Thread: Turning green wood

Originally Posted by smidsy

Hei Guys,
Just for the hell of it I've turned a couple of bowls out of very green (the tree came down about 6 weeks ago) marri.
I know I need to let it dry, should I turn it only rough and leave it to dry out before final shaping?
Do I need to recoat the bowls with endcheck while they dry?
Any advice appreciated.
Cheers
Paul

Yes for rough turning unless you go real thin. Under 3/16th.

Most turners use a heavy coat of wax.

Paul,

I rough turn green bowls to about 15 – 20 mm thick and then park them for a while in a cardboard carton in the shed. In the Queensland climate they seem to be okay to ‘finish-turn’ after about six months or so. Write the month/year on the bottom of the bowl so you can evaluate their progress.

I don’t bother to end-check them. Once they have been rough turned they seem to dry out fairly evenly and much of the stress has been relieved anyway. I guess if they crack now they probably would eventually, due more to a defect than irregular drying.

Regards,

Hi Paul,
I turned a platter 300mm about 2 weeks ago and it was green as green and i turned it to finish so i could watch what would happen to it once it started to dry. I used EEE and The liquid wax from the same company and it has only cracked in 4 areas and they are only small. Standing back from it you cant really notice it. I have left it outside on my verandah to see if this will speed up the drying process.
Anyway mate my 2c. I can send you photo's if you want. It was made from Yellow box.

Some comments

IMHO if the final work is not perfect (ie without defects of workmanship) it is better not to do it. It is thus necessary to have techniques which usually yield good results, and discard those items which crack etc.

That out of the way, the following:

Turning wet to a final finish I have found to have limited appeal. The problem is not the issue with shrinkage/warping, as although I do not like this, it can still be attractive. My dislike comes from the fact that sanding and finishing wet turnings does not give a finish that I find acceptable in a finished piece. A possible exception is that of thin walled endgrain bowls and vases, (usually with natural edges)

I rough turn to final form, and a wall thickness of ~ 10% of diameter (usually about 20mm). I use a woodscrew for the outside, and then turn an oversize dovetail recess for the Nova chuck (expanding) and reverse to hollow out. After drying and distortion is complete, I rechuck on the (now oval) dovetail, which is secure enough to allow me to true up a recess in the inside bottom of the bowl. Depending on the bowl, I will either use this as a dovetail recess, and reverse the bowl over the chuck in expansion mode, or attach a VCR head with hotmelt, and grip this in the chuck. (This is one application where the regular Nova outdoes the Super)

Return outside, base and recess, sand and finish, and then heat the VCR head, remove, and chuck and finish the inside as normal. If you are one of those who is allergic to leaving any chucking detail on a bowl, you have further options. I have done this sucessfully up to diameters of 22 " and depths of 8".

As to how to dry, I regularly microwave, (extensively covered elsewhere, and more successful with some timbers than others) or dry naturally, (either as is, or in paper bag, with variable success)

Other well publicised (sp?) methods I have seen include boiling, freezing, and soaking in PEG, or in concentrated dishwashing detergent, before drying naturally. All of these are reputed to reduce the amount of distortion and degrade on drying, as well as reduce the time taken.

Hope this offers some food for thought, or ideas.

Alastair

Another "drying" method which I have used with some success is to turn your bowl to a wall thickness of about 15 to 20 mm, then place it in a plastic shopping bag that you have rescued from a seal, dolphin, seabird or landfill. Tie the bag loosely and every week or so, depending on the climate, take it out of the bag, turn the bag inside out and then retie. If you want to get fussy then weigh the thing when it is wet and then wait till the weight stabilises. I have found that this method is quite efficient in time and effort and usually gives me a nice stable bowl with no wax, plastic, dried snot to turn off.

Christopha your technique sounds interesting but are we meant to remove the seal, dolphin. seabird or landfill from the bag or leave them in it too?

I'm glad there are other like minded souls who are looking out for the dolphins.
I like dolphins very much but there's no way I could eat a whole one.

Originally Posted by echnidna

Christopha your technique sounds interesting but are we meant to remove the seal, dolphin. seabird or landfill from the bag or leave them in it too?

Christopha,

I tried to find a bag as described, and had some success .... how do you get the dogpoop out of them, or don't you worry about it??

Cheers,

P

I have also found that turning seals and dolphins when wet is very messy, and gives a poor finish in the final article.

Alastair