SS Pots (proper grounding) Is this mic on??

[Kregg]

I've decided to use P.E.C. stainless Steel Pots on my Express Francesca inspired build (costly little buggers). Does anybody have any recommendations on grounding the pots? I thought of grounding them by using 1/2" lug terminals between the pot and the star washer.

[billyz]

I use a ground rail made of copper rod connected to the board at two points, then run a Ground wire to the chassis. I then run individual grounds to the rail.

[kineteks]

search "Pot grounding buss lugs" in the TW discussion, I'd give the link but don't know how...
The subject is covered pretty well. I bought some of the BNC lugs discussed for an upcoming build & they look like they'll work quite well.
You CAN solder to them as well, I did in my first LP kit build, but it's a pain in the keister.

[drz400]

I've decided to use P.E.C. stainless Steel Pots on my Express Francesca inspired build (costly little buggers). Does anybody have any recommendations on grounding the pots? I thought of grounding them by using 1/2" lug terminals between the pot and the star washer.

I wouldn't use the pots as a ground path, they can just be normal star washer to chassis and do your ground path separate from the pots, in other words dont use the back of the pot. Like Billy said use a ground buss on the board or suspend a buss on the back of the pots but not touching them.

[Kregg]

Thank you gentlemen, that works for me.

[francois2000]

You can solder stainless steel if you use a phosphoric acid based flux. The steel surfaces must be clean. Use an abrasive paper or a green 3M Scotch-Brite pads for that. A large, hot iron is recommended. The solders with phosphoric acid must be clean with water after soldered. I use a toothbrush for that. It works with a regular tin lead solder. I’m not sure with a RoHs stuff.

It has phosphoric acid in rust dissolver like a Naval Jelly.
http://www.homehardware.ca/Products/ind ... elly_237ml

I used this process to solder my pots in my Express.
http://www.internet.uqam.ca/web/t6762/express.html

English is not my primary language, but this forum is good to practice it.

François

[Kregg]

I came along this in my search for soldering SS: http://www.techni-tool.com/content/reso ... ester.html

[francois2000]

This article tells about hydrochloric acid based fluxes. It's for this reason, I’m not used the regular acid flux solder and I used phosphoric acid.

I read in other article, this article says, “Phosphoric acid-based fluxes are generally suitable and have the advantage of being innocuous if any residues remain after the joining process has been completed. Hydrochloric acid is sometimes added to the phosphoric acid based flux where molybdenum containing stainless steels such as 1.4401- 316 are being soldered. Hydrochloric acid based fluxes should however be avoided as corrosion can result to poorly cleaned joints, during service, after soldering.”

I hope it’s true, but it isn’t possible to have a deposit zinc chloride, because it doesn’t have chlorine in phosphoric acid.

François

EDIT:
This article is there:
http://www.bssa.org.uk/topics.php?article=150

I searched about phosphoric acid, because I read this post:

"No problem soldering stainless if you get it up to the proper tempreture and use the right flux.I've worked in the metal fabrication trade and have soldered a lot of stainless.You must use an acid type flux on stainless.Solder will adhere just fine.If you try using rosin flux,it won't work.It has no effect on stainless.From the net:
"All grades of stainless steel can be soldered with lead-tin soft solder.
Recommended procedure for soldering:

1. The steel surfaces must be clean and free of oxidation.

2. A rough surface improves adherence of the solder, so roughening with grinding wheel, file or coarse abrasive paper is recommended.

3. Use a phosphoric acid based flux. Hydrochloric acid based fluxes require neutralising after soldering as any remnant traces will be highly corrosive to the steel. Hydrochloric acid based fluxes are not recommended for soldering of stainless steels.

4. Flux should be applied with a brush, to only the area being soldered.

5. A large, hot iron is recommended. Use the same temperature as for carbon steel, but a longer time will be required because of stainless steel's low thermal conductivity.

6. Any type of solder can be used, but at least 50% tin is recommended. Solder with 60-70% tin and 30-40% lead has a better colour match and greater strength."
http://music-electronics-forum.com/show ... 0#poststop

[Kregg]

Thanks François. I love the way your amp looks, very nice. Have you posted any clips?

[Structo]

Kregg,
If there is room above your pots you can run the ground buss wire above the pots with short jumper wires from the CCW lug to the wire.
Then take the right end of the buss (looking from behind the chassis) to a ground point by the input jack on the chassis floor.