Page 2 of 4 FirstFirst 1234 LastLast
Results 16 to 30 of 46

Thread: Drying bowl blanks

  1. #16
    Join Date
    Jul 2018
    Location
    Knoxville,TN.
    Posts
    46
    Looks interesting Alex. I will check the temperature controller out? Looks like a good plan.I put six green bowls in a metal trash can tonight with a 100 watt light bulb. I coated some with Anchorseal some partially and two with nothing. We will see what warps or cracks. They are all one inch thick. Thanks for your help. Roger

  2. #17
    Join Date
    Jul 2018
    Location
    Knoxville,TN.
    Posts
    46
    Alex, I found one about same price. I have 2 -150 watt reptile heaters. A controller that just cuts off will do, right? Would a ceramic heater be better with the fan? Thanks Roger
    Last edited by Roger M. Davis; 02-07-2019 at 3:45 AM.

  3. #18
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    7,341
    Quote Originally Posted by Roger M. Davis View Post
    I coated some with Anchorseal some partially and two with nothing. We will see what warps or cracks. They are all one inch thick. Thanks for your help. Roger
    That's a good test but perhaps don't base your analysis solely on a half-dozen data points! The natural structure of wood varies so much you might need to dry 100 with one method to "prove" anything!

    I didn't get to read the entire thread. Do you have gentle air circulation inside, some ventilation holes for moisture to escape, good separation and/or shielding so the bowl closest to the bulb doesn't overheat? Weigh before starting and periodically to track the drying?

    JKJ

  4. #19
    Well, I don't use a kiln, and probably never will. I have never understood using an old fridge or freezer. I would think it would be easier to build a plywood box with some wire shelves in it to put bowl blanks on, and a bulb at the bottom. Convection currents should do an excellent job of moving air through the cabinet with no need for a fan as long as there is ventilation on both bottom and top of the box... Depending on woods and size of box, I would think smaller wattage bulbs would be safer to prevent more cracking.

    robo hippy

  5. #20
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    7,341
    Quote Originally Posted by Reed Gray View Post
    ...I have never understood using an old fridge or freezer. I would think it would be easier to build a plywood box with some wire shelves in it to put bowl blanks on, and a bulb at the bottom. Convection currents should do an excellent job of moving air through the cabinet with no need for a fan as long as there is ventilation on both bottom and top of the box......
    I think the idea of using a fridge or freezer is the insulation keeps the heat from escaping out through the sides. Maybe save on energy or maybe distribute the heat more evenly through the volume, I don't know.

    JKJ

  6. #21
    Join Date
    Apr 2018
    Location
    Cambridge Vermont
    Posts
    279
    A plywood box would work just fine. Once you price out a couple sheets of plywood, insulation, hinges for the door, and wire racks it makes a free dishwasher or fridge seam more attractive. My main reason for a commercial fridge/ freezer is that they usually will be one or the other. A household fridge will be part fridge and part freezer. Household freezers often have fixed shelves. Not that it would be hard to drain the freon and make the shelves adjustable. Has anyone experimented with using a small fan to help keep the air circulating.

    Those industrial heaters just turn on and off so I would think a reptile heater would work just fine. It might even work better as the industrial ones have extra settings you could mess with (but don't need to) as they can be used for applications where you want to control to 1 degree. If you know how to change a light switch you could just use a dimmer to control the heat the bulb puts out. You could use a digital oven temp meter to monitor it. I know some people just start off with lower wattage bulbs and keep going up in size but the engineer in me likes to be more precise.

  7. #22
    Join Date
    Jul 2018
    Location
    Knoxville,TN.
    Posts
    46

    Aluminum trash can dryer

    I only have a 100 watt incandescent bulb under a wire separation in the 30 or 40 gal can. I tried to place six bowls evenly to distribute the convection heat. There are holes in the bottom and the trouble light cord out the top crack. So far no warping after several days. The bowls were wringing wet as they were turned. I have to purchase a moisture meter or scale, which is better? Thanks for helping me, Roger.

  8. #23
    Join Date
    Apr 2018
    Location
    Cambridge Vermont
    Posts
    279
    I have both a scale and a cheap moisture meter. The scale is much more accurate. I'll write the weight and date on the bottom of the bowl that will get removed when I finish it. A food scale will work just fine and is cheap. If you get one with a stainless top it's easy to clean so you can use it for other things as well.

