The Unofficial Mamod and Other Steam Forum

Steve_S · Posted: Tue Nov 07, 2006 10:38 pm Post subject: Burnac Vulcan

I bought this Burnac Vulcan on ebay recently. It was in a pretty sorry state... chimney, piston, burner, sight glass and safety valve all missing, and the steam pipe had been wrenched from the top of the boiler.

This Vulcan has a copper boiler with a brass top. (Some of them are all brass... very nice examples on the websites of Mooseman and John Chapman.) These engines were made just after the war when materials supply must have been problematic, and legend has it that the brass Vulcans are made from war surplus shell casings. Anyway, this one being largely copper I thought that a copper chimney was the way to go. Luckily standard 15mm copper plumbing pipe is exactly the right diameter.

I made a new piston and connecting rod from some bits of brass from my "pieces-that-may-come-in-useful" box. It turned out that a Mamod safety valve is the right size for the thread, which was lucky!

The glass tubing from the sightglass assembly was missing. I'm still on the lookout for some suitably sized borosilicate glass tubing to replace it. It needs to be about 4mm OD, and there is a seller on eBay who sells 600mm lengths in quantities of 20. Its not expensive, but it seems a waste to have to buy 40 feet of it when I only need about 4 inches! Anyway, for the time being I've soldered a copper patch over the holes in the boiler where the glass tubing fits in. It doesn't show because its hidden by the brass sightglass holder. To make it look right I've put a glass fuse which I found at work in the holder.

The copper steam pipe has been replaced with a new piece. I was slightly surprised to find that the original pipe had a threaded end which screwed into the engine block. I haven't got a die of the right size to thread the new pipe, so I soldered it in.

Finally, I made a burner from scraps of brass sheet and part of a small tin.

Sandman · Posted: Tue Nov 07, 2006 10:43 pm Post subject:

One of the best restos I've seen.

A wonderful job. You should be really proud. Model engineering at its best.

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Mamodman123 · Posted: Tue Nov 07, 2006 10:46 pm Post subject:

Wow wonderful job Steve!

You are very skilled! how did you make the chimney?
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James · Posted: Tue Nov 07, 2006 10:50 pm Post subject:

IM SPEECHLESS

in a nut shell it is simply one of the best, if not the best restoration i have ever seen

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Steve_S · Posted: Tue Nov 07, 2006 11:11 pm Post subject:

Thanks for your kind words gents!

The chimney I made by heating the end of the pipe with a blowtorch then twisting the end of a pair of pliers in the pipe to bell it out a bit. I had to reheat it several times. Then I heated it again and put the ball end of a ball pein hammer in the belled out end, and tapped the other end of the hammer with... er.. another hammer. I've just read that back and I'm not sure it makes much sense! I'll post some pictures of how I did it tomorrow. I'll also give it a run and post a video.

I should add that I got the idea for the chimney making from Wallace... there was some discussion about how to do it in a thread a while ago.

tmuir · Posted: Wed Nov 08, 2006 12:04 am Post subject:

Nice job.
Well done
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Wallace · Posted: Wed Nov 08, 2006 3:40 am Post subject:

Great job steve
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oldstuff · Posted: Wed Nov 08, 2006 4:42 am Post subject:

Outstanding job, Steve! Not to impose, but how does one make a new piston? Has to be precise...special tools? Did you have another one to copy from? Lovely Burnac!

-Chuck

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First class job - I always ask - going to steam it?!

yosa · Posted: Wed Nov 08, 2006 7:43 am Post subject:

Genuinely stunning piece of work Steve. A real jewel in any collection. Well done mate.
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Steve_S · Posted: Wed Nov 08, 2006 1:07 pm Post subject:

Mike: Yes I'll definitely steam it! I'll post a video later.

Chuck: I'm afraid the process of making a new piston wasn't quite as scientific or precise as you imply! I found a bit of brass rod that seemed to be a good fit, that is, it moved freely in the cylinder without any lateral movement... or very little anyway! I drilled a shallow hole in the centre of one end and soldered in a piece of smaller diameter brass rod to act as the connecting rod. I heated the other end of the connecting rod and hammered it flat then tidied it up with a file. Then I drilled a hole in the flat section to take the pin on the crankshaft. I didn't have a Burnac piston to copy, but the overall length of the piston/connecting rod is determined by the distance between the steam hole in the port face and the position of the crankshaft pin when its at top dead centre. That can be measured with a ruler... exact precision isn't necessary, so long as its not so long that it obscures the steam hole at top dead centre, or so short that the piston falls out of the cylinder at bottom dead centre, then it should work!

sparky · Posted: Wed Nov 08, 2006 2:14 pm Post subject:

cant wait to see the videos mate

erikl · Posted: Wed Nov 08, 2006 6:14 pm Post subject:

wow! that's a superb restoration!
I think we all here might be able to learn a great lot from you.

Can't wait to see the video
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MooseMan · Posted: Wed Nov 08, 2006 9:34 pm Post subject:

That is just absolutely excellent - brought back from the dead. The burner's particularly impressive!

That's what I like, somebody using a bit of ingenuity in their restorations....first the 140, now the Burnac....what's next Steve?

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Steve_S · Posted: Wed Nov 08, 2006 10:10 pm Post subject:

Thanks Odilon, and everyone else! The burner works well, but it gets very hot which makes the meths vaporise a little more quickly than I'd like. I've had to make the air hole between the wicks a bit bigger because I was getting flames around the edge of the lid. I think this is a common problem with burners which have the meths tank so close to the heat... the Bowman style with the tank away from the flame is a better arrangement. I think you've made the same point on your site Odilon? Apart from the over-enthusiastic burner the engine runs very well, and its very responsive to adjustment of the exhaust throttle... I can slow it right down to a very slow tickover, or at full throttle it goes like the clappers! I'll post a couple of vidoes in a minute.