How come bowl blanks cost so much?

[minilathe22]

For me I simply dont have the space for a reasonably sized bandsaw, and I am not aware of any (sensible) way of cutting a large plank into circles. If you have the bandsaw and are prepared to spend the time then I think it is well worth it - nothing magical about a "bowl blank", its just a piece of wood cut in a circle! Looks like you have come to that conclusion anyway.

in terms of drying, you might want to consider a rough turning, where you get to the approximate shape, but leave it thick and then wax and wrap in newspaper for a month or two. Then cut the final shape. Often changing the shape will release stress within the wood, and it can distort.

 

[Chris152]

I even tried sanding sealer, but there was still tearout - I think I could have tried again, but felt it was a pretty fruitless task. But as you say, it's answering my question about blanks and more generally what makes for good turning wood. Also, faced with this problem I've had to try to refine my technique and hopefully that'll show on the next pieces I do with more stable wood. We'll see...

Many thanks Chas.

 

[Chris152]

Often changing the shape will release stress within the wood, and it can distort.

I think I'm aware of this happening even when using a blank (quite apart from the board I've just been struggling with) - if I leave the bowl on the lathe overnight, when I return to finish it the next day it's 'out of whack' (to quote one Australian woodturner I've been watching on the web). Thanks minilathe.

 

[Phil Pascoe]

If the rim is at the bottom in your second photo you'll get less figuring that if it were the other way up - the closer the shape follows the annual rings, the less grain pattern there'll be.

 

[CHJ]

Unless you are deliberately turning oversize to allow drying or some stresses to take effect it is never a good idea to leave a turned item on the lathe with the intention of taking finishing cuts later, in some instances even minutes can be a killer, hours and days even more problematical.

With narrow rimmed Bowls and Vases and the like, cut and finish the outer and inner surface rim area as soon as possible and continue down the inner sides, finish cutting as you go, by the time you reach the base area in most instances the rim will be running out of true enough for you to have difficulty maintaining bevel contact and invariably forestalling a 'finishing' cut.

 

[Chris152]

If the rim is at the bottom in your second photo you'll get less figuring that if it were the other way up - the closer the shape follows the annual rings, the less grain pattern there'll be.

Right, got it - I was going to use the second blank to warm the house a little, but think I'll have a go so I can see this in practice. Maybe it's just me, but I find I have to actually do these things before they stick properly in my mind. Reading, even seeing it in videos doesn't seem to work the same way! Thanks Phil. Maybe this wood's too bland to make much of a difference either way, but here's the one I just did (in all its torn-out and crudely sanded (80g, I didn't bother going any further) glory). I'll post one of practically the same blank turned the other way in due course for comparison.

Unless you are deliberately turning oversize to allow drying or some stresses to take effect it is never a good idea to leave a turned item on the lathe with the intention of taking finishing cuts later, in some instances even minutes can be a killer, hours and days even more problematical.

With narrow rimmed Bowls and Vases and the like, cut and finish the outer and inner surface rim area as soon as possible and continue down the inner sides, finish cutting as you go, by the time you reach the base area in most instances the rim will be running out of true enough for you to have difficulty maintaining bevel contact and invariably forestalling a 'finishing' cut.

I've spent hours and hours reading and watching, but nobody said that (as far as I remember - maybe it's there but I'm too busy worrying where the bevel is etc to notice). Really helpful advice, thank you!

 

[CHJ]

Another 'Trick' that can save hours of frustration if tackling a narrow rimmed bowl.
1. Finish the outer shaping,
2. True up he outer front/top face to beyond the rim width.
3. Then use a parting tool to form a shallow groove in the top face at your intended Rim Width.

This then fixes the width of the rim and keeps the thickness constant regardless as to how it moves later, any minor irregularities inboard of this will be disguised.

It has another very important role:-

It gives you a 'shelf/lip' to start your bevel on the inside and stop the centrifugal forces causing the gouge to skid across the edge face if you get it slightly wrong.

 

[Phil Pascoe]

If you are experimenting, get some stain/dye and colour and finish the flat top/rim first - you can then turn through the coloured part into the the actual bowl. This will give a clean edge to the colour. Good practice for staining as well as turning.

 

[Chris152]

Well, I didn't have any dye or stain so applied some dark polish, and cut the shoulder with a parting tool. I really enjoyed it, the clean-cut line of the parting tool into the relative darkness of the waxed wood revealing the whiteness of the wood beneath. Thanks both for those suggestions - I'm going to order some dye so I can experiment a little with that.
The wood simply won't allow me to scrape it without lots of tearout, so I finished the back with the gouge, gently scraping the turning lines away with the point and front end of the wing. Not a complete success but ok. I tried the same on the inside, got a catch and had to re-turn the shape. That was ok, and I now know the danger of catching the wing on the inside of a bowl.
I got to this point, and decided I'd had enough of this piece of wood. It's so stringy - I almost like the shape it's formed as I was cutting toward the centre.

ps I left the voids where the bark had been to get a bit of practice turning into where there's nothing.

 

[Lazurus]

Also consider the profile of the gouge you are using it can make a big difference, unless shear scraping I invariably get some tear out, which is why I don't bother. have a look at Lyle JAMIESON on youtube, he has some great techniques which I now use all the time. he has simple technique but backed up with the reasons why, it does work.

 

[Chris152]

I just took a look at a couple of his videos, thanks Lazarus. Not sure I'm ready to scrape with the bowl gouge as he does (almost vertical - can't help but feel the upper wing'll catch, in spite of his demo that it won't!). It's odd - plenty of videos online showing a scraper on the inside of the bowl doing what looks like a great job, but he says not to use them and just the bowl gouge with bevel, at 45 degrees. That's what I ended up doing on my last attempt, but as you can see my turning lacks the finesse of his! So I end up trying to scrape the turning marks away and on this piece, that means loads of tearout. I need to keep practising that final cut with bevel on the inside, whatever happens.

 

[CHJ]

... I need to keep practising that final cut with bevel on the inside, whatever happens.

If you are trying to finish a reasonably deep Bowl Hollow with the same tool you are invariably likely to fail.

Using Two Gouges with different Nose Angles so that you can maintain good Bevel Contact without the gouge fouling the bowl lip enables you to maintain a good bevel contact.

 

[CHJ]

Have a look at the nose angles shown in this extract from the Tormek Manual, and note the differing nose angles and ***** how you would hold the tool to maintain good contact.

post499317.html#p499317

 

[Chris152]

The first of those posts is really clear in terms of profile/ function - my bowl gouge has a fingernail shape and definitely works easier on the way down the inside than across the bottom, though the hollowing I've been doing is not deep and I'd imagine anyone experienced would manage that in one go? The shapes I've been doing do have a flat base - looking at the diagram, I guess I want a shallow grind for that.

Sticking with cutting blanks from boards, I collected a piece of maple today - it's about 36 x 14 x 2 inches, and 17% moisture content. It was in a barn and I've brought it into a slightly-heated part of my house. Do I need to wait for the mc to drop before I cut into rounds and turn? I know it'll drop to about 12% when I bring it into the house proper.

One last thing - you've all offered some brilliant advice in this thread and others, and I see a few other beginners are posting questions at the moment. Is it worth starting a newbies thread where some of the more experienced turners can offer advice/ answers for beginners? Some of your advice is now buried in a thread about the cost of blanks. There's lots of info on the web, but being able to ask particular questions and get answers from experienced turners is different from that and invaluable.