turning punky wood

[Matt Mackinnon]

I have some box elder burl that I am looking to turn to make roofs for a Christmas birdhouse ornament. I was planning to make a backing board from white maple that can be glued onto the elder that will be held in a chuck for turning. But I have never tried to turn punky wood before and fear it will just disintegrate if I try. The Elder is so light and porous.

I have used CA on some hardwood flooring that had punky sections and it did harden it up but gave quite a bit of smoke in the process and of one heck of a stink. Considering the spot was about 1x1x1/2" and used quite a bit of CA, I don't know if that is an option for me here to turn a 2.5" cube of Elder.

What is anther alternative? I need to get these done in the next few weeks so if I need to order some product to harden this, I need to get it ordered and fast.


HELP!

Matt.

[Bill Bulloch]

Look for Minwax Wood Hardener, it works for on punky wood.

[Brian Kent]

I had not heard of this, Bill. It gets some good reviews. I see each reviews starting with words like "stinky, sticky, use outside, and disposable brush" along with words like "great, sand-able, really hard".

[Jim Burr]

You need to have it stabilized. Minwax and wood hardeners are a waste of time and $$. If you look at the ingredients, you'll notice about a 70/30 ratio of solvent to solute, typically Acetone and Plexiglas. Once the 70% solvent dries and off gases, you are left with about 30% product in the parent material. I stabilizes stuff every month and have never had a failure with my vacuum system.

[Dan Hintz]

I'll also suggest stabilization, but suggest against making your own. As mentioned, Minwax is mostly solvent. Even the stuff you make yourself will end up with a high percentage of solvent. Use something like Cactus Juice (I order Resinol directly from Loctite), which is, essentially, 100% solute (it uses low heat to polymerize rather than waiting for a solvent to boil off). The downside is you really need to use a vacuum chamber to get good infiltration (though that's true for all of the options mentioned). The punkiest of wood will becomes solid as a rock (literally)... I've done stuff that would blow away if you brushed against it in a breeze (that's often the coolest looking stuff), but once soaked and baked, you'd never know.

[David Reed]

I suppose the comments re stabilization and Cactus Juice have a lot of credibility but the cost is something I considered and found the Minwax hardener to be a very cost effective and functional product. Typically I rough turn any punky wood to about 1/8"-1/4" of desired finished product. Paint it on, allowing it to soak in and when it leaves a shiny surface, I re-turn and have been very happy with the final result. I use cheap disposable brushes. Stinky yes, but then so are many finishes we use. Use appropriate protection. My only negative comment has to do with sanding, and it probably is a reflection of my less than ideal sanding technique. Easy to burn with sandpaper. Easy fix; go slower. I have a great looking piece of pretty rotten BLM burl waiting for final finish (otherwise I would add pic) and the final cuts and sanding give no suggestion of soft, rotten wood but the grain is fantastic. Also I see no indication in the final finish in other pieces of finish problems using shellac, WOP, lacquer or WTF.
Minwax Wood Hardener review. *****

[Jim Burr]

I suppose the comments re stabilization and Cactus Juice have a lot of credibility but the cost is something I considered and found the Minwax hardener to be a very cost effective and functional product.

And you are the only one...that stuff is proven to be trash unless you need to secure a fence post in place. Move into the 90's at least!

[robert baccus]

Try epoxy or polyester resin with hardner, thinned by acetone. Soak in a vinyl bag overnite Does not discolor or fill the pores of the wood. An old boatbuilding trick.

[David Reed]

And you are the only one...that stuff is proven to be trash unless you need to secure a fence post in place. Move into the 90's at least!

