Wood Drying Kiln WIP (or paint/finish dryer)

[teter09]

I thought this might be useful to folks on here since knife makers often send wood off to be stabilized, but it has to be dry first and who wants to wait YEARS for that? I created this with 2 purposes. First is to help dry wood faster, obviously. Second is as a 'parts' dryer since I often restore machinery and needed a clean place they could dry while I continued to work around them....but without nasty stuff screwing up my finish! Maybe you don't need to dry pieces of machinery....but what about finishes to your wood handles?

Obviously wood drys by being exposed to air. This alone isn't enough though for me since I live in Central Florida.....the state which seemingly doesn't hardly EVER drop below 90% humidity. So since this was dual duty purpose...I needed a way to help counteract the effect (practically double drying time on paints and polyurethane) that the humidity has. Heat is an obvious choice, but I don't want something dangerous so no heating elements nothing pricey. I'd researched many home made wood kilns already, but most of them wanted to use the sun. This is cool, but slow and wouldn't really help me with all the thunderstorms we get in Florida. While standing at my work bench thinking about what to use for heat, I realized my back was on fire though my chest was cool because I was too close to my Halogen light. And it hit me....a light bulb can produce a lot of heat depending on what type of bulb and wattage it is. I already had a fan which I could use, so I figured between a light fixture and the fan....I could be in business!!! Here is what I built....with some of my thoughts thrown in.

First thing is I didn't want a ton of cost, but who sets out to build something for MORE than they should? I didn't build some fancy cabinet of Cherry that could go unnoticed in your kitchen. I stuck to 2x4's for the frame and particle board since I had 2 identical pieces on hand to serve as the base and top. Also, I wanted to keep the heat inside and somewhat insulated so as to not worry about the frame getting too hot. Granted, a light bulb probably wouldn't catch a board on fire...but why risk it? Also, I wanted to contain the heat and direct the air, so the cabinet needed to be enclosed. Rather than more particle board and make this thing SO heavy I couldn't move it, I used a fixed insulation board called Thermo-ply....they have various names at the usual Home Improvement stores. It is a 1/8 inch thick, 4 foot by 8 foot sheet. One side is silver and reflects heat which for this purpose...works very nice and at around 14 bucks, its cheap!

Here come the pictures.....
This is the rough sketch I had in my head. Base and top would be a frame of 2x4s,
with 3/4 particle board mounted flush so that the Fan could be mounted to the top
and the light fixture could be mounted to the bottom. The Thermo-ply is rigid...but
not stable enough on its own, so it would need to be screwed in to the vertical
supports. I wanted it to be fairly air tight to help with directing the air, so I had
the 'sides', 'front' and 'back' Thermo-ply recessed in the top and base so it could
sit around the particle board. I'll emphasize that in a later picture.


Here are the materials all cut out. Since I already had two matching pieces of particle
board, I adapted my design to use those. I have 23 inch vertical supports of 2x4,
21 1/4 inch horizontal pieces that would span the width and 8 1/2 inch pieces to span
front to back (these go between the horizontal pieces.


This is a side shot of the frame before assembly. Base and top match so it represents
either, but hopefully you understand the relation now of the 8 1/2 inch pieces to the
21 1/4 pieces.


The picture above shows how I needed the pieces to fit together, but a joint such as
those above is HARD to make strong. I take no chances so I bought 16 of these bad
boys..... 2 x 4's are actually 1.5 x 3.5....so with 6 inch screws, I was able to grab
roughly 2 1/4 inches of the 8.5 inch piece. With 2 screws per joint....it will not give!


Here is the joint with 2 screws looks pretty stout doesn't it?


Side shot of the joint showing the screw and how deep it goes....along with the
joint already assembled. Maybe overkill, but I prefer to err on the cautious side!


Particle board has ZERO strength if you screw in to it from the side vs down
through that 3/4 inch dimension. So when I cut my pieces, I knew I would need
to router out 3/4 of an inch to allow the base (or top...remember, they match)
to sit flush with the top of the frame. Somewhat rough since I didn't have a router
table or guide, but not horrible. Keep in mind, the particle board has an extra 1/8
inch removed around the entire piece so that the Thermo-ply pieces can fit down
IN TO the base (or top piece)


Thermo-ply was easiest cut by just a razor blade, so here I set the piece down,
screwed in 1 or 2 to hold it and then trimmed the edges so there was no overlap.


Next up...I get fancy....with FILTERS!!!!!

