Take two, Khaya senegalensis

[DarwinStrings]

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Originally Posted on: Jul 29, 2010

There is an abundance of African mahogany coming out of Darwin parks and gardens, it won't last forever because they are generally removed now and not replanted. Post cyclone Tracy they were handed out free to re-vegetate (when they grow up they tend to fall over in the wet season with a combination of wet soil and a bit of wind). Years ago I cut a bit up but could not get it to dry without checking in the striped figure on the quarter sawn faces. I gave up on it relegating it to uses such as 50mm thick bar, kitchen and table tops.

Some recent post here have sparked new interest as it is beautiful wood to look at. All I did at the time was air dry it so I am interested to know if anyone has any tips on what methods I may be able to use to season it up without the checking which renders it useless for guitar wood.

Jim

Life is good when you are amongst the wood.

[Dennis Leahy]

Hi Jim,

From my understanding, air drying thick planks of many species is a crapshoot. I have heard (from tonewood sawyers) that it is best to coat the end grain very well, then create billet-sized (or over-sized) slabs, then immediately resaw the material into thin slices. Sticker between each piece, stickers and a flat board with weights on top, and put a fan on low or medium, blowing through the stack. Salt and pepper to taste, and wait a few weeks and eat, er, I mean build with it.

My guess is that 'weeks' might need to become 'months' for some species to truly be ready to build with, but that generally, those thin slices get down to 8% MC pretty quickly because a thin slice holds so little water.

There are a few species especially prone to surface checks, (Snakewood jumps to mind), that may benefit from a thin coat of shellac on the face surfaces of the wood, to slow down the drying.

Good luck!

Dennis

[DarwinStrings]

Thanks Dennis. I have tried the methods you mentioned (without a fan) with no success. This tree grows at a unbelievable rate up here (I guess that this has something to do with why it is hard to season) especially in a garden situation, a little slower on the fringes of parks where it doesn't get much water in the "dry". The pic below is one from Bagot park, not far from me. The park was a speedway track till the early 80's and this tree did not exist in aerial pics from 1979 and I would think it was not planted till after the park was converted to a soccer field in the mid 80's.

FIL3845.JPG (76 KiB) Viewed 21050 times

Jim

[Kim]

Godang tree hung'in, VB drink'in, boltnecked, litterbugg'in, freak'in hippy, git ya godang big ass out the godang way so's we kin seez what we spose to be look'in at.

Sorry Jim, just had a bowl of mex chilli for lunch

I can't be of much help except to say that you may need to tackle this in a closed and controlled environment like a shipping container. May be Tim Spittle will pop in with better advice.

Cheers

Kim

[Nick]

Sorry Jim, just had a bowl of mex chilli for lunch
Kim

Farting

[DarwinStrings]

I knew I should have thought before I posted this, I swear I was not hugging the tree, I know it looks bad but I was...ammmmmm...errrrrr..... just gauging it against the bar length on my chainsaw, honest I was.

Jim

[Dennis Leahy]

Jim, Jim, Jim...

OK, I get it: you "love" the tree ( )

I don't think this is what they meant when they mentioned transgenic species. Khaya senegalensis jimii ?

Dennis

[liam_fnq]

standard Darwin attire too there Jim..................

[reconstructor]

Reply by "Tigermyrtle (guest)"

Jim, I can not understand some of the answers that you are receiving to this question as I have been air drying billets 50mm 60 mm 75mm and some times 100mm thickness for longer than I care to remember.
With no problems.
Not bad for a bloke that knows nothing.

Question how are you milling this timber.? are you milling with a chainsaw just slabbing the timber or are you milling it on the quarter.?
Are you end sealing the timber.? where are you storing the timber.?
If my post is deleted what seems to happen a lot here, by a couple of paranoid people feel free to contact me and I will try to help where I can.
Cheers, Bob

[Kim]

If my post is deleted what seems to happen a lot here, by a couple of paranoid people feel free to contact me and I will try to help where I can.
Cheers, Bob

Last chance Bob.

