Very high value resistors

Only pole transformers may not necessarily have a fence. They're mostly in sparsely populated areas.

A fair bit of industry takes 11kV from underground cables, a few heavier industries take 33kV, Foundries with blast furnaces take too high voltage for buried cables - probably 275kV. Around town distribution is probably less than 11kV, but I don't know the figures. The lower the distribution voltage - the more they have to spend on copper.

What about ethyl?

Good with orange juice. Replace the stock with some drugstore IPA....

My drugstore has both. What's it for? If IPA has water and maybe mineral oil in it I wonder what's in the ethyl. I doubt it's pure.

Then of course there is the IPA that already has ethyl alcohol in it. It's in the drugstore, but it's over in the Beer and Wine department... under India Pale Ale. I don't suppose it's very good with orange juice, however.

Bob Masta DAQARTA v9.20 Data AcQuisition And Real-Time Analysis

Since I'm usually only stuffing and testing one or two of each board, I just use the same solvent I use for optics: HPLC-grade methanol. (Or at least it was HPLC grade before I put it in a Nalgene wash bottle.) ;)

That and a toothbrush seem to work fine, as long as there are slots under the super-high-Z parts, and guard traces sprinkled appropriately (with the solder mask removed, of course).

Cheers

Phil Hobbs

If you go light on the OJ, the IPA makes a good chaser. ;)

Cheers

Phil Hobbs

Or a Shandy... (Something my wife might do.)

George H.

John Stuart Mill / Of his own free will / on half a pint of shandy/ was particularly ill/ ....

Cheers

Phil "Not as fond of his dram as Thomas" Hobbs

I recall little humming dehumidifiers in the basement of Physics Hall, where the astronomers were redistilling their alcohol by evaporating from a pan (below boiling temperature) and wafting the vapor over cold coils to condense. Their concern was with cost, of course. No ethanol involved. No tax issues, either. Honest.

If you heat to boiling, the bubbles burst and create droplets of impure solvent, which gets into the output. So, they didn't do that.

Cleaning up denatured ethanol is a pain, and so not worthwhile when Polmos is $17/litre retail. (My liqueur-making spies tell me that Polmost rectified spirit is much better than Everclear. I've never done an A/B test myself.) ;)

Smart, if you have the time available. The other approach is to run the vapour through a sufficiently fine filter. Ultrafilters down to 15 nm pore size are readily available.

Interestingly, those ones are made by solvent-casting polyethersulphone with a little water in the mix. It forms a foam whose pore size is a very predictable function of the water content, and the matrix is pretty inert, at least to polar solvents.

Cheers

Phil Hobbs

Why is denatured alcohol a pain to clean up? (are you worried about absorbing the methanol?)

So you Polmos, to clean your circuit boards?

George H.

(My liqueur-making spies tell me that

"Clean up" as in "distill into pure ethanol". I was alluding to W's reference to tax and ethanol.

Nope, 99.9+% methanol, about $60 for a 4-litre jug from Fisher Scientific. I'd be quite unlikely to use anything with much water in it, and I'm sure not using anything remotely resembling aqueous ammonia.

But all my boards are Sn63 with rosin flux. ("No clean" flux in leaded solder paste is good old RMA.)

Cheers

Phil Hobbs

If there's anything ionic to be removed, distilled water or water/alcohol azeotrope (i.e. don't take water-removal steps on the solvent) should work better than anhydrous solvent. The removal mechanism, diffusion, scales with square root of time, so a wash ten times more effective than a ten-second rinse, takes a quarter hour. Maybe that's why water-soluble flux (which is ionic) is antipreferred.