Author Topic: annealing brass sheet  (Read 1303 times)

Offline PJW

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annealing brass sheet
« on: December 24, 2018, 06:56:38 PM »
I have a piece of brass sheet 1.5mm thick  13 x 22cm, I need to anneal it, all I have is a gas blow lamp, how is the best way to go about it. I need to put a big radius for a loco cab roof but it is like a big spring at the moment?? any ideas please.
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Offline Jo

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Re: annealing brass sheet
« Reply #1 on: December 24, 2018, 07:03:07 PM »
You don't need to anneal it to put it through a set of rollers to form a single direction curve.

Jo
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Offline Jasonb

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Re: annealing brass sheet
« Reply #2 on: December 24, 2018, 07:15:34 PM »
What type of brass is it? The harder brasses such as CZ120 will not bend as easily as as "half hard" brass like CZ108 which is the better brass for any sheet work that required bending and should be easy enough to get to stay in a curve even with gentle hand bending.

You can usually tell the CZ108 as it is a less silvery and when drilled will produce spirals of swarf not fine chips.

Offline PJW

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Re: annealing brass sheet
« Reply #3 on: December 24, 2018, 07:30:00 PM »
Hi Jo, I haven't got any rollers or know anyone who local who does (Mansfield area), I have tried to gently form it by hand but it is like a big spring, that is why i thought of annealing it. I didnt want to attack it with a blow torch as I want it even and not leave parts that have not been treated enough???
if anyone local has some rollers that would be nice.
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Offline crueby

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Re: annealing brass sheet
« Reply #4 on: December 24, 2018, 07:34:21 PM »
Annealing any brass will require getting up to a dull red color - one thing that could help is making a little cave out of stacked firebricks to contain the heat and get it to heat evenly, will allow use of a smaller torch than normal - you want it heated fairly evenly, not just one small hot spot at a time. As Jo said, if you can get access to a roll bender that would be the best, would not need to anneal it. Very careful bending over a form can work too, something a bit smaller diameter than the roof shape is best, though it can be hard to find - if you have a bandsaw you can cut a block of wood to bend over by hand.

Offline Ramon

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Re: annealing brass sheet
« Reply #5 on: December 24, 2018, 07:54:07 PM »
Hello PJW -

I really wouldn't consider annealing it by flame as you will, in all probability, induce a buckle in to it.

If you cannot find anyone locally to help you then providing you are happy to pay the post each way I'll be more than happy to roll it for you FOC. You would need to send a template of the radius of course. PM me if that's an option you are happy with.

Regards - Tug
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Offline PJW

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Re: annealing brass sheet
« Reply #6 on: December 24, 2018, 08:11:25 PM »
Thank you for your kind offer & I will take you up on it, I will make a template for you and I will organise postage after Christmas, i was  not happy with just taking a blow torch to it, that is why I asked advice. if you can message me with your address i will sort out a box and return postage for it, once again thank you so much,

Peter
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Offline Ramon

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Re: annealing brass sheet
« Reply #7 on: December 29, 2018, 03:14:03 PM »
It's in the post Peter  ;)

Hope this is up to expectations, it's the best I could do with what I've got.





It's as near as I could get to your template - you may have to tweak it a little

Happy New Year - Tug
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Offline steamer

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Re: annealing brass sheet
« Reply #8 on: December 29, 2018, 03:18:17 PM »
To bend radiuses like that, i cover the piece with thin cardboard and using a cylindrical anvil, and a rubber mallet, slowly beat it round    only strike on the center line of the anvil.   It will slowly start to curl and you will find you have a lot of control over the process
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Offline steamer

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Re: annealing brass sheet
« Reply #9 on: December 29, 2018, 03:24:02 PM »
And no it doesnt leave hammer marks.   Lots of light strikes gets you there
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Offline steamer

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Re: annealing brass sheet
« Reply #10 on: December 29, 2018, 03:44:24 PM »
My Launch engine is lagged with 16 ga brass sheet manipulated as I described.  It was polished to begin with, in the flat, and the cardboard keeps it from getting scratched.

Masking tape would work as well

It's not a close up, I can take a close up if you want but it's nice and smooth and mirror finish without any sanding.   It's a very gentle process actually.



Dave
« Last Edit: December 29, 2018, 03:49:15 PM by steamer »
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Offline PJW

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Re: annealing brass sheet
« Reply #11 on: December 30, 2018, 09:38:05 AM »
Thank you Ramon, that will look so good when it is finished, a set of rollers is super to have but the sort of item I would use every ten years, & would take up valuable space in my little workshop. I will make a donation on your behalf to our local food bank if that is ok with you!

A Happy new Year to you & all the other forum members!
Peter
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Offline Ramon

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Re: annealing brass sheet
« Reply #12 on: December 30, 2018, 10:56:24 AM »
Hello Peter - you are more than welcome, glad to be of help. I made the rollers as a 'lunch time' project at work so many years ago. As you say, they sit under the bench just waiting for the right opportunity  :) Though I posted it yesterday I don't think it will go until Monday so I guess you should get it by Wednesday.

Dave - that's some very nice work on that lagging especially with doing it as described :ThumbsUp:

Happy New year to you too guys and to all of course

Regards - Tug



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Offline steamer

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Re: annealing brass sheet
« Reply #13 on: December 30, 2018, 01:20:14 PM »
It was quite easy.  The trick was to strike on the anvil only.   Its no different than an english wheel or a planishing hammer.
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Offline steamer

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Re: annealing brass sheet
« Reply #14 on: December 30, 2018, 02:11:47 PM »
Here's a schematic.   Only strike directly over the anvil   Only strike with a rubber faced hammer

The more you strike, the tighter the bend radius.  Work from the center of the bend out evenly by moving the work left to right and move the hammer front to back

Work across the piece evenly.  It's a slow process, yes, but that makes it very controllable.

Dave

"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!