The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
awemawson:
The other day I managed to break my coarse bandsaw blade for my upright Startrite 18V10 bandsaw, and although it has a blade welder, this particular blade stock doesn't butt weld very well, so . . .
. . . it had to be the horizontal band saw which gives worse holding issues with a piston shaped object - however two cuts and one piston was reduced to manageable pieces for the pot.
I deliberately hit it with rather more energy than really needed as I wanted to load up the engine to make sure that the lift pump was pumping at a goodly rate. 50 kW and the alloy was jumping out of the pot, but the engine note never missed a beat.
So one piston reduced to ingot and the lift pump is performing apparently OK, however I strongly suspect that with the tank sited where it is at least 12" above the injector pump it would probably run without a lift pump at all!
mattinker:
Hi Andrew,
I imagine that here are no gas bubble problems with your induction furnace! I was thinking, is it worth ingotting? By the way , you probably know, Al car wheels are a really useful alloy, tyre shops are sometimes a good source!
Cheers, Matthew
awemawson:
Not sure about gas bubbles yet Matthew as I've not machined any of it, but it's on the to do list - in fact I'll try and do it this afternoon.
Yes alloy wheels generally machine nicely when cast, but with tight lock down at the moment I cannot drive around to make suitable contacts. It's tempting just to buy an expensive pallet load of LM4 or LM5 - no point in small quantities as the transport gets too pricey.
(Awaiting my invite for the vaccination as I'm in the second tier age-wise - hopefully this week)
awemawson:
OK Matthew, I've machined both the 'Diecasting Alloy Ingot' and the 'Piston Alloy Ingot'
No signs of porosity / gas bubbles in either and they machined beautifully, despite being a rough and ready hand feeding bit of machining using an end mill out of my 'waiting to be sharpened' box !
Quite pleasing really :thumbup:
(no saying if there are defects further in, but this is a good indication )
vtsteam:
--- Quote from: awemawson on January 25, 2021, 04:11:48 AM ---What I find odd about the rubbery one that I removed is that the illustration definitely shows it as flat, whereas mine is exactly curved to sit fully against the cover with no air (or fuel) behind it, and it it fixed at the periphery by the cover and the centre by the retaining screw thus greatly reducing any potential movement.
--- End quote ---
HI Andrew. My experience recently rebuilding a couple of outboard motor fuel pumps is that plain rubber diaphragms do often retain stretch over time even though they may start out flat. I also think that some of the modern fuel additives (not just ethanol in petrol but also additives in diesel) can soften the rubber and accelerate that kind of aging.
In normal usage, even though the pulsator is pinned down in center, the thinness of the rubber does allow elastic flexing into the space surrounding.
I think you're right that the height of the fuel tank relative to the engine intake probably provides fuel pressure by itself. I think the function of the pulsator diaphragm is not to provide fuel pressure (that's the function of the pump diaphragm) but to smooth the fuel pulses, and reduce the peak loads on the pump diaphragm and fuel line components. I don't think problems if any will show up in the short term.
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