[Paul_Guraedy]

Several months ago I read an article on the advantages of vacuum drying wood. Looking for more information, I did a google search (noncommercial wood vacuum kiln). Found an interesting articl on the "Woodcarver's Ezine".

http://carverscompanion.com/Ezine/Vo.../LynnDiel.html

which gives the details of building your own.

I talked to my brother (his business does commercial airconditioning) about building one using these plans. He says that it would be simple and fairly inexpensive. We would have to buy a small vacuum pump, but, he plans to build me one out of PVC salvaged from construction jobs. We plan on building it about 12-15" in diameter and 6-8' long. This should handle most of what I need. He says that given the small amount of vacuum needed that he could build me one to whatever size I would like.

Unfortunately, for me, things are booming in NW ARkansas and he has had to divide his time between current business and seeking new employees. You can't really tell a guy who depends on his own business to stop making money and work on my project for free. I will just have to wait on his free time. Oh well, I guess I will just try and get the 15+ roughouts I bought over the years finished.

[Hugh]

Paul, that sounds great. I'm going to try and make one. Thanks Hughj

[Paul_Guraedy]

Hugh,

Lynn will be instructing at the Spring Seminar the 2nd week of March. I want to meet with him and talk about this process (including the system itself). If you have any areas that you would like to have me go over with him just drop me a message (pdguraedy@yahoo.com).

I became interested in this process since I first heard about it. My wife and I have a ranch here in the Ozarks (650 acres) that is about 1/2 wooded. A few years ago, I started carving some small decoys about 4-5" with minimal detail. Finished them with tung oil so that they would remain fairly close to the raw wood in look. People are fascinated by these carvings (could even have sold several). I want to carve examples of the wide variety of woods here on the ranch. It is simply not feasible to pay for drying of small blocks individually (even if I could find a kiln drying outfit in this vicinity). This offers me the opportunity.

The photo shows basswood, redwood, black walnut, and oak (sp. unknown). Only the black walnut is from the ranch. Got it from my stack of firewood. Sure does bother me when I am burning black walnut in the fireplace.

[nadcarves]

Couple of comments..First of all, you need a trap to collect and condense the condensate before it gets to the pump...I don't know if the sugar in the wood will come through,but the water can mess up a vaccuum pump..Second,the heat penetrates from the outside in....This means, according to Boyles Law????? that the moisture removal will start at the outside of a block, not the inside.. Heat lowers vapor pressure, vac. draws it off....Sound reasonable...???? At the present time,I have a seven foot log by 20 inches in cherry...My micro wave can only handle14 inches,by seven by 10 inches..Am trying to find one that will let me get 20 inch pcs in....For Cherry, Weight the block...micro wave 15 minutes at 50 percent power, let sit in plastic bag outside two hours AWAY from anything that can burn.Take out of bag, weight,let surface dry...repeat process,until graph flat lines..If from same log, I only use one piece for the control....You can do app. 8 pcs in two hours, before repeating the process, and going to the next moisture level..End checking in cherry, sometimes it does, sometimes not..That is why I bag it, the water will be still coming out as it sits, the bag to produce a moisture laden buffer....I've done a lot of aerospace vac. bagging,,you could use just a black garbage bag sealed on a hot sunny day...Plastic chamber and heat..Most plastic pipes are thermo plastic, which means they soften under heat and pressure...You will be putting pressure from the outside, heat from the inside.If the combination exceeds the heat distortion point of your pipe, it is possible to get a plastic something with wood in it..Am not sure,but the equivalent may be some sort of burst pressure rate,the higher,possibly better...I'll stick to micro wave and try and find a larger one.it's a no brainer and I can handle that,cordially NAD

[Paul_Guraedy]

I wish I could say it sounds reasonable....but, I don't have the slightest idea what you are saying! It looked simple to me when I saw the diagram! From your comments, I did gather that the condensation thing-a-ma-gig needed to be on the line somewhere before it got to the compressor.

Does this Boyle's Law mean that it won't work? Where does the heat come from that lowers vapor pressure?