 

[teter09]

So...continuation....here we go! As I mentioned, this isn't just for wood drying. It also is for helping to keep drying items clean from dust or contamination as well as helping to facilitate the drying. So a hole in the base and top for airflow isn't quite going to cut it. In order to direct the airflow, I needed a fairly small opening for the air to enter and exit but also a way to clean the air of particulates. I needed some sort of filter, My fan is not rated for pressure, so while it may not blow quite as hard (not a bad thing, it is strong!) I am basically using it to pull the air through the cabinet, thus it will be mounted to the top of the cabinet...pulling air in from the bottom. So the filters need to be easily accessible, cheap and small as well as easy to set up initially. I scoured the Home Depot looking. Lawn mower filters usually had odd shapes and just no real solid way to mount them even if I did adapt them. In the aisle with A/C filters was also a package of heating register filters. While rather large (4 x 12 inches), they filter out smoke, dust, pollen etc but I could cut them down...and decided to do just that! Since they are held in place by a register grill sitting on them, I decided I would do something similar.

I elected to basically hold the filters in place by use of a 'frame' and magnets. For the base piece the construction is as follows: The Thermo-ply is going to be the top, which is where the filter will be pressed against. The filter will be fit in place from below, so the particle board is cut out so the 4 inch x 6 inch filter can fit inside it, but I only cut the opening in the Thermo-ply as 3 inch x 5 inch....to allow the lip where the filter would be pressed from below. To hold it in place, I used rare earth magnets on the frame piece below and on top, so the magnets would attract to each other and not tear the filter while holding it firmly in place. Pictures are below to help show what I'm talking about.

Here is the trace of the 4 x 6 inch hole I need to cut out which the filter will
fit inside. The upper right corner is slightly chiseled out as I made a hole to
use my jigsaw to cut the rest out.


Here the base particle board has the filter slot cut out, with the filter piece
set above it as I used it to be sure that the fit was tight.


Here is the bottom view of the base. The top insulation board has been put
back so I can make my outline of the 3 x 5 inch section to cut out. This makes
sure that I have everything lined up. I used scrap pieces of the insulation board
to create the 'frame' to hold the filter from below. Cut this on the fly and made
adjustments so that the frame would fit inside the particle board. Quick note,
I numbered the particle board and the filter 'frame' pieces to match, so I could
keep them straight for where it fits.


Filter frame removed so you can see the outline of the hole I need to cut.


Here the base reflective board is removed from the particle board and then the
3 x 5 inch cut out is made.


Here is how the filter is layered....Frame on the left .....


Gets stacked on the filter.......


Which is put in to the particle board and snugs against the insulation board above.


Obviously when this thing sits correctly, the filter would fall right out. I needed an
easy way to hold them, so I just used rare earth magnets I had. Super glued in place
(one on the frame you see and one on the other side of the insulation board which
is inside the chamber) and they are easy to pull out to replace the filter, but strong
enough they won't give out.


At this point, the insulation boards are then re-mounted to the particle boards to complete the cabinet top and bottom pieces. I marked where I wanted the vertical supports to be placed and used clamps to secure them while I screwed them together. Difficult solo....so no pictures unfortunately. Since I was running through the base (or top, depending on which piece I was screwing through) and at only 1.5 inches I just used some 3 inch Torx head screws I had. I used 2 screws again through the base and in to the vertical support from below and above. I used two verticals on each side and 2 in the rear (none in the front since I need the 'door' to be easily removed). Again, to make things air tight, I put the verticals in the back and the rearward verticals from the side snug against each other to create a solid corner that the insulation board could be pressed against and fitted tightly together.

I unfortunately don't have pictures as this took place, but here is one from the back that gives some idea. I will explain the wires later, but you can see how I positioned the rear vertical supports directly next to the side vertical supports in an 'L' shape.


With the insulation board tightly fit on the sides and back of the cabinet, I screwed them in with smaller screws. Not a lot, since the board is rigid enough to stay up on its own, but a few so it won't shift when moved or shelves are adjusted. Now comes the wiring.

Since I don't want any liability when it comes to electricity...I'm not showing step by step pictures of how I wired things or installed them. I will show pictures of my end results with explanations but that doesn't tell you the process and I'm ok with that. If you don't get what I did or how....hire an electrician!

But that will wait for tomorrow. I'm tired and need some sleep!

 

[teter09]

Here we go again, closing in on the end. Not quite sure if anyone really cares or thinks this is even valuable!

This is a picture of the interior corner. As you can see everything fits up
nice and tight together, which helps retain the heat and keep airflow
going where I want it...which is around my little maze of shelves! For
any gaps that might arise later, it would be easy to tape them up with
duct tape or metal tape, whatever is handy.


Here is a shot of the base as it sits. Obviously the magnets for holding
the filter are visible around the air entry, and the light is a simple light
fixture that you'd find in a home improvement store or might see
installed in a closet in your house. I did this for a few reasons:
1st...its CHEAP.
2nd...the fixture minimizes air restriction.
3rd...the maximum wattage is 150...which means I can increase or
decrease the bulb to help me reach my target temperature.


The first picture of this post there is a visible hole (2 rather) in the
side panel. My cheap and easy shelf holders are simply wooden dowels
that fit in about 1/2 inch. I just drilled them with 1/4 inch bit and used
1/4 inch dowel. They work great and can be moved whenever I need.
This is a picture of the bottom of the shelf. I had some wire shelving to
use up, and so to keep the air flowing around instead of just up and out, I
cut a few pieces of the Thermo-ply boards and use them as shelf liners.
Depending on what I'm drying...I place the thermo-ply above or below
the shelf because I might want to hang items from the wire shelving,
but still need it to force the air where I want it.


Anyone wondering what that black thing was in the center of the last picture? Yes? Wow, someone IS reading this! Keep reading to find out!!!

Quick little background before the next picture. One thing to keep in mind with wood is that it is very much like Goldilocks, in order to dry evenly and without checking or splits it doesn't want too little heat, or too much, but just the right amount. I don't know about anyone else, but I don't want to have to manually keep checking the temperature in order to either turn off the fan if it is too cold, or turn off the light if it is too hot. So I started trying to find a cheap automated way to do just that. The cheapest thing I could find was a Seed Matt Warmer. Basically it is a thermometer with a control panel and a plug on it. It goes up to 110 degrees F, and has a programmable point where you can turn off something when it reaches that temperature (whatever you've plugged in to the unit). Easy to find on Amazon and I bought mine for $29.

Here it is...Tada! Just screwed a small block of 2x4 to the side of the
front vertical post and hung it there so the temperature displays out the front.


This is the fan I'm using to pull the air through the cabinet. Simply positioned
on the top over the filter hole and held there by screen window clips. They
just fold out of the way when I need to replace the filter so I can move the
fan. I have been debating if I need to put a piece of tape or something on the
front edge you see (and the rear) to be sure the air is pulled ONLY through the
cabinet, but so far it hasn't been necessary (according to the temperature).


This is a shot of those same screen window clips that I use to hold on the front
door. Since the bottom slides in to a slot around the base, I just needed to keep
the top from falling out, and these were cheap and fit the bill well.


Well, since I want to hold the heat at a certain point and I live in Florida
(understand while most of this country is below 30...I had 69 degrees today!) I
decided I wanted the fan to run nonstop...but the heat to turn off or on
depending on the temperature. Since I knew I would need to run a single wire,
I basically created an extension cord that I mounted to the side of the cabinet. I
plug the Seed Mat Thermometer and the fan in to this 'extension cord'. The
light has its wires run up the outside of the cabinet and plugs in to the Seed
thermometer. The other black wire crossing around the back is the actual
probe that you saw in the picture with the shelf.


This is a full interior shot of it when I was using it for a Christmas project. Two
shelves wouldn't work with parts of a gun I was refinishing, so it hung from the
shelf as did 2 handles I added in there since there was room. I used a little cover
over the air inlet to force the air over to the right so it would pass near the light bulb
to hopefully then be sucked back to the left side and over the wood pieces and then
up the left side and over the shelf and out. Seemed to work as the handles and the
gun pieces (which were finished in Tru-Oil) dried fast enough to put on another coat
in about 30 minutes where as normally I would have to wait 4-5 hours.


Here are the handles (gun stock was shipped off and I forgot to take pictures!!!.
Christmas presents of Badger hair brushes for my father and soon to be Brother-in-law.
They are Coolibah Burl and despite the crappy picture they look great!

 

[teter09]

And we are all done. I've been using it quite a lot since I finished it and its become quite invaluable to me. Didn't realize just how much I'd use it until I made it.

Front view of my very boring front door! when I took this I hadn't quite
fitted the door to the rest of the cabinet, which is why you see the
light shining out from either side of the door towards the base.


Inside view with 2 shelves. The dryer sheets are in there because I
wanted to make sure the air was progressing as I intended, so I could cover
the front of the cabinet up to the lower shelf and make sure the air passed
up the slot since I could see the dryer sheet move. Then I closed off up until
the 2nd shelf and confirmed the same thing....so despite not having seals or
caulk or really being super airtight....it does what I wanted.


I would like to specify that if you make one, you'll have to play with it. Different light bulbs give off different heat and you'll have to experiment to determine which is right for you. For those of you in much colder climates...you might have to plug in an actual heat lamp bulb from a pet store or feed store to get the temperature up to where you want it. I popped in a 100 watt flood light on a night here when the temperature in my garage was at 55 degrees, when I checked back about 30 minutes later the temperature was turning off at my preset temp of 94. During the summer I used a 75 watt flood light and it was a breeze to reach 94.

Not sure how many folks here will really need to dry wood for sending off, I hope to do it quite a bit. But I KNOW most of us here could make use of decreasing drying time of wooden handles as we finish them. Hopefully I at least gave someone an idea that will help them in the future. I don't expect there will be questions, but ask away if you have one!