[Amps] amp hardware

[Peter Chadwick]

Steve asked:
>If I'm building up an amp (the RF compartment particularly) with aluminum sheet and angle stock, should I be using aluminum bolts/nuts/washers to avoid galvanic corrosion?<
Is it going to be in the shack, or outside in a damp shed?
If in an indoor shack, I wouldn't bother.
Even in a damp shed, I've had no problems with aluminium and BZP (bright zinc plated) steel hardware. For parts in a RF field, I'd use plated brass for preference. . I've never found aluminium alloy screws too succesful, although it may be that I'm too heavy handed - they always break before they seem to be tight!
It's worthwhile for a nice finish to 'soak' the aluminium for 15 minutes or so in a strongish caustic soda bath. Do it in a well ventilated area because of the hydrogen given off. Afterwards, ideally dip in a 20% nitric acid bath, and if that isn't available, swab down with a cloth soaked in vinegar - this will remove the black deposit. It helps paint to stick, too. An alternative attractive finish is a wire brush in the electric drill. In that case, wear goggles and gloves, and afterwards, give it a coat of clear lacquer. Even if the aluminium isn't in view, it's good workmanship.....
73
Peter G3RZP