You keep being a smartarse and I will delete your account without further warning.

The only previous post of yours which have been deleted have been in direct breech of forum rules regarding 'unwlecome' promotion of your commercial enterprise. You have been warned about this enough times and the admin team have run out of patience with you. Please do not PM me about this because I am not interested in entering any form of off line dialog with you, just understand that you have been told that this forum is not your promotional tool and you are only welcome here as a standard member and strictly on a noncommercial basis.

As for Jim's question and some of those answers you do not understand, you are correct, you known nothing and that is why you will not be accepted as a preferred vendor here anytime soon. Jim lives in Darwin. High humidity makes it difficult to dry wood, especially when the wood has grown so fast that it's cellular structure is large and hold a great deal of moisture.

[reconstructor]

Reply by "Tigermyrtle (guest)"

Well there you go Kim, you have just answered part of Jims problems.
But it is still possible to dry this timber in Darwin if it is kept under control.
And Kim you say that I have only had one post deleted, I had a post deleted a couple of days ago saying I was promoting my business but far from it.
Kim I do not want to be a vendor in this forum.
But I should be able to answer questions that I do know a lot about that is wood , my god you remind me of school teachers when I was little up in Scotland, if you dont eat your dinner you cant have any pudding, where is your bloody sense of humour.?
Cheers, Bob

Jim lives in Darwin. High humidity makes it difficult to dry wood, especially when the wood has grown so fast that it's cellular structure is large and hold a great deal of moisture.

[DarwinStrings]

Question how are you milling this timber.? are you milling with a chainsaw just slabbing the timber or are you milling it on the quarter.?

Years ago I cut a bit up but could not get it to dry without checking in the striped figure on the quarter sawn faces.

Are you end sealing the timber.?

Thanks Dennis. I have tried the methods you mentioned (without a fan) with no success.

See Dennis's post

where are you storing the timber.?

At the time I tried in the shed as well as outside under a awning ( that is out of the sun but in the breeze.)

Jim

[DarwinStrings]

You mention it is possible if it is "kept under control". The methods of "control" is the answer I am looking for. The post of me not really hugging the tree was to show just how fast these things grow as I assume this has something to do with the fact that it is difficult.

Jim

[Allen]

So it seems that it's drying out too fast if it's checking. Tough nut to crack with the humidity the way it is up in the top end.

So sealing the end grain is a must. Then it seems you are going to need to have some method of controlling just how fast that initial moisture is lost.

The dehumidification kilns I've seen in Canada are set up to keep the RH at a relatively high level for a set time, then vert gradually lower it as the wood looses it's moisture.They aren't trying to hurry up the process, but get the best yield possible. Very similar to what you would want.

Some of the sinker and float logs that have been in lakes for close to 150 years comes to mind. Some mates of mine make a very lucrative living out of harvesting this wood, and it's totally saturated, but very valuable. Any loss is a big hit to the paycheque, so they really pay a lot of attention to this.

The simplest one I've seen is just a enclosure made from poly sheet much like a green house. Roof vents that are adjustable. Hygrometer and thermometer inside. Some experience and luck required to adjust the vents to best suit the conditions. This in a much colder and drier environment than yours though Jim.

[kiwigeo]

I knew I should have thought before I posted this, I swear I was not hugging the tree, I know it looks bad but I was...ammmmmm...errrrrr..... just gauging it against the bar length on my chainsaw, honest I was.

Jim

Whenever Ive been in Darwin on cyclone evac Id often find myself hugging trees so I didnt fall over on the way home from the boozer to my hotel.

[DarwinStrings]

So it seems that it's drying out too fast if it's checking.

The dehumidification kilns I've seen in Canada are set up to keep the RH at a relatively high level for a set time, then vert gradually lower it as the wood looses it's moisture.They aren't trying to hurry up the process, but get the best yield possible. Very similar to what you would want.

I had thought it was drying too fast even in the wet season it still seems to be to fast. the enclosure of some type to slow it down sound like a sound idea and I guess that is my best option if I am going to try again.

