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Rustic furniture
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Discussion Starter · #1 · (Edited)
I'm drying a pyramid shaped triangle that Tennessee Tim had cut for me a few weeks back.
Here's the scoop.
I'm speed drying it. It is a 3 sided pyramid, with 18" sides at the base and it sits 16" tall. It is Chinquapin Oak. Now what I'm doing is running a space heater and blowing dry air over it. I've drilled a dozen holes on the underside, 3/4" x 8", to relieve tensions and also let the piece vent out moisture faster.
There is no way to accurately check the moisture content since the center is approximately 12" in to the center.
So I'm weighing the piece to tell me how much water weight is coming out of it. So far, the piece has went from 81 lbs to 64 lbs in 3 weeks. I'm using the weight as a guide. I'm going to use 50 lbs as my target weight.
The piece is cracking/checking/splitting as expected and is part of the overall design. I'm assuming the cracking/checking/splitting is aiding in the drying process, by acting as vent holes.

The ?????
Is there a means by judging by the weight, to assume the piece is dried sufficiently to where I can work with the piece. It's going to be a base for a coffee table.
 

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where's my table saw?
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some questions

Why not get a moisture meter since you work with the slabs frequently? I got mine from: Sonin 50215 4-in-1 Stud, Moisture, Metal and Voltage Detector - Amazon.com

probably a better one:
\


Why the target weight of 50lbs...based on what?

The last drop in moisture content is the hardest to get and takes the most time by air drying.

What about case hardening from drying too fast? This may be helpful:
http://en.wikipedia.org/wiki/Case_hardening_(woodworking)

If the splits and check are part of the design, what's the reason for a specific moisture content or weight? Does it matter as far as a finish coating?

Just curious and maybe I'll learn something .... :blink:
 

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Rustic furniture
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Discussion Starter · #4 · (Edited)
Ya know Cab't?
Your answer is so obvious I'm surprised I didn't think of it. Thanks.

wood.
I have a meter but the pins only go in so far. Right now, the outer surface is bone dry.
The target weight I guess is irrelevant after Cab't's answer. The finish coatings I use are generally epoxy, and the wood needs stabilized to the point that it won't shatter the epoxy from shrinkage and a crack opening up further.
After a few months of drying with hot air blowing around it, it's going into a kiln. Then I'll cook her hard.
 

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Sawing against the Wind
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You know there's NO strange questions here ESPECIALLY about a strange cut!!! We're all here to learn AND we all have differ theories on what's "proper". Heavy thick chunks/blanks carry extra drying problems and speed is against all of them...as you know I'm into slow drying but on a large chunk like this shape/size very few come out without checks and since that is part of the design it'll all be great and won't be disappointing. Drying as cab'man said is the way I'd judge it in this circumstance. Have you dried using some sort of dehumidifier???

I can't wait to see the progress, IMO take a deep breathe and slow down the heat to a slow/low setting and be patient....there's lot's of water that has to work it's way out.

There is a process being tried now that uses the high heat first and then remove the moisture??? I've only read a part of the article/post I'd seen and haven't deeply investigated. It's basic theory was the immediate high heat locked the cells open and they could relieve the moisture quickly instead of being locked in. This contridicts that speed drying causes case hardening???? research and form your own opinion, this theory has pros and cons IMO.
 
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Rustic furniture
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Discussion Starter · #6 · (Edited)
Well Tim, you know...It's a strange piece...you cut it! Strange piece, strange question.
My brother in law came over yesterday and just drooled over this triangle. He couldn't stop talking about it...


No Tim, I haven't used a dehumidifier.
In all my drying in the past, the fan on a small space heater does enough to drive out the moist air through a vent hole in a tarp. Got pieces down to below what the meter would detect (6%). I'm not to that stage of drying yet. The space heater is on the lowest setting and will run warm air around the piece for likely a few weeks more.

The cracks and splits are what I'm looking for and are fine. The checking was expected but not what I want to see. In the past I've used sawdust from 600 grit and white glue, and rubbed it into the checking. Then I start sanding. It doesn't remove all of the checking but it does quite a bit, and makes it slightly less noticeable. Seems oak has a tendency to check more than other woods I've worked with.
 

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Record the weights to try to dry down to a constant weight (whatever that is) = you're done.
On graph paper, I'd imagine the line will eventually slope downhill very gently = you will never see a true constant weight. When the piece isn't losing more than a few ounces per day, I'd consider it done.
The array of vent holes in the underside was a very good thing to do and for the reasons that you give.

Given the thickness of the block, the drying is bound to be uneven with the surface very dry and the inside not so much. Remember, all those little water molecules have to find their own way out of a very thick block!
 

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Rustic furniture
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Discussion Starter · #8 · (Edited)
Thanks.
Yeah, the piece is trying to slightly distort in shape. It's only a chainsawed piece at this point so I'll be able to grind it back into shape.
Lotta stresses on it.
And yeah, you can run your finger into the drilled holes and feel slight moisture. Surface is bone dry.
 

