Hardening spalted, punky wood

[Gevan Marrs]

I purchased some spalted Myrtle knowing it was pretty advanced and punky. I have rough-turned a small bowl, but clearly need to harden the wood before finishing. My questions are:
1. What hardener to use.
2. When toapply - before light final turning? After sanding?
3. What finishes then can and can’t be used?
Thanks in advance!

 

[Wally Crawford]

Following with interest. I have some flaming box elder that is just too pretty to throw away but it is wayyyy past its prime. End grain tear out is a real problem regardless of the tool, its sharpness or lathe speed. So far I have tried sanding sealer, Minwax wood hardener and another product I cannot remember the name of with varying degrees of success, but none of them really noteworthy.

 

[Gevan Marrs]

Funny - those are the two I know about and was thinking of trying…

 

[Jeff Jackson]

I usually use epoxy mixed 50% with acetone or denatured alcohol.

 

[Gregory Hickman]

Couldn't this benefit from a Cactus juice vacuum bath? Asking for knowledge sake.

Gregory

 

[hockenbery]

1. What hardener to use.
2. When toapply - before light final turning? After sanding?
3. What finishes then can and can’t be used?

Your tearout doesn’t look too bad.

For slightly punky wood I use a stepped approach
first try of just spritzing with water. This will swell the fibers making them more likely to cut than tear.
Next step is thin shellac ( I mix with 2x the alchohol) apply liberally letting soak in. It dries in minutes and I finish turn.

Thinned lacquer is preferred by many and does about the same level of hardening.

The shellac doesn’t go very deep so I reapply if I take more than 1/8” wood off
Also really before sanding and reapply before sanding with 320.

With thinned shellac or water any finish will work
With lacquer thinner lacquer works for sure. Other finishes may work.

 

[John K Jordan]

I've never noticed any improvement with the minwax wood hardener.

I did have success with another method on the final turning on a spalted maple bowl maybe 14-16" diameter, turned to rather thin. It was so punky in a wide band near the middle (where wavy spalting zone lines were most prominent.) The wood dented easily with my thumbnail - I could have pried out chunks if I tried.

What worked for me: I applied thin CA glue to the punky spots all over, inside and out, let it cure, then turned a tiny bit. Repeated this until I reached the thickness I wanted.

Every time I applied CA I let as much soak in as the wood would take and waited until it had a chance to cure completly (didn't use accelerator). I think I used 3 bottles of CA. After I was satisfied with the punky area I wiped CA all over to give create a consistent surface. Sanded smooth (by hand), then finished with multiple coats of "danish" oil, using the one coat per day method.

The result is a hard, smooth surface that looks and feels good to me.

Sorry, I haven't taken a photo since I have not yet reversed it with a vacuum chuck and finished the bottom.

However, I did use the identical CA method on this little vessel from a piece of wood someone sent to me - I think the wood had special significance to him. It too was so soft and punky in spots that I did pry a chunk out of that small blank with my thumbnail while testing the wood. I applied as much thin CA as the wood would accept, multiple times. The end result was the same - went from punky soft to hard and strong, smooth surface.

He said the wood was Liquid Amber. It's only about 2" high.



JKJ

 

[Bryan Field]

I apply thin CA glue occasionally as I am turning. Seems to to the trick and dries quickly between spins.

 

[Gevan Marrs]

Your tearout doesn’t look too bad.

For slightly punky wood I use a stepped approach
first try of just spritzing with water. This will swell the fibers making them more likely to cut than tear.
Next step is thin shellac ( I mix with 2x the alchohol) apply liberally letting soak in. It dries in minutes and I finish turn.

Thinned lacquer is preferred by many and does about the same level of hardening.

The shellac doesn’t go very deep so I reapply if I take more than 1/8” wood off
Also really before sanding and reapply before sanding with 320.

With thinned shellac or water any finish will work
With lacquer thinner lacquer works for sure. Other finishes may work.

Thanks. It’s not tearing out too badly, but it is too soft to leave as-is. Your ideas are helpful.

 

[Gevan Marrs]

I've never noticed any improvement with the minwax wood hardener.

I did have success with another method on the final turning on a spalted maple bowl maybe 14-16" diameter, turned to rather thin. It was so punky in a wide band near the middle (where wavy spalting zone lines were most prominent.) The wood dented easily with my thumbnail - I could have pried out chunks if I tried.

What worked for me: I applied thin CA glue to the punky spots all over, inside and out, let it cure, then turned a tiny bit. Repeated this until I reached the thickness I wanted.