Whenever Ive been in Darwin on cyclone evac Id often find myself hugging trees so I didnt fall over on the way home from the boozer to my hotel.

Don't lean on one of them mahoganies around "cyclone watch" time. Next time they evac you give me a yell when you get here and I will point out the most suitable trees to hug on the way home from the pub.

Jim

[TimS]

Hi Jim,

I thought I might add a few thoughts to this discussion that might be of some help.

The way you breakdown the log will have some effect on the way the recovered boards react to a range of tensions that may exist in the log prior to milling. Namely spiral twist in the log, heart shakes, knots and bark inclusions. Given that you are probably going to use the wood for musical instruments you might be able to cut the log in usable sections (600mm or 900 - 1200mm) and thus be able to track the position of defects as you work along the log. Just remember make the initial cut in line with any dominant heart shake in the log. In addition avoid the tendency to aim for maximum recovery rather than quality pieces.

Assuming that the you have cut the material into boards and you get surface checking in humid conditions then you are most likely dealing with tensions in the wood, be it moisture or sprial tension. I would personally aim for back and sides boards no thicker than 28 - 32mm if air drying. End sealing is essential, racking out must be even (18 - 25mm thick rack sticks). One piece neck material may result in some loss given the thickness. Slightly elevate the boards off the ground to avoid any fungal activity and provide a cover over the stack to reduce direct sunlight. You may also be well advised to control the rate of free moisture in the board to avoid any case hardening. This can be done by covering the wood in plastic and control the amount of air movement. Humidity readings will provide you with some guide. Of course too little air movement will promote fungal activity.
I am away tomorrow but will be in on Sunday should you want to call.
08 62782187
regards

Tim

[Kim]

But I should be able to answer questions that I do know a lot about that is wood ,

The only thing more dangerous than he who knows only enough to get into trouble is he who calls himself an expert and leads others to trouble with ignorance and misinformation.

That's why you will never be a preferred vendor at this form Bob, because you don't really have a clue about lutherie. How's that weissenborne going, buddy? Found someone with skill enough to finish it for you yet? Did you ever even start ? Confused

Phhhwwet!

Kim

[kiwigeo]

Go to bed Kim!!

[Kim]

Exits stage right



Cheers

Kim

[kiwigeo]

Good lad.....

[Pete Howlett]

This is all a bit heavy... glad i din't witness the **** storm

It must be hard in Australia/New Zealand to dry wood. However some basic principles can apply. When felling create your cants by 'splitting' or 'riving' rather than sawing. Can be hard with hardwoods but it is possible. End seal and 'end rear' cants for 3 months then 'sticker' them in small covered stacks with the ends facing into prevailing wind. If cant's are 'thick' then stickers need to be likewise. Old school recommends felling in autumn through winter. Allow one year air drying for every inch of thickness. When stickered turn cants in the stack every three months during the drying cycle. Store in the workshop for a good year before conversion. Resaw and sticker for 6 weeks in the environment you are going to build your instruments. NEVER TRUST ANYONE WHO SAYS THEIR WOOD IS DRY - one man's 'dry' is another man's unseasoned...

[kiwigeo]

It must be hard in Australia/New Zealand to dry wood.

Why? The tonewood suppliers I use here in Australia dont seem to have too many problems supplying me with properly dried wood.

[Pete Howlett]

I wasn't refering to luthier's suppliers who know their customer requirements. I think this thread is about DIY supplies of wood isn't it where provenance is unknown to a degree. ie: I bought some lovely burry yew for drop tops from a turner's suppliers. usual question: "Has the wood beeen dried?" Affirmative answer. get it back to the workshop, resaw it and put it with my stack of burrs in the conditioning room where it turns into a potato crisp... Got some koa like that too.

[Puff]

Hey Jim - possibly coals to Newcastle but have you thought of PEG. Have never used it on big thick stuff but for 'veneers' sliced at chop-down time it works. Even better when done as a 50-50 mix with gelatine glue in the bath. Bit waxy but naptha clears the glue lines.
Cheers