  9. #24
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    7,341

    Checking moisture

    Quote Originally Posted by Roger M. Davis View Post
    I only have a 100 watt incandescent bulb under a wire separation in the 30 or 40 gal can. I tried to place six bowls evenly to distribute the convection heat. There are holes in the bottom and the trouble light cord out the top crack. So far no warping after several days. The bowls were wringing wet as they were turned. I have to purchase a moisture meter or scale, which is better? Thanks for helping me, Roger.
    I air-dry a lot of wood blanks and I find a moisture meter good for a general check of dryness. The pin-less Wagner I use is far more expensive than a scale and can only be used on flat sides. A cheap pin-type meter can be used on curved wood. A search should show useful past discussion about moisture meters.

    A scale works on anything and is far cheaper. I have several but this is one I use now when drying blanks: https://www.amazon.com/gp/product/B013WU0FUO For serious moisture testing with the oven-dry method I use smaller scales with more resolution, these: https://www.amazon.com/gp/product/B002SC3LLS and https://www.amazon.com/gp/product/B0012LOQUQ

    The accuracy of the scale doesn't matter as much as having the appropriate resolution for the size of the sample - oven-dry samples can be pretty small.

    A single weight tells you nothing, you need to periodically weigh the piece/blank/sample during whatever drying process you use and record the weight. When the weight doesn't change after several periods the piece is dry. When I air-dry blanks I write the weight and date on a piece of masking tape but could write it on the wood with a marker. Every month or two, depending on the thickness of the wood, I weigh again and record the weight.

    I don't have experience with kiln drying but drying loads of lumber can take months. Perhaps the trashcan you use will be quicker, in which case you might want to weigh each piece every day or so. Different species, thickness, and positions in the kiln could dry differently.

    You said you have ventilation holes in the bottom but don't mention the top except about the crack for the cord. I'm imagining it would be helpful to have vents near the top of about the same area as those in the bottom so the air could flow through. If you find your kiln dries too quickly and causes cracks you might adjust the wattage of the bulb or the size of the vents to slow down the air flow. Keep in mind that what works for walnut might not work for cherry, etc.

    There is a lot of information available about large-scale kiln operation. There are careful tables for the temperature, humidity, and time for various species to get the best results. Maybe you can find similar parameters for a bowl kiln. If no one here has extensive experience, you might check Glenn Lucas's web site - he uses kilns for drying tons of bowl blanks. If his web site doesn't say, he might answer an email, or a phone call if you feel like calling Ireland. Also, Cindy Drozda might be a good person to ask.

    Here is a good document on kiln drying if you are interested in getting an understanding of how complex it is to cover all bases:
    https://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr81.pdf

    JKJ

  10. #25
    Join Date
    Jul 2018
    Location
    Knoxville,TN.
    Posts
    46
    Thanks Alex and John, Costco has a kitchen scale that will fit the bill. I will look up all the information offered. Tonight I worked on spalted/ punky maple bowls. Tear out is major. John I am trying to follow your use of 60 degree included angle NRS which is working great eliminating the holes. I notice that my skews look the same except for the burr. I am coating with tung oil and buffing out for a finish. I really like this look. God bless you and yours....thanks again for the help. Roger

  11. #26
    Join Date
    Oct 2008
    Location
    Kapolei Hawaii
    Posts
    2,837
    I built a fridge kiln, as many have already mentioned. I bought a cheap indoor/outdoor remote temp/humidity meter, and put the outdoor in the kiln. I use 40/53/72 watt bulbs (electricity, not light) I think they may be 60/75/100 watt lights. Anyways, when the humidity stops going down, I increase the wattage. For me, a week per light rating is good enough, if you want to make sure or you get old and forget, 2 weeks at the higher wattage does not hurt. I'm a weekend turner, so this is awesome. The biggest benefit is the fridge kiln also doubles as a storage locker that keeps the bugs away. At least they haven't found mine as of yet. Also a old age factor, when you open it up to load more roughs and see all the already dry roughs I had forgotten about.
    I got my upright freezer free from an appliance recycler. I think they (commercial people) have to pay to properly dispose of them, so he was more than happy to help me load it up. No fan, just the cheap clamp on lamp from the Depot. From what I read, the low wattage to start helps raise the temperature slowly and supposedly less cracking. Some still do crack. I'm pretty sure that this is the cheapest alternative, and its pretty fast. Relatively I guess.

  12. #27
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    7,341
    Kyle, for those who might want to try this, could you provide some specifics? Details of what you found works for you might help someone get started.

    For example, you said you use "bulbs". How many?
    Are the bulbs at the bottom of the cabinet below a wire shelf?
    Does the clamp on light fixture have a reflector and if so, is it aimed up?
    Did you cut vents? Bottom, sides, top? Approximate area?
    Do you have this in the shop or outside?

