Author Topic: DIY Vacuum Kiln . . . HELP! (Read 5361 times)

UrbanLogger · « **on:** January 23, 2005, 10:09:25 am »

Alright Den,

Here's yer chance to show off yer know how!

I was just offered a propane tank, roughly 10' long and 3' in diameter. It appears to be sound.

Before I manhandle this thing back to the shop, will it work as a vacuum kiln chamber?

If so, what do I need to make it into one?

Will the heat coils out of a large 220v ceramics kiln work for the heat (I have one that I'm not using)?

How big would my pump need to be to evacuate this tank?

I assume that I'll have to cut the end off the tank and turn it into a door for construction access and later for loading. Would added flange, rubber seals and adjustable hood hold-downs work for this?

Many more questions to come should this tank turn out to be practical.

WH_Conley · « **Reply #1 on:** January 23, 2005, 10:21:24 am »

Don't know nothin about vac kilns, just be careful puttin the torch to that thing.

UrbanLogger · « **Reply #2 on:** January 23, 2005, 11:51:42 am »

Thanks WH!

i hadn't even considered that yet

Den Socling · « **Reply #3 on:** January 23, 2005, 12:09:06 pm »

Yes, the tank will work. Yes, you should have professionals cut one end and weld on flanges for a door seal.

I would use Sergey's design. Circulate hot water (maybe from a little outdoor furnace) through piping that runs back and forth in the bottom half of the chamber. Put a trough top center and circulate 'cool' water through some finpipe. Stack and sticker your wood with a gap in the center. I can calculate a vac pump to give you various drying rates but, in the end, you can vary the heat to match whatever vac pump you have.

UrbanLogger · « **Reply #4 on:** January 23, 2005, 01:25:44 pm »

Yea!!!! Yippieyitiyay!!!!

The fellas with the shop nextdoor to me do custom concrete castings and as part of their process have become master fabricators building the teel self releasing molds for complicated junction boxes, etc.

They're extremely nice having already offered to mix and pump all the concrete I want at cost. I'm sure they'll be more than glad to help with all the cutting and welding necessary--especially since they've been wanting me to rebuild their barn doors

What is the best way to attach the door?

Where can I find Sergey's design?

How does the water condensed by the cool water running through the finpipe exit the chamber under pressure?

Would the temperatures reached by an on demand water heater be high enough for the heating? Where I want to set it up would be convenient to wire (3 phase even) but complicated to plumb for gas or water. :-/

If I used water for heat, I'd probably run the drainlines from my sump pumps to a passive heater/storage tank. If the controller thought the water needed to be higher, I could have an on demand heater in line and waired to the controller(?)

Last question (not), can a cast iron aircompressor be turned into a vacuum pump?

UrbanLogger · « **Reply #5 on:** January 23, 2005, 01:52:52 pm »

Hey Den, don't spend too much time responding to all the questions in my last post.

I just found the "Vacuum Kiln" thread on all this and I'm studyin'

I'm sure I'll come up with a slew of more challenging questions later

Ga_Boy · « **Reply #6 on:** January 24, 2005, 06:11:12 am »

Hey Urban,

If you don't mind can you keep us upto date on your cost to put this beast intooperation.

After I get my convential kilns up, my next project will be a vac system.

Mark

UrbanLogger · « **Reply #7 on:** January 24, 2005, 07:08:56 am »

Will do GA_Boy!

I'm goin' about this opposite of you. I hope to get the vac up so I can sell a few KD crotch slabs to pay for a Nyle

Den,

I want you to know that your assistance will not be totally unpaid--I'll likely want a small controller from you!

serg · « **Reply #8 on:** January 24, 2005, 09:09:39 am »

Hello, friends! I have transferred(translated) in meters. Diameter of 2.9 meters, length of 9 meters?

? I want to lead(carry out) calculations. What thickness of a wall metal?

