Official Luthiers Forum!

So wht wood be the best way to dry a few peices of wood. Namely Indian Rosewood maybe some mahogany and pine.
I cant invest In a complex methods and machinery. So wht do u guys think. Cause i have access to a lot of rosewood as it grows where i stay and there are some saw mills dealing in them but i dont think ill get them completely dry. Wht form should i buy it in (6mm thick peices or would they warp upon drying).
I can also get mahogany and a few other sutiable for building woods and im looking at the quickest most economical way to dry them cause im obviously looking at building as a hoby and not as a large scale activity. Im also trying o keep evrything limited to hand tools.
**Another question i had was about bracing and i didnt want to start another post on it just looking for a simple answer. If im making 3 or 4 peice tops wt would be the best method for bracing the tops (would it be a different method?)
also looking for some info on these woods and wether they are suitable for any parts.

1]http://en.wikipedia.org/wiki/Michelia_champaca
2]http://www.woodworkerssource.com/online_show_wood.php?wood=Dryobalanops%20lanceolata

if i were you i would buy sets ready cut from the many mills in india that supply old growth indian rosewood (pm me i will tell you who i use).
go for the old growth stuff not the plantation stock (sonokeling).
they will come from the mill wet (guitar sets are cut wet in india and sold wet) so you will have to dry yourself.

the best way to do this if you do not have a dehumidification kiln is to air dry using a method we call sticker and stack.
i am sure if look in the archives you will find a deatailed explination but in short you some need short square sticks (10"x.25x.25" aprox)
these are placed between the slices of wood every 8" or so and the wood is stacked in this manner untill they are all on top of each other.
you then place some weight on top to keep the wood flat.

the idea is to keep the air circulating freely around the wood.
you can make the process more efficient by the use of a fan.

It should take about a year to get an indian rosewood set ready to use in this manner.

the only other option is to make a small dehumidification kiln big enough for say 10 set sets with a standard household dehumidifier(or two as i have).
i have made a small one of these for ebony fingerboards that i get shipped from india and it works very well as long as you keep the amount you are drying to a modest level.

I can give you instructions on how to do this if you are interested but its quite complex and the construction of the kiln box is very important.

I hope this helps a bit,

Joel.

thats some really neat advice joel. . Im in calcutta and have met a cpl of suppliers here who supply the old groth rosewood backs and sides but tehy deal mostly in bulk. so i am looking at getting them sawed from the millls myself. As of now i am just starting on my first guitar actually but do want to build many more hopefully.
Itd be really helpful to know how to construct a kiln for drying if it does substantially quicken the process. Also i want to use it to dry maybe other more indigenous wood varieties that i would like to experiment with.

thanks

Hi ganesha,

Old growth indian rosewood is sold in auctions by the indian government to the guitar wood mills.
this has to be then processed before being shipped out of the country.
as you live there it may be easy for you to get lumber etc from the mills that buy from the auctions.

as for making a kiln its quite a project and an investment.

I have two kilns.
one commercial kiln that was purchased to dry lumber and some processed parts (it will dry a cubic meter)
and one small home made one.

The home made one will dry about 50-100 indian ebony fingerboards in about 1 month- six weeks and does a very good job of it but i would not try to dry more than that.
it also works for about 10-20 sets any wood but i raerly use it for that.

To make the kiln you need to make a box first.
this is made from 8mm ply with a layer of plastic sheet/polystyrene/plastic sheet with another layer of 8mm ply.

This acts as an insulator box.
the dehumidifier lives inside the box and is a 30 liter machine with the intake hose etc outside the box.
i then have two fans at the top of the box.
one facing in one facing out.
Under neath the fans oposite the dehumidifer is the heater.
i keep it about 65-70.

The wood is stickered and stacked in the middle of the box in the same way you would whilst air drying

The idea is to keep the heated air circulating around the wood.
the heat draws the moisture out of the wood while the dehumidifier draws the moisure out of the air.

