burls

[herb]

Hi,

Got some green burls. Generally with green I'll turn a blank, dry it in paper bags and then finish turn. Can one do that with burls? Is it better to finish turn them right away?

Herb

 

[Odie]

I've always roughed burls that have more than 12 percent MC.....exactly the same method I use for other wood. With all wood, each piece can be seen as with humanity, in general.....every single one of them have a personality all their own, so nothing is an absolute when considering hard rules to follow!

Pretty much the only reasonably reliable rules about drying and cracking, can be applied to species in a loose sense, but wood cut from the same tree and have similar grain pattern is the only place where rules apply with any regularity......even then, nothing is absolute.

As I see it, there are no drawbacks to naturally "seasoning" bowl blanks.....other than it takes more time. Everyone is in a hurry to finish turn. We live in a time where instant gratification is what is expected, but the cold hard truth is, there are faster, more technologically advanced methods of seasoning bowls that work to a degree, but the best way is still the "old-fashioned" way that turners 100 years ago new and applied to their trade......they knew that speed in drying, is exactly what you don't want.

My suggestion is to try finish turning one of your green burls into a bowl, and see what happens. You'll have a lot more definitive answers about what you specifically want to do that way........😉

ooc

 

[hockenbery]

I have turned lots of hollow forms from burls. I finish turn them green.
Usually I let them dry a few days then sand.

Occasionally I sand the form wet. When they dry the surface usually gets a soft texture as parts of shrink differently.

Burls make great natural edge bowls
Have fun,
Al

 

[Thomas Stegall]

Probably the best advice we could give you would be based on knowing the specifics. What species? How thin do you plan to turn it, and is maintaining semitry in the piece important? Or are you ok with it moving on you? If you want it to be perfectly semetrical, then you need to rough turn let it dry and turn again. But the thicker you leave and/or the faster it dries, the greater your risk of having checks in it. The thinner you turn it the more likely it will move, but the less likely it will be to check. Turning endgrain vs. sidegrain can also impact this. Another challenge is the drying of various surfaces, outside surfaces usually dry faster than the inside and this causes checks. This is especially true with hollow forms. Slowing the drying process reduces this disparity. So those specifics of the wood and intended final piece determine which approach I usually take. The species of wood and density of eyes etc in the burl will also determine how likely you are to get checks. So the advice from others above is very good advice, but you need to apply it in the context of your particular wood, and intended outcome etc.

 

[Mark Levitski]

Hello, Herb-

Good advice from others here so far. As with "normal" wood, different species can yield different results/effects. If you have pure burl and not straight trunk or limb wood with it, it seems to give more stability when drying. You are not dealing with strictly concentric wood and associated pith. The various grain patterns in burl sort of average out the stresses of drying and do not produce as much in the way of checking and cracking. But then I am not familiar with more species than maple, cherry, poplar, and birch.

I routinely rough out pieces based in burl that I dry and re-turn with few problems. However, I and many others, also turn green to finished thickness and let it dry. Less thickness will yield less movement in general. Slower drying, as you probably know, helps in avoiding the stresses that produce checking and cracking. Use your paper bags.

Short answer to you is, yes, for me and the species I deal with, burls are usually easier to dry then finish turn if you don't have any "standard" wood along with it.

Mark

 

[MichaelMouse]

Burls can't organize a lot of shrinkage stress where the grain is randomized. Truth. Problem comes if you want to do a turn thin and let go, and there's a crack or a loose bark pocket in the mix. I've had one side move north while the other moved south on a few occasions. So now if there's a problem like that, I don't turn thin immediately. Suggest it as a good action plan.

Turn burls with your ears attuned to the slightest click. Hunt the offending crack, run in CA, repeat as necessary when you start removing more wood. They sometimes fly apart if you don't. I keep some bark of the tree handy to stuff into buttered broad spots as well. Looks very natural to have bark versus sanding dust, which neither hides nor enhances a fault as I see it.

 

[Odie]

The best answer is ... "It all Depends".

IF you are uncertain of the exact final use of the burl, then keeping it cool and in a less dry spot for a while might be best.

I never turn a bowl out of a burl IF... I think I might want to re-saw later into inlay material.

So it all depends on the texture of the burl and the color. Tight burls that are really light in color, or dar or have good contrast can be much more valuable as inlay pieces than as a whole Bowl.

Sorry, that might sound real bad on a woodturning message board but I do moree than just turning so I nrrd to look at the BIG picture.

"It all depends"......yes, that's the way I see it, too.......😀

I purchased some bowl blanks from CSUSA the other day, and read some of the rules of drying they include with the order.

On that sheet, I see it says that generally speaking, burls do dry faster than non burl.........when looking at the overall picture, I think that's probably true.

......but, "It all depends" applies here, too........😉

ooc

 

[Odie]

"It all depends"......yes, that's the way I see it, too.......😀

I purchased some bowl blanks from CSUSA the other day, and read some of the rules of drying they include with the order.

On that sheet, I see it says that generally speaking, burls do dry faster than non burl.........when looking at the overall picture, I think that's probably true.

......but, "It all depends" applies here, too........😉

ooc

edit: I took a look at that sheet again, and it says burls dry "easier", not "faster". I'm not so sure about that, but my guess is that whoever authored the information on that sheet may have been thinking about the huge warps that some bowl blanks have. I don't believe I've ever seen a burl warp to the extent that some straight(er) grained bowl blanks exhibit, but there are probably exceptions to that generalization as well.......😀

ooc

 

[hughie]

depends

For me the origin has a big part to play. If I get green burls from Tasmania they are wet, very wet. I mean wear a rain coat and be prepared to clean down the walls in the shop etc. So Tassy burls at best rough them out leave them to dry in carboard boxes afew at a time, too much movement as they dry.

Whereas burls my my local state are drier and more predictable and I can get away with a great deal.

I have found simplest way is to continually collect burls so I have a good stock on hand some dry, some drying. Sometimes I get burls off dead trees, they are always a challenge. They maybe the most stable but are extremely hard and its a bone jarring rough out on some.