?
I think aircompressor the vacuum furnace poorly.
All my design on a site www.vacuums.ru

Sergey

UrbanLogger · « **Reply #9 on:** January 24, 2005, 10:43:49 am »

Sergey,

Have not me time do conversions now myself

But I will double check yours as I give you more exact dimensions myself. The dimensions I posted to begin with are a guess from having seen the tank once and if it's like my initial judgement of logs, it'll actually be much bigger.

I would appreciate all the help you can lend

I hear you on the compressor/vacuum question and I am looking into getting a good pump that I could use for laminations too.

How hot does the water in the heating coils need to be? How cold does the water in the condenser need to be?

Are you using stickers to separate the lumber in the chamber? If so, how thick?

I see on your website that your heating coils loop back and forth up the sides of the chamber. Can I use sweated copper for these or will that be a problem in the vacuum?

More questions and specs on the propane tank when I come up with them,

Scott

serg · « **Reply #10 on:** January 24, 2005, 12:05:07 pm »

Scott, hello! You very well understand and correctly ask. I, on a forum can speak, write much. I shall tell the truth. The translator will tell all on the contrary

;DTherefore I do not want that you have gone in the bad way.

Sergey.

UrbanLogger · « **Reply #11 on:** January 24, 2005, 01:06:36 pm »

Ya best watch out Sergey, I'm fixin to get southun on y'all.

How does the translator do on that?

Den Socling · « **Reply #12 on:** January 24, 2005, 04:26:03 pm »

GA-Boy,

If you get a vac kiln, a Nyle would bore you to death.

Urbanlogger,

A vacuum cylinder is normally around 5/16" thick. Pressure vessels are thicker.

The compressor won't work. Water won't compress. get a liquid ring pump that can swallow some water.

The heating water needs to be regulated between 95'F and 140'F. The cooling water should be under 75'F.

Use 'regular' stickers and spacing.

Sweated copper for the heating coils will be fine.

Den

serg · « **Reply #13 on:** January 24, 2005, 07:10:22 pm »

Hello! I completely also in part agree with Den. soon vacuum drying chamber should be in America. We shall meet. Sergey.

UrbanLogger · « **Reply #14 on:** January 25, 2005, 08:06:43 am »

Thanks Den!

That's good news on the water temps--I was hoping that I could go with a passive tank and on-demand heater for the hot and a closed loop for the "cold". It sounds like I could at the temps you spec.

Sergey,

How soon will you be in America? If I build this thing using your ideas and share my results with other DIYs, will I be steeping on your toes?

I look forward to having you come through Memphis and see my little operation. Maybe I could take you to see a couple of the biggest conventional kilns in the country that are just down the street from me.

Be good!

Ga_Boy · « **Reply #15 on:** January 25, 2005, 08:55:50 am »

Den,

I believe you about the Nyle. Just kidding Don.

As in my e-mail last night, I need to decide between two 1500 bf convential units or a vacuum unit. Decissions, decissions, decissions......

I look forward to seeing you and Garrtett in a week or so.

Mark

serg · « **Reply #16 on:** January 25, 2005, 09:12:37 am »

I & partner, we have a lot of work Europe. One Germany, an exhibition Hannover. Two, delivery of the vacuum drying chamber to America. I shall inform in addition time. Sergey.

old3dogg · « **Reply #17 on:** January 25, 2005, 02:49:03 pm »

I sure am going to miss all of this vac kiln stuff but hey!
If you need someone to treat all of that process water that you are going to need send me an email.

UrbanLogger · « **Reply #18 on:** January 25, 2005, 04:02:56 pm »

Whaddya mean treat? Couldn't you just evaporate it outside?

old3dogg · « **Reply #19 on:** January 26, 2005, 02:36:41 am »

Unless you have an endless supply of clean,cold water for your vac pumps and condensors you are going to have to recycle your process water.Either with a chiller or cooling tower.This water will become bio fouled in no time.All of the slime that builds up in the cold loop will clog and rot your system.
I got out of drying[with vac kilns] and into water treatment.So now I can help with your process water treatment.

Ga_Boy · « **Reply #20 on:** January 26, 2005, 05:44:45 am »

last night I found several Liquid Oxygen (LOX) tanks for sale as military surlpus.

The specs are 20' L X 8' X 9', pressure rating is 75 PSI
Temp ranges rating between Dang cold; minus a coupla hundered degrees F to plus a few hundred degrees F. Material of construction is unknown at this time.

Would a tank like this work for a chamber assuming one of the ends could be modified with a door that seals?

Mark

GaS · « **Reply #21 on:** January 26, 2005, 07:05:13 am »

I am wondering what happens to the strength of a cylinder when you cut the dome on the end off. Does that open 'ring' then need reinforced or braced against the door to return some of the support that it had at time of manufacture?

A oxygen tank rated at 75PSI can withstand forces of 10,000 (75x144) pounds per square foot pushing out. Pulling a vacuum on the chamber only exerts about 1700 (12x144) pushing in (not a hard vacuum, a 'serge' reduced pressure vacuum). I can't imagine most tanks having any problem, unless it was some exotic design which was very specific to the forces involved.

old3dogg · « **Reply #22 on:** January 26, 2005, 12:37:21 pm »

All 8 of BWP's vac kilns are round.They have a steel ring welded around the outside of the chamber every few feet for suport.On 4 of these kilns both the front and back open.In the 10 years that I ran those kilns I have never had one collaspe.
I was pulling an average of 60 torr but on cold days or on near dry loads I could get down into the 40's.I would be afraid of anything below 35 torr on any chamber.
If you can get a chamber good enough to hold 60 to 70 torr you can vac dry.

GaS · « **Reply #23 on:** January 27, 2005, 05:44:10 pm »

Dennis mentioned that you can purchase flanges in a tremendous range of sizes...even to fit around a large pressure tank, if it is cut correctly.
The flange would brace the cut, open end and provide a way to clamp the door onto the body...
None of this had even occured to me, I think I'll go

sawwood · « **Reply #24 on:** January 30, 2005, 07:28:06 pm »

Den what size tank would you need to dry about
500bf of lumber. I don't have room here at the
house for any thing bigger. I have considerd a
solar kiln but its slow and the vaccum will do 8/4
better. I may think about this soon.

Sawwood

Ga_Boy · « **Reply #25 on:** January 31, 2005, 09:10:00 am »

Scott,

What have you found in terms of a door and a door flang?

Mark

UrbanLogger · « **Reply #26 on:** January 31, 2005, 11:17:07 am »

GA_Boy,

We haven't started building yet, just a lot of talking over beers

I've got a mchine shop down the street from me that has a machine that will bend angle to a radius and they sid they'd do it for at after hours rates. We figured we'ed get 2 "hoops" made out of 1/4", 3"x3" angle and weld one to the tank and one to the cutoff end.

For clamps to seal it I was thinking of those lever type clamps like hold the propane tank on a forklift(?) with a neoprene seal between.

Like all my best DIY ideas, this project appears destined to stay just behind all the immediate paying jobs.

Buzz-sawyer · « **Reply #27 on:** January 31, 2005, 11:53:38 am »

Hey Urban
I built on by simply , carefully cutting the end of of the tank, then using a flange welded to the end piece and to the tank...then add the gasket material....
The dommed end is much stronger than using plate or reinforced flate steeel.....and its already the right size

UrbanLogger · « **Reply #28 on:** January 31, 2005, 01:39:40 pm »

That's what I'm saying Buzz--I just have a hard time speaking metaleese

I spent an hour one time trying to get a guy to know I needed a "rabbet" cut on the end of a shaft.

Probably thought I was into animal cruelty or something

Ga_Boy · « **Reply #29 on:** January 31, 2005, 02:48:31 pm »

Buzz,

Where did you get the flang?

Is something home brewed?

Mark

Buzz-sawyer · « **Reply #30 on:** February 03, 2005, 12:19:55 pm »

Use a comercial flange....they arent cheap, but beat the heck outta trying to build .........unlesss........well ya could use heavy walled angle and ..........welll buy a flange....just google search the net all sizes are there

Ga_Boy · « **Reply #31 on:** February 03, 2005, 05:59:16 pm »

Buzz,

I have fond a few flang manufactuers on the East Cost.

What kind of coin did yours set you back?

Mark

Buzz-sawyer · « **Reply #32 on:** February 04, 2005, 07:22:56 pm »

I built it, but I priced some up to 24' for 50 bucks or so ...what did you find?

Ga_Boy · « **Reply #33 on:** February 05, 2005, 07:04:32 am »

So far I have located an Enigneering firm down in Richmond, Va. that manufactures flanges. There are several other firms up and down the eastern sea board. If I do not have any luck with the Richmond guys, I'll go to one of the others.

I will call and ask for a quote for a set for door flangs for an 8' door.

I'll pass along what I find out.

Mark

Fla._Deadheader · « **Reply #34 on:** February 06, 2005, 08:42:59 pm »

Ga_boy,
Sounds like your Propane tank is like the one I have. It is standard size. It is 40" O.D. and 12' long. It is ¼" thick. We bought some vacuum pumps off of ebay, and there are 5 available. Could sell you one. They are at Shopteachers, near Pittsburg Pa., Not that far from you.
We might start ours before too long. Pass along the places you found flanges. Hinging the door will be REAL easy. We visited a pressure treating outfit, and their tank is vacuum-pressure. I scoped out the door, no problema. Keep in touch.

Ga_Boy · « **Reply #35 on:** March 01, 2005, 04:34:47 pm »

Buzz,

I forgot to post this. I got a estimate for a flang:

This price includes cutting the tank, building the new flang, installing the new flang, building and installing hinges.

$10,000.00

Mark

GaS · « **Reply #36 on:** March 01, 2005, 06:54:49 pm »

That is way way way way too much.

Unless we are talking about a propane tank that is 30 feet long and 10 feet around...

In my humble opinion, I think you need a second opinion.

It took us a long time to find fab shops that wouldnt' gouge.

Buzz-sawyer · « **Reply #37 on:** March 01, 2005, 07:06:15 pm »

And yours is the last job he has to do this year

Seriously $500 would be the highest I would go....You could do your own work for under a couple of hundred.
Its a days work for a pro shop...10 k a day

FeltzE · « **Reply #38 on:** March 01, 2005, 07:39:08 pm »

I hope this works,,,,....

I pulled this image out of my archives of mistakes, not mine this time

This is an example of what a partial vacum can do, a worker steam cleaned the tanker got out close the hatch..... the trapped air cooled, water condensed, pressure dropped and boom flat tank car.

Moral of the story, these tanks are made for some pressure not vacum, your propane tanks should fair better but may need some reinforcement as well.

Eric

Ga_Boy · « **Reply #39 on:** March 01, 2005, 07:48:50 pm »

The estimate was for work on a liquid oxygen tank.

The dimension on the tank are 21' X 8' X 9'

This estimate was the design and install of a door flang.

No idea if this is high low or what. This company specializes doors for vacuum chambers and the design and build of vacuum chambers.

We can use this as a point of reference.

Mark

Buzz-sawyer · « **Reply #40 on:** March 01, 2005, 07:59:13 pm »

Mark I wasnt laughin at you in any way , I thought thier price rediculous because II thought they estimated that number on a propane cylinder like we had discussed, I still think thier price is high considering what a new kiln can be bought for ...........but I am always workin on a budget.

Fla._Deadheader · « **Reply #41 on:** March 01, 2005, 10:25:18 pm »

Our plans, if we go ahead, are to cut the end off and weld a channel that is rolled to fit the tank. The open face of the channel will face the door. Weld a heavy flat bar around the edge of the door, so it fits inside the channel. That will give a place for the seal, and the door will fit every time it's closed, and the vacuum will not suck the seal out of the groove. Swing bolts with wing nuts will clamp the door to the tank. The door needs to swivel a little to allow for proper fit. A rigid door will be tough to seal without a lot of pressure.

The hinge needs to be long, extending out from the door somewhat, so the door swings out as it swings open. That way, you don't snag the seal. We will put 2 channel or angle rings around the tank, for added strength.

The one we saw, had a ring that had tapers welded to it. The door fit into "notches"and when the door was closed, the ring was turned by a hyd. cylinder. The tapers squeezed the door against the seal. When vacuum was applied, you could see the door being sucked into the seal.

It's not as difficult as it sounds, except keeping things flat as you weld them.

We are going to be looking for a tank from a truck that delivers Propane. Need to dry bunches of wood at a time. That should hold 2500+ bd/ft, I would think.

GaS · « **Reply #42 on:** March 01, 2005, 11:31:25 pm »

http://www.pcspecialties.com/oldcigo2.jpg

That is one way to do it.

Deadheader, you sound like you are on a good track

For the amount of work and welding, I'd say $10,000 is definately on the high side. However, are they fabricating an entirely new door? How elaborate are they going? This isn't a terribly complicated thing to do to a cylinder, the reason that cylinders have been so popular is how SIMPLE and CHEAP they are compared to a square chamber such as our design.

Fla._Deadheader · « **Reply #43 on:** March 02, 2005, 06:07:57 am »

I just see no reason to make this difficult. All you are doing is making a door from the dome end and making it seal

The cylinder is the expensive part, and the Propane Tank is readily available. We gave $200.00 for the 40" X 12' tank

Actually, traded some welding for it.

The day we saw the treatment plant, I didn't have the camera

Might could stop in there and snap a few pics

Ga_Boy · « **Reply #44 on:** March 02, 2005, 06:53:56 am »

For those interested, check out :

http://www.govliquidation.com

There are 2 compressed air tanks for sale, located in Jacksonville, Fl.

Do a search on tanks and you will find them.

Buzz,

Did not think anyone was lauging at me. I agree with FDH, the hard part of this effort is keeping the metal flat and properly alligned during the welding process. FDH is on the right track with his design for a door seal. You will need a way to keep the seal in place during the vacuum cycle.

Like you I am on a budget for my design, well that is a stretch, I don't really have a budget for this. My business plan does not include a vaccum chamber. Now I wish I had used a vacuum design for my kiln. My vacuum kiln budet will come from proceeds from lumber sales, if they ever come.

Den and Garrett with PC Specs have some good material for this purpose and a simple way of keeping the seal in place.

My thought to re-enforce a tanks is to weld ribs on the out side of the cylinder then weld gussets to the ribs for added strength. Just a thought.

Mark

Fla._Deadheader · « **Reply #45 on:** March 02, 2005, 07:00:23 am »

The tank we saw, had 3" channel wrapped around it, every 4' I believe.

FeltzE · « **Reply #46 on:** March 02, 2005, 07:14:01 am »

Talking about seals, our aircraft at work use a simple seal around the door jams, no groves just a lap joint with a soft seal between. The aircraft pressure increases to a maximum of 6.1 psi above ambient pressure with cam locks keeping the door tight.

Eric

Fla._Deadheader · « **Reply #47 on:** March 02, 2005, 03:35:29 pm »

2 reasons I suggested channel for the seal, seal can't fall out easily, and the door edge will always line up.

Eric, is that seal material solid or have a hollow center? Can it be cut and glued together ??

old3dogg · « **Reply #48 on:** March 03, 2005, 05:52:01 am »

If you have a McMaster Carr around look for gum rubber tubing.This stuff is very cheap and makes great door seals.I used it on 4 or 5 vac kilns and never had a problem.