Every time I applied CA I let as much soak in as the wood would take and waited until it had a chance to cure completly (didn't use accelerator). I think I used 3 bottles of CA. After I was satisfied with the punky area I wiped CA all over to give create a consistent surface. Sanded smooth (by hand), then finished with multiple coats of "danish" oil, using the one coat per day method.

The result is a hard, smooth surface that looks and feels good to me.

Sorry, I haven't taken a photo since I have not yet reversed it with a vacuum chuck and finished the bottom.

However, I did use the identical CA method on this little vessel from a piece of wood someone sent to me - I think the wood had special significance to him. It too was so soft and punky in spots that I did pry a chunk out of that small blank with my thumbnail while testing the wood. I applied as much thin CA as the wood would accept, multiple times. The end result was the same - went from punky soft to hard and strong, smooth surface.

He said the wood was Liquid Amber. It's only about 2" high.

View attachment 71644

JKJ

Interesting. I did have a couple small tear-outs, so after some sanding put that dust in the hole and hit it with thin CA. Seems to work, but of course changes the color. Doing the whole bowl is gonna cost a bit in CA, but maybe worth it. I’m glad to hear an oil finish will work after the CA. Thanks.

 

[John K Jordan]

after some sanding put that dust in the hole and hit it with thin CA. Seems to work, but of course changes the color.

A long time ago Sir John Lucas taught me a technique that fixes small tearout spots without staining the wood: Put a tiny bit of thin CA glue on a small piece of coarse sandpaper (maybe 220 or 320 or even 400, depending), and sand the area by hand. The sanding dust is picked up, mixed with a little CA, then packed into the spot. Since glue is not added directly to the wood, it doesn't wick out and stain the area. Since the sanding dust comes from the wood just around the hole, the fix is usually invisible. Works on all kinds of small, shallow voids.

I back up the sandpaper with a white "magic rub" eraser - my soft sanding block - maybe a smaller piece and a smaller piece of eraser for this technique.



JKJ

 

[Gevan Marrs]

A long time ago Sir John Lucas taught me a technique that fixes small tearout spots without staining the wood: Put a tiny bit of thin CA glue on a small piece of coarse sandpaper (maybe 220 or 320 or even 400, depending), and sand the area by hand. The sanding dust is picked up, mixed with a little CA, then packed into the spot. Since glue is not added directly to the wood, it doesn't wick out and stain the area. Since the sanding dust comes from the wood just around the hole, the fix is usually invisible. Works on all kinds of small, shallow voids.

I back up the sandpaper with a white "magic rub" eraser - my soft sanding block - maybe a smaller piece and a smaller piece of eraser for this technique.

View attachment 71654

JKJ

That sounds like it’s worth a try! Thanks.

 

[Bill Alston]

The thing that concerns me about “hardened” wood is the toxicity (or not) of the wood dust when turning and finishing?

 

[John K Jordan]

The thing that concerns me about “hardened” wood is the toxicity (or not) of the wood dust when turning and finishing?

Same issue with any wood dust, especially that from some species, hardened or not, steel dust from sharpening.
If concerned, consider wearing a good industrial respirator with P100 filters when concerned about wood dust.

I keep multiples of each in the shop for myself and anyone who wants them.


They will fit under this:



Or just go with this



The industrial filters are very good.
The pink filters are for particulates, easily switched for filters for volatiles like finishes or chemical sprays.
Good or around the farm too - cleaning out chicken houses, the full-face for spraying chemicals.
If concerned about chemicals on the skin, Tyvek suits are inexpensive.
Some are available at Home Depot. I purchase from Amazon.

JKJ

 

[Gevan Marrs]

The thing that concerns me about “hardened” wood is the toxicity (or not) of the wood dust when turning and finishing?

I'm not so worried about dust from turning it - a particulate mask should suffice. However, yesterday I went all in a covered the whole bowl with thin CA and the odor from the reaction nearly choked me off. Hard to know what kind of vapor canister would filter those fumes.... I don't think I'll do that again.

 

[John K Jordan]

I'm not so worried about dust from turning it - a particulate mask should suffice. However, yesterday I went all in a covered the whole bowl with thin CA and the odor from the reaction nearly choked me off. Hard to know what kind of vapor canister would filter those fumes.... I don't think I'll do that again.

