Home made vac kiln

old3dogg · October 04, 2013, 02:01:09 PM

Quote from: Den Socling on October 04, 2013, 01:21:37 PM
Hi Mike,
I still tell the story of vacuum packed newels. I'll never forget that one. It's hard to believe that BWP is gone. All of the vac kilns were sold for scrap. :-\ I saw the list of equipment that was auctioned. It was everything. Right down to Mona's Crown Vic.

Buckeye,
All the wood would need to withstand is a ton per square foot. And radio frequency kilns were kind of like microwaves. I read at another forum about a guy who still runs RF/V kilns. They keep an electrical engineer on site.

Darn shame about Dale and Joe too.

You should have been there the day both rear cables snapped on the lift while brining 8000 bft of Hard Mable out of the pit. Just one of the many days I quit that job.

I think my favorite was when the mouse knocked the power out from Emerickville to Brookville.

mesquite buckeye · October 04, 2013, 02:05:53 PM

That is one serious timber frame job. ;D Bet it would make noise like mine timbers taking weight. ;D

old3dogg · October 04, 2013, 02:16:19 PM

Quote from: mesquite buckeye on October 04, 2013, 02:05:53 PM
That is one serious timber frame job. ;D Bet it would make noise like mine timbers taking weight. ;D

You should hear round vacuum champers complain when you get then down around 35 torr.

Den Socling · May 27, 2014, 04:33:47 PM

I hadn't heard from John in England for a while. He had to take some time out from his kiln. He's now back at it and sent some pictures of his heating system.

The wood blocking represents the thick wood he intends to dry. Each plate is a different width. He calculates that he will get a little over 1000 bf in the chamber.

A kiln condenser from a junk yard. It's nice work these guys are doing.

Den Socling · May 29, 2014, 10:43:56 PM

I just reread this topic from the beginning. John and his friend have done so much nice work, this kiln is going to work. I don't care if it takes a year of debugging and schedule development. I don't anticipate any problems but I surely will not abandon them. Very nice work, guys.

John.Howard · July 03, 2014, 07:42:26 PM

Ok Den, we've pretty much got the heating system installed. We just need the flue for the boiler. We filled it and checked for leaks. There were leaks, about half of the compression fittings! Sealed now. The important thing was that none of the solder joints on the expensive 35mm (1 3/8") pipe leaked! We got a computer and made a little shelf for it to go on. Now we need to turn our attention to the control system. Another little shelf will be needed for the PLC. Today for the first time we reduced the pressure in the tank! We took it down to half a bar (we have a manual vacuum gauge on it) whilst we had a couple of beers to celebrate. By that time it was after 10:30pm and starting to get dark. Tomorrow we will take it lower...

Den Socling · July 03, 2014, 07:46:49 PM

Looks great. Was there any noise from the chamber while pulling the pressure down?

John.Howard · July 03, 2014, 07:52:50 PM

None. There's about 77lbs of welding wire on those ribs, so hopefully she won't implode! We'll soon see how noisy she is and maybe, just maybe, we might actually have a go at drying some wood one day!

Den Socling · July 03, 2014, 08:11:13 PM

Good. Now comes control. You need to control water temperature accurately. That is easy in a closed system and a proportional heating control valve. Then comes the chamber pressure. You will want a set point and a dead band. We use freq drives to turn the vac pump on and off but you can use an electromagnetic starter.

Den Socling · July 04, 2014, 05:18:01 PM

I really like your manifold and heating water piping. Very nice. Look world at what a couple young guys in the UK have built. 8)

mesquite buckeye · July 05, 2014, 10:29:00 AM

Very cool. ;D Lots of us are looking forward to success. 8) 8) 8) 8) 8) 8)

John.Howard · July 09, 2014, 07:19:54 PM

The vacuum gauge on the tank is currently reading -28"Hg. I make that to be about 49 Torr? Took about 25 minutes to get down to that pressure and not a peep from the tank. After 24 hours the gauge remains unchanged. 8)

Den Socling · July 09, 2014, 09:12:27 PM

That's great. Now get a good pressure transmitter for control. But it's good that we don't have to worry about the chamber anymore.

5quarter · August 08, 2014, 01:44:54 AM

John...I've been watching this thread with great interest and amazement. Did you have any Idea of the complexity when you started the build? I'm anxious to see what you can do with it.

John.Howard · April 13, 2015, 12:17:01 PM

Well, that was a lot of hard work.

Den Socling · April 13, 2015, 06:28:47 PM

Did these young fellows do a spectacular job or what!!!! From reports I got today, their slabs are drying just as they should be. Glad there isn't too many guys like these around or I would be without a job. We've been feeding them information for more than a year but they did the superb job of building their own vacuum kiln from a propane tank. Congratulations, John. 8)

Edit: Just looked back to page one. It's been more than two years!

Den Socling · April 13, 2015, 07:39:55 PM

John says his couple slabs have dumped 40 liters of water since start-up on Friday. That's good!

fishpharmer · April 13, 2015, 10:09:20 PM

Really astoundingly nice work! 8)

Den Socling · April 13, 2015, 10:17:21 PM

And John has been exploring the technology with pictures and explanations. He actually built it! He even learned to build his own control system. He has a vacuum kiln and he knows every inch of it.

thechknhwk · April 14, 2015, 01:16:14 AM

That is some dang impressive work!

John.Howard · April 14, 2015, 05:58:47 AM

Thank you very much Den. It's been a long journey.

5quarter, sorry I never answered your question. Our plan to dry wood has come a long way since the lightbulb in a box idea. But no, I didn't fully appreciate the complexity, or the amount of time or money this project was going to take. There's been a lot of head scratching, and we've had to make a lot of mistakes to get all the systems running right, because if any part is off, the machine won't perform. We've also had quite a bit of bad luck, but when you're trying to build something on a shoestring, time is the sacrifice. Even 2 weeks ago we were still ripping apart bits of the system and rebuilding the vac pump. We basically squeezed a tank in the narrow space between a building and a fence, then built a house around it. This thing owes us a lot and she's been fighting us all the way. Now it's time for her to earn her keep...

John.Howard · April 20, 2015, 06:32:24 AM

This isn't what we were hoping for! :-[

Keep calm and carry on....

and on and on....

james04 · April 20, 2015, 09:00:20 AM

Ouch! Sorry to see your first go at it not going too well. Good thing you didn't start with the Walnut. Thick oak is a tough test material. So you may not bee too far off. Any ideas as to what went wrong?

Oh and thank you, for sharing your experience. I am sure there are many of us that are very jealous of you guys. This gives us a chance to live vicariously.

Regards,
James

Den Socling · April 20, 2015, 09:02:01 AM

Now comes the hard part! ;) I need to get a piece of his oak under a microscope. I thought it was drying like Red Oak but the results look like White Oak. Glad he had only two slabs in the kiln.