I rough turned this small bowl about 2 years ago and turned it to finish size yesterday. In the process these small voids occurred. Anybody know why?
Would sanding with oil fill these? What kind of oil?
Thanks for any suggestions.
[OP]
Contributor
I rough turned this small bowl about 2 years ago and turned it to finish size yesterday. In the process these small voids occurred. Anybody know why?
Would sanding with oil fill these? What kind of oil?
Thanks for any suggestions.
Contributor
I'm not sure, what is the wood.
When working I had more money than time. In retirement I have more time than money. Love the time, miss the money.
Moderator
Those voids look like tearout from the gouge. Sometimes the tear out is masked until the finer sanding grits.
The solution is to re-mount it, and finish turn it with sharp tools, very gently - so you don't cause more tear out.
If you choose not to re-turn; you can mask somewhat by wetsanding the wood with your finish, and using a satin type finish so it doesn't cause reflections and attention to be placed on the voids.
Last edited by Prashun Patel; 05-18-2017 at 10:34 AM.
Member
Yeah, it's just tearout. Like Prashun said, you need to make sure your tools are sharp. You might also work on your presentation of the tool to the wood -- a shearing cut (i.e., at a 45 degree angle) gives the best results. I don't have time to explain it, but you should be able to find plenty of information on finish cuts online.
Contributor
Tear out as noted, but it may be a sign the wood is a bit punky. If so, you will need to take extra care with your cuts and use a super sharp edge.
Left click my name for homepage link.
Moderator
Jim,Originally Posted by Jim Hipp
The tearout looks pretty bad to me. I agree the wood might not be perfect there. If the tearout is as deep as it looks from the photo it may require a lot of wood removal to get below it. But then, more fibers may tear out and nothing changes except the piece gets smaller!
I do several things when I encounter tearout. One, before recutting (with very light cuts, very sharp tools) I use something to stiffen the wood a bit. I like shellac sanding sealer, let dry, cut a bit, apply another coat. Lacquer sanding sealer works too.
For very soft and punky spots I also like thin super glue. I soak in a much as it will take, let harden, make a light cut then apply more glue. The result can be a glass-smooth surface from even crumbly wood. There are a few problems with this method - one, the fumes are horrible, two, the wood can react and and get hot and smoke, three, it can take a LOT of expensive glue, and four, it is difficult to apply to one spot without leaving a visible line. To avoid the last one I wipe it all over the surface so the stabilized area blends in.
I've tried Minwax wood hardener and I was not impressed. If the wood is spectacular or special for some reason, the wood can be stabilized with something like Cactus Juce, but that is a big effort and expense.
I have pressed fine sawdust into voids and added drops of superglue with some success.0
Turner John Lucas told me recently of a method he uses and when I tried it on mild tearout it worked well: wet sand with superglue! Put some thin super glue on sandpaper and wet sand until it set up. Repeat. This packs superglue-soaked sawdust in the voids. I don't know how well it will work on extensive tearout or if the final look will be satisfactory. At some point it is easier to just get a new piece of wood and start over!
JKJ
[OP]
Contributor
Cherry I think based on the wavy lines. If it is not Cherry then it would be Bradford pear.
Member
I know you asked about how to fill the tearout, but that wood doesn't look punky to me. I think your best bet is to practice finish cuts then re cut it.
BTW given those choices, the wide growth rings strongly suggest bradford pear. It doesn't look like cherry.
Member
Most of the tear out, and the deepest tear out, follows the growth rings. That would indicate weak wood to me. There is some minimal tear out in between the rings, which could be soft/punky wood, and/or need of sharper tools and a higher shear angle. The wet cutting is one solution. Even water works for that. Get the entire piece damp, like with a wet rag or spritzer bottle. Let sit for a minute or two, then very light cuts to turn away the wet wood. It may take a couple of applications. Honing the edges of your tool may help. I prefer a shear scrape, and it is easy to get a 70 degree or higher shear angle.
robo hippy
Member
When working with a piece of wood prone to tear out where a sharp tool just doesn't completely help, I too use the sanding sealer and light cut method and it works well for me. If the tear out is very minimal I will sometimes wet sand with thinned sanding sealer, let dry and then sand as normal. This works quite well for me as well.
Contributor
Last year I saw a different approach to tear out and slightly punky wood at a demonstration. The fellow (perhaps Mike Mahoney) used a freeze spray and liberally sprayed the teaar out area, temporarily freezing it. Then he used his very sharp tools for some very light cuts and removed the tear out. I suspect that the freeze spray freezes the surface plus the water moisture from condensation acts a little like a lubricant as would a spritzer bottle.
I just thought that I would share this....
Moderator
That's interesting. Oh no, I can see it now, advertisements for must-have for the shop: a dewar of liquid nitrogen.
Some freeze spray used to be flammable but I think now most is not. Don't spray it on your skin! I use it for debugging electronics.
JKJ
Contributor
John, I used to use the official Circuit Cool spray for electronic troubleshooting. But, I found that if I just get a can of compressed air for blowing dust out of a computer keyboard and turn it upside down, that it works the same as circuit cool. It shoots out liquid propellant that comes out super cold. It definitely can freeze.
I've wondered if there would be any benefit of putting a piece of wood into the freezer (along with the chuck) to get a similar effect. Or perhaps a combination of the two?
Moderator
That would make a good experiment!
I once started to turn a block of ice just for fun but couldn't stand to keep my shop cold enough. Maybe I'll try again sometime by taking a mini lathe out on the porch in the winter.
I did turn a big carrot once...
carrot_wide.jpg
JKJ
Posting Permissions
Reply With Quote