flattening a sheet of brass?

K

kungfucowboy

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Oct 27, 2008
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I've decided to attempt to make a slipjoint and have been following the tutorial by chris crawford. on problem i have is i bought some 1mm thick sheet brass to use for the liners but it's a little warped, how should i go about flattening it? i tried clamping it in my vice between a couple pieces of steel but it didn't do much.
 
Hi Friend,

I would take a rawhide mallet to it on a flat smooth anvil (any piece of heavy plate steel will do). It will help if you cut out a piece close to the size you'll need, as it will be easier to flatten. You need to finesse and tap it, not just wail on it. Flip it over and over as you work it. Also hold it up and eyeball it as you go and use your fingers to tweak it as needed.

Once you have it completely flat this way, then contact or rubber cement some sandpaper on a smooth flat surface and rub one side of the piece back and forth on it until the sanding mark are evenly and thoroughly distributed. If needed, you can use tape as a handle to hold the brass. Take a strip of tape and carefully fold it in half to stick an inch or so together in the middle of the strip. Fold out the two unstuck ends so they are at opposing right angles to the pinched together center. This will make a "T" shape. Stick it down on the surface of the side not being sanded for a nice little handle. Do both sides until completed.

Good luck, Phil
 
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Phil has some good advice... finesse is key.
I will cut out a liner close to shape, file any burrs off and then I have two big flat chunks of O-1 on my bench, and I'll slam the liner between those a few times. Then I take a full sheet of maybe 80 grit to start...glue it to my granite surface plate....do the tape deal like Phil says but then I sand in a figure 8...this helps keep everything nice and even. You really need to tweek them flat good before you sand them flat.
Good luck...lets see some pics!
Mace
 
I'm not sure about the fiberglass, as I've always used rawhide. Between jewelry and leather work, I usually have a few mallets of various sizes/weights kicking around. Do you have enough brass that you could try it on a small piece to see if it leaves dents or not?

Mace is right, his figure eight sanding suggestion will give you much better result than just going back and forth. Try to keep your downward pressure as evenly distributed as possible. Check the underside frequently to make sure your sanding evenly. Adjust pressure as necessary. If you have trouble seeing where the sanding is happening on the brass, get a big magic marker and thoroughly ink the surface. Sanding will rub off the ink. It will be easy to see what's happening then.
 
ok i'll give it a try. i have enough to mess up a few peices. will a clamped down peice of steel be ok? the closest thing to an anvil i have is th back of my vise that is for peening pins and other things. and it's smaller than the liners i will want to make. i'll pick up a fiberglass mallet and a rubber one next time i goto the hardware store.
 
The brass might flatten easier if it is annealed first, no spring back to the brass then.

Annealing brass...cut pieces to rough size, heat with a propane torch until it begins to glow, dip in bucket of water to cool. Start tapping the brass flat.

George
 
George beat me to it.
First anneal the brass. Them straighten gently. Do not strike it hard.
One trick is to place it between two smooth pieces of 1/4" steel and hammer the steel. This usually straightens small annealed pieces in one blow. George was spot on about cutting out rough size pieces,too.If you just place the whole brass sheet on a smooth surface and hammer on it, it will warp worse. Each hammer blow, regardless of the hammer type, will slightly dent the surface, The metal displaced will try and move to where the hammer is not at, so it raises a curve next to the micro-dimple you just made. So you try to flatten this new place....and the sheet warps more. This is how we raise a bowl from a flat sheet of metal. A good silversmith can, with many annealing cycles and thousands of well placed hammer blows, raise a cup from a 4" circle of 16 gauge sheet silver.
Stacy
 
Whoops, I never thought about how you might be starting with a piece of work hardened brass, but it sure could be possible. The metals we get for our classes are not. The 11th grade jewelry classes have been making rings from pierced copper sheet sweat soldered to sterling sheet. Each of the students flattens their distorted copper strip (after cutting it off the sheet with shears) with a rawhide mallet on a piece of steel without dents. In 9th grade we do almost what Stacy just mentioned... make bowls from 6"-7" pieces of copper sheet. You can kind of make out a piece leaning against the Buddha in the photo.

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I'm not sure what your sources are there in China. Seems like you should be able to find one. The leather and jewelry making supply stores here carry them. There are always some available on eBay.
 
I'm not sure what your sources are there in China. Seems like you should be able to find one. The leather and jewelry making supply stores here carry them. There are always some available on eBay.
Click to expand...

i'll look around over here, since shipping is usually a killer. unfortunately internet shopping over here is fairly primitive.
 
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