It's best to apply a little at a time. However, Parfix and maybe some others have low-odor CA formulations. The medical grade I have puts off no noxious odors. For other glues that do, what gets me the most is the fumes in the eyes - simple safety glasses with soft seals around the edges help with this, but not with what you breathe.

What does work is applying the CA outdoors!

In my experience these filter cartridges seem to do an excellent job with many chemicals.
https://www.amazon.com/3M-Cartridge-60923-Respiratory-Protection/dp/B00AEFCKKY
I mostly use them on 3M full face respirators to keep chemicals and fumes out of my eyes as well as my lungs.

Amazon.com

Hey, I discovered an off-label use for the full face masks! Coming home one day I looked up the hill and saw smoke in the woods - someone with sub-average intelligence fell asleep and let a small brush fire at the bottom of the hill get out of hand and it was headed up the hill towards my farm. I called the forestry service then grabbed the tractor and started cutting fire lines before the "big guys" got there with the big equipment. I took a full-face respirator. I'm not sure how much of the smoke it filtered, but it sure kept the smoke out of my eyes the whole time! I noticed the workers on the ground were wearing similar protection.

JKJ

 

[Charles Cadenhead]

I went all in a covered the whole bowl with thin CA and the odor from the reaction nearly choked me off.

Wear your respirator and you should be ok. I wear mine when I work with CA glue and the fumes don't effect me.

 

[Tom Lucas]

Someone mentioned Cactus Juice. I tried that on a piece. It did harden it significantly. I did the whole raw block. Took quite a bit of juice, and was time consuming to bake out. If I were to do again (I probably won't), I'd rough turn it first to save on juice. I pretty much came to the conclusion that punky wood isn't worth it, usually. Just select a better piece of wood.

 

[John K Jordan]

I pretty much came to the conclusion that punky wood isn't worth it, usually. Just select a better piece of wood.

Agreed. Someone said (I heard it from the other John Jordan, the famous one) that "Life is too short to turn crappy wood."

On the other hand, my Lovely Bride liked the 360-deg spalting in the punky one I mentioned so that decided that!

JKJ

 

[Robert Lindstadt]

I've never noticed any improvement with the minwax wood hardener.

I did have success with another method on the final turning on a spalted maple bowl maybe 14-16" diameter, turned to rather thin. It was so punky in a wide band near the middle (where wavy spalting zone lines were most prominent.) The wood dented easily with my thumbnail - I could have pried out chunks if I tried.

What worked for me: I applied thin CA glue to the punky spots all over, inside and out, let it cure, then turned a tiny bit. Repeated this until I reached the thickness I wanted.

Every time I applied CA I let as much soak in as the wood would take and waited until it had a chance to cure completly (didn't use accelerator). I think I used 3 bottles of CA. After I was satisfied with the punky area I wiped CA all over to give create a consistent surface. Sanded smooth (by hand), then finished with multiple coats of "danish" oil, using the one coat per day method.

The result is a hard, smooth surface that looks and feels good to me.

Sorry, I haven't taken a photo since I have not yet reversed it with a vacuum chuck and finished the bottom.

However, I did use the identical CA method on this little vessel from a piece of wood someone sent to me - I think the wood had special significance to him. It too was so soft and punky in spots that I did pry a chunk out of that small blank with my thumbnail while testing the wood. I applied as much thin CA as the wood would accept, multiple times. The end result was the same - went from punky soft to hard and strong, smooth surface.

He said the wood was Liquid Amber. It's only about 2" high.

View attachment 71644

JKJ

I am wonder why you didn’t have luck with the minwax hardener, how did you apply it , I have a bowl that seem to super dry now and was thinking of pour the minwax in and letting it soak in rather then brushing it on!

 

[John K Jordan]

I am wonder why you didn’t have luck with the minwax hardener, how did you apply it , I have a bowl that seem to super dry now and was thinking of pour the minwax in and letting it soak in rather then brushing it on!

I tried it on several things and just followed the instructions on the can. Sorry, it's been a while and can't remember the details. I do remember repeating the application on once piece but couldn't tell a significant difference in the before and after.

Maybe I did something wrong or maybe there's a better method. Or maybe I was expecting too much.

JKJ

 

[John Walls]

I use cactus juice or minwax hardener on punky wood. Cactus juice runs appx $110/gallon and Minwax $18/ small can, not cheap so I turn close to size, it takes alot. I use a 5 gallon vacuum pot (for cactus juice) first then an old smoker for baking the juice hard, only takes a couple hours. Use in well ventilated areas!