Ironwood · « **Reply #49 on:** March 04, 2005, 01:17:16 am »

FLA_DEADHEADER,

I live up the road from Shopteacher, I saw your vac pumps. Are they liquid ring? I have a cylinder ready to go and need a pump, no real hurry just thought I 'de ask. REID

Fla._Deadheader · « **Reply #50 on:** March 04, 2005, 06:50:45 am »

Hi Reid. We bought them off Ebay, as Liquid Ring. Teech did some digging, and thinks they MAY be vane pumps. Being as how I only will pull ½ vacuum, with the discontinuous Vacuum system, I don't see why they won't work.

From my Dairy Farmin days, I know that Vane Pumps will take moisture and not hurt them, if they are taken care of properly. Besides, they were cheap enough to play with, and get the drying experience, so I could upgrade if needed.

Haven't figgered out all the "terms" involved in Vacuum, but, we would pull 15-16 on the Vacuum guage, with preset "Bleeders" to control vacuum. I am sure we could pull over 17, whatever that equates to

I had figgered that ANY decent Vacuum would help in keeping the temp down in a kiln, until time to set pitch. Our Timber is pretty finicky.

If yer interested, talk to Glenn and he can deal with you. We have more than we need, and he was talkin about changing his plans. HEY TEECH.

FeltzE · « **Reply #51 on:** March 05, 2005, 07:04:14 am »

fdh

They are hollow on some aircraft with a ribbed surface and others are an inflatable tube, uses about 2 psi.

One advantage you have is that with a simple medium soft solid seal when the door closes and vacum is applied, the seal will be crushed in place by the pressure from the door.

a 12x12 inch door would have 144 inches of surface space with a 7 psi vacum you would incure 1008 lbs of crushing force on the door jam assuming you had a one inch wide seal on that 12x12 opening the pressure per sq inch on the seal would be 21 lbs I don't think that would slip around much

PS I'm sure my simple math has missed some other issues...

Eric

Fla._Deadheader · « **Reply #52 on:** March 05, 2005, 11:31:19 am »

Thanks Eric. I was referring to the seal coming loose, in case it was knocked by a board or something. The channel would just be insurance and very strong for the door to close into.

Buzz-sawyer · « **Reply #53 on:** March 05, 2005, 12:05:01 pm »

This is , I believe, some thing like the hing you plan on fld?
This is an air tight tank built for wood gas production, but as you can see, the door swings wide out of the way and comes down straight on the gasket (not on in this pic).

And one of it closed

Fla._Deadheader · « **Reply #54 on:** March 05, 2005, 12:17:07 pm »

Dat's basically it, Buzz. Dish Network won't preshiate ya using their antenna mount, though .

The way that's constructed, as you said, the door swings OUT, then away. Can't tear up the seal thata way.

I'm gonna leave ours loose a little, where the bracket meets the door, so the door can "settle" into place. It will pull down even, then.

With the door swinging away, you don't hafta worry about the bunks of lumber hitting the door when ya load and unload.

Gotta get me a bigger Propane Tank. Need one off a delivery truck.

Have kiln---will deliver.

Buzz-sawyer · « **Reply #55 on:** March 05, 2005, 12:33:06 pm »

Use the a/c compressor on the truck to draw you vac and dry while you deliver...just paint it black and its cookin....
I Thought you would like that hinge

Suprised you didnt comment on my high tech tank

Den Socling · « **Reply #56 on:** March 05, 2005, 02:42:06 pm »

I couldn't find a good picture but the Italians have an easy way of swinging doors. They weld a boom on two pieces of nested pipe (one inside the other). The inner pipe is welded to the top of the cylinder. The boom pivots. The door hangs from a fork with a roller bearing. The bearing rolls on the boom. yeah I need a picture.

Fla._Deadheader · « **Reply #57 on:** March 05, 2005, 02:56:19 pm »

Den, what's yer opinion on trying things with the Vane Pump, if that's what we really have

Den Socling · « **Reply #58 on:** March 05, 2005, 03:48:01 pm »

Rotary vane pumps can pull low pressure and can tolerate moisture but they are intended for applications that require relatively low volume (from what I know).

