Natural Edge Bowl WIP

[Grumpy John]

Thank you to all who responded to my original post http://www.woodworkforums.ubeaut.com.au/showthread.php?t=74837 many helpful tips there. I am using this document as a rough guide http://www.woodturner.org/community/youth/projects/Natural%20Edge%20Bowl2.pdf. Here is the WIP as promised. The timber is Chinese Elm and quite wet, not the most user friendly shape but should make for an interesting bowl.

[Grumpy John]

Blank mounted in lathe and not very balanced as you can imagine. Have managed to get a rough shape going, however some nasty cracks have developed and I am unsure whether it's worth continuing with this piece. Any and ALL comments welcome I'm reasonably thick skinned and will take any criticisms as help offered.

[rsser]

Call it a practice piece John and plough on. Elm is easy turning so you can concentrate on tool technique.

Fill the cracks for safety.

When not turning it, wrap it up in plastic.

[Stryker223]

John, go ahead and finish the bowl unless you have lots of other things you need to get done. You can always soak it in polyurethane after it's finished and dried.
I'm going to get a paint pot and a vacuum pump and use it for wood stabilizing. I'm going to turn a couple vessles and put them in the vacuum and see how they come out.

[orraloon]

John,
Are the cracks due to the wood being wet?

[orraloon]

Sorry should have read the whole thing. I would be leaving it for a year then trying again.

[weisyboy]

go ahead and contnue when finished lever it aside to dry if it breaks up then so be it but if not then tfill the cracks.

going good so far. althow not the way i do it.

[Grumpy John]

John,
Are the cracks due to the wood being wet?

Most likely. Once the end grain sealer came off with the first cut and a bit of heat from the gouge it was probably inevitable :unsure:. Not the best day at the lathe for me, first my new shear scrape blade won't fit the new hollowing tool I bought, now my first NE bowl looks like falling to pieces :cry4:. I've covered it in end grain sealer and buried it in shavings (the bowl that is) and I'll have another look at it in light of a new day.

Funny thing is I turned a bowl from another piece from the same tree about 6 weeks ago and apart from warping it didn't crack at all.

[joe greiner]

Assuming the last picture in post #2 is the current state of affairs:

The tenon is too shallow for proper purchase in a scroll chuck. This is GOOD! Because the piece will never be balanced in this condition. OK if you're after a lopsided bowl, but I'd advise against it for now.

I think you'll have more success if you re-mount the piece for a level (+/-) rim. The tailstock can engage the outside curve at a new central region opposite the drive spur. Then re-turn the outside about the new axis of rotation, and cut a new tenon concentric thereto, with depth and diameter suited to the scroll chuck and your desired proportion of foot-to-total diameter. When starting or re-starting for each session, stand aft of the headstock before doing the actual cutting - you probably already know this. And wear a face shield - you probably already know this too.

The cracks appear too wide to patch with CA glue and sawdust; such patching wouldn't go deep enough anyway. Rout the the cracks to a depth of about 1.5 times your anticipated wall thickness. A Dremel with a very narrow bit is ideal for this. Smaller dental bits can be used in the Dremel with an auxiliary collet. Fill the cracks with a mortar of epoxy and ground something-or-other; fresh coffee mixed 1:1 by volume makes a nice infill, but there are lots of other possibilities. At the moment, I'm working on a tutorial, but the foregoing is enough to proceed.

After the epoxy cures comes decision time. You can proceed to final turning, rough turn to a generous wall thickness (probably best), or set the piece aside. Rough turning will allow the blank to dry more uniformly, with less likelihood of new cracks developing. For the inside cutting, it's safer to leave a central pedestal for the tailstock to engage, at least for a while. Belt and braces, one might say, with the piece secured by both the chuck and the tailstock. The region in the inside bottom isn't very vulnerable to cracking, so the extra material of the pedestal won't affect anything.

Joe

[Grumpy John]

Call it a practice piece John and plough on.

Thanks Ern, it was only meant as a practice bowl anyway, but it's still disappointing when things go wrong :(.


John, go ahead and finish the bowl unless you have lots of other things you need to get done.

Michael, I've always got a lot of other things to get done SWMBO never lets me forget that :D.


Assuming the last picture in post #2 is the current state of affairs:

The tenon is too shallow for proper purchase in a scroll chuck. This is GOOD! Because the piece will never be balanced in this condition. OK if you're after a lopsided bowl, but I'd advise against it for now......

Rout the the cracks to a depth of about 1.5 times your anticipated wall thickness. A Dremel with a very narrow bit is ideal for this.......

Fill the cracks with a mortar of epoxy and ground something-or-other; fresh coffee mixed 1:1 by volume makes a nice infill.......

Joe

Joe, the picture you're referring to was the most recent at the time of posting. I have since put a tenon on the base and turned a recess in the top to take a small faceplate. I have decided to go for a lopsided bowl (in for a penny in for a pound as they say). Good idea using epoxy/coffee mix I think that's the way I'll go, that's what Ern did with his Cyprus WIP that developed cracks (BTW Ern what's happened to your WIP, it seems to have come to a screeching halt :D?). Lucky thing I've just bought a small die grinder off Ebay that takes 1/8" carbide burrs, perfect for opening out the cracks :2tsup:.

Some new pics of current state of affairs, change of colour is due to coating of end grain sealer.

[rsser]

Opening chuck jaws into the bark side gives you a good positive hold; the drawback is that if you need to reposition the piece to get better symmetry you're stuck. An alternative is a large two prong drive dog.

(My WIP has no P at the moment John; no feel with the splinted hand).

[Grumpy John]

Opening chuck jaws into the bark side gives you a good positive hold; the drawback is that if you need to reposition the piece to get better symmetry you're stuck. An alternative is a large two prong drive dog.

(My WIP has no P at the moment John; no feel with the splinted hand).

Ern, not possible to expand ghuck jaws if you take a close look at the third photo you'll see that the faceplate isn't even fully seated.

Cheers
GJ

[rsser]

Sorry John, was referring to an earlier post about starting off mounting. Not relevant to where you are now, or maybe it still is depending on how much wood you're prepared to lose.

As for one bit cracking and another not, yep, name of the game. Your current lump could have had more stresses on it while standing so when you take some material away ... or you may have been breathing on it harder ;-}

[Grumpy John]

... or you may have been breathing on it harder ;-}

It's not musk Ern :D.

[weisyboy]

iv found if you hop on one leg wile turing green wood it dosent crack:2tsup:.

[rsser]

It's not musk Ern :D.

LOL ...

but then look at what happened last time there was musk in the shed :p

[Fredo]

John,

Be prepared for some disappointment when learning new tricks. Some things are beyond your control: cracks, voids, gnarly grain - sad, but true. Do continue on, the only way to gain experience is by putting in time on the tools. As Joe said, a balanced rim, rather than a lopsided one, makes for a much better looking bowl. Your bowl looks way out of balance so think safety, you don't want it jumping off the lathe.

Press on rewardlessly, :biggrin2:

Fredo :U