    Thanks,

    JKJ

    Quote Originally Posted by Kyle Iwamoto View Post
    I built a fridge kiln, as many have already mentioned. I bought a cheap indoor/outdoor remote temp/humidity meter, and put the outdoor in the kiln. I use 40/53/72 watt bulbs (electricity, not light) I think they may be 60/75/100 watt lights. Anyways, when the humidity stops going down, I increase the wattage. For me, a week per light rating is good enough, if you want to make sure or you get old and forget, 2 weeks at the higher wattage does not hurt. I'm a weekend turner, so this is awesome. The biggest benefit is the fridge kiln also doubles as a storage locker that keeps the bugs away. At least they haven't found mine as of yet. Also a old age factor, when you open it up to load more roughs and see all the already dry roughs I had forgotten about.
    I got my upright freezer free from an appliance recycler. I think they (commercial people) have to pay to properly dispose of them, so he was more than happy to help me load it up. No fan, just the cheap clamp on lamp from the Depot. From what I read, the low wattage to start helps raise the temperature slowly and supposedly less cracking. Some still do crack. I'm pretty sure that this is the cheapest alternative, and its pretty fast. Relatively I guess.

  13. #28
    Join Date
    Oct 2008
    Location
    Kapolei Hawaii
    Posts
    2,837
    I essentially followed Cindys info, someone above posted the link.

    I use a single bulb in the bottom. As mentioned I bought that cheapo clamp light. It has a shield, a switch and a plug. If you would price out components in Cindys page, you would need a 6 buck light fixture, an inline switch 3 bucks, box and cover about 10, plug another 3 bucks and wire. And you would need to fashion a shield for the light. For more heat, I have though of an additional light, an easy splice in. "Bulbs" meant more than 1 wattage rating. Have not had to add more heat. The single 72 watt gets the kiln over 100 degrees. I found that sufficient for my climate, since ambient "dry wood" is 12% or so here. Cooler drier places could use a pair at the end. I think for us, 100 kills all the bugs. Or maybe they just die from lack of water.

    I built a small clamp stand for the clamp light, an upside down T with scrap. Clamp the light on, I face the shield and light down to keep the dried rubbish from hitting the light.

    Per Cindy, drill 1/2" through holes, 5 on a side (10) at the top and same on the bottom. None on the very top as my kiln is outside. Seems to be adequate. I did have my doubts. That bit could be the most costly item, but I do have a good tool seection, so I already had one.

    Easy easy build. Getting an upright freezer may not be that easy to find, that makes the build really easy. They have built in shelves, and no fridge freezer partition to deal with. I lucked out. Actual incandescent light bulbs are getting harder and harder to find. LED/CFL will not work. LOL. The bulbs do burn out, so get several. All you really need is is a cheap 6 buck outdoor thermometer to monitor the temperature. I got the temp/humidity remote monitor mostly because I'm lazy, and didn't want to open the door to look at the temperature. Wastes a lot of heat I would think. The monitor makes it easy and fun. Cheap ones run 30 bucks or so. That was the most expensive part.

    That is about it I think. Good luck!

  14. #29
    For what it's worth... I have a STC-1000 temperature controller I tried to use on a sous vide conversion of a crock pot. It has too much lag for a sous vide crock pot (the pot not the controller) but would probably work great for a small drying kiln.

    Controls heat and cool with 10 amp relays, -50 to 210 c control. Dirt cheap! Digital display.

    Search STC-1000 and you get many results.

    The usual, I'm not associated with any company related to this controller blah, blah, blah. Just a satisfied customer. I would buy it again.

    Clint

  15. #30
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    7,341
    Quote Originally Posted by Kyle Iwamoto View Post
    I essentially followed Cindys info, someone above posted the link.
    ...
    Actual incandescent light bulbs are getting harder and harder to find. LED/CFL will not work. LOL. The bulbs do burn out, so get several. All you really need is is a cheap 6 buck outdoor thermometer to monitor the temperature.
    Incandescent bulbs are still available from Amazon. I always buy the 130v bulbs instead of the more usual 120v bulbs. 130v lamps will put out a tiny bit less light/heat but can last a lot longer. I usually get "rough service" bulbs, just because. For example, https://www.amazon.com/CEC-Industrie.../dp/B00JS9SAA6

    Thanks for your notes. I was the one who posted the link to Drozda's page and it's fairly complete, but it's always great to hear ideas from others with experience.

    JKJ

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •