The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
awemawson:
Thanks Tom :thumbup:
The 'High Flow' propane regulator arrived this morning. Output supposedly 3/8" BSP and is printed on the outside of the box but when I looked at it and tried a 3/8" BSP fitting it wasn't ! Delving into the box the instructions say 3/8" NPT
Now 3/8 BSP is 19 TPI and 3/8" NPT is 18 TPI - they are NOT compatible when hoping for a gas tight seal :bugeye:
A pain as I've had to order up an NPT hose tail, and NOT the sellers fault as Silverline had marked the box BSP - some one has screwed up !
awemawson:
Time to replace the hoses on the Torch associated with the Ceramic Chip Forge. It occurred to me that I hadn't taken a picture of it burning previously then I realised that it was that the old hoses were SO stiff and inflexible I couldn't hang it on it's allotted hook for the picture. Not so now - I'm using 8 mm i/d propane hose for the gas and 10 mm for the forced air. These are close but not identical to the originals which are undoubtedly Imperial sizes.
It was such a struggle to get the fittings onto the hoses that I had to resort to unusual means. I'd tried loads of lube and boiling water to no avail, what I wanted was something hot and slippery - a cup of very hot oil to dip the hose in. Searching about for a suitable flameproof metal container I settled on a 'turn over handle' that I'd made to set the timing on the Thwaites dumper truck. Set in the vice. 3/4 filled with oil and heated to 125 C with a blowlamp it worked quite well. Hold the hose end in the 'cup' let the rubber heat up, push it on. Still quite a struggle but far easier than using hot water !
I'm still waiting for the proper double ear 'O Clips' for the 10 mm hose so that has temporary ones on at present. Torch now easy to manoeuvre with no more fighting the hose to get it where I want it.
There is one 'strangeness' that I want to get to the bottom of. If the hearth is burning there is no gas going to the torch, despite the fact that there is a direct connection from the gas supply to it (via a ball lever valve) I have a feeling that maybe it is because the gas to the hearth is drawn into its burner by air flow through the venturi and perhaps the gas pressure in the internal plumbing is pulled down sufficiently that air is drawn in via the torch gas jet. This effect is also exhibited by the 'Bunsen' pilot jet.
When my 'High Flow' regulator is plumbed in (awaiting an 8 mm 3/8" NPT hose barb) maybe this symptom will be eliminated.
hermetic:
Very interesting Andrew, that torch looks a lot like mine, and yet the flame sems to be reversed, you have a flamein the centre, whereas I have a flame round the outside? I wonder if some idiot at this and has the hoses reversed?
Phil
awemawson:
Phil the air hose is fatter than the gas hose so hard to get them wrong :scratch:
hermetic:
I am going in this morning so I will check, but I think mine are the same diameter, and both RH thread on the torch end. My torch seems to be blasting air out of the centre hole, producing a cold core to the flame. Any road up, summats not Jannock, as my old boss used to say, i will check it out and let you know!
Phil
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