Copper or Brass for a bluing tray

Hi, all.

I'm looking to make a bluing tray much like clickspring does here (though undoubtably without the same level of quality ).

He picks brass, presumably for it's thermal conductivity - to even out the heat input.

However, I believe that copper is somewhat more conductive and is only a little more expensive.

Is there any reason why copper would be a worse choice? For example, would it oxidise more? I ask the question with regard both to the tray and also to the swarf which is used to full the tray.

Many thanks - as always!

Iain

I doubt if there's much, if anything, to choose between the two materials as far as the bluing function goes. Cutting the v-grooves for construction would go much better in brass I think but that, though elegant, seems an OTT method to me.

Can only think that for the swarf in the tray brass comes off in finer chippings than copper. My own attempt which came out ok was using the gunmetal swarf from cylinder castings in an old tobbacco tin heated stood on a copper plate on a camping stove. I blued the replacement needle of a large old pressure gauge and it came out much better than hoped for. the only critical bit seemed to be getting the steel needle super clean.

Mine is currently a folded steel tray and I use brass turnings as I generate a lot of those.

It doesn’t really matter much, you really only need to heat gently and have something to even out the heat.

It only gets really fiddly if you are attempting to blue something really slender and long like a centre second hand for a large clock. For that you really need something a little more controlled like an oven.

regards Martin

Thanks, all. An associated question - can you re-use the brass shavings or does the act of heating damage their conductivity?

I ask this as I've made a steel tray (very badly welder ) and had only modest success. I was hoping a brass tray would make things easier. Bad workman and so on...

Iain

You can use the brass shavings as often as you like, they are only to even the heat. I've used fine sand in the past.

I reuse mine. How are you heating. I prop my tray on some firebricks with a channel underneath to form a flue for the gas torch. You need to be patient and go slow so you can watch the colour develop. Once everything is a reasonable dark blue I then lift the part out into clean oil. Comes out virtually black and has good protection.

regards Martin

Edited By Martin Kyte on 15/03/2023 20:27:20