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My dehydrator for turnings

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Forum topic by RussellAP posted 03-06-2013 06:56 PM 1612 views 1 time favorited 17 replies Add to Favorites Watch
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RussellAP

3059 posts in 1746 days


03-06-2013 06:56 PM

I’ve taken the wet turning route as opposed to the dry turning. This means that I turn wet fresh wood instead of old dried wood.
This presents new challenges and makes some stuff easier at the same time.

One of the challenges is the balance between how much you turn and how quickly you can dry.

Many times I’m wet while I turn my bowls because of all the water it throws out. If you turn a bowl down to a uniform thickness of 1/2 to 3/4, you have to come up with a way to either let it dry naturally, which is harder to do that it seems, or you need to find a way to gently dehydrate the piece quickly.

This is my experiment into a dehydrator method.

Previously I used the microwave method, but I don’t like the way it warps my bowls.

The bowl that is in this dehydrator is sapel and it has already cracked but that’s because I put it in a sack of sawdust which is the natural way to dry.

I know it doesn’t look safe but it’s not that bad either. The bulb is a candelabra style at 40 watts. It gets hot, but it does not get too hot.
The fans are blowing inward against the light and the air exits from natural cracks in the cardboard box at the top.

So far it’s averaged a little over 80 degrees in the box. Perfect temp.

-- A positive attitude will take you much further than positive thinking ever will.


17 replies so far

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Tomj

204 posts in 1842 days


#1 posted 03-06-2013 07:48 PM

I do this with my bow staves but the box is about 2’ high by 2’ wide by 7’ long and has 4 100 watt clear bulbs inside which I can’t find anymore in stores around here due to them being phased out. Flood light bulbs will work to and I also have the inside covered with foil backed foam insulation. I have never heard of the saw dust method but it makes sense.

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bondogaposis

4020 posts in 1811 days


#2 posted 03-06-2013 07:49 PM

It looks like good innovation. If it works out I would make one out of wood.

-- Bondo Gaposis

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RussellAP

3059 posts in 1746 days


#3 posted 03-06-2013 08:32 PM

Bondo, I do plan to once I come up with a system that works. I think air flow at 82 is about prime for drying slowly yet not too slow. Should take a couple weeks. The next one I make will be large enough to accommodate several bowls at once. I can’t be held up waiting, I have about 12 blanks that need turning. All exotic woods too.

-- A positive attitude will take you much further than positive thinking ever will.

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a1Jim

115201 posts in 3037 days


#4 posted 03-06-2013 08:51 PM

Interesting idea Russ,I would be careful about saw dust and non-explosive proof motors being combined. Many of the fires in saw mills of days gone by where from electric motors sparks causing fires and explosions .

-- http://artisticwoodstudio.com Custom furniture

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RussellAP

3059 posts in 1746 days


#5 posted 03-06-2013 08:54 PM

Rick, I actually have some of this, but forgot about it.
I think that warping on a bowl is unavoidable because as it looses moisture it will pull the grain together and an oval usually occurs.
How exactly does this work, does it seal or evaporate the moisture?

-- A positive attitude will take you much further than positive thinking ever will.

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RussellAP

3059 posts in 1746 days


#6 posted 03-06-2013 08:55 PM

I do need to clean my shop Jim. NOt being able to open the garage doors due to snow is why it’s a mess. The lathe shavings are beginning to block me from the door. I need to open them and sweep all that out into the yard. Its great for paths.

-- A positive attitude will take you much further than positive thinking ever will.

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a1Jim

115201 posts in 3037 days


#7 posted 03-06-2013 08:57 PM

I’m talking about the saw dust in your home made dehydrator and it’s motors

-- http://artisticwoodstudio.com Custom furniture

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Wildwood

1881 posts in 1594 days


#8 posted 03-06-2013 08:58 PM

Russell, technically you have built a small kiln, just check out drying wood over at woodturning on line. There is a learning curve; think will find air circulation more important than temperature. Folks eventually add auto timers to run things and better control.

I would not buy Pentacryl after reading directions and declaimer, and cost of the product.

-- Bill

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RussellAP

3059 posts in 1746 days


#9 posted 03-06-2013 09:08 PM

Jim- Oh that is shavings form turning. It’s all big stuff no dust.

-- A positive attitude will take you much further than positive thinking ever will.

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RussellAP

3059 posts in 1746 days


#10 posted 03-06-2013 09:11 PM

Bill- This is just a trial of a kiln. I’d love to have one as big as the guy I get my lumber from. When I make the final kiln I plan to use a design similar to a smoker. The light box will have about four sockets and I’ll play with the wattage and I plan to suck the heat from that box out and bring it through a long rectangle box about 16” in diameter and about three feet long. That way I can do multiple bowls.

-- A positive attitude will take you much further than positive thinking ever will.

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REO

889 posts in 1534 days


#11 posted 03-06-2013 09:56 PM

It is possible to run a dehumidifier in a box as well. the temp will raise because of the energy expended by the motors but the condensing section will take the moisture out. I burned out two units trying to maintain 110 degrees. So I converted a window air instead.The window air is still going. I think if you hook up a stat to keep the temps between 80 and 90 it would work without harm to the system. I think the control boards went on the dehumidifiers because the motors worked individually connected. it is hard to find something w/o an electronic control anymore.

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TheDane

4997 posts in 3123 days


#12 posted 03-06-2013 10:13 PM

Russell … I knew a guy in my old turning club that built a kiln out of an old refrigerator, a light bulb, and a couple of small fans. He would have half a dozen or more bowls cooking at a time.

—Gerry

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

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moke

860 posts in 2236 days


#13 posted 03-06-2013 10:43 PM

Russell,
Awesome idea…I have been thinking about it most of the afternoon. I am not sure the shavings serve any purpose. I am not sure I would want want that in my shop with the heat and shavings….but aren’t the shavings are really for drying with out any aid of heat. What are everyones thoughts…

Also, anyone have a good idea of how long the bowls have to stay in there? I have a video where I guy drys huge bowls outside in a big box and a dehumidifier, about 25 bowls at a time and his takes about a month.
Thanks for the idea..
mike

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RussellAP

3059 posts in 1746 days


#14 posted 03-06-2013 10:48 PM

Mike, I thought the shavings might help absorb some moisture. It’s a basement garage which tends to be hard to control humidity wise.

I’m thinking that a couple weeks on a bowl cut out to 1/2” diameter.

-- A positive attitude will take you much further than positive thinking ever will.

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RussellAP

3059 posts in 1746 days


#15 posted 03-06-2013 10:56 PM

I think the key to a kiln is to keep a constant temp and a constant airflow. so anything thermostatically controlled will likely not react timely enough to do constant temps. I need it to work full out, maybe a couple 60 watt bulbs and fans drawing the heat from the heat box to the drying chamber which I’ll have to make stand up on the floor because I’m running out of room. The good thing about my shop is that it stays pretty much in the 60 – high 70’s all year round so my input air will affect the kiln and it will need to be turned down in the summer and turned up in the winter. However the air flow must remain the same even if you have trouble stabilizing the heat. I’m considering a three light configuration to allow for any low temps in the winter and sometimes the air can be colder if you catch a draft from the garage doors. So in the winter 3 lights would be good and I’d put a limit thermo on the third light.

-- A positive attitude will take you much further than positive thinking ever will.

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