Cleanup cuts on punky wood

Would anyone be willing to give me some advice on getting a clean finish cut on some rainbow-streaked tulip poplar with a minor amount of spalting?

The wood is pretty gorgeous, and the tree was very old for a poplar. The sections that did not succumb to the fungus rot are pretty dense and hard for poplar. There is some bee's wing mottling in the grain from irregular rays being cut with quartersawn grain. Very lovely wood.

Is poplar naturally hard to get a clean cut on? I am getting some pretty deep tearout with most cuts I take. I have tried (with a winged gouge) slicing cuts, shear scrape, push/pull, from foot to rim and from rim to foot. Gouges are definitely sharp. I even did an experiment where I sharpened right before taking 1 cut each time.

Cannot seem to prevent the tearout. Some of the blanks cut well on the inside of the bowl, and bad on the outside. Some bowls/forms cut well all around, and then another from the same section of log, cuts poorly with high amounts of tear out.

I can get insanely good finish quality with a skew chisel. Does anything that can be used on bowls cut similarly to a skew? Is there a technique I am missing with my winged bowl gouge? I have noticed that my crown HSS tools have a much greater rate of success with my finish cuts on this wood than my Thompson gouge does.

Any help would be greatly appreciated.

Regards,
Hank

I too sometimes struggle with tear out on some wood types and conditions. So, I'll be following this thread to get tips from others. I have found things that help but none that work 100% of the time:

1. Coat with an oil and then final cut. I'm a bit embarrassed to mention it, but have even used WD-40 and got some amount of improvement.
2. Use minwax solvent-based wood hardener. At $10 a pint it is pricey.
3. Use a negative rake scraper with a brand new burr *** (this is becoming my "go-to" approach)
4. Spritz with water
5. I watched a wood turner demo one time where the professional demonstrator sprayed "circuit cool" on an isolated area and then quickly turned it while it was still frozen. A can of compressed keyboard air (well, it also has a propellent) squirted upside down works well too. Maybe sticking in the freezer overnight would provide similar improvements. But this may only give you 10 or 15 seconds of working time.
6. If it is just one small area, I have used thin CA glue. Nasty stuff but helps to stiffen up a punky area.
7. If I am going to throw in the towel in defeat I have sometimes wet sanded with an oil, DO, Friction polish or even poly. The fine sawdust kind of fills the pores.

Thinned lacquer helps--then next is thinned(acetone) epoxy or poly resin soaked in overnite in a vinyl plastic bag. This will turn the punky wood to like brand new wood. Also try a bottom-feeder gouge very sharp--even honed, on the inside.

Henry, As pointed out, you could try and apply a coat of what ever you think you are going to use as a finish to help stiffen the fibres before cutting them.
With your gouge, have you tried turning the speed up a little bit and slowing down the progression of your cut? Sometimes if you can keep the tool moving very slowly, then the wood will slice rather than pull out. Also with your gouge, are you using a 60-ish degree grind or 40-ish? Maybe try something closer to 40 or a beefy spindle gouge, but once again keep the tool speed across the wood slow.
Generally for tear out I have found that I have not needed to resort to a finish to stiffen the fibres if I can get the lathe speed up a bit and slow the tool motion down. It is very light cuts in any case, so it is not a quick fix. You need to make sure you do not push too hard on the bevel or the tool will sink in a bit on the punchy area and get pushed out on the harder areas and start to pulse since you are moving so slow.
If it does that, then stop and move back an 1/8" of so to where it was a smooth cut and start the cut again, being light on the bevel. If you do not stop cutting once the tool starts to bounce, the it will only get progressively worse the further ahead you cut.
Good luck

I like turning spalted wood and have encountered tear-outs. I have found that if I apply as much shellac as the piece will absorb and let it dry and harden, then my chances of turning with very light cuts will improve. On occasion when this doesn't work I have resorted to applying the shellac and then going over the outside of the piece with a high speed sanding disk. This creates a cloud of dust but has worked for me.

Punky wood is sometimes more trouble than it's worth but beautiful when it comes together.

Jay

Quote:

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Originally Posted by Jay Mullins

I like turning spalted wood and have encountered tear-outs. I have found that if I apply as much shellac as the piece will absorb and let it dry and harden, then my chances of turning with very light cuts will improve. On occasion when this doesn't work I have resorted to applying the shellac and then going over the outside of the piece with a high speed sanding disk. This creates a cloud of dust but has worked for me.

Punky wood is sometimes more trouble than it's worth but beautiful when it comes together.

Jay

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Same here. I have applied multiple coats of shellac, usually starting with thinned shellac (sanding sealer) which I hope will soak in deeper. I let each coat dry completely before the next. After cutting a bit I even repeat this as fresh wood is exposed.

In extreme cases I use thin CA glue. Watch out for fumes and heat! I have used an entire bottle of CA on a piece, sometimes coating the non-punky parts too to avoid lines, adding more as needed after turning a little. It has to be pretty spectacular wood or have some special significance to do this rather than just toss it! The result can be very good - I've salvaged pieces so punky chunks would crumble it touched with a thumbnail.

Another thing - if any small spots of deep tearout remain after all this I've occasionally resorted to a trick I learned from John Lucas - wet sanding with thin CA glue. The sawdust makes a slurry that fills in small voids, often making them undetectable. Gotta take care to keep from gluing the sandpaper to the fingers!

JKJ

First and foremost, sharpen frequently.
Use a tool with a more acute cutting edge if possible. I have a bowl gouge with STewart Batty's 40/40 grind. It will cut much cleaner than my normal bowl gouge which has a 55 degree edge.
I use a Hunter Osprey or Hercules or #5 tool when I have problem woods. The edge is highly polished and quite sharp but I believe it's the combination of polished edge and small diameter round cutter that gives a cleaner cut. I've been experimenting with the smaller radius and find that when I have tearout if I can go to a smaller tool with a smaller radius tip it will often cut cleaner.
Don't force the cut. Speed up the lathe, reduce your forward pressure and let the tool cut at the rate it want's to cut. This almost always gives a cleaner cut.
Use the tool so the wood passes the edge at a shear angle. You can often rotate the tool and get the wood to cross the tip at a steeper angle and this will give a cleaner cut. I have a bowl gouge I ground to look almost like a spindle roughing gouge with the wings almost vertical. using this tool with the flute up and cutting with the left wing gives a very clean cut.
Poplar can be difficult. I will often coat the areas with thinned lacquer or thin CA glue. Large areas take multiple coats of Thinned lacquer. small areas I just use thin CA however it can stain the wood and leave an ugly mark that won't come out so I use the lacquer as much as possible.
Sometimes using a scraper with a fresh burr as a shear angle will get rid of tearout that other tools won't. sometimes it makes it worse but is usually worth trying.
Try cutting in the reverse direction. For example if your cutting from the rim down inside a bowl, try cutting uphill. This may require a different tool or different cutting technique. Usually you get tearout on the uphill portion of the grain on the inside of a bowl and the tearout will be 180 degrees apart. When you cut in the opposite direction these areas will cut clean but now you will have 2 new areas that are 90 degrees from the old areas. Sometimes however these 2 new areas will be less tearout than the original making them easier to clean up.

Quote:

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Originally Posted by JohnC Lucas

. . . small areas I just use thin CA however it can stain the wood and leave an ugly mark that won't come out so I use the lacquer as much as possible.

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I use two things to avoid this stain. One way as I mentioned is to flood the entire piece with CA. I did that recently, inside and out, on a punky 12" bowl with beautiful figure, in effect "staining" the entire piece. Takes a lot of glue but works just like any other finish. The slow-setting Parfix CA is perfect for this. I sometimes apply a coat of sanding sealer first then add the CA - maybe this helps too.

Another method usually works - with a bit of paper towel in one hand and the bottle of thin CA in the other apply a little glue then IMMEDIATELY wipe it with the paper towel away from the spot and along the figure if possible. This may create a slightly darker area but it feathers out the edge so it's not visible, especially if there is a any interesting figure or spalting in the wood. I might repeat this several times, perhaps wiping a different direction, to get more glue to soak into the soft spot, sometimes applying and wiping a dab more just to even out the spot. I try to make successive applications right away, maybe even before the glue has set up in the wood. After this is set up you can add small drops to the middle of the treated section to soak deeper into the punky spot. I've done this many times with success.

For those who haven't tried them, the little capillary tips are perfect for applying just the tiniest drops of CA precisely in a spot of tearout or a crack. For me they are indispensable at the lathe. Clean them out with a fine wire after use if necessary. I have several different types but I like these the best:

https://www.amazon.com/gp/product/B000H7H4NW
Attachment 386918

JKJ

I highly recommend the cappilary tips. They are fantastic for repairing small tearout spots with thin CA. Also great for getting into small cracks.