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Guy28
7th October 2011, 11:42 PM
Hi Folks,
First post from a newbie.
I bought myself a mini lathe earlier this year. I've been having fun using various scraps and bowl blanks, but I've been building up a store of green logs. Cut to the same length as the width and halved through the middle. As I couldn't get any end grain wax sealer I used what I had - Solarguard decking paint. I've had some stuff there for nearly 10 months and almost no visible splitting. (Well everything but some Hakea - boy did that split! - shame to, - great grain pattern.)
Any comments or improvement suggestions on the method?
As of yesterday I'm the proud owner of a new Carbatech bandsaw, so I can really get stuck into my stock pile! I'll have plenty of time as the wife isn't speaking to me......
The question to you experienced folks out there - do I just cut them into round blanks, paint the ends and leave them, or cut them into blanks and rough turn them?

Cheers,
Guy
PS: its amazing what you can pick up if you keep your eyes open - This week alone, some Oak, Elm, Birch, Mahogany Gum and a large Blackwood that had fallen down and prompted me to do my civic duty and remove for the Council (well the trunk anyway)

hughie
8th October 2011, 12:12 AM
Guy try turning your green timber, rough turn it allowing about 25-30mm wall thickness. Then look at drying the rough outs, they will dry faster and its much easier to rough out green timber than dry.

Drying, well there many views on this matter. This is what I do, after roughing I coat the outside of the bowl [ oh I do alot of bowls HV etc no spindle stuff at all.] back to the coating, I use BLO or boiled linseed oil then place several bowls in a cardboard box and generally check them weekly and fill any cracks as they appear with CA or superglue.

As they dry they get lighter and depending on the timber 3-6 months later they are ready for finishing

Guy28
8th October 2011, 12:25 AM
Hi - Might be a dumb question, but do you rough them with a spigot or recess? Wondering if the warping during drying makes a difference when re-mounting.

Paul39
8th October 2011, 02:56 AM
Hi - Might be a dumb question, but do you rough them with a spigot or recess? Wondering if the warping during drying makes a difference when re-mounting.

There are no dumb questions. This is how most of us learned. Trial and error takes much longer.

If large I make a recess, if smaller a spigot.

The bowl and recess / spigot will usually dry to an oval shape.

Grab the bottom as best you can when starting to finish and make the outside of the rim round and flat, turn the bowl and put the rim into a jam chuck made from a piece of plywood or medium density fiberboard, bring up the tail center and recut the recess / spigot round and even.

Finish the outside as mounted, turn the bowl and re chuck, finish hollowing and any part of the outside not reached in the previous mounting.

Remove from chuck and again place in jam chuck bottom out. A layer or two of cloth or paper will take up any gap between bowl rim and chuck, if still too loose make a new jam chuck, run tape over sides of bowl to back of face plate 3 or 4 places and finish recess / spigot.

Done.

robo hippy
8th October 2011, 07:33 AM
You can't dry a whole log without it splitting. Cutting blanks reduces the mass, so there is less stress when drying, which leads to less cracking and some warping. You can leave slabs. Important to seal (commercial sealers, old paint, old oil finish, some wood glues even work) the end grain, and leave the blanks longer than they are wide (14 inch log, leave in 18 to 20 inch lengths). Store out of wind and sun light.

You can rough turn the blanks, using 10% thickness rule, so 10 inch bowl should be about 1 inch thick, and this will work for most woods. Seal the blank, start it out on a concrete floor (generally cooler, and more humid), then move to shelves. Dry in a year or less.

You can turn the blanks to final thickness, 1/4 to 1/2 inch, wrap the outside with paper and leave the inside open, or I use plastic stretch film over the rim and part of the outside, making sure to round over the rim first. Start out on the floor for a few days, then up on a shelf. Dry in 10 to 14 days, sand and finish. Note, power sander really helps, and you may not be able to do it with the lathe spinning any faster than 10 to 15 rpm.

You can thick turn, and then boil, which relaxes a lot of the stress in the wood. Boil about 1 hour per inch of thickness, bring the wood to boil in the water, allow to cool in the water, then seal and dry as normal.

Microwave: done in short bursts, 60 seconds max or it can/will catch on fire. Allow to cool between heatings. Do not use the house hold micro wave or "she who must be obeyed" will be severely offended.

There are bowl drying kilns, involving an incandescent light bulb, computer fan, big box, and some times a dehumidifier.

Thing with drying is too fast it splits, too slow and it rots/molds which isn't always bad. Exact methods can vary a lot, depending on how hot or cold, and how humid or dry your local weather and seasons are. Another art/science of woodturning to learn.

Of course, some woods start to split some time between when you get the chain saw out to when you fire it up.

robo hippy

Guy28
8th October 2011, 02:19 PM
Thanks all.

Looks like I'm going to get a bit of practice for my technique roughing out all those blanks
.
Oh, I can attest to the reaction of the family when you don't pay attention to a piece drying in the microwave. I wanted to have a look at the Hakea branch that I'd been given. Cut it, put it in the microwave and then got distracted. The stench hung around for 2 days,

Cheers,

jimbur
9th October 2011, 10:17 AM
Thanks all.

Looks like I'm going to get a bit of practice for my technique roughing out all those blanks
.
Oh, I can attest to the reaction of the family when you don't pay attention to a piece drying in the microwave. I wanted to have a look at the Hakea branch that I'd been given. Cut it, put it in the microwave and then got distracted. The stench hung around for 2 days,

Cheers,
Olive is the exception. You can just tell everyone that you have been cooking.:U

Bazza
9th October 2011, 04:45 PM
Do a search for "Ron Kent detergent" there is a bit of information on the net about using dishwashing liquid to speed up the drying/preserving of woodturning bowls blanks etc.

Bazza

turnerted
9