I need brazing barrier, or pin for brazing alignment that won't solder!!

[gellfex]

So I'm in a jam I need help with ASAP! I'm silver soldering little 1/8 set screw collars to a flat plate, and I really need an accurate placement so I have a 1/8 hole in the plate so a pin can keep it all good. But enough solder is wicking under the collar to screw me by soldering the pin in also. is there anything I can put on the steel pin to keep it from soldering? Or is there a common metal for the pin that would work? AL would melt out.

Thanks for reading this far, I'm off to experiment and hope I hear the email ping!

[Ken_Shea]

You can coat the necessary areas using typist's correction fluid.
Problem is , who has typing correction fluid nowadays.
It can be purchased at any office supply store tomorrow

[alanganes]

What you want is sometimes called an "anti-flux". There is stuff made specifically for that, but one common and readily available thing I have used when silver soldering is White-out, the correction fluid stuff that those of us who can't think before we write but still write in ink use to fix our mistakes (I have used a lot if it...).

Put some whiteout on the areas you do not want the solder to flow, let it dry for a minute or two, then heat it with your torch. If you do not have the water based type, the fumes are a bit nasty, avoid breathing them, use good ventilation and good sense. This will leave a residue that is not conducive to solder flow. Think of it as selective contamination. Then put your parts together, flux and solder.

You may want to try it on a few scraps first just to see how it works.

Late edit: You guys are quick. Ken beat me to it, but only because he seemed to be able to say it in far fewer words than me...

[Doozer]

Can't you just heat the pin till it falls out?

--Doozer

[gellfex]

Thanks. White out huh? I'll get some, but I've got to get back to the drawing board, the damn collar idea, 2 pins 2.5" apart on one flat bar and mating collars on another doesn't work so well, they bind too much sliding up and down. I really don't want to make this stupid thing more elaborate with a tube section to hold alignment so it slides easier. But I have to deliver tomorrow morning. Grrrr.....

[Tony Ennis]

Trivia time. 'White out' was invented by one Bette Nesmith, mother of Monkee Mike Nesmith.

[Boucher]

Try marking the pin with soapstone.

[Duffy]

I assume that you have an O/A or at least an acetylene/air torch. That being the case, you can "soot up" the pin. Apparently silver solder wont adher to the carbon black. Duffy

[gellfex]

Thanks for all the info. I think most of the dry coating options might get scraped off inserting the pin. I tried just some synthetic grease, which worked well enough that I was able to bang out the pins. Then I opened up the damn holes to #29 so now it's sloppy enough to slide to where it gets locked down.

Good enough for my show and tell tomorrow on the prototype. It's midnight here, now I go bed! Maybe Staples has whiteout.

Cheers.

[dp]

Try a ceramic pin.

[tattoomike68]

thats a tough deal, i want to here the answer to this problem

[doctor demo]

Apparently silver solder wont adher to the carbon black. Duffy

Try a carbon rod.

Steve

[Forrest Addy]

I always use a thick pencil line. Neither silver or soft solder will flow past it at least as a dilm. A blob might depending on tilt.

[QSIMDO]

Simple!
All you have to do is WANT the pin to stick.
That's my experience anyway.

[hornluv]

Graphite, like Forrest said. Get a tube in the lock section of your hardware store and squeeze a bit out into a small container. Roll the pin in it. You should be good to go.