OldTools Archive
Recent | Bios | FAQ |
63699 | Paul Comino <p.comino@q...> | 1999‑06‑09 | Drying alcohol (for shellac) |
Galoots, Previously it was written in part: > One way is to use "absolute alcohol", and this >is what I would do if I could. But I can't, so I try to dry my own. But >that's for a future post. In days past water was removed from alcohol by methods of azeotropic distillation which left traces of nasty chemicals in the alcohol. Not good by today's standards. A Galoot-friendly method is to use "molecular sieves". These "sieve" materials are adsorbent crystalline zeolites in the form of pellets or beads with tiny "holes" in them that you can hardly see. (: There are three types commonly available - called 4A, 5A, and 13X with holes of 4, 5, and 13 Angstrom, and all are suitable for our purpose. All will remove alcohol from other substances, but they like water best! They can be bought from many scientific reagent suppliers, or you may be able to track down some discarded material. They are used to remove water and certain gases from infra-red equipment, and this is a possible source. Bags of the sieve are placed into the IR instruments, and purged with dry nitrogen to keep a clean spectrum and to protect components from moisture. Some manufacturers recommend that these be replaced every six months, and the old ones are thrown out. Some "re-charge" them by removing from the open-weave bag and heating, and they are as good as new. Better than new, in fact, as new mol. sieve should be dried before use if there is any question of it's history. Try a university science lab for discards. To regenerate used mol. sieve, it should be heated for a few hours in an oven or furnace to between 150 and 300 degrees centigrade, with cooling in an empty desiccator preferable. A word of caution for used sieve - find out what the ms was used to dry in it's previous life. As it is heated the residue will be forced out of apparently dry sieve. Best is the stuff used in IR instruments, or for drying gases (even refrigerant gases, I now remember). Even if only alcohol has been dried, it will be forced out as it's heated. And another lesson I learned in the School of Hard Knocks is that you can fill the space in an oven with alcohol fumes, and when the door is opened, you can end up with a spectacular eyebrow-singeing ball of fire!! The safest approach is to soak the ms in water for a day or so, drain off, let dry, then heat in the furnace. Don't be tempted to rely on the fact that water boils at 100 c, and that should be enough. We had a postdoc who didn't appreciate this until I took his regenerated-at-105 sieve and put it in a furnace at 250c. He couldn't believe the water condensing on the furnace above the door (it holds at least 15% of water). He ended up having to replace a $1500 beam splitter. Sorry, Mom's - back to the point. I'm sure there's a reasonably easy method to determine if the alcohol is dry, but I can't think of one right now (Add to dried copper sulphate, pot. permanganate?? GC(ms)/TCD? Anyone?). But if you work on 5 to 8% water, and 15% adsorption, then you can work how much ms you'd need to dry a certain volume of ethanol (easy if you're metricated). Of course if you need only to determine if it's over "proof" or not (about 50%), then all you need to do is to wet some gunpowder with the alcohol. Apply a lighted splint, and if it goes "POOF", you have your proof! Dry the ethanol by adding the cool dry ms to it in a sealed bottle. Leave for a day or three, mixing occasionally. Regenerate and repeat if necessary. Then carefully decant off the dry alcohol directly into your shellac container. Don't shake or mix first, or fines may be carried over. Unless you have a ready supply of ms, I wouldn't put any in with the shellac solution, or the shellac will have to be washed off before the next regeneration. I'm close to the wind topic-wise, but I reckon that in this case the end justifies the means. Keep your alcohol dry, Paul |
|||
63708 | "Nuno Souto" <nsouto@n...> | 1999‑06‑09 | Re: Drying alcohol (for shellac) |
Thanx Paul, for a most informative post. I'm always suss of commercial alcohol and its "dryness". Back home it's easy to buy ethanol at any pharmacy and one can get it near 100%. But here in Oz it's strictly verbotten... Never thought of using the drying crystals, though... Cheers Nuno Souto nsouto@n... http://www.users.bigpond.net.au/the_Den ----- Original Message ----- From: Paul Comino |
|||
63757 | Paul Comino <p.comino@q...> | 1999‑06‑10 | Re: Drying alcohol (for shellac) |
At 08:23 PM 6/9/99 +1000, Nuno Souto wrote: >Never thought of using the drying crystals, though... Nuno, Don't confuse molecular sieve with silica gel or the calcium chloride / calcium sulphate type desiccants. The ms appears as dull cream/white hard pellets which are sodium or calcium aluminosilicate. Under the right conditions they can take the water content down to 10ppm (10 parts per million) or better. Cheers, Paul |
|||
63758 | Minch <ruby@m...> | 1999‑06‑10 | Re: Drying alcohol (for shellac) |
Date: (Date Unavailable) I am an energy efficiency contractor (accepting questions) and have been building things in wood since 1968. My brother, the arch'tect, and I had a little house building business going in the 70's - solar stuff when there was still a tax credit. We would do everything in the house from concrete to framing to finish carpentry. The only things we subbed out were plumbing, heating, electrical, and carpeting - we did the rest. It took us about 5 years to realize that we can't compete with the guys who do each trade as a specialty and still make any money. However, in that time we "apprenticed" to a couple of different old galoots and came out of it with a healthy respect for hand tools. We had our share of p*w*r (12" radial saw!) but still had a respectable box of good handtools (I still have the primo Sargeant 424C) Over the years I have acquired more tools as needed for building a house full of furniture, several additions, about 6 houses, and a 40' sailboat. Since '93 I have been a volunteer carpenter on the Kalmar Nyckle, a replica of a1620's Swedish colonial ship that started their first settlement here in Wilmington Delaware. Have you ever seen 30 tons of purpleheart? However, it wasn't til the fall of '97 that I was epiphanized. I have a friend in Albany who enjoys his hand tools, and he came up with 2 toolboxes: One was owned by a carpenter working before the turn of the century, and the other by his son working in the 20's and 30's. The two boxes were roughly parallel in their contents except for the age of the tools - one had a wooden compass plane, the other a 113, one had a set of woodies, the other all metal planes (including an Auburn #6 with adjustable throat). There must have been 400 tools laid out in the basement. They were all used, but not abused, and the sight, the feel and the smell of the whole scene was intoxicating. I was being sucked in. Then in September of '98 I spent a couple of hours in the basement of a friend of a friend here locally. He said "I am not a collector, I am an accumulator". He has bought every tool that he came across that was cheap since 1980. His pride and joy is a small cabinet full of 147 tools that he paid a total of $150 for. Saws, planes, chisels, a #45 with a dozen blades, etc, etc. He has over 1500 planes, everything from 2's to 608's, 8 circular planes, countless block and rabbet planes, milk crates full of boxwood handled chisels and rosewood handled mitre squares, 3 leg vises! For the last 10 years he has been travelling to England and has been stricken by their stuff - over 50 infill planes including a Norris 1 - none higher than 40 pounds (about $80). About a dozen record 042's. A drawer full of little ebony and brass levels, etc, etc. He had 10,000 tools in that basement. Well, since fall of 98 I have been on the steep end of the learning curve. My mid-life crisis seems to be owning more tools than I could possibly use, but I also like to get them for others in need. I have been lurking for about 3 months and really enjoying the opinions, philosphy, and expertise of the accumulated mass. I have finally signed on. I have no idea how big the porch is , but it must be huge, and I enjoy being here. Now if I can only find a turn of the century caulking gun so that I can actually "use" my hobby! |
|||
Recent | Bios | FAQ |