Nancy: I'm not familiar with the Galvanel surface treatment, but if it is some type of zinc coating on the steel, welding is a bad technique. I understand that the heat of welding vaporizes the zinc, resulting in hazardous vapors in the work area. Secondly, the zinc tends to contaminate the fused metal, making for a lower quality joint.
Next, I think the surface coating on the base steel is generally irrelevant to the shielding performance. The surface treatment (my favorite is electro tin and fuse) can maintain conductivity, but any mild steel barrier that can support itself will have almost unmeasurably high SE. Aside from the cosmetic aspects, a 60 mil thick sheet of steel, with a 2 mil thick layer of rust on each side, will still be an excellent shield. As long as the joints are welded, you could just let it rust. Or spray paint it, or even bond on a fluidized bed epoxy layer. Regards, Ed Subject: Re: Conductivity Question Date: Wed, 14 Oct 1998 12:17:50 -0800 To: EMC-PSTC <[email protected]>, Nancy Ludvigsen <[email protected]> > Hello Group! > > The following is a non-member post which was submitted to the admins, but > which really ought to be posted. (If you post a reply, remember to copy > Ludvigsen, but not me.) > > ------------------------ > From: Nancy Ludvigsen <[email protected]> > Subject: Conductivity Question > Date: Wed, 14 Oct 1998 15:53:56 -0500 > To: "'[email protected]'" <[email protected]>, > "'[email protected]'" <[email protected]> > > > > Hi Guys: I am a manufacturers rep. for a sheet metal fabricator. I have a > > customer that is currently manufacturing an enclosure our or Galvannel. > > This unit is welded and they are not currently painting over the welded > > areas. This will cause corrosion over time. > > > > I am suggesting that they go to a zinc plated cold rolled steel for a > > better finish, and also our buying power is suited for steel. > > > > My customer has already gone through their EMI Testing and is hesitant to > > change to zinc plated cold rolled steel because they do not know the > > difference in conductivity between the two materials. > > > > I have done a ohms test on the two materials. Both testing at .3 to .4 > > ohms. > > > > Can you direct me to a source to get more information on the conductivity > > of the two metal finishes? Or give me more direction as to how to address > > this issue? > > > > Any information is greatly appreciated. Thank you in advance. > > > > Nancy > > -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: [email protected] Date: 10/15/1998 Time: 09:56:38 -------------------------- --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
