Machining Spalted Maple

[Burkhardt]

I have a nice blank of curly spalted maple left over from my woodturning times. Has been sitting in the "pretty wood" box for the last 15 years and I finally wanted to make a bowl from it on the CNC machine.

Not a problem per se, I have made a lot of bowls that way. But I found during first roughing passes that the bit leaves deep tear-out holes in the spongy spalted sections. I stopped for now and suspect I need to stabilize the wood first.

I am leaning towards soaking with thin CA and hope that will also reinforce the rot and make the bowl less susceptable to breakage since the wall thickness will be only 3/16".

Any other suggestions?

Thanks, GB

[barrowj]

GB,

I've used a penetrating epoxy and it takes several coats to help stabilize it. I have a good bit of that wood laying around myself, mostly salvaged from the firewood pile and cut into block or thick slabs. I have ended up using my big drum sander to to get boards that look good but for turning or putting on the Shopbot, it's a hit or miss for me. Good luck, would love to hear how it comes out and what you did to stabilize it.

Joe

[steve_g]

Gert…
I’ve hadamazing success using Minwax wood hardener in both spalted pecan and Western RedCedar. If you use it, do it outside! The fumes are BAD!
SG

[dmidkiff]

I think the CA glue would dry too fast to penetrate enough. I've used the slower setting CA when turning pens out of spalted woods with limited success.

[scottp55]

G.
Had a cutoff of REALLY punky Quilted I tried thin CA on and fumes drove me out of shop and reacted so much I got a lot of that white crud in the wood.
I'll do a little cutoff through a section in a couple of hours and sand to show penetration and see how deep that white reaction went. Rockler Thin CA.
Steve, For bowl thickness stuff how far does Minwax penetrate? Have you ever Soaked a thick chunk? Or do you just puddle it on?
scott

[steve_g]

I’ve always just brushed it on in 3 or 4 applications, until it didn’t want to take more… I know it went ½” deep, likely deeper…
SG

[scottp55]

Thanks Steve,
Pretty good penetration for brush on. Keep meaning to buy some,but my brain continues to take a hike whenever I'm inside the hardware store:)
Turns out I had sanded off the white crud on that piece and I can't remember how much of the Rockler Thin I had puddled on before my eyes and myself took a hike from the fumes.
Out of Thin it turns out, but just puddled Rockler Medium, KrazyGlue brushon poured, and for kicks and giggles GF Woodturners Finish.
Letting it dry now while updating to 3.8.36.
Probably run a .5" BN in profile with very light passes across the treated areas.
Wish I had Thin, but now I'm curious:)

[scottp55]

G. ,
Probably won't do you a bit of good, but had this chunk of Quilted I stuck Rockler Thin CA on a couple spots in February. Reacted into that white smoke and bubbled like crazy and drove me out of shop so just set it aside.
Probably Way punkier than yours, but just wanted to see how much of this piece was going to be usable and what it would look like.
Out of Thin so used KrazyGlue brush on(kind of like a thin Medium), Rockler Medium, General Finish "Woodturners Finish".
For some reason the Thins don't penetrate as much as I thought and reacted more than the Medium? Thin's were whiter because of the bubbling I think.
Maple is around 18 yrs old and stored in garage and we just went through a very humid week, but 75F and 65% today. Board's almost 1/4" out of flat and only need 3/4" thickness so good chance to cut and see the inside.
Thin's are no good for my use here apparently. Medium was OK but uneven penetration. GF WTF was worthless for this, but love it for other stuff.
I used a dental pic under the CA's to show where it never got to. ROT.
Then decided to use a 25/75 Deft Brushing Lacquer/thinner I use when I know I'm going to be making buttons with VERY acute angles and unsupported end grain where I used to get tearout. Soaked about 1/4" in on decent flat grain and over 1/2" on endgrain. At bottom of the .25" deep .5"BN cut it was still easy to impress softer area on bottom with fingernail, but an 1/8" down it was hard.
Think a second or third coat would have helped as it was thirsty even though I fed it for about 10 minutes the punky sections kept soaking it up.

Like I said, probably no good for you, but I'm going to machine it within .05 of final, and then give it several coats of the thinned lacquer. and then final pass.
For what it's worth, here are a couple pics.
I'd listen to the other guys though:)
Good luck,
scott

[Brady Watson]

Anybody try Cactus Juice (http://www.turntex.com/index.php?page=shop.product_details&flypage=flypage.tpl&category_id=144&product_id=2132&option=com_virtuemart&Itemid=121) ? I've often heard it recommended for turning punky bowls.

I'm not sure how practical it would be for one offs, but I would think that vacuum infusion would be the best guaranteed method for anything that's too soft to machine. No other method (including full immersion), will offer better fluid penetration.

The same technology is used with vinylester and epoxy for boat hull construction. Maybe a cobbled together FoodSaver vac bag setup could work...don't forget a fluid trap/separator...unless you want juice in your vacuum motor.

-B

[Burkhardt]

Anybody try Cactus Juice (http://www.turntex.com/index.php?page=shop.product_details&flypage=flypage.tpl&category_id=144&product_id=2132&option=com_virtuemart&Itemid=121) ? I've often heard it recommended for turning punky bowls.

