Burl Advice

[Brandon Sloan]

Posted in a different thread about this but wanted the advice from the AAW community as well. This is my first time processing and turning a green burl.

I think I turned it a little thin for the amount of movement that will take place as it dries. Should I just turn it thin and let it warp? It’s a little over 16” and 4” tall 1 3/8” thick. I should add that the wood is Alaskan paper birch and is incredibly stable and hard. I’m using m42 steel sharpened on 180 CBN wheel and sharpened 3 times while hollowing.

Thanks in advance!

 

[hockenbery]

think I turned it a little thin for the amount of movement that will take place as it dries. Should I just turn it thin and let it warp? It’s a little over 16” and 4” tall 1 3/8” thick.

no experience with this wood. Burls don’t have the growth ring grain that predictably warps in two dimensions going oval because the Tangential shrinkage is about 2x the radial shrinkage) burls usually will dry nicely for double turning.

I usually go to finish thickness on burls. The issue then comes one of sanding.
The surface of burls will dry rippled because The different densities of the wood.
Hard to sand the ripples to a smooth surface takes time.
I like to sand wet burl hollow forms using abranet. Then when the surface ripples as it dries, it will have a wonderful textured surface that feels so nice when you hold it.

 

[Brandon Sloan]

no experience with this wood. Burls don’t have the growth ring grain that predictably warps in two dimensions going oval because the Tangential shrinkage is about 2x the radial shrinkage) burls usually will dry nicely for double turning.

I usually go to finish thickness on burls. The issue then comes one of sanding.
The surface of burls will dry rippled because The different densities of the wood.
Hard to sand the ripples to a smooth surface takes time.
I like to sand wet burl hollow forms using abranet. Then when the surface ripples as it dries, it will have a wonderful textured surface that feels so nice when you hold it.

Thank you for the tips, I’m going to turn it thin. Should I CA the edges of the inclusions?

 

[hockenbery]

Thank you for the tips, I’m going to turn it thin. Should I CA the edges of the inclusions?

Yes - if you want to absolutely keep the bark.
I use thin and saturate the bark. Don’t get Ca in the wood. This give it some body strength so is doesn’t crumble later.

no if you want to remove the bark. The. You will have an organic contour where the bark was.
if the burl has spikes. I would remove the bark so they show.

plusses and minuses to both.
does the bark add visual appeal?
Does the bark make the piece look unfinished?

when you turn thinner you will likely have larger voids where the bark is.
Removing the bark makes the larger

removing the bark is always more work.

 

[hockenbery]

One caution- you probably have looked at the second bowl photo. The bark inclusion runs all down the side.
You will need to tape or support the two sides of Inclusion or you will have two halves of the bowl flying apart.
During hollowing they will flex. When the side you are cutting an 1/8” deep cut will flex out a little from the cutting pressure and the side across the gap will flex in an out randomly making at best and uneven wall and if it flex’s in your cut hits the or Other side of the void at a 1/4”+ deep and the wood cannot take that extra stress.

taping the outside or using shrink tip wrap will keep it from vibrating and give support a cross the void.
If the distance across the void and wall thickness cause the hollowing tool to cut the tape I use a stiff wire to hold the tape in something close to the curve.

 

[Brandon Sloan]

One caution- you probably have looked at the second bowl photo. The bark inclusion runs all down the side.
You will need to tape or support the two sides of Inclusion or you will have two halves of the bowl flying apart.
During hollowing they will flex. When the side you are cutting an 1/8” deep cut will flex out a little fro the cutting pressure and the side across the gap will flex in an out randomly making at best and uneaten wall and if it flex’s in your cut hits the or Other side of the void 1/4”+ deep and the wood cannot take that extra stress.

taping the outside or using shrink tip wrap will hike it from vibrating and give support a cross the void.
If the distance across the void and wall thickness cause the hollowing tool to cut the tape I use a stiff wire to hold the tape in something close to the curve.

Awesome advice, I usually use a folded paper towel in my left hand against the outside of the bowl to minimize flexing while making my final cuts. I knew this wouldn’t be possible with the uneven surface and was wondering how to approach this.

One more question. I’ve always finished on the lathe, with the voids and warping that will occur I don’t think i will be able to use my usual finishing process. Is this one of those cases where I’ll need to spray on a finish? Maybe a spray lacquer?

 

[Dennis J Gooding]

I would be a bit suspicious of that tenon. A good fraction of it seems to be bark and may crumble under pressure. Depending on how much stress the remaining work is going to exert, you may want to consider flattening the base and gluing a solid tenon onto the present one.

 

[Brandon Sloan]

I would be a bit suspicious of that tenon. A good fraction of it seems to be bark and may crumble under pressure. Depending on how much stress the remaining work is going to exert, you may want to consider flattening the base and gluing a solid tenon onto the present one.

Thanks for the reply. I was initially apprehensive with the tenon. After I seated it in the chuck and tightened it, the bark area didn’t compress which led me to believe it was solid enough to proceed. The finishing work definitely won’t exert as much stress as the roughing out did. Really surprised at how hard the burl was compared to the rest of the log. Is that a typical characteristic of burls?

