drying thin wood for coaster stock.

[doc henderson]

I have been doing laser engraving for gifts for a few years.  I can do groups of similar things like coasters.  I want the wood thin so the laser can cut out the coaster.  it can round the corners and leaves a flat black charred look to the edges.  I like 1/8th inch.  It can do 1/4 inch, but it is slower (takes longer) and if there is a knot or figure (pretty to look at) it may not shear all the way through.  the goal is stock that I can pull out and use, that is thin and stays flat.  I hate to have to plane a 4/4 board to small thickness, and hard to plane a thin board in maple as it can chip out.  I tried it in my heater with thin stir stick, and it warped bad, and did not dry well with heat, but little air movement.  so here it is in 1/4-inch rough stock, and 1/4 x 1/2-inch stickers every 8 inches.  



 

here is the maple that we split last week.  this is a thin could pieces to try.  18 inches wide, 9 feet long, 1/4 inch thick.



 

hand for scale.  



 

came from a tree alive 1 month ago, a bit ugly but will have some character on a 4 x 4 inch scale for wedding coasters.



  
my engraver table will hold and 18 x 24-inch piece. so that is why they are 18 inches wide.  and cut to 24 inches long.  



 
here is the stack with tiny sticker and every 7 inches or so.  

 

here it is with top boards and clamps.



 
using the same length clamps on the corners allows it to sit up off the table.  



 

starting out above 32% MC, the max for my meter.



 

here is the 19 buck WM fan, and the velocity feels strong coming out of the stack.  it smells of maple sap.  now to test it.  it felt stronger out of the stack as it was going straight, I think.  



 

here is the piece of yarn being blown at a 43° angle so about 320 M/sec.  +/- 310 M/sec.    8)  



 

yarn control group at 0 M/sec.  

[doc henderson]

If these can dry flat and plane out a bit, I can do groups of 24 coaster at a time.  after set up, it will engrave about and hour, then I put in the next blank.  I have done groups of 200 or more initially 1 at a time, then 6 at a time with 5 x 24 inch pieces.  


<br picture of a coping saw



 

wand store sign



 

 
          what fun to have thin stock.  lets see how this works

[doc henderson]

 

 

this is how we did it before the engraver.  they had a little ink stamp.  maple.  the corners were rounded on a belt sander.  note the walnut cookies on the steps for center pieces.



 

 

 

 

for metal there is a spray on ceramic coating, that turns to glass with the laser heat.

[JoshNZ]

Pretty cool Doc, we've just got a CNC table with a spindle so looking at similar stuff for my partner. Would sure like a laser to go with it.

When do we hear results of the 1/4" drying stacks, or is that what ended up as the coasters?

[thecfarm]

You will be The Yellowhammer of coasters!!  ;D

[doc henderson]

@JoshNZ



 

so already below 32%, who knows where it started.  I should have done a dry weight calc for the actual MC.  and maybe have a piece just setting in the shop to see how the airconditioned space with 320 M/sec. air and without does by comparison.  the edges are staying flat, but the other time did too until I undid the bundle (they did not have the air that time and were not dry).  you may have noticed but the top and bottom boards are 3/8th and that is the wood that is being tested.  that gave the internal 1/4 inch boards some protection, as the open top may dry faster on the open side.  I will try to do better on the next run/version.   >:(  

[doc henderson]

this is real time.  want to get industrial stock.  I put off doing projects if I have to make/process the wood for it each time.

[Crusarius]

Looks good doc. I have had some luck drying thin stuff. Definitely dries fast.

[doc henderson]

staying straight and drying fast.



 

 

this is at 24 hours with fan at 70° in shop, humidity at 40%

[Old Greenhorn]

Well that happened quickly! :D :D ;D ;D

[Crusarius]

I think I was happy with the dryness after a week or less. Biggest issue I had was crown. When I dried it I did not have any weight just sitting on top of the stack.

[doc henderson]

I give each clamp a squeeze and keep them tight.  at 7% I will dead stack but keep them clamped flat.  prob. make a press with all thread.  what do you all think would be the best MC to plane at.  too dry will chip.  I could do it now and then restack and dry some more.  I may drop my rollers on my planer so the wood is supported by the table and not up on the rollers.  I think that is why some of the thin stuff does not plane well.

[boonesyard]

I'd plane it now , will plane very well. Then dry it down as far as you're going to go with it. Even if it moves a bit more after you've planed it, which won't be much from 15%, it will all still be a uniform thickness. 

