Oh Shit!
by John
PART 1
I was drilling a hole in the end of the Trevithick burner today. The burner was securely held in the vice, but the heat annealed brass was not as strong as the torque in the 6mm drill bit.

After the initial self hatred at misjudging the situation, I thought …oh well, I will have to make another one. Then I thought, …I wonder if I can repair it…..
I still have the wooden forms which I used to make the burner originally, so, roughly twisted the part back into shape. It was pretty malleable still. Then forced it into the wooden form. And beat it into shape with the copper hammer. This was looking promising.

Then forced in the other part of the form, and applied the 20 ton hydraulic press.

The curved shape was pretty good, but there was still some twist.

I still had to drill an 11.5mm hole, so this time I used the form, successfully. Then removed the twist by hand after knocking out the form.
Tapped a 1/2″ x 26tpi thread, and assembled the burner.

All beautiful again. And now the burner tube is properly secured. The bulge under my thumb was pushed straight.
PART 2
My reader/advisor Huib, suggested filling the tube with stainless steel scouring wool, in order to improve the flame.
I asked SWMBO, and was directed to the appropriate supplier.. the local supermarket.

Bought 3 types of stainless steel scouring pads. The finest grade was available only impregnated with soap. I am not sure how soap burns, probably pretty well, but I do not need that added complication. Fortunately it mostly came out when tapped. All very inexpensive.

Then I experimented with all 3 grades, various degrees of packing it in, and using various lengths. I even tried mixing the different types of steel wool. It cuts easily. Eventually I decided the best way was to have a loose wad of the fine mesh in the first 1-2 cm of tube, then a very light piece of the fine mesh in the distal 10cm.
It has improved the flame; there is no back lighting of the jet itself, and there is a more even flame along the length of the tube. I think that I will be able to improve the flame further, but will wait until I can test it inside the boiler itself. In the video the roaring of the flame drowns out my voice somewhat. You will not miss much. I am varying the gas control.
So, sorry about the voice track. The stainless steel stuff is interesting. It is like swarf, but not sharp. I wonder how they make it. I imagine that it works in the gas-air tube by creating swirls and eddies, and better mixing the gas and air, without impeding the flow much.
Back in the workshop tomorrow. A few connectors to make, check the feed pump, then make an appointment with The Boiler Inspector.
By the way. The parcel opening post was apparently not very interesting, so I wont bother with that format again. I am aware that my video technique was pretty ordinary, but I am not inspired to try that one again. Pity. I enjoyed making that one.
Well John I beg to differ re opening the present.
I had a great time wondering what was next and was envious of those tiny milling cutters and what they might be used for. Love those precise small projects.
Your patience and experimentation with the burner is admirable John. Understanding the final successful set up will benefit all who want to GASS fire.
Cheers,
Tim
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Thanks Tim. I will see if your opinion is repeated by others John
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would two burner pipes side by side work ?somewhere I seem to remember seeing this the angle of the two flames also makes a difference
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with one jet? Might be worth trying but I would prefer to be moving onto other things. The burner has been bugging me for a couple of weeks. I am hoping that this latest iteration will be OK.
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Really nice save! It always feels great when you can recover from a mistake that threatens to trash many hours of work.
Well done…
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Yes it was quite satisfying!
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John I’m pretty sure you’d know this, but just in case…Venturis work best with a small air inlet and a much larger outlet. This setup accelerates the air entering (in your case the combustion area) thus providing a good fresh flow of oxygen.
I’m not sure how you incorporate this. Perhaps restricting the area of intake significantly is worth a try. Blocking most of the inlets is a quick and easy experiment.
FWIW.
Tim
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I tried blocking some of the inlets Tim, and it made the flame worse. Most gas camping stoves have the sort of air openings which I have here. John
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Two idendtical burners with jets could you replicate the first without too much trouble twice the gas twice the air but allow them to be rotated to give the best burning position . Nothing to lose .just a lot more holes to drill
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Hmm. Worth considering, but I will test my current setup first, with steam. I am reasonably optimistic that it will be OK.
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ps. drilling multiple holes is quite satisfying with CNC. The 60 holes in the current burner probably took all of 5 minutes, including centre drill and through drill and changes. Hmm.. video idea.
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