Please Help?

[MikeH]

  I need someone to invent/mass produce a very small vacuum kiln for low cost. I can not believe they are not out there yet! I am talking small 13" pvc type non-continuous type vac. kiln I have seen other people make.
 Just think; what bowl turner, hobby woodworker would not want one? Again we're talking small unit!!!!!!!! Not only that, but think how many more people would be looking for a custom sawyer if they had their own mini-kiln.
  I can buy a computer with dual processors that can compute a million pieces of data a minute for $450.00.  There must be a WAY to make a vacuum kiln controller for that price if you met the right person from India.
 Come on Den, You can do it!
  How many city folks would think twice about having their tree turned to mulch/firewood if they could buy a small kiln that would fit in their basement/garage?
 And who would they need to make the tree into useable lumber first?
 Thats right! Your local bandsawyer!!!
 
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[LOGDOG]

Well said Mike.  Sounds like a challenge. CHALLENGE!!!!! 

LOGDOG

[AusLJW]

There has just got to be a market if someone could produce such a kiln to dry 1 decent logs worth of boards.  Last time looked they where big industrial units and big money.

AusLJW

[RSteiner]

This sounds like a good idea. 

I work with vacuum pumps for high vacuum and ultra-high vacuum processes.  A decent rough vacuum (in the 5 Micron pressure range) pump is not cheap.  Some vacuum pumps handle water better than others.  Being that you want to remove water from the wood and chamber in a controlled manner you will also have to have a controller for the drying cycle.

The chamber would not be difficult to make, it is all possible.  There is quite a bit of used vacuum equipment available which would bring the price down considerably.  I'll have to give this one some thought. 

What would be the average size load a person would want to dry?  What would be the length of the piece?

Randy

[Den Socling]

I've been dreaming about an affordable 100 to 500bf vac kiln for years. Now that I have other people taking care of manufacturing the industrial version, maybe I can spend some time on a hobby model.

I can't include used equipment in any design. The systems have to be alike.

[MikeH]

 How about a 10' x 13" pvc pipe, shorter if needed for less expensive pump. The idea is so Joe the woodworker would have to buy one.  The lower you can get the price the thousands of more units you will sell. Get it to around $700 and it will be in every wood magazine in the world. The key is the controller. Here is where Den gets rich. 
 Here is a picture I drew, holds 25 bdft. Air goes through top and back around bottom. Stickers the long way if that would work? Air bag on top. Heater and fan in front. 
 
 I want to buy stock in this.
 

[beenthere]

Interesting idea.

Can a vacuum be pulled on the pvc pipe, without caving it in after heat is added? Maybe something to try out.

Anyone with the parts and pump to try ??

[LOGDOG]

Actually with a Vaccume kiln couldn't you eliminate the stickers and replace with flat heating plates?

LOGDOG

[woodbowl]

How much vacuume is needed? Would a refrigerator compressor pull enough?

[gharlan]

I would think you could pull a good vacuum on pvc pipe just fine. The problem would be the cost. It has been several years since I purchased any and  then I only used 6 inch  if I recall correctly a 6" 90 was in the $80 range. The pipe itself was just as bad. To plumb a downdraft cook top usually cost $300 for the pvc under the slab. I do not think it would be for the faint of heart to price 12". Might be interesting to find out though. Gary

[Furby]

6" 90° sch. 40 runs around $15-22 or so at the box stores if I'm recalling correctly.
More and more box stores are carrying 6" pipe and a larger selection of fittings.
It's much harder for the average person to buy much bigger than 6" from what I've seen.


Not sure about the prices here, as I think 10' x 6" white PVC sch 40 at the box stores is something like $20-30.
They want $10 per foot here. 
Link

[beenthere]

McMaster Carr goes to 8" diam, but brings up the point that PVC is good up to 140°F, whereas hot water to boiling temp. needs CPVC plastic. 
The price for 8" CPVC (10' length) is $51 a foot, whereas 10' PVC is $17/ft. This is schedule 80. Not sure that the heat added to the wood under vacuum would mean CPVC would be necessary. Finding a larger diameter at a large plumbing contractor would likely be possible.


I like Furby's link to better information in larger diameters. 10' of 12" run about $500, looks like.

[Den Socling]

If you set up a vacuum system that could pull to the neighborhood of 50 to 60 torr, the boiling point of water is in the neighborhood of 100 to 105°F. Schedule 40 pressure PVC would work if you didn't apply heat to the PVC while trying to heat the wood.

[gharlan]

Thanks for the link Furby. I looked on their site and a 6" 90 was 49.31 I think. We use the longer sweeping 90's in air flow so so I guess I did not get bent over to bad. I noticed on the site that !2" sch 40 pvc is 27.86 per foot. A 6" sch 40 cap was 23.24. I did not find any sizes listed in fittings bigger than 6". They did list a sch 80 6" cap at 61.27 though. I suspect pricing 12" fittings would be frightful. One thing to look out for is that most box stores are now selling the cellular core pvc. It is cheaper but I do not know how it would hold up in a heat and vacuum situation. Might be worth a look. Gary

[Dan_Shade]

Den, how "small" is small?  I've thought a bagged effort to vacuum dry might work, has any work been done in this area, or is it just too much hassle?

[Fla._Deadheader]

 Before I moved down here, Florida was rebuilding I-95 from Daytona, North. They had what appeared to be 24" dia., maybe 30" dia, PVC or something similar. Color was white

  I would check out Highway contractors, for "Drops". Pieces cut off and MAYBE could be bought as scrap, before it was thrown away

  Ed and I talked about Plastic Pipe for a vacuum Chamber, A LOT. Problem we couldn't get around, was sealing the ends.

  Check out well drillers, for casings. Environmental testing drillers use 18" as do oil and gas drillers. Steel is MUCH easier to work with, for making ends and plumbing for piping.

  What is common in "YOUR" area

  I know 2 guys that have a total of 5 vacuum pumps and tanks and plumbing, maybe gauges What do y'all need  

[dundee]

I have just arrived back from Australia and saw a 450BF Vac chamber being unloaded, this came from Malaysia, this company exports such vac driers to Japan / Korea for some years I understand.

Richard

[Furby]

One thing to look out for is that most box stores are now selling the cellular core pvc. It is cheaper but I do not know how it would hold up in a heat and vacuum situation.

Correct, the pipe is cellular core but the fittings are not.
I've only seen cellular core in 2-4" pipe so far.
I have a piece of 4" cellular core laying right here, cost me $9 or $10 for 10'.
It's a bit lighter and when you look at a cross section you can see how thin the pvc shell and lining really are.
I'm pretty sure it wouldn't work in any sort of vacuum application.

[Jason_WI]

How about plastic culvert pipe? Most county shops carry this stuff and will sell to the public. Just need to find a source for end caps. Then the only thing that is needed is a pump, heating , and control system that a company could supply as a kit.

Jason

[shopteacher]

24" culvert pipe here is 400 a stick. You could get 2 out of each stick.  A company here in town makes plugs and adapters out of 2" black polypropylene.  I think they might be cutting it out with a CNC by the looks of the scrap.