I don't want to be party to a flaming dialogue here, but since a few soakings with a brush seals and firms up the rotting fiber, allowing the combination to then be cut cleanly with a sharp tool, sanded and finished, I'm at a loss what about it makes it "trash"? Simple, inexpensive, convenient and a good end product. No idea what the end result would be like if a dye were applied, but in my shop, I would think the convenience if nothing else would justify a test drive. I am in no way implying it is the best or only way to achieve the desired result, merely that it works well in my shop without the need to send the wood out and does not require an investment in extra equipment.
The solvent/solute ratio argument would make sense if a single application were applied, but like film based finishes, this is seldom done. It seems that many finishes, especially the newly popularize WTF are largely solvent but they perform admirably when applied correctly.

[Dan Hintz]

The solvent/solute ratio argument would make sense if a single application were applied, but like film based finishes, this is seldom done. It seems that many finishes, especially the newly popularize WTF are largely solvent but they perform admirably when applied correctly.

There's an issue with multiple coats, however (this applies to all high-solvent hardeners, not just Minwax)... once the first coat has hardened, the pores are mostly sealed, so further application does not enhance the durability as you're just applying a surface coat. This is generally okay if you've already cut the piece to finish size, but if you're trying to stabilize a blank (even if roughed out to size), you need a good vacuum to ensure the hardener soaks down to the area you'll be cutting to.

[David Reed]

When I apply multiple soakings of the hardener, it continues to disappear deep into the soft wood. It does seal the non-punky areas readily but it readily penetrates at least 1/2" into the punky stuff. It continues to disappear after a number of soakings until it is fully saturated with solid 'resin'. Once it ceases to be absorbed, I stop application. I think the pores in wood are a moot issue when treating heavily spalted/punky wood as the cellular structure is breaking down. I have been able to finish turn and sand to a very smooth finish both inside and outside of turnings after only applying to the outside, not that I typically apply to only one surface.
The statements against use of the Minwax appear to be based on theoretical conclusions rather than practical experience. Still, I have no experience with vacuum based systems and I am quite certain you could attain much deeper penetration using one but when penetration requirements are 1/2" or less, and the wood is heavily spalted or punky, it works great. I also suppose if the vacuum setup is available in your shop, you could prep a piece in one day and even stabilize a large block rather than a rough turned piece. They both appear to have a useful place in the shop.
I am carrying on like a Minwax salesman, but I assure you I have no association with the product or sales of same. Just a satisfied user and I don't like to see skewed or misinformation disseminated.

[Chip Sutherland]

I have used Miniwax hardener several times primarily because it is readily available, easy to use and I don't (yet) have the vacuum & materials for other approaches. I have only had one bad experience and that was 'stupid user' related when I tried to add some hardener on a piece that was almost finished turned. The result was a crack in the bowl sidewall. It was heavily spalted wood so I just repeated my mistake on the opposite side and got a similar affect. Only someone from this forum would recognize it as a crack. I have not had any problems with treated wood taking finishes....although I doubt the wood would take dyes very well.

What I have learned is when I buy one can....I always buy 2.

[robert baccus]

Epoxy is cheap also. I have done whole bowls and vases to 14" like this and the pores are not filled. When turned you cannot tell the soaked wood from the firm untreated wood. I've done probably 15 pieces like this. Roughturn to !" first and the stuff goes all the way through doty wood. Overnight too. Stabilization is fine but expensive for small pieces and this allows large pieces to be treated overnite.

[Michael Kellough]

Robert, can you describe your method of applying epoxy?

[robert baccus]

Easy--obtain some clear poly or epoxy resin and hardner. Mix as usual and thin 20-30% with acetone. Thin lightly until it just drips freely off the stirring stick. Guess at the amount needed. Put into a Vinyl bag and add the solution and play shake and bake several times to spread it around. Do this several times. Next day it is hard and looks like hell but cut the wood and it looks like new. This also works on soft stuff like red palm ect. You can throw it across the shop after this treatment. Gotta do a roll of toilet paper some day to slow down the nonbelivers.