Pretty simple really.
i domestic dehumidifier will work for this job but only on very small amounts of wood like those mentioned.
my other kiln dries much larger amounts and Therefore uses a much larger dehumidifier.

I you want to use this method you to do some reasearch and learn about hoew wod dries.
hoadly,s book understaning wood is a good place to start.
as is The conversion and seasoning of wood by william h brown.

I would advise lots of practice with cheap wood becouse it will take a while to before you get it right and all sorts of wierd and wonderfull things can happen when drying wood.

joel.

Has anyone ever tried this technique for drying wood? Seems interesting but I don't know
all of the possible problems this might cause....[url]
http://www.woodworkerswor...cached_files/24654_files/ [/url]

The link may me down, I save a copy, let's see if this comes out:


VACUUM KILN
by Lynn Diel [edit]

First, I would like to thank Mr. Judt for the undertaking of such a worth endeavor of an Electronic Magazine. I await each issue with anticipation. I truly feel that this medium is the wave of the future. Besides this publication, Mr. Judt maintains a listserve for woodcarvers. There are a great bunch of folks who are members.
Introduction

I have been involved with technology and wood for quite a few years. Over the years, I have become an avid reader of technology and wood information. A while back, I ran across an article talking about a company that was using a vacuum chamber as a kiln. Further researching the topic, I found that Vacuum drying was first introduced by Dr. Pagnozzi in the early 1960's. His design consisted of a round pressure vessel in which the lumber was placed between heating elements and a vacuum was then drawn.

I was intrigue and since the article lacked details I consulted with a friend (who happens to be a Refrigeration Engineer). After our discussion, he decided to construct a vacuum kiln. Since he was in the process of remodeling his house and wanted to use Oak wherever he could, but didn't want to pay the local price for Oak, which is quite expensive.

We are blessed to have a Mennonite community about 25 mile north of where we lived and they harvest Oak trees and sell to the "English" (what they call people who are not part of their group). My friend bought the 1" x 4", newly sawed Oak very economically and brought it for me to his kiln. After about a week in the drying process of the Vacuum kiln the wood was dried to moisture content of 10.6%. After letting it acclimate in his house for another week, the moisture content was 12.1%. After milling, sanding, installing and finishing, he has a beautiful house for a fraction of the cost.
The Drying Process

The wood is stacked in the tube and the end is sealed. The vacuum pump is turned on and let run. How long you let the pump runs depends on several things; 1) the quality of the vacuum pump, 2) the quality of the seal on the holding tube, and 3) how good the piping is constructed.

If you are planning on building a vacuum kiln, invest in a good pump. The better pumps will pull a higher vacuum than a cheaper one. However, you should be able to do an adequate job using old automobile air-conditioning compressors.

Given my friend's system, all three of the concerns were addressed and the pump was let to run for 24 hours. After that time, the pump had pulled a 29.7-inch of vacuum on the tube. Closing the values and turning off the pump, he let the tube set for 48 hours. After that time, the vacuum had dropped to 27.1 inches of vacuum (due to pressure equalization of the wood and any minute leaks. The pump was run for another 8 hours or until it reached 29.7 inches of vacuum for three to four hours. Again the pump is shutdown and the valves are closed. The moisture content at this time was about 12%. After three days, the moisture content was down to 10.6% and the wood was removed from the tube. The wood was moved inside his house and was allowed to acclimate for a couple of days before milling and installation.

Since the wood is dried without high-heat there is very little checking. In addition, there is no tempering, making for a very solid piece of wood. The wood machines beautifully with no warpage. Over the past year, the kiln has been used to dry over 1500 board feet of Oak.

The construction of the Vacuum Kiln is simple in nature and typically can be built for less than $200.00.
How it Works

Bear with me (I am not an engineer), but in essence when the wood is placed in a vacuum, the pressure is greater inside the wood then on the outside, thus the moisture will migrate to the surface and then into molecules that move the to the lowest pressure (pump). In the study of physic, it is stated that: the higher the vacuum inside the drying chamber, the higher the water circulation rate from wood core to surface; the higher the vacuum the lower the water evaporation point.

