Ouch! Coolibah cracking badly (with pics)

[gketell]

Ok, so Friday I posted pictures of my Coolibah Burl pen for the Farmer's market. Today I went to show off the pen to a friend and it is cracked all over the place. Not one crack, not two, at least a dozen different cracks.

I drilled it nice and gentle: 1/16"-1/8" at a time. I turned with sharp tools. I sanded with 320, 400, oooo steel wool, MM 3600-12000. 4 coats of thin CA followed by 5-6 coats of medium CA (trying unsuccessfully to build a nice shine).

Any ideas what I might have done wrong? Or, more importantly, what I can do to prevent it in the future? I've done Amboyna burl and redwood burl with no problems. What is different with Coolibah Burl?

GK

 

[Snazzypens]

Greg it sounds very green. I have never had a problem except green

Toni

 

[PenPal]

Coolibah Burl is known here as very stable even when green it dries well and normally stable,contact Burls Down Under with the question he markets in quantities and has for some time.He will know. My mate who handles it by the ton has told me in the past he rarely covers the whole burl especially in our summer outside but always covers Mallee.As with all Burl shortly before reaching your final shape C.A. glue let dry naturally can stabilise the timber very well,great care in sanding and through the grades with cleaning between changes helps.

The only problem I have is burl chipping it is without grain after all in one direction,to help after drilling leave it for a period before gluing the brass,square pressing.

You could have a piece of punky wood regardless that can occur in any species.The strongest burl is often further in,near the bark can be more brittle. Hope you solve your problem. Peter

 

[PenPal]

Greg,
I had a look in your album maybe the sapwood combination caused the failure,really interested now where the splits occurred. Peter

 

[gketell]

I'll try to get photos of it tonight. The cracks are pretty much everywhere. All the blanks came wax-encased and I guess this it why. I should go out and strip all the others and let them dry. I wish I had a moisture meter.

GK

 

[gketell]

Ok, here are some pictures of the cracks. Mind you this isn't all of the cracks, just the ones that would photograph well. *sigh*

Wow, those came out better than I thought. Maybe it is all the cracks. Either way, .... *SIGH* One of my nicest pens now destined to be just so much more sawdust after I turn the blank of the tubes.

GK
ps for those who might ask, this was a canon EOS 20d with 50mm macro lens (at closest focus point) and light tent.

 

[Fred]

Greg, Try boiling your wood as per the instructions found in Steve Russell's article here ... http://www.woodturningvideosplus.com/boiling.html

His Main Site Page is http://www.woodturningvideosplus.com and here you will find an interesting wealth of information. [Thanks Steve!]

Following the boiling process immediately place the hot wood into a cardboard box, close it up, and let it get accustomed to your area for several days. You just may have a pleasant surprise awaiting you in the end. This process also immediately stops any spalted wood from continuing to spalt away. I also like the process because it removes 99% of any wax used to seal the wood. change the water when going to a different species to avoid possible staining, but any staining usually does not get to deep and may be turned away if making a bowl. Do a search here on the FORUM for Steve's articles. BTW, the deep frying pot from Northern Handiman is excellent for this process.

Second, don't trim the wood away on this cracked pen ... disassemble the parts and refinish the pen with thin CA and let it cure naturally - no accelerant. I have had the same cracks - as have many of us - and I simply follow this method and at least save a pen for my own use. Use the finest sawdust you can generate to fill these cracks, if you use matching colors of sawdust in the cracks I'll bet you these cracks will disappear!

BTW, nice detailed photographs you gave us all to look at. []

 

[Darley]

Cracks at the knobs are normal ( just fill with CA ) as for the rest I think you sand your pen blanks on a high speed, therefore heating up the wood.

Originally posted by gketell
<br />Ok, here are some pictures of the cracks. Mind you this isn't all of the cracks, just the ones that would photograph well. *sigh*


Wow, those came out better than I thought. Maybe it is all the cracks. Either way, .... *SIGH* One of my nicest pens now destined to be just so much more sawdust after I turn the blank of the tubes.

GK
ps for those who might ask, this was a canon EOS 20d with 50mm macro lens (at closest focus point) and light tent.

 

[GaryMGg]

Like others, I've had nice work crack after the fact -- an Amboyna Burl Baron did that to me.
I disassembled the pen, refinished with thin CA followed by medium and it's been good to go since.
Don't toss it; you'll have a nice and possibly saleable pen when you're done.
Gary

 

[Blind_Squirrel]

As a precaution with ALL of my wood pens I soak the inside of the drilled blank with thin CA to help stabilize it. After the CA has set up give the tube a test insertion; if it fits tight ream the hole out with the proper drill bit.

I also use thin CA as a sanding sealer on all of my wood blanks.

 

[bdar]

Some good advice by all, Blind Squirrel hit the nail on the head by lining the drilled hole with thin CA, something that Serge ( Darley ) taught me. I agree with Serge about the cracks apearing due to heat from sanding, I would fill cracks with CA only and not sawdust. Burls have cracks naturally, make it a feature of the uniqueness of the burl. For finishing I sand to 600 then start at 1500 MM to 12000 MM, throw away the 0000 steel wool as using MM eliminates the need for it. I first polish with tripoli and then finish it off with Dilux polishing rouge.
Darren

 

[gketell]

Thanks all! I will rework the blank this weekend and post pictures of the "new" pen.

My wife reminded me that the day before we noticed the cracks was the Farmer's Market when she had the pens on the table in the sun. So maybe the heat of the sun/day is what caused it to crash. I'm thinking that if the wood is that sensitive to heat then it definitely needs to be stabilized or my customers' will just have the same problem and that would be very bad for business.

GK

 

[Darley]

Greg you can fill the void with chrushed stone like Turquoise