How to build a DIY timber drying kiln

[farmerjohn]

CDRM,

Looks awesome, I have been wanting to make a kiln but small scale (3.2m long, 1.5m wide, about 1.8m tall) i was thinking of a similar idea but i was going to fibreglass the inside to stop the timber degrading.
It looks like you have the fan blowing down the length of the timber rather than across it (the same way i was thinking i would to it as mist of the timber i will dry will be around 3m long. if this is the case will you run the stickers down the length of the timbers, and do you have a fan at the opposite end to blow the air back to get good circulation.
does the fan suck the air through the sliding box, past the heater and back out?

 

Thanks, John

 

 

[CDMR]

14 hours ago, farmerjohn said:

CDRM,

Looks awesome, I have been wanting to make a kiln but small scale (3.2m long, 1.5m wide, about 1.8m tall) i was thinking of a similar idea but i was going to fibreglass the inside to stop the timber degrading.
It looks like you have the fan blowing down the length of the timber rather than across it (the same way i was thinking i would to it as mist of the timber i will dry will be around 3m long. if this is the case will you run the stickers down the length of the timbers, and do you have a fan at the opposite end to blow the air back to get good circulation.
does the fan suck the air through the sliding box, past the heater and back out?

 

Thanks, John

 

 

Thanks John.

 

I did think about lining it but as it isn't a sauno style kiln I am not sure how much abuse the timber will get. I'll keep a watching eye and report back.

 

I thought quite a bit about air circulation. My conclusion eventually was that 3000 cubic meters per hour is quite a storm in a small box. Even if you don't duct it perfectly through and round the wood pile it is going to get pretty much everywhere. The percentage being extracted by the heat recovery unit is very small so you don't have a perfect system from point a to point b so much as a constant tumble of air some of which is syphoned off. I have test load in at the moment and have marked each piece at three points with its current MC. If I find I have a trend of dead spots, I shall add a duct in the ceiling to push the hot air down the back wall and from the the sliding door down to the bottom front to pick up cooler wetter air from there.

 

The stickers are perpendicular to the timber and yes, the sliding vent goes into the plenum with the heater from which the fan takes its input.

 

Two things learnt so far: Insulate the mounting on the fan or it booms like hell. Make sure your heater controller doesn't open and close too frequently as it buggers the element on the heater. Currently it sitting at 32 degrees and is heating with a 2kw heater about half the time so the equivalent of 1kw on heat.

[Big Beech]

Are You still using this 

Jon?

[ARV]

On 15/11/2020 at 17:13, Big Beech said:

Are You still using this 

Jon?

Big J moved on from milling to forestry. I took on his milling business and we do still use the Kiln he put together.

Andrew

[Big Beech]

20 hours ago, ARV said:

Big J moved on from milling to forestry. I took on his milling business and we do still use the Kiln he put together.

Andrew

Oh! I see!!

Good to hear. Haven't seen John post much, guessing that may well be the reason why

[Big J]

1 hour ago, Big Beech said:

Oh! I see!!

Good to hear. Haven't seen John post much, guessing that may well be the reason why

Mostly in the politics bits of the forum these days ?

[Big Beech]

20 hours ago, Big J said:

Mostly in the politics bits of the forum these days ?

Afternoon J,

What was the decision to go back to work on the saw instead of the mill?

Forgive me for asking, incase I missed a post a while ago ?

[Big J]

41 minutes ago, Big Beech said:

Afternoon J,

What was the decision to go back to work on the saw instead of the mill?

Forgive me for asking, incase I missed a post a while ago ?

I should stress I'm more of a site agent/machine operator. If I claim to do saw work my subbies will roast me.

 

Just fancied a change of direction and working in the southwest, it was easier to get into forestry than start a sawmill from scratch.