This process is based on this principle in that the water will boil (turn to gas) at a lower pressure thereby creating low-pressure steam. (Note that water boils at a lower heat temperature the on top of Pike's Peak than in Orlando, Florida, which is near sea level).

The wood dries from the inside-out. In this carefully controlled humid environment, drying times are dramatically shortened, energy efficiency is greatly improved, and one of the advantages of this method is the kiln produces quality dried wood.
Construction

The tube is standard 12-inch plastic pipe, that was cut to a 12-footlength. The ends of the tube were trued and sanded to provide a good surface to seal. In looking around the local Wal-Mart store, suitable endcaps were located. A 12-inch frying pan with a glass lid works beautifully. The handle was removed from the pan end and attached to the end of the tube with a layer of silicon sealer and a soft rubber seal. The lid was held in place with bungee cords and duct tape until the silicon dried. The other end was prepared with a silicon bead and a soft rubber seal applied to the one side of the seal and the pipe. The glass lid was placed on the other side of the soft rubber seal.

A hole was bored into the plastic at 24" from the end. (Note this is not critical, it just happened that 24 inches placed the pipe in the ideal location to connect to the pump). A 1/2 plastic nipple was inserted into the pipe and was sealed using plastic pipe connection glue. Towards the front of the tube, two small holes were drilled to place wires through that would allow the connection of a Moisture meter. To ensure a good seal, the insulation was removed from the wire where it would go through the tube (See Figure below). The wire and the hole were sealed using silicon sealer.

The tube is connected to the vacuum pump using standard plastic water pipe. Placing a tee somewhere along the line will allow the connection of a Vacuum gauge and/or manometer. Near the compressor end a valve should be installed that will allow the pipe and tube to be sealed from the pump. At the end of the pipe, place a connector so that the pipe is connected to the compressor. You should use a flex type of connection in that the compressor does generate a vibration in the line. A simple flex connection can be constructed from 1/4 inch I.D. copper pipe coiled in a small loop. The output of the compressor should have a similar coil to provide a means to condense the water vapor back into a liquid.

Parts List

Description Comments
12-inch by 12-foot plastic
SD Drain Pipe from Plumbing house Check with contractors for scraps.
Vacuum pump Refrigeration suppliers, check at local Universities surplus.
Vacuum gauge Refrigeration suppliers
Manometer Refrigeration suppliers
Ball Valve Refrigeration or plumbing suppliers
Copper Tubing Refrigeration or plumbing suppliers
1/2" Plastic Pipe Plumbing or Hardware stores
1/2" Plastic Pipe tees and elbows Plumbing or Hardware stores
12" Frying Pan Wal-Mart or equivalent stores
Moisture Meter Wood working supplies (or borrow One from a friend during the initial setup.
Silicon sealer Plumbing or Hardware stores
Soft rubber for seals Plumbing , Hardware, or Roofing stores

In closing, since this E-zine is primarily for carvers, you may not want to invest in a 12-foot pipe. For small volumes of wood (i.e. carving blanks) a pressure canner could be utilized for a tank. If you have any questions, please feel free to email me.

Good luck and happy carving!

Lynn E. Diel,
Technology Infrastructure Manager
[edited]

_________________
Bruce Herrmann
"What lies behind us and what lies before us are tiny matters compared to what lies within us."

Thanks for that bruce,
Very Informative. I just got hold of some old growth Indian rosewood today. Dry and cut into fingerboard dimension. And found a source from where i can get almost fresh cut good quality old growth rosewood. So i guess shortly ill be looking at setting up a small dehumidifier, once i move into my new house.
I found the rosewood somewhat hard to work though. Its got a really really smooth surface once plained but its quite difficult to get the plain to move over it. Or maybe i just dont have enough practice. Do any of u find old growth rosewood difficult to plane ?