I'm not sure how practical it would be for one offs, but I would think that vacuum infusion would be the best guaranteed method for anything that's too soft to machine. No other method (including full immersion), will offer better fluid penetration.

The same technology is used with vinylester and epoxy for boat hull construction. Maybe a cobbled together FoodSaver vac bag setup could work...don't forget a fluid trap/separator...unless you want juice in your vacuum motor.

-B

I was tempted to buy the Cactus Juice a while ago. It is a polyacrylate resin, practically resulting in an acrylic plastic like plexiglass. Very thin liquid and should be perfect for this pupose. But it is a bit involved with very good drying in an oven or kiln, a suitable vacuum chamber, long time soaking and when everything is impregnated it need a few hours oven process at 200 degrees to set off the catalyst. So far I did not try it but maybe when I have another such project.

[Burkhardt]

G. ,
Probably won't do you a bit of good, but had this chunk of Quilted I stuck Rockler Thin CA on a couple spots in February. Reacted into that white smoke and bubbled like crazy and drove me out of shop so just set it aside............

Good experiment! Actually the wood I used was not as rotten. I tried the Minwax wood hardener on another similar thing and while it penetrates quite well, the solid content is less than 20% and after evaporation of the solvent, the resulting wood is still quite spongy. So I went ahead today with the thin CA because that is what I had at hand. I did a rough cut first with a generous skin of about 1/10" so that tearout did not affect the final surface.

Then I let the CA soak in; the spalted wood sucks it up immediately and you are right, when applying too much at a time it starts fuming or even white foaming. The CA reacts with the wood within seconds. But applying in several sessions with a few minutes apart made it work without fumes. Then I did a finish cut, leaving another 0.015" skin, wiped on one more layer of CA and repeated the finish cut at the target depth. Took a little longer than a normal bowl but I think the result is worth it. There are still a few small rough spots that I could not sand out but overall I am quite happy with the result. It is sanded up to 500 grit plus steel wool and finished with natural, unpigmented wood stain. Given the 98 degree temperature outside it dried up within an hour.

The curly figure is spectacular and it might even have looked better without the spalting.

https://lh6.googleusercontent.com/-jv4UAOae_Rs/Vd_CEhKIrZI/AAAAAAAAF_E/ZhXW0Whunmo/w1108-h857-no/DSC03316.JPG

https://lh6.googleusercontent.com/-y3Q5I3q99Gk/Vd_CCC2sIXI/AAAAAAAAF-s/n29KU_wSiYw/w1102-h857-no/DSC03306.JPG

[myxpykalix]

WOW that is pretty...good job!

[dmidkiff]

That turned out beautiful. Glad the CA worked. Being patient with a project pays big rewards. I have thought about the cactus juice before but never tried.

[Brady Watson]

Real purdy! Love the quilting/figure :)

-B

[scottp55]

Congrats Gert!!:o
Gorgeous full figure Curly(up here they call that Fiddleback when it's that tight) and personally really like the contrasting Spalt!
I can see why you kept it stashed.
Thanks for the gradual CA tips! Counter intuitive to an oil guy where first coat is the most important.
Makes sense with the multiple cuts though. Got a thin rip of live edge Quilted that fades to a sharp point with a little punk before the tip I want to use as an accent piece and think I'll try the gradual Thin approach. Just sanding involved ,but should work. Thanks again as I was wondering how to deal with it.
You forgot to sign your piece of Art!! :)
scott

[scottp55]

Oh, G.
What's the best way to spread a lot of Thin like that?
I tried an AARP card once, and it worked great as a squeegee on a flat piece of thin stock.
Accelerator on that?
Thanks,
scott

[Burkhardt]

Oh, G. What's the best way to spread a lot of Thin like that?....

Good question and I have not found a good method yet. Unfortunately, CA is not self-spreading like a good laquer. When you brush or wipe it on, it will always have streaks. I have tried an epoxy squeegee and a thin piece of silicone rubber but eventually I just use a disposable nitrile rubber glove and my fingers to spread it. The remaining streaks have to be sanded out.

But that is the reason I do not use CA as the finish and only as a filler or in this case as stabilizer. If you apply a real coat of CA on top of the wood it is rarely consistent thickness and after sanding I notice regularly some blotches of glass-like CA surface mixed with spots of matte wood grain surface so I don't do that anymore. I machine or sand the CA back to the wood surface and use laquer or stain as the finish.

The problem with this thin wall bowl is however that it warped a little after application of CA. Re-machining a thin skin did not reach all surface spots anymore. I had to sand it manually on the lathe using a vacuum plate chuck.

[scottp55]

Thanks G.
Glove sounds about right for the punky live edge:)
Yeah, used CA ONCE on some Maple I burnt with torch thinking it wound keep tearout low on .09" font, but all it did was bond more to the carbon than the wood and minuscule tearout just ripped the entire black layer off in most places, and entire letters with others.
Thinned Lacquer was the ticket(more brittle?).
Increased font to .12" and it worked fine with CA.
scott