I spent my working years as a Park Ranger, dealt with biological science in general terms. When we got into the details of laws and such the scientists told us in layman terms what it meant. My brother probably understands all of this stuff but he is in Louisiana for a while working with his business down there.

Could you tell me what I would need to do to make this work? Or should I just forget it? Thanks.

[nadcarves]

Whoops..When I saw the diagram,I automaticly thought of a heated vac. chamber..The trap is a container between the wood and pump.Line from wood goes to bottom of container, line to pump ends above possible fluid level..like a hooka, that the Asian smokers use..There is a hell of a lot of water in a piece of wood...OK we want the water to boil off,in other words vaporize..Heat, lowering the air pressure,,Freezing??, can get the water out..I would think the speed goes in the reverse order of what I listed.. If you use vaccuum, the water closest to the reduced air pressure is going to go first..Surface water isn't going to hang around and the center water (of the block) rush out.With a microwave, you heat the center first,driving that moisture out..In THEORY, shrinkage occurs here first..Cracking in a log,may be that the outside layers dry and shrink first..Since they have no place to go, cracking takes place..I go with the most simple process available to me, and that is microwave..Most carvers don't have an accurate balance to weight the wood and determine the end point.. A simple beam balance can be made from a 2x4, put the wet wood on one side, a bucket with stones on the other., and balance... As you dry the wood, remove stones..When you don't have to take any more stones out of the bucket,the wood is as well as it is going to be..If you dry from one tree, and the process is all the same,you only have to weight one piece of wood..Need to warn you about this method..Don't do it when friends are around....The word will get out that you are stoned....Boyles law? gas..heat, reduce surrounding pressure, it expands., compress, it shrinks...A lot of carvers are thinking about casting and getting bubbles on the surface...If they put the mold and resin in a paint pressure pot, added 60 psi, the bubbles would shrink by a factor of four?? for you , big cherry log, very cold, water in log frozen????Can I cut it with a chain saw?? Going to some carving shows,want to take extra tools along..Will display either leaning or ,on the cherry blocks..I figure, carvers being carvers, will look at wood and say ,how much?? 10 bucks?..I figure to robbed blind at least 15 to 20 times...Micro wave, do what I am trying, on Yahoo, there is a give away,or wanted group(for free)..Am going to post an add for a micro wave 20 inches long or better...Someone was looking for a band saw recently, if you can find the post suggest they try the Yahoo group.You never know..If you have problems with my reply,don't feel bad. I send a bunch of e-mails to the poor gal playing with my site,,,She did everything bass ackwards..I looked at what I had sent her, and didn't understand my instructions,cordially nad

[Cut_Fingers]

I didn't quit understand all that was said in the previous post, but do have a question (which may have been covered)

I carve small pieces under 8". A stupid question - If I get green wood in about 10", could I dry it in a standard microwave? If so how long would it take. I know htat is based on the type of wood.

I am also interested in the vacuum kiln. Keep us updated on the results.

[Kenny_S]

I believe the answer is yes, you can use a microwave. Check it often so as not to burn thewood. I wonder if the defrost cycle would be best.

[Hugh]

The microwave works fine. If you microwave on high at first, for a short period of time, its all according to the size of the block. Let it cool, try it again, at a lower setting and a shorter time. Keep it up, until no moisture boils out of the wood. I have ruined a few small blocks trying to get the hang of it. They got too hot, and started burning in the middle. But if your careful, it does a good job. I picked up an old microwave, (after the boss started growling about me using her microwave)
PAUL, I picked up a good Heavy Duty vac pump, and scrounged a piece of 10" Heavy Duty plastic culvert pipe 10 feet long. , with a cap on one end. O cost so far. Can't wait to try this thing out. Might be a few more weeks before I can come up with the guages and valves. But thats the fun, scrounging, making something from nothing.

[Cut_Fingers]

Hugh,

I'm excited to hear your results. Please keep us posted! Also any others that attempt this method, give us your results.