Cling wrap to control the drying of bush timber.

[greybeard]

A reasonably sized off-cut of a black wattle stump was lying near the fire pit down at my archery club. As I am always on the look out for suitable timber that can be added to my stock of bow making materials this stump would appear to be suitable for bow risers. Although the tree had been felled about two weeks earlier we had a few days of rain shortly after and the stump off-cut was still quite wet.

01 Black Wattle Stump.jpg (153.24 KiB) Viewed 1935 times

The stump was reduced to six 3½" square billets and taken home for sealing. A generous coat of sealer was applied to all surfaces and the billets were stacked for the drying process.

02 Black Wattle Billet 002.jpg (21.07 KiB) Viewed 1935 times

No matter where you stack something in the workshop it seems to get in the way at some time or another.

After three or four months curiosity got the better of me and I decided to dress the billets through the band saw. Having cleaned up the four sides of the billets one could feel the moisture that had been retained.

Not wanting to seal them again in the waxy type coating that every bit of dust wants to stick to I decided to wrap them in a couple of layers of cling wrap.

03 Black Wattle 001.jpg (28.35 KiB) Viewed 1935 times

Twelve months down the track I put one of the billets through the bandsaw to see how the drying process was going. I could tell by the feel through the bandsaw that the timber was still wet.
Drying had only occurred to about ½" into the billet, the center was still moist to the touch. To my surprise there was no end checking, but this may have been the result of leaving the original sealer on the ends.

04 Black Wattle 002.jpg (20.97 KiB) Viewed 1935 times

From my initial experience cling wrap may be an alternative when drying timber. Perhaps a few cuts in the in the cling wrap may help to remove the moisture at a slightly faster rate.

Black wattle can yield some beautiful timber for bow risers and quality black wattle can produce excellent core laminations.

Daryl.

[pdccr]

How did you cut down the wood into the billets? I recently acquired some pine logs but have no idea how to reduce them.

[greybeard]

With a chainsaw.

[pdccr]

Right, i was thinking of splitting them but i remember hearing "if green then saw if dry then split".

I wouldnt be able to let them dry as they are would i?

[Mike-dy]

Ive used Cling wrap to do exactly this greybeard, and found 12 months later the timber wet as the day I cut it, it stopped any checking though. I was thinking of leaving the ends open next time time and trying that, easier than using wax or paint etc and allows me to rough saw timber at collection rather than splitting logs at home.

[Brumbies Country]

I'd read about cling wrap somewhere and wrapped a 4" diameter hawthorn stave in it immediatley after cutting and debarking before Christmas. Weighed it every second day for two weeks after placing it in an old grain store and it lost only a few grams. The latter is all corrugated iron with a raised timber floor. Between Christmas and New Year I read significant portions of the 4 editions of Traditional Bowyers Biblesthat Ainslie gave me for Christmas, split it and wrapped a stave in cling wrap, removing the cling wrap for a few hours every day. I got good drying with very small, around 1/16" deep cracks near the pith and 1" checks either end. Bit seat of the pants stuff on the moisture estimation, but a week ago I reckoned it was getting close to being workable. I thought I'd try something else and coated it in lard for a week to mimic American Indian use of animal fat. It was fine in the grain store where I reckon the temperatures are 10 degrees higher than ambient temperatures but when I took it into the open shed where I work and within half an hour it was covered in ants. They love lard, as you'd probably expect. Anyway Saturday I roughed it out as a flat bow and am hoping that it might make a character bow.

The hawthorn didn't split evenly; I'd reckon the other stave wasn't going to make a self bow so I've used it as a control. In summer temperatures and in our low humidity, as you'd expect it's developed substantial cracks and is an interesting contrast.

So I guess my one experience is also that cling wrap retains moisture when no openings occur, but can be used judiciously for reasonably rapid drying.

Simon

[longbowinfected]

Simon.
Just make a number of pin holes in the ends. Do one with nominal rate of 25 holes per square inch, another with double that rate along with a non perforated as a control and see how the rates compare.

You could use smaller billets in an oven at elevated temperatures to determine an advanced rate as well. Then graph number of holes per square inch and then temperature.
Simon, I could loan you my two prong Tramex moisture meter if you want to do the comparisons properly.

Kevin

[Brumbies Country]

Simon.
Just make a number of pin holes in the ends. Do one with nominal rate of 25 holes per square inch, another with double that rate along with a non perforated as a control and see how the rates compare.

You could use smaller billets in an oven at elevated temperatures to determine an advanced rate as well. Then graph number of holes per square inch and then temperature.
Simon, I could loan you my two prong Tramex moisture meter if you want to do the comparisons properly.

Kevin

Thanks Kevin

The number of holes per square inch sounds like a good scientific approach and worth trying next time around. Because I aim to finish usually with a one piece self bow of around 68" I may have trouble finding an oven to accomodate, but to be honest the elevated temperatures of the grain store do a pretty good job.

Have to say that having read relevant articles from the 4 editions of the TBBs that a moisture meter sounds the way to go. Thank you for the offer. Getting it from and back to you at a time to suit both of us may be a logistics problem. What are they worth to buy?

Simon

[longbowinfected]

I have a Tramex [Irish].
Mine has two prongs and has an aluminium cast body....around the $300 mark.
Do not get the pad type as they only measure surface moisture.
Pest Controllers canot use the pin type as they damage the surface appearance.
Their distribution is a limited master dealer system.....they cost almost $800....ouch. I have to have one of each. You can buy some nice ones that have both a pin and pad system on a plug in lead attachment.

These should all be much cheaper from Taiwan / China if you search the www

Kevin

[Steven J]

I use cling wrap a lot when drying timber or preserving the moisture inside it. If I want to create some spalted timber, I just wrap it and leave it for as long as I can wait. It takes months to a year for the fungus to grow right through the wood of a 6 inch block but the technique works well.

I prefer to carve and craft things from green rather than seasoned timber (spoons, toys etc..) and wrapping fresh timber in cling wrap keeps it moist for all the time I need to use the pieces up. If I want to keep it from spalting I dip the timber in a dilute bleach first to sterilise the surface and prevent fungal growth.

If I want to dry timber at a slow rate to avoid cracking I wrap the timber in 3 or 4 layers of brown paper making sure that the ends are folded and taped down neatly like a parcel.

Steve

[Brumbies Country]

Thanks for an idea on the prices Kevin. After reading relevant articles by Tim Baker I really got the impression that a direct knowledge of moisture content, especially given the low humidity round here, is the way to go. My first two bows were from a hickory plank and I thought at that stage it was indestructable, but a second plank I bought more recently shows small drying cracks; obviously selected board can dry too much and I've moved to local staves in which I can at least attempt to control the moisture.

Steve, you mentioned spelted wood and it's a term I hadn't come across. It's obviously a fungus and sounds like it might be used to artistic effect. Can you explain a bit more? The most attractive bow I've seen is one of Longbow Steves. It's a pecan bow with cambium on the back. Opened my eyes to the possibilities of using the things nature puts there.

The brown paper wrapping sounds worth looking into.

Simon

[pdccr]

I have some big logs in the shed (pine) and wonder to what extent the timber will crack if i don't seal the ends? They will be left almost as is but they will have the bark taken off once dried. They are about 15-20" in diameter and 20-50cm long.