If you want to dry only 100 bf of Red Oak at a rate of 1% per hour, you have to vacuum-pump out 1/2 gallon of water. That 1/2 gallon of water makes about 114 cubic feet of vapor. A rotary vane might handle that but if you go up to 1000 bf, I'm not so sure.

Fla._Deadheader · « **Reply #59 on:** March 05, 2005, 04:09:18 pm »

Thanks Den. We have several of them, sooooo, how about using more than 1 ??

Minnesota_boy · « **Reply #60 on:** March 06, 2005, 12:28:57 pm »

Harold,
That soulds like a good idea. As soon as one goes bad, replace it with another.

Doc · « **Reply #61 on:** March 08, 2005, 09:43:02 am »

Quote from: UrbanLogger on January 24, 2005, 10:43:49 am

Sergey,

Have not me time do conversions now myself

But I will double check yours as I give you more exact dimensions myself. The dimensions I posted to begin with are a guess from having seen the tank once and if it's like my initial judgement of logs, it'll actually be much bigger.

I would appreciate all the help you can lend

I hear you on the compressor/vacuum question and I am looking into getting a good pump that I could use for laminations too.

How hot does the water in the heating coils need to be? How cold does the water in the condenser need to be?

Are you using stickers to separate the lumber in the chamber? If so, how thick?

I see on your website that your heating coils loop back and forth up the sides of the chamber. Can I use sweated copper for these or will that be a problem in the vacuum?

More questions and specs on the propane tank when I come up with them,

Scott

Hit Surplus center up on the vaccum pump. They had some larger units in the last catalog that may be big enough to do waht you are looking for.

www.surpluscenter.com

carl · « **Reply #62 on:** March 08, 2005, 09:28:24 pm »

HELLO MY NAME IS CARL WINNIPEG MB CANADA
I HAVE BEEN FOLLOWING THE VAC DRYING THREADS FOR QUITE A WHILE. VERY INTERESTING.
IAM A WOOD TURNER AND WOULD LIKE TO GET SUGGESTIONS FOR MY NEEDS EG DISCONTINIOUS VAC DRYING OF BOWL BLANKS. WALL THICKNESS 1-1 1/2 IN USING ELM ASH OAK ETC.
I HAVE A GAST 1/4 HP ROTARY VANE PUMP I USE FOR VAC CHUCKING ON MY LATHE. COULD THIS BE USED....OR HOW ABOUT AUTOMOTIVE A/C UNIT... CHAMBER WOULD BE 14-15 DIA HD PVC WATER/SEWER PIPE. HEAT.. CONVECTION AT NORMAL ATMOSPHERIC PRESSURE. DRYING TIME IS NOT AN ISSUE, WOULD BE MANUAL OPERATION. WOULD THESE SMALL PUMPS BE ABLE TO GET LOW ENOUGH VAC TO LOWER TEMP OF WOOD.. BOWLS WOULD BE HEATED TO APPROX 110 F. CHAMBER WOULD BE APPROX 5FT LOG AND HOLD APPROX 10-15 BOWL BLANKS. SOME OF THE BLANKS WOULD BE GREEN SOME AIR DRIED. THANKS CARL

Furby · « **Reply #63 on:** March 08, 2005, 09:39:29 pm »

Hmmmmmmmm..........
Interesting!
I wanna hear what ya all have to say because I'd make a longer one and do a couple boards here and there, as that is all I need sometimes.

serg · « **Reply #64 on:** March 08, 2005, 10:52:53 pm »

Hello! These guys do(make) so look. http://www.sushilo.ru/aerovak.htm
The vacuum chamber of aerodynamic heating. Sergey.

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Author Topic: DIY Vacuum Kiln . . . HELP! (Read 5361 times)