Karen 7/19/08

Hi everybody. I have been working on a mountmaking job and have come across a problem I've never had before -- brass that doesn't soften substantially after annealing. One example -- some recently ordered half-oval from Jamestown Distributors -- developed multiple cracks after the most minor bending. With a little more force applied it snapped, and the interior was a sort of pale grey. Am I doing something wrong, is this just the wrong kind of alloy, or what? Thanks for any and all feedback.

Suzi McG 7/19/08

Hi Karen,

I've had the same thing happen half-oval brass and I figured it must've been the alloy.  The only solution I could come up with, given that I didn't have much time was to just keep annealing over and over and solder closed any cracks I could see forming.  I got my half-oval from a local source but more than likely they came from the same manufacturer.

Good luck and if I discover anything else I'll let you know.

Suzi

Howard 7/21/08

Did you ask Jamestown Distributors? If they don't have an answer, you might ask them for the name of their source. I would be interested to know. I would polish an end to make certain it wasn't brass plated something or other.

steve 7/21/08

RE: [mountmaking-forum] Re: Problems with brass I have found that sometimes if you polish the surfaces and slightly round off any sharp edges, you can help prevent this from happening. The sharp edges or any grind marks set up stress risers that can cause cracking. Multiple annealing is often necessary for tight bends.

Jamie Hascall 7/21/08

RE: [mountmaking-forum] Re: Problems with brass I find this very interesting since I've never had any problems with bending the half-oval I'd gotten from Alaskan Copper and Brass in Seattle. In looking at Jamestown's site, it claims that the half oval is solid brass, although it doesn't specify metals content. It makes me wonder if the supplier/manufacturer is shorting the copper in the alloy. I'd definitely call Jamestown and see if they have any thoughts. I especially think they'd like to know about problems since they're a marine industry supplier and to be selling an alloy that isn't up to snuff could be bad for them down the road.

Keep us posted on how things are going. Good Luck, Jamie

Philip Brutz 7/21/08

RE: [mountmaking-forum] Re: Problems with brass I haven't had any problems annealing the half oval that I get from Benchmark.  Just remember that annealing brass is the opposite of tool steel.  Tool steel needs to be cooled very slowly.  With brass you heat it until the flame coming off of the metal turns orange and then quench it in cool water. Philip

Karen 7/23/08

Thanks for all your responses. I've used half-round brass many times before, and have never had any problems with it. I can't recall whether or not I've ever used half-oval. I've always gotten my half- round from Special Shapes (K&S), which carried a wide variety of sizes. They discontinued HR a while ago, and I've yet to find a good replacement supplier. Someone on this board mentioned that McMaster Carr carried half-round, but I couldn't find it there during a recent online search.

I'm annealing brass in the standard way that Philip describes. The bends I was attempting were not extreme at all -- barely a parenthesis. The cracks that developed were might have been fillable with solder, as Suzi suggested, if I hadn't taken the bend any further, but I would have worried about it -- something just seemed funky about the metal being so brittle under so little stress.

I polished an end of one of the rods, as suggested by Howard, and the brass is the same color all the way through, so a problem with the alloy seems likely. I wouldn't be surprised if Jamie is right regarding the copper, since copper is so expensive these days. The half-round maker may be trying to save some money. Does anyone know what the ideal content should be?

Steve, I haven't yet had a chance to try your rounding off tip, but that is a good suggestion.

I've contacted Jamestown Distributors and will post their response as soon as I receive an answer.

Thanks again for all the good thoughts and information.