Keeping the bark on

[jaybird]

Just turned this flower out of a no name wood that was green its 200mm high. It was turned 2 days ago and now the bark rim is separating. I covered the bark and the edged with super glue at the time of turning and it looked OK at the time. Is there any method of stopping this. Thanks470769

[plt43]

I've only used CA for this - I try and make a fine cut around the strip of bark I wish to keep and drip medium or thick CA into it, to bond between the bark and timber before any further actual shape turning. Then stay away from the strip. Sometimes it works, sometimes not....

[jaybird]

Thanks for the reply. I haven't had experience in wet turning or how bark behaves. I have turned 3 of these mostly for the challenge and after watching a Japanese woodturner on utube. My observations so far is that it probably depends on the timber used as 2 of them are fine except for the one in the photo. The stem on this one is just over 3mm along with the petals which are about 3.5mm, the japanese turner is turning down to 2.5 in the stem and the flower petals, like him I'm turning the flower with a LED light on the opposite side to the cut to see how thin I can get and it's proving to be an interesting exercise in chisel control, also lathe speed (as fast as) and very sharp chisels so all round a good exercise.If anyone is interested in his turning he is on utube.
YouTube (https://www.youtube.com/results?search_query=yamabiko1220)

[NeilS]

My observations so far is that it probably depends on the timber used as 2 of them are fine except for the one in the photo.



Yes, it depends very much on the timber species. Also, the size; the larger the size the more it wants to shrink out of its less flexible skin.

IME, bark left on natural edge bowls, where the shrinkage varies between the cross grain and end grain areas of the rim are challenging, especially on larger pieces. The radial shrinkage is always greater than the axial shrinkage in most woods. And, is also the reason why a green turned cross grain bowl with rim to the centre of the log will warp the way it does.

With natural edge bowls that were turned green I've found that I have had to keep revisiting them as they season to apply CA to any areas where separation has started.

Fun to do as one offs, like exhibition or competition pieces (not that I do those anymore), but far too time intensive for production type work. Although they always sell (people like them), but I find that I can't get a price that will recoup the extra time that I have to put into them.

Keep having fun and practising those tool skills.

[NeilS]

Jaybird

Should you get into making those with longer and thinner stems you might like to take a look at some experiments I posted on the forum here last year about a setup I arrived at for pulling (not pushing) long thin spindles between centres.

With that setup you could turn spindles that are much longer and thinner. My experiments got down to 2mm over 250mm and I reckon you could get even longer with a 2mm size. The 250mm was just arbitrary for the experiment.

Here is a page from that thread that has my final report. The earlier pages will explain how I ended up there, including the equipment options tested along the way.

https://www.woodworkforums.com/f8/thin-spindles-pulling-pushing-226482/2#post2133319


I reckon those pieces you are doing with, say, a 300mm long 3mm diam stem would look extra specky!


PS - on the page link above, 250mm was mistyped as 2590mm in one place.

[jaybird]

Thanks for the link Neil and if I continue to go down this path then will have to look further into it. So far I've turned a few more of these and have managed to get down to just under 3mm but it is slow going and only turning the stem about 10mm at a time sanding and finishing as I go. It just fascinated me when I first saw it done and just enjoyed it for lessons in chisel control.

[bruceward51]

The best fix is timber selection. It is probably a combination of factors including the makeup of the plant, the time of the year, and the drying process may all contribute. I think I have seen one of the northern hemisphere YouTube turners talk about the seasonal influence on bark adherence, but it was a few years ago and I don’t think is was the main subject of the video, just something mentioned.

I have a few pieces of local Black Wattle in my pile. The bark is loose and peeling in some places and bonded tightly to the sapwood in others.

Bruce

[Colin62]

I have a few pieces of local Black Wattle in my pile. The bark is loose and peeling in some places and bonded tightly to the sapwood in others.
Many farmers locally grow black wattle in plantations, to be used in the paper industry. If they harvest it too late in the season, it’s too dry to strip the bark off easily, and it’s then sold (at a much lower price) as firewood or used to manufacture charcoal.

If it’s harvested before everything dries out in winter the bark can be pulled off by hand.

[jaybird]

Knowing hardly anything about green turning and bark here is some of my observations and some might like to reply if I'm correct in my thinking. I have turned come small bowls out of local green timber mainly Banksia, Wattle and gum. The Banksia and the Gum was from trees down by the lake where the water table is very near the surface (under a metre) both of these timbers split a lot as they dried where as same timber from the same area but where the water table is down deep did not. The timber near the shallow water table was much wetter with water spraying out as I turned. So my thoughts are don't turn that timber until it has dried out a bit, it must suck up and hold a lot more water. The wattle I have turned was wet but the log had dried for about 2 months it had beautiful grain and the bark has stayed on the bowl edge with very little warping.