Making a Bowman Burner, by Steve_S
My Bowman M140 and M158 both lacked burners so I've had a go at making some, the intention being to make them look reasonably similar in style to the originals. I haven't included any exact dimentions for length of wick tube or depth of tank as I think it's best to make them to fit the individual engine, and there's quite a bit of variation in firebox dimentions in the Bowman range. The tank is made from two inch diameter brass tubing, but copper would be just as good. The slotted tube is 5/16 inch diameter brass tubing which can be obtained from model shops.

The first job is to cut the two inch tubing to give the desired depth for the body of the tank, but don't forget that the overall height of the finished burner will include the domed top. The top and bottom of the tank are made from brass or copper sheet. For the bottom I cut out a square just big enough to cover the end of the pipe, but for the top I cut out a slightly bigger square, about 5mm oversized.

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Forming the domed top is easiest done with the aid of a wooden jig which consists of a bit of wood with a two inch diameter hole in it. I cut this with a hole saw, but it could be done by other means... exact size isn't critical.

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I annealed the brass for the top by heating it, then started hammering. I used the ball end of a ball pein hammer, and re-annealed the brass two or three times during the process.

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After some initial shaping, I placed the tube which will form the body of the tank on top of the domed top piece, and drew round it with a pencil. Then I marked a point about one third of the way in from the circumferance to the centre, and drilled a hole for the wick tube. It's best to make this hole a bit smaller than the diameter of the tube at this stage. The hole will need to be oval in shape so that the wick tube can emerge from the top of the tank at the correct angle. It's a iterative process... a bit of hammering... a bit of filing... checking often to see if the tube fits properly and if it's coming out at the right angle. If it's not, hammer and file some more. At this stage I also trimmed the brass top with tin snips to be roughly circular but a bit bigger than the diameter of the body of the tank.

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Eventually, with a bit of luck, the wick tube will emerge from the top cover horizontally as it should. Check also at this stage that the top cover touches the top rim of the body of the tank all the way around the circumferance. If it doesn't.... more hammering.

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When everything seemed to be the right shape, I cleaned the mating surfaces with wire wool, applied some flux, and tinned both halves with solder.

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The top cover was now be soldered to the body of the tank by placing it in position and applying the heat, and a touch more solder if necessary. I cleaned the brass sheet which will form the base of the burner, and the bottom rim of the tank, then fluxed them both. I didn't bother to tin them this time, I just positioned the burner on the base and applied heat and solder.

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Next I filed off all rough edges and gave the whole thing a good rub with wire wool. At this stage it's a good idea to look for any obvious gaps in the solder and remedy as required.

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Next, the wick tube. I placed the tube in position in the burner body and checked the length required against the firebox of the engine. I cut the tube to be slightly too long, say about 2mm, to allow for a bit of filing later. I marked out the position of the required slot with masking tape. The exact size and position of the slot depends on the particular engine. I'd suggest, as a rule of thumb, that the tank end of the slot should start about 1cm from the body of the tank, and the other end of the slot should be about 1cm from the end of the tube. Of course, if you have a real Bowman burner to copy from, then take dimentions from that. The slot was cut with a disc cutter in a Dremel clone, then tidied up with a file and wire wool.

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Next I soldered the tube into the body of the burner after the usual cleaning and fluxing. This looks like it's going to be tricky, but if the parts are well cleaned and fluxed the solder should flow around the joint easily. I also sealed the end of the wick tube by soldering in the head of a suitably sized bolt.

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Then I sawed off the protruding bolt threads at the end of the wick tube, and filed the end flat. I also cleaned up the solder joint between wick tube and body with wire wool. It's starting to look like a burner!

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It needs some sort of screw-on filler cap. In the past I've used brass nuts and bolts which are fine if you can find a suitable size. On his occasion I found in my bit box a short length of threaded brass tube and some brass nuts which fit it, so I've used these. I soldered a small flat piece of brass across the end of the threaded tube, and filed this to be circular. Whatever you use, don't forget to drill an air hole in it. I filed the flats off a brass nut to make it circular, and soldered this over a hole drilled into the top cover of the burner.

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Almost there, just needs painting. You could leave it unpainted and just polish it if all the joints are neat enough! Bowman burners are usually cream or green, and I decided to go for cream which will suit the colour schemes of my M140 and M158 I hope. I also decided to depart from Bowman practice and not paint the full length of the wick tube. I suspect it would very quickly look tatty where the paint would be almost in direct contact with the flame. I masked off the appropriate parts and sprayed it with four coats of cream enamel, followed, after it had dried, by an hour or so in the oven at 110 degrees. A quick rub with some Tcut makes the paint
shine, but don't rub too hard or you'll be down to the brass.

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