although I am sure it does. I purchased it because it said it was high content silver and I felt I needed the strength of silver. I have leaned that I can get by with brass and have. But still want to learn!

I braze a washer to a stainless steel rod to act as a bail which has nylon line passing over it at high speed. In the past I have used music wire and after a while it will form groves and was hopping the stainless would not. The washer is only a stop so a nut can be tightened to hold the rod in place.

[eeengineer]

I Googled "Hi-Sil" and found a reference its 45% silver Cadmimum Free (CF).
should be similar to what I am using.

Try the new flux but clean the SS with (say) 500 grit SiC first,

The flux should be liquid and runney, brush it on. As you heat the part it will bubble and then dry to a white power. Further heating will turn it clear an runney.You will see that where the flux is, the metal is bright and where it is not, the metal is oxidized. Just when the metal starts to show color is when you should apply the brazing rod (solder).

I think the heat should be 1145. thats about the right flow temperature for the braze. You could get a Templac stick around that temperature range if it would make you feel more comfortable.

Jim B.

[jbrandon]

Thanks, I did try the new flux and that seemed to take care of the flowing problem. I get a good filit around the joint.

Thanks for your input.

[Cyclotronguy]

I was told years ago by the Handy & Harmon guy that the "B" prefix was "Braze alloy". Don't know how true that is

BAg-7, the one I use for about everything either as wire or powder and black flux mix is the following chemical mix. Seems to be OK for cast Iron and steel... great for SS in vacuum.

Silvaloy A-56T (BAg-7)
Nominal Composition:
Silver 56.0 ± 1.0%
Copper 22.0 ± 1.0%
Zinc 17.0 ± 2.0%
Tin 5.0 ± 0.5%
Total Other Elements 0.15% Max.

Cyclotronguy