Resurrection of a CFEI 100 KVA Induction Furnace

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awemawson:
It's a squally wet day here today so no outside work - what a shame I'll have to get on indoors with those hoses :clap:

First off, before anything is cut, I need to sort out the hose lengths - they are not all the same, but I'd made the originals to be the same resulting in them sitting at odd angles - set them up and measure the difference. Turns out that the two at the top (A&B) need to be six inches longer than those at the bottom (C&D) at the Furnace Driver end due to the A&B angled fittings having to clear the C&D ones.

Then I did a forensic dismembering of one end to remind me how I put them together - it seems that:

A/ I've crimped the 70 mm CSA stripped welding cable into a tubular lug, which I've brazed to a length of 3/4" Imperial copper pipe

B/ The copper pipe is brazed into the screw end fitting

C/ The Brewers Hose is pushed on to the 3/4" copper pipe

D/ Three 1/4" Band-It clamps have been fitted

E/ All is then served with black heat shrink tubing

I have all the bits (must check my box of Band-It bits though) bar the heat shrink which is coming on Tuesday

Now I noticed that in the act of pushing the Brewers Hose onto the 3/4" scalped the innards of the pipe leaving a bit of rubber pushed down the pipe, so I must take precautions when I do it this time.

russ57:
Looks like there isn't a lot of room for water /coolant inside that hose...

Certainly hope the copper cleans up. It looks pretty manky...

So close and then someone orders a couple more meters of tunnel.

-russ

awemawson:
Yes that was my reaction when I first opened it up just now Russ, but I think what has happened is that manipulating it to cut the rubber has scrunched the weave of the welding cable up making it fatter and more open weave.

The new hoses will be about one metre shorter so I can lop quite a bit off each end, but I did just now go and check that when twisted back there is room, and it should be fine :zap:

hermetic:
this could partly be the reaction of any sulphur in the rubber leaching out and attacking the copper, especially in the presence of warm water! Same reaction seen in early VIR cables, which was why they started using tinned copper wire in VIR.
Phil

awemawson:
So I stripped out the cable from one old hose (the burst one, not that that matters much) and un-brazed the crimped lug. I'd hoped to do it with a propane torch but in the end had to use the big guns and dragged the O/A set out. The Portapak had a cutting torch on it but we managed!

OK time to get brave and cut some new hoses, but first I needed to check that the 16 metres had indeed been delivered. It just fitted stretching from the foundry to the end of the welding shop tied between two 1 CWT cast iron weights which not only let me check it's total length (marginally over 16 metres :thumbup:) but also mark out the two versions of two shorter by six inches.

Time to pull the copper wire into a length of hose. That went easily using the reel of yellow fibreglass duct pulling rod.

What didn't go easily was getting the 3/4" copper pipe with the lug brazed on into the new rubber pipe -far too tight. It's the lug stopping it, so I'm going to have to re-design the fixing but that's enough for today.

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