 

[hockenbery]

One more question. I’ve always finished on the lathe, with the voids and warping that will occur I don’t think i will be able to use my usual finishing process. Is this one of those cases where I’ll need to spray on a finish? Maybe a spray lacquer?

like most things in woodturning you can do whatever you like or whatever works for you.
generally with bark inclusion edges you don’t want to do anything that will catch on an edge and break the wood.
I do almost all my finishes off the lathe. You can use a wipe on finish or spray finish. Keep in mind some will darken the wood.

this Is a maple burl with voids about 15” diameter. I bleached the inside and applied no finish. The outside is finished with multiple coats of Waterlox. Wipe on, wipe off, Use light compressed air to blow water lox from ant crevices, wipe again., let dry over night, level the surface with grey scotch brite. Repeat.
.

this is hollow form 13”diameter probably mulberry but might be Osage orange has voids due to unusual to topography on the log
Waterlox outside like above. Inside one coat of watco which darkens the wood much more than Waterlox.

 

[Brandon Sloan]

I’m going to give the Waterlox a try. I’ve heard a lot of good things about it. As always, beautiful work. I’m still working on getting the insides of my vessels smooth enough for public consumption.

 

[hockenbery]

I’m going to give the Waterlox a try. I’ve heard a lot of good things about it. As always, beautiful work. I’m still working on getting the insides of my vessels smooth enough for public consumption.

Thanks, I Don’t sand inside except once in while the bottom dead center if it needs it.

I use a scraper on Dennis Stewart bars ( straight and bent )or a scraper on a custom bar CA Savoy made me. This gets a Visually smooth surface that is a little bit rough to the touch.
Buyer look inside the don’t reach inside.
These tools by Trent Bosch are close match to the Stewart bar or the CA Savoy bars.

https://trentboschtools.com/product/34-radius-scraper-straight/
https://trentboschtools.com/product/34-radius-scraper-bent/

I find them easiest to use with some type of stabilizer. I use either the Jamieson handle or the Simon Hope system.

 

[Brandon Sloan]

Thanks, I Don’t sand inside except once in while the bottom dead center if it needs it.

I use a scraper on Dennis Stewart bars ( straight and bent )or a scraper on a custom bar CA Savoy made me. This gets a Visually smooth surface that is a little bit rough to the touch.
Buyer look inside the don’t reach inside.
These tools by Trent Bosch are close match to the Stewart bar or the CA Savoy bars.

https://trentboschtools.com/product/34-radius-scraper-straight/
https://trentboschtools.com/product/34-radius-scraper-bent/

I find them easiest to use with some type of stabilizer. I use either the Jamieson handle or the Simon Hope system.

I just ordered some replacement cutters from Trent, I had the scraper in my cart and convinced myself not to buy it. I used the money to buy a new tool rest from Johannes Michelsen. I’ll have to pick up one of those scrapers when my tool fund replenishes itself. My primary tool rest is the one that came with my grizzly lathe. Really looking forward to the upgrade.

 

[hockenbery]

I just ordered some replacement cutters from Trent, I had the scraper in my cart and convinced myself not to buy it. I used the money to buy a new tool rest from Johannes Michelsen. I’ll have to pick up one of those scrapers when my tool fund replenishes itself. My primary tool rest is the one that came with my grizzly lathe. Really looking forward to the upgrade.

Someday you will get hollowing to the top of the priorities
Always something in the virtual cart for the next order.
I had a great class with Johannes in the late 90s. A great teacher and a great guy too.
Enjoy the tool rest

 

[Brandon Sloan]

Someday you will get hollowing to the top of the priorities
Always something in the virtual cart for the next order.
I had a great class with Johannes in the late 90s. A great teacher and a great guy too.
Enjoy the tool rest

Thanks again for reply’s. It helped with my confidence in moving forward with this bowl. I went ahead and finished what I could do on the lathe. It behaved exactly like you said it would. It’s still pretty wet, I’m gonna remove the tenon in the morning before it warps to much. Learned a lot from this process. Biggest thing is not to become too attached to a piece of wood. Happy with the results so far.

 

[Glenn Lefley]

View attachment 34007 View attachment 34008 View attachment 34009 View attachment 34010 View attachment 34011 View attachment 34012 View attachment 34013 Posted in a different thread about this but wanted the advice from the AAW community as well. This is my first time processing and turning a green burl.

I think I turned it a little thin for the amount of movement that will take place as it dries. Should I just turn it thin and let it warp? It’s a little over 16” and 4” tall 1 3/8” thick. I should add that the wood is Alaskan paper birch and is incredibly stable and hard. I’m using m42 steel sharpened on 180 CBN wheel and sharpened 3 times while hollowing.

Thanks in advance!

You need a corer. I have tons burls like that that I’m afraid to turn as I refuse to waste the cores . When tool fund gets bigger getting Oneway coring setup. Very nice.