Hardenfast
24th February 2008, 04:58 PM
I’ve witnessed with some interest a few posts herein regarding various turning projects which have gone wrong for one reason or another – whether it be vagaries of the timber used (warping, shrinkage, splitting), failure or destabilisation due to inherent defects, equipment deficiency and user error. I’ve also read the horror stories of lathes which have flung pieces of disintegrating bowls etc around the workshop like deadly ninja knives.
I have also seen some brilliant recoveries of projects which weren’t completely destroyed, and thought I would add a couple of my own for consideration and comment by the learned assemblage. I have written this thread over a little while, so I hope it doesn’t bore the bejesus out of you all.
Although I’ve only been at this turning discipline for a little while I already have a couple of faux pas worthy of mention, as well as recoveries and completion techniques which may be of interest to some.
The first was to be a fairly simple bowl from a nice little piece of spalted root stock found in a local paddock after some clearing works. Steve from the Lumber Bunker recently identified the piece as most likely to be from a Sydney Blue Gum, which would seem to be consistent with local timbers - so SBG it is. The piece was already quite dry when found it but I kept it for 6 months or so before roughing it out to a bowl of about 200mm diameter. It had some brittle edges and associated cracking, as well as a large-ish split near the base, but I thought these defects would just add to the appeal of the piece if finished correctly.
I decided to try a bit of the Turquoise filler I had purchased to fill the crack at the base and make it a feature, and persevered with turning the bowl to about 10mm thick even though the rim was getting a little fragile. Of course the inevitable happened. A chunk of the rim caught on the gouge and went whistling off somewhere, at the same time tearing the base of the piece out of the chuck. Not sure that these photos are great, but you can probably see the cracked edge of the bowl and the missing piece, and the torn out chuck mortice adjacent to the Turquoise filler. You can see the rim a little better in the photo below as I set it back on the chuck a few months later to amputate the offending section. Anyway, I quickly lost interest in this piece and set it aside with a few others for future contemplation.
67877 67878
<o></o>The second was to be my 4<sup>th</sup> segmented bowl. Flushed with moderate success after a few previous pieces - http://www.woodworkforums.ubeaut.com.au/showthread.php?p=550499#post550499
- I started to cut and glue together some random offcuts that I had gathered. I had some small chain-sawn pieces of She-Oak from a family property down at Goulburn - a few offcuts of the Sydney Blue Gum from the above piece – a few small strips of White Beech – and a small section of Eucalyptus burl which I had obtained from the Lumber Bunker. Something good must come of all this this!
As usual I didn’t bother with any setout detail or any idea of the shape of the finished piece – just start glueing some pieces together and see what we end up with is my usual modus operandi. Well, we ended up with something which was perhaps architecturally interesting, but which left a nasty little hollow at the intersection of the top hexagonal Eucalyptus burl sections. I tried to be inventive and fill these missing sections with some more of the coloured fillers used in the Turquoise experiment above – this time using some rose stone chunks in a pink resin just to see how it looked. How it looked was actually shitehouse – and this piece ended up on the unwanted/unemployed pile as well.
67888 67889
So, a few months later my wife spotted the SBG bowl and commented that our daughter’s birth stone was Turquoise, and that she would probably like that bowl for herself. Could it be repaired? I therefore decided to revisit this bowl and consider the recovery options, and at the same time have a shot at fixing the segmented piece as well.
The first thing was to cut a new chuck mortice on the first one. Luckily there was still plenty of thickness in the base, so I was able to simply drop a forstner bit into the original mortice and cut it a little deeper. I then remounted it and reshaped the bottom section up to the chuck. I then decided to cut the unstable rim section completely off the bowl. I used a parting-off chisel to cut a small trench and then grabbed a handsaw and held it in the trench as the piece was turning.
67879 67880
Even at slow speed the pieces soon started flying off everywhere and the process was getting a little hairy, so I switched off the machine and finished the saw cut with the piece still in the chuck. Easy. I then trimmed up the new edge to a nice flat finish. Once the rim was cut off the bowl was shallow enough to be able to remount the piece from the inside, so I turned another chuck mortice in the bottom and remounted it to re-finish the external base.
678816788267883
The new rim still had a few cracks which I thought looked ordinary, so I decided to laminate a new top edge to it – from the perspective of both stability and aesthetics. It was already finished down to a fairly thin wall thickness (6mm-7mm) so it had to be a good fit – but what to use? I had recently found a section of old hardwood ceiling joist while doing some renovation works on an old townhouse in Redfern. The building was over 130 years old and this stuff was hard – I mean it was hard. Still, I had re-sawn a piece of it and it looked interesting, so I thought I'd give it a go. My best guess is that its Brush Box but I’m happy to be corrected. I cut some small sections around 35mmx20mm and fitted a hexagonal layer to the rim using Selleys Tradesmans Choice PVA. It’s all I ever use and have had no failures to date.
67885
The next day I remounted the piece and quickly turned the rim down to suit the piece, then a careful scraper finish to whole thing. Sanding process up to a 500 grit finish and one heavy coat of Shellawax. I was quite happy with the finished item, as was wife & daughter.
