vaccum kiln pics and problems solved.
steve knight
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Here is a picture of my vacuum kiln. This sucker had a real hard birth ad a lot of mistakes. First trying to get a perfect seal this was the first battle. Never did solve that one. So the pump has to run all the time. But I found out it needs to anyway so that problem was solved (G) second was heating it. I had these heating bars that were inside and worked ok but they were pretty uneven. I had an electric blanket that died. The new ones have 10 hour shutoffs. I had some under floor heating wire. The first roll was perfect and worked well on 120. But I had hacked it up for my first kilns and I could not use it again. The second roll I got was not the same. It only worked on 220 and the 50 or 60 feet I used at once got way to hot and melted the insulation off the wire. At 120 it kept tripping the 20 amp breaker.
I finally broke down and bought these silicone heating pads. It was 20.00 more each to have self sticking so I just used aluminum tape. They were spendy at about 50.00 each for 12x24. Though they are rated at 700 watts max they don�t seem to draw that. I bought these from MSC and got the recommended heating controllers. 80.00 Each and I needed two of them.
Well it worked fine for a bit. But one controller would help making the pads overheat. I had one replaced and the second did the same thing. It really pissed me off to spend that much and have them fail.
A couple people here helped me out and I got the right type of controllers. Variable voltage controllers. The two shown here were built for me and made practical. I am testing them right now.
The last part is a vacuum pump. Not any pump will do. You need one that will pull atleast 29� of vacuum. You also need one that can handle some moisture. Or you need to make a condenser to get the water out of the line or your in trouble.
But after all that is met you can dry wood. I start heating the wood really slowly over a several day period. Then I turn on the vacuum pump. I use this to only finish drying woods that are not dry enough and I take my time and don�t use too much temp. Usually a couple of weeks.
My first wood to dry is a 500.00 piece of ebony for Wayne to make infill�s out of.
