Annealing is basically just heating the metal to make it easier to work and the instructions say that you can do this by simply placing the part on an electric cooker hob for about 10 minutes. Unfortunately we have a gas cooker and I wasn't sure how I'd support the part in the flames, so instead I decided to use another item from the kitchen, a blow torch. Usually the blow torch is used for melting the sugar on top of a creme brulee or this excellent Lime and Passion Fruit Tart, but I thought it should be able to heat the brass well enough so I set up a sensible looking work area and turned on the blowtorch.
Fortunately I'd decided to measure the part (10.75mm by 23.5mm) while it was flat before I tried annealing it, so I made a replacement using some 0.25mm brass sheet from Albion Alloys. This sheet is slightly thinner than the part from the kit, but not noticeably so, and can just about be formed without annealing. I gently rolled the part using the handle of my modelling knife and then soldered it in place which definitely transforms the look of the rear of the cab.
Your description of this build is very honest and much preferable to the usual accounts one reads where the model apparently falls together. It also echoes my own experiences...but you are making great progress and I do admire your determination, I have a feeling this is going to be a super build. Very keen for the next instalment now :-)
ReplyDeleteYes, it's definitely not a kit where you just shake the box and out falls a finished model. Of the six parts I've put together so far, one broke while trying to form it to fit and one part I destroyed so not a straightforward build. This isn't to say it's a bad kit and I'm sure someone with more experience of putting these kits together would have less problems than I'm having. I'm still enjoying it immensely though.
DeleteNext up will be the smoke box and boiler according to the instructions.
Nothing in a p/e brass kit needs annealing, at least for a gentle curve like that. You could have rolled that round a broom handle trapped in a vice or even with your thumbs.
ReplyDeleteFor future reference, when using a blow torch, hold the point of the flame about an inch away from the brass and keep it moving constantly. You should see the discolouration on the metal start to dance between colours. At that point, cherry red glow or not, it's annealed. Let it cool naturally. Water cooling can distort thin sheet, but really, you don't need to anneal anything below about 1.5mm (1/16th") in order to put a gentle bend in it. I've been a brass basher for 40 years, trust me.
Useful to know thanks. I'm guessing my problem was that I got the blow torch too close and held it still for too long. Amazingly the kit suggests to anneal all the parts that need rolling even the half-etched parts ((can roof, etched saddle tank) which I thought I could form without heating. I did try rolling the coal bunker but I didn’t seem to be making much of an impression hence my attempt at annealing. Fortunately as it had no etched detail on it at all making a replacement was nice and easy. I certainly won't be trying to anneal anything again unless it is a lot thicker than the metal in this kit.
DeleteMark just after the cone is the hottest bit.
DeleteOdds has got it right Mark.
ReplyDeleteIf it's brass shim it is springy. Brass shim is a different alloy. Ask the kit man what stock he is using.
I used to hammer a lump of coke to powder pop in a box I welded up and put the box on the gas ring. The coke does catch fire if you leave it two long. It also smell horrid so best to do it when she is out. Brass just lay it on top and as soon as it changes from a brass colour it's done.
Should you need to anneal aluminium then wipe it with soap as soon as the soap turns brown it is also done. If you need to harden either then quench immediately in cooking oil or diesel. Might be good for valve slides.
You are having a grand time. I suspect I can see a day when you settle into live steam.
As far as I know, etchers use a nice CZ120 sheet. That's what I always used for my brass car masters. It's called engravers' brass or half hard, also silicon or leaded brass, but it's springy as Adrian says and it polishes up like a good gold, better in my view. I rarely annealed sheet to start a master, but after the first silver (hard) soldering joint the whole thing would be annealed anyway! Fine detail then went on with soft solder.
ReplyDeleteI shall just continue watching and learning and being fascinated even though I will probably never use the information in a practical way.
ReplyDelete