[Jim Burr]

It's not a flame thing David...dozens of hours of research have gone into this...it's not your fault that you didn't see it. At the same time...don't bash the one's that helped with the work on it. We do this so people get the right advise, not what "you think". Get a vacuum system, get some Minwax solution and try both before you dispense advice.

[Scott Hackler]

I used some of the Minwax stuff once for some extremely spalted and punky sycamore pen blanks. I probably didn't read the instructions and layed the blanks in the bottom of an old aluminum bread pan and covered the blanks with enough of the Minwax stuff to submerge them. Then I went about goofing around in the shop and over the next few hours I sloshed the pan back and forth and flipped the wood blanks at least once. Eventually most of the hardner had been absorbed and I took them out, sat them on some wire racks and let them dry. I worked up a few of them as pens later on and they were pretty hard. No punky areas. So I guess it worked OK for my trial. Keep in mind that those blanks were 3/4" square stock and about 6" long. The one thing I noticed was that the hardener did darken the wood, similar to applying as oil finish.

Seems like it was $10 or so for the metal jug and I found out later that the 1/2 that I didn't use solidified in the can.....

I looked at a vac chamber while at SWAT and almost bought one, but they didn't have the size I wanted and I don't own a pump. I did see the Cactus Juice stuff and it seemed a little more reasonable product and from the wood samples they had, I didn't think the wood darkened as much, if at all. I did notice a superb penetration using the vac chamber systems and the stabilized wood blanks were 5x heavier than the non stablized samples.

I still might order one but I have to round up a Gast pump first.....

[Dan Hintz]

I looked at a vac chamber while at SWAT and almost bought one, but they didn't have the size I wanted and I don't own a pump. I did see the Cactus Juice stuff and it seemed a little more reasonable product and from the wood samples they had, I didn't think the wood darkened as much, if at all. I did notice a superb penetration using the vac chamber systems and the stabilized wood blanks were 5x heavier than the non stablized samples.

I still might order one but I have to round up a Gast pump first.....

Scott,

The Cactus Juice (or Resinol I mentioned earlier) will not darken the wood, a big advantage over the Minwax stuff if you care about the color of the piece. The vacuum chamber, as you found out, makes a huge difference in the saturation level. A well-soaked blank will feel quite dense, almost like a piece of ironwood.

[Scott Hackler]

Yeah, those stabilized pieces were super hard and dense feeling.

[robert baccus]

It must be nice to know everything. Try all 4 procedure before you advise and one must be a 14" x8" red palm vase. Maybe we can all learn. Also add in material and equipment costs.

[Peter Blair]

Hey Robert.
Thanks for the tips.
I frequently use wood hardener but would like to try your method.
I am not sure what a vinyl bag is or where I could get some. Any suggestions?
Thanks.

[Michael Kellough]

Thanks for the notes Robert. I noticed in an earlier post (that I'd skipped over before) that you said this was an old boat building trick. Recently I read Robb Whites book of stories Flotsam and Jetsam (http://www.amazon.com/Flotsam-Jetsam-Collected-Adventures-Opinions/dp/1891369830) and he told of tenting a boat so he could heat it up to 130 degrees and then cut the heat, turn on the air conditioner, and apply as much thin epoxy by brush as the assembly would take, as quickly as possible. Kind of a bootstrap vacuum bag substitute. The heat dove some of the air out of the wood and when the wood cooled it sucked epoxy in.

I don't have enough turning experience to predict if Robb White's method would help turners.

I also wonder about the vinyl bag. Wouldn't polyethylene work as well?

[robert baccus]

That's a new boat trick for sure. The acetone is a solvent for many plastics and will go right through most bags. I use the black yard bags labeled vinyl. I'm sure there are others also. I have a 2 acre yard and a good supply of these and they are usually very tough to tear.

[Scott Lux]

I'll second the min wax hardener. I've used it a couple times on punky wood. Yeah, it's sticky and it does darken the wood. But it does work. And forgive me if I find $10 to be more cost effective than buying a vacuum system and pump.