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EssOilChem
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Quote: Originally posted by peach  | I spent today jet washing someone's garden at 3,000 psi with a 13hp washer. Fun stuff!
The alumina used for blasting is produced by melting oxides, letting it cool, crushing it and then sieving. That method (the bulk fracturing of lumps)
means that the resulting grit has sharp edges to cut away at paint, barnacles, scale, gunk, etc.
There's an interesting video from one of the manufacturers showing the process, here.
Aluminium oxide dust, from grinding through refractory, is kind of soft feeling by comparison.
I remember going to a place that sold refractory when I was about 16, to get some bricks. The place looked like a Columbian coffee factory with guys
in air fed bunny suits walking around, surrounded by clouds of white dust. |
I always thought the Columbian plants were run by naked women playing in gasoline... or maybe thats a different Columbian plant.
| Quote: Originally posted by starman | The tech specs for lab armor only give uasable range to 180C max ,kind of disappoimting. Material is stated as "metal beads",which could be
anythiing,presumably alloy.
Small brass bearings are available and may be suitable for use with magnetic stirring.
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That is quite disappointing, especially considering the price, those guys are making a mint off of what sounds like chopped up scrap metal. I was
definitely under the impression that it was pure aluminum, and could be used for higher temp applications.
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ksj_6808
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Allright, well i used to use an oil bath until i realized it stains the glassware and near impossible to get off...I havent found a reagent yet that
will remove the oil stains..Well i don't know if anyone here has tried this but i use a 3a molecular sieve bath, it's much like the bb bath, i haven't
tried the bb bath but it seems they would heat faster, anyways works well for me since i have a bucket of sieves laying around to make anyhydrous
solvents, i figured i may as well use them for baths too. regenerates them.
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weschem
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Plus you can buy about 10000 for like 15 bucks
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Swede
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How about #9 soft Pb shot as used by skeet shooters? One bag from a reloading store is 25 lb worth.
Non-magnetic, MUCH finer and softer than steel or Al shot.
Plus, you can use the Pb when needed for chemical reactions!
On the negative side, you'll have Pb toxicity to worry about, and it may stain ceramic mantle covers. I can't imagine the mantle getting hot enough
to melt the Pb, but it's possible.
Tin shot? Bismuth shot as used by the waterfowl shooters for non-toxicity reasons?
[Edited on 19-11-2012 by Swede]
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CaliusOptimus
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McMaster has a good selection of shot in lead, steel, and stainless. The 35-70 mesh stainless shot would probably make a really effective bath. I'd
try it, but I don't have a hundred bucks to burn.
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weschem
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Remember lead has a relatively low melting point at around 327 Celsius.
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l0k1
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stainless steel ball bearings would not be ferromagnetic. but, and i could be mistaken, but wouldn't any kind of metal bath cause eddy currents and
reduce the power of a magstir? for the purposes of up to around 700 celsius, i would think that tiny glass beads would be better and would not
concentrate the heat quite so much.
another option that might work better still would be small beads of compressed carbon. carbon has high thermal conductivity like metals but does not
acquire magnetic moments, in fact the opposite, magnetic fields are partially opposed by diamagnetic materials like water and carbon, but the
counterforce is so small as to be insignificant.
a product of the type i am talking about would be this: http://www.vascaaquariumsupply.com/Seachem_500_ml_MatrixCarb...
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Oscilllator
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It is possible to use an alloy with a low melting temperature e.g. woods metal as a bath, however they often contain lead, are expensive and some of
them wet glass. Other than that, they would be the perfect heat bath!
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weschem
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at the same time clean up would be a problem for using low melting metals. Indilloy 117 would be the best for that. It literally melts from the
temperature created from you hand.
[Edited on 11-26-2012 by weschem]
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watson.fawkes
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| Quote: Originally posted by weschem | | at the same time clean up would be a problem for using low melting metals. Indilloy 117 would be the best for that. It literally melts from the
temperature created from you hand. |
It would be a great, except for the toxicity of both lead and cadmium in
that alloy, and the expense of the indium. Fact sheet from Indium Corporation, which has the trademark on Indalloy.
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chucknorris
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How about steel grains? I found a bag of 0.2-0.4mm sized stuff. I also found 0.5-1mm sized, which one is better, the smaller or larger ones?
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Oscilllator
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| Quote: Originally posted by chucknorris | How about steel grains? I found a bag of 0.2-0.4mm sized stuff. I also found 0.5-1mm sized, which one is better, the smaller or larger ones?
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If they are to be used with a magnetic stirrer then they wont work because steel is magnetic, silly.
Good stainless steel is pretty much non-magnetic however, so you could use that.
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hyfalcon
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aluminum or copper would have a better heat conductivity.
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Dr.Arz
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| Quote: Originally posted by Bot0nist |
"I don't know if they are copper (probably plated), but they are BB's for airguns. They work much better (and less mess) than sand." ~smuv
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What is that electric heater circuit in there? Can anyone tell how it can be made or where those can be bought? I have done some nichrome heaters
before so if it's that simple, then I'm interested how did you insulate it?
Btw does anyone know how to calculate nichrome wire specs?
[Edited on 19-10-2014 by Dr.Arz]
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Funkerman23
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| Quote: Originally posted by Dr.Arz | | Quote: Originally posted by Bot0nist |
"I don't know if they are copper (probably plated), but they are BB's for airguns. They work much better (and less mess) than sand." ~smuv
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What is that electric heater circuit in there? Can anyone tell how it can be made or where those can be bought? I have done some nichrome heaters
before so if it's that simple, then I'm interested how did you insulate it?
Btw does anyone know how to calculate nichrome wire specs?
[Edited on 19-10-2014 by Dr.Arz] |
Are you asking about the heating mantle? I could explain but... the truth
is you'd be better of buying the thing alreeady made. as for Nichrome wire usually the( reputable) seller will either label the resistance or will
gladly tell you. One needed forumla can be found here http://hyperphysics.phy-astr.gsu.edu/hbase/electric/resis.ht... and a general resistance value for nichrome is 1.1 × 10-6 Ωm but that value
does change with temperature.
this might help as well ( PDF download link) http://www.google.com/url?sa=t&rct=j&q=&esrc=s&a...
EDIT: WIth matles I've had the best luck with a genuine Variac but I also restore tube electronics so I already had one to use. there are a few
threads here that talk about using a dimmer switch with mixed results. If you mean the blue thing that is just an IKA brand hotplate /stirrer.
[Edited on 25-10-2014 by Funkerman23]
" the Modern Chemist is inundated with literature"-Unknown
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Oxirane
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Has anyone think of heating steel shot bath with induction heater?
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Oscilllator
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Personally I think air baths are underrated. I use an old propane barbecue burner in conjunction with an aluminium saucepan. Place the RBF inside the
saucepan and temperatures of 2-300° are easily achievable. Obviously this method takes even less time to heat up than BB's or sand, as well as being
less messy.
I imagine that this method would could be difficult to use with a hotplate though, because of its lower heat output.
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