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Allen, I wondered about that, too.

Is there a reason why you can't chisel out all the web wood among the underside holes?
Just leave a cavity?
Upside down version of how I hog the void wood out of a carved wooden dish.
 

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Sawing against the Wind
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Sounds like Allen has seen your plans!!???!!! LOL

The hogging out the interior sounds like an awful good plan.....it'll reduce the wieght, speed up the drying and make things dry less stressed!!! a 3 in one punch. hollow the walls down to 3" and you'd be WAY ahead!!!

For the ones whom didn't see the other thread on the pyramid...link here... http://www.woodworkingtalk.com/f26/would-csm-milling-58231/
 

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Rustic furniture
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Discussion Starter · #12 · (Edited)
Yeah, it does sound like Allen has seen the plans.
Hi allen. Check your e'mail. Plan is included. I need the flat top area for future top attachment, but the idea is sound.

Robson, I'm not set up tool wise, to do that at this time. I have most of my tools packed for upcoming move.
 

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Sawing against the Wind
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Bandsaws do miracles!!! ....IF set up right!!! Actually we discussed sawing it that way.....VERY tricky!!!
 

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That seems easier said than done. How did you plan on doing that and getting a clean cut across the three sided structure?



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I would use a bandsaw somewhat like making a bandsaw box. It would be easier with a horizontal bandsaw like a small sawmill.That way the base is sitting on the bed and you're just sawing off the top.
I see your point about getting a clean cut because no matter what the kerf the edges of the two triangle pieces will no longer line up evenly. If you have to clean up the cut much then the difference only increases. It would most likely need a spacer or bezel between the top piece and the base if you did it this way.
 

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Sawing against the Wind
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Old School
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I would use a bandsaw somewhat like making a bandsaw box. It would be easier with a horizontal bandsaw like a small sawmill.That way the base is sitting on the bed and you're just sawing off the top.
I see your point about getting a clean cut because no matter what the kerf the edges of the two triangle pieces will no longer line up evenly. If you have to clean up the cut much then the difference only increases. It would most likely need a spacer or bezel between the top piece and the base if you did it this way.
Just for a point of discussion, it's not just the differential due to the kerf. Lets back up a bit in setting up the pyramid to be cut. Either on the BS or TS, it would have to be sitting horizontally, with the base on the table, and the point positioned and held at a centerline to the center of the base (which would be vertical).

You would need a jig of sorts to have the pyramid held at the right position, and a way of moving it through a cut.







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Sawing against the Wind
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Just for a point of discussion,.... .... Either on the BS or TS, it would have to be sitting horizontally, with the base on the table, and the point positioned and held at a centerline to the center of the base (which would be vertical)....."

MMMmmm, Technically not....and actually on table saw or vert bandsaw the base can't sit on table horizontally and make the cut....impossible due to blade to table position....

...."You would need a jig of sorts to have the pyramid held at the right position, and a way of moving it through a cut."....(cabinetman)

...yes with a jig for this and pyramid on it's side and with the correct angle on blade it can be done... BUT with a horizontal mill as Allen and I have, to cut the little tip off we lay the pyramid on as you say with base flat down, clamp and cut (there is a few things we have to do just to make 'mid sit there).....the centerline will automatically be correct IF all sides are correct/exact length....AND our sawhead moves while the base sits still.

On the table saw it can be done (provided all lengths are correct) easily with just the saw guide and proper blade tilt angle (and the blade has enough height). Being a pyramid and not square has an advantage here, on the HD TS's 90% of the baseline is against the guide and table prior the tip being cut enters the blade..so no jigging..any of the sides of the base can be used, angle is the same (just not by our eyes, we want to see square).

Now if we were cutting a pyramid that had one longer ridge length than there'd be SO many varaibles a table saw cut would be a nightmare BUT on a mill as Allen's or mine, you just sit the base flat and the blade runs horizontal and center automatically is correct if there is one due to a longer length ridge..????...

Ooohhhh!!...head rush...TOO much brain processing first thing of the morning...LOL!!!
 

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Old School
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Just for a point of discussion,.... .... Either on the BS or TS, it would have to be sitting horizontally, with the base on the table, and the point positioned and held at a centerline to the center of the base (which would be vertical)....."
=Tennessee Tim;561198]
MMMmmm, Technically not....and actually on table saw or vert bandsaw the base can't sit on table horizontally and make the cut....impossible due to blade to table position....
What I was referring to was cutting the pyramid with machines like a table saw, or a band saw. Tools that a hobbyist may have, not a horizontal mill.

The statement about the base on the table, I meant the edge of the base as indicated in the drawing below, orienting the pyramid horizontal (on its side), not vertical. To get the absolute dead center line of the base and tip of the pyramid to be absolutely parallel to the table (saw), would be necessary. And as you pointed out..."the centerline will automatically be correct IF all sides are correct/exact length...." A shop made pyramid fitting the parameters is a chore.

Figuring out projects like this reminds me of the times I had to split bowling pins and baseball bats.
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Line Parallel



 
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