[doc henderson]

 

 

 

 

[doc henderson]

the thickness does not have to be a precise number, but thin as you mention.  the question is as the board gets thinner, will the edges and board get wavy?  want them flat.  @GeneWengert-WoodDoc  so what would be the ideal MC to plane them but not have them go all pringles potato chip on me.     at the lower mc, they could be dead stacked after planning.  i will prob. make a screw press to hold the 18 x 24 inch size boards.  may just store blanks in there.

[scsmith42]

Doc, I'm no Dr. Wengert but have dried 1/4" veneer material from green before. Here are a few things that I discovered.

1. Wood movement is closely related to grain structure. Sheets with varying grain tended to move more. Wavy edges occurred is there was much sapwood present. Sheets sawn with little to no sapwood dried flatter.

2. I used a much lower air speed than you. In my case it was 200 - 350 FPM, versus your much faster 350 meters per min. 

3. The sheets remained very stable after drying as long as I gave them a few days of continued drying after they reached EMC. If I destickered immediately after reaching targeted mc% they moved more afterward. An extra week of drying past EMC resulted in little discernible post drying wood movement.

Species that I've dried this way included white oak and sycamore.  I used 9" sticker spacing.

I've been told that there are special drying racks for guitar blanks. These look like the old egg crate style of fluorescent lighting grills except that the  egg crate is groves on both faces in one direction for air flow. Spacing on them is around 1" and they are 3/4 - 1" thick.

[Larry]

We turn lots of maple and cherry bowls from green wood to a wall thickness of 1/4" or less.  If in a hurry we microwave dry to 10% or less.  The warp stops at 18% but it will still shrink down to 10%. 

I would think for coasters anything less than 15% is good to go.

[doc henderson]

Thanks guys.  I appreciate all your comments and am considering them all and combined with my schedule, will plane soon, and restack to keep them flat.  too dry and the soft wood get brittle and chips out.  but I think I want it fairly dry, then it can all equilibrate in the dead stack.  after the coaster is cut, it will be tolerable.  if the whole sheet warps, then the laser is in and out of focus.  thanks everyone.  I find I get comments from Gene when his name is invoked, so there you go.  

[doc henderson]

so the planer chewed stuff up.  there tends to be areas with grain that is very intersecting, but as the wood thins, it self destructs in the area of the wild grain.  I could have lowered the rollers, but it is clunky on mine (reset them, not just a knob).  I then turned to my 24 inch drum sander, and it worked well.

[doc henderson]

I put together the next level of clamp using all-thread and knobs.  I made the clamps from left over oak stair treads cut 1.5 x 1.5 inches and 21 inches long.  everything is designed to make thin sheets 18 x 24 inches.  this fits the engraver and will fit in the heater.  



 

 

 

 

 

 

 

[K-Guy]

" That's the problem with you, Butch, your always thinking"  smiley_clapping

Well done Doc.

[Crusarius]

That is looking a little more than a fly by night operation. Nice.

[JoshNZ]

Quite the impressuve structure on its own haha. Would weight set on top of it not work just as well?

I've got a spiral head thicknesser arriving in October will be interested to see how well it works in comparison to knives in that regard.

My lady here has gotten into making coasters with funny covid quotes on them so I'll prob be doing something similar to this

[doc henderson]

I can pick this up and carry the whole stack.  it can fit in my fluid/blanket warmer so I can sterilize it if I want.  I will tape a second fan to reach the top of the stack.  I could make several sets, and stack them one on top of the other.  easier to handle.  when they are dry and sanded, I will dead stack them for later use.  21 deep, 24 wide, 36 inches tall.  prob. weighs about 20 pounds.  I had one thin one go wonky, but most are doing great.  I did not have it ready, so the thin sawn boards sat for a week and prob. started to dry on the edges.  overall pleased.  made some letter engravings for jimmy to frame as coasters,  did 6 across on a 4.5 x 24 inch strip of maple.  these will get 24 per sheet and the laser can do the shearing.

[doc henderson]

thus the reason for not doing the weight.  I can crank the knobs every 12 hours and still move the assembly.  I plan to make a wrench to tighten them, as the little knobs were giving me a sore spot.  (boo hooo).   I would love to hear about the spiral head.  I thought about dropping the bottom rollers on my planer, but it is too hard to readjust.  requires Allen wrenches, dial indicator and wrench to set a nut on the eccentric.

about 20 bucks for the hardware and another 20 for the all thread.