67886 67887
The segmented bowl required a similar remedy, but I think I've run out of image space so I'll add another post.
Comments, suggestions, criticisms welcomed.
Wayne
I have also seen some brilliant recoveries of projects which weren’t completely destroyed, and thought I would add a couple of my own for consideration and comment by the learned assemblage. I have written this thread over a little while, so I hope it doesn’t bore the bejesus out of you all.
Although I’ve only been at this turning discipline for a little while I already have a couple of faux pas worthy of mention, as well as recoveries and completion techniques which may be of interest to some.
The first was to be a fairly simple bowl from a nice little piece of spalted root stock found in a local paddock after some clearing works. Steve from the Lumber Bunker recently identified the piece as most likely to be from a Sydney Blue Gum, which would seem to be consistent with local timbers - so SBG it is. The piece was already quite dry when found it but I kept it for 6 months or so before roughing it out to a bowl of about 200mm diameter. It had some brittle edges and associated cracking, as well as a large-ish split near the base, but I thought these defects would just add to the appeal of the piece if finished correctly.
I decided to try a bit of the Turquoise filler I had purchased to fill the crack at the base and make it a feature, and persevered with turning the bowl to about 10mm thick even though the rim was getting a little fragile. Of course the inevitable happened. A chunk of the rim caught on the gouge and went whistling off somewhere, at the same time tearing the base of the piece out of the chuck. Not sure that these photos are great, but you can probably see the cracked edge of the bowl and the missing piece, and the torn out chuck mortice adjacent to the Turquoise filler. You can see the rim a little better in the photo below as I set it back on the chuck a few months later to amputate the offending section. Anyway, I quickly lost interest in this piece and set it aside with a few others for future contemplation.
67877 67878
<o></o>The second was to be my 4<sup>th</sup> segmented bowl. Flushed with moderate success after a few previous pieces - http://www.woodworkforums.ubeaut.com.au/showthread.php?p=550499#post550499
- I started to cut and glue together some random offcuts that I had gathered. I had some small chain-sawn pieces of She-Oak from a family property down at Goulburn - a few offcuts of the Sydney Blue Gum from the above piece – a few small strips of White Beech – and a small section of Eucalyptus burl which I had obtained from the Lumber Bunker. Something good must come of all this this!
As usual I didn’t bother with any setout detail or any idea of the shape of the finished piece – just start glueing some pieces together and see what we end up with is my usual modus operandi. Well, we ended up with something which was perhaps architecturally interesting, but which left a nasty little hollow at the intersection of the top hexagonal Eucalyptus burl sections. I tried to be inventive and fill these missing sections with some more of the coloured fillers used in the Turquoise experiment above – this time using some rose stone chunks in a pink resin just to see how it looked. How it looked was actually shitehouse – and this piece ended up on the unwanted/unemployed pile as well.
67888 67889
So, a few months later my wife spotted the SBG bowl and commented that our daughter’s birth stone was Turquoise, and that she would probably like that bowl for herself. Could it be repaired? I therefore decided to revisit this bowl and consider the recovery options, and at the same time have a shot at fixing the segmented piece as well.
The first thing was to cut a new chuck mortice on the first one. Luckily there was still plenty of thickness in the base, so I was able to simply drop a forstner bit into the original mortice and cut it a little deeper. I then remounted it and reshaped the bottom section up to the chuck. I then decided to cut the unstable rim section completely off the bowl. I used a parting-off chisel to cut a small trench and then grabbed a handsaw and held it in the trench as the piece was turning.
67879 67880
Even at slow speed the pieces soon started flying off everywhere and the process was getting a little hairy, so I switched off the machine and finished the saw cut with the piece still in the chuck. Easy. I then trimmed up the new edge to a nice flat finish. Once the rim was cut off the bowl was shallow enough to be able to remount the piece from the inside, so I turned another chuck mortice in the bottom and remounted it to re-finish the external base.
678816788267883
The new rim still had a few cracks which I thought looked ordinary, so I decided to laminate a new top edge to it – from the perspective of both stability and aesthetics. It was already finished down to a fairly thin wall thickness (6mm-7mm) so it had to be a good fit – but what to use? I had recently found a section of old hardwood ceiling joist while doing some renovation works on an old townhouse in Redfern. The building was over 130 years old and this stuff was hard – I mean it was hard. Still, I had re-sawn a piece of it and it looked interesting, so I thought I'd give it a go. My best guess is that its Brush Box but I’m happy to be corrected. I cut some small sections around 35mmx20mm and fitted a hexagonal layer to the rim using Selleys Tradesmans Choice PVA. It’s all I ever use and have had no failures to date.
67885
The next day I remounted the piece and quickly turned the rim down to suit the piece, then a careful scraper finish to whole thing. Sanding process up to a 500 grit finish and one heavy coat of Shellawax. I was quite happy with the finished item, as was wife & daughter.
67886 67887
The segmented bowl required a similar remedy, but I think I've run out of image space so I'll add another post.
Comments, suggestions, criticisms welcomed.
Wayne