The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
awemawson:
Every now and again I start up the generator to warm it up and blow the spiders away, and often fire up the furnace for the same reason - but it gets boring just heating a bit of steel to a nice cherry red, and I'm still not equipped to actually decant any into moulding boxes (no boxes made yet and the pump up table that will hold my moulding boxes during a pour currently has a VAST transformer on it that I can't move single handed :bang:)
Now kicking about at the back of my bench has been the remains of the die cast frame of a Dell Optiplex 'All in One' frame (PC and monitor all held together for desktop convenience - I just wanted the PC sleeve and it's mounting to screw to a wall by my desk!)
So rather than chuck the scrap out it got popped into the crucible during one of those 'spider clearing' sessions this morning. I reasoned that it is either a zinc or aluminium alloy, and if left to cool in the crucible it should shrink enough to shake out - just so long as there is no antimony in it, as that EXPANDS on cooling !
Sure enough hitting it with 30 KW for three minutes produced one kg of molten mystery alloy and on cooling it was easily removed - so what is the alloy?
This question prompted me to dig out my "Analoy Portable Alloy Identifier" - I'm sure I've shown it here before but probably a few recently joined members won't have seen it. There has an 8085 (I think) embedded microprocessor driving it. Basically you strike an arc between a graphite point and an earth terminal and the device gathers up the emitted spectrum and works out what proportions of what metals are present. (A predecessor to the XRF analysers of today)
Not surprisingly it turns out to be 85% aluminium, 7.5% silicon , 1.27% copper, 1% zinc with traces of Magnesium and manganese but what did surprise me was the 3.64% of Iron. I'm not at all sure that that was a deliberate inclusion or maybe something dissolved into the mix during processing.
. . oh and yes I HAVE ordered a new ribbon for the printer !
hermetic:
Sounds like chinese aluminium! not enough copper for duralumin, nowhere near enough zinc for zamak/mazak type alloy, so it must be mongrel aluminium! I like the look of that Analoy box of tricks. Clever stuff! How is the water level?
Phil
awemawson:
I've no doubt that the die-casting WAS made in China - much Dell stuff is / was but it actually was a very well made item.
No doubt the Chinese Dell assembler would have subbed out the die casting and although the alloy would have been specified the correct specification material probably wasn't used.
Subbies not using the correct specification materials has happened before. The MOD had a new sniper rifle, developed by Accuracy International who were a small outfit. When many more than they could provide were ordered the manufacture was subbed out and the wrong steel was used for the firing pin resulting in dangerous jamming and breaking - the weapon firing when the bolt was closed and not waiting for the trigger to be pulled :bugeye:
Accuracy International brought manufacture back in house and re-designed the pin so that it was visible at the rear of the bolt but of course if the right steel had been used it wouldn't have happened anyway .
awemawson:
--- Quote from: hermetic on January 21, 2021, 01:37:39 PM ---Sounds like chinese aluminium! not enough copper for duralumin, nowhere near enough zinc for zamak/mazak type alloy, so it must be mongrel aluminium! I like the look of that Analoy box of tricks. Clever stuff! How is the water level?
Phil
--- End quote ---
No more major floods but still loads of condensation on the floor the minute we go from cold to marginally warmer
vtsteam:
I'm sure you know Andrew, the only practical remedy for that is to seal all outside air openings as much as possible. Unless we heat the space, or dehumidify, or insulate above the slab. Well, or wait for spring.
I feel your pain. I think it's a common experience for any of us with small shed shops, unfortunately whatever the slab is doing in a high humidity warming environment, anything massive will also do, even if the slab were covered. So equipment in that situation will also have condensation on its surfaces. Even metal stock.
If a shop is tight and insulated -- that is lessened because the shop goes through longer temperature and humidity transitions than the outdoors so it sort of averages out enough to make the temperature differentials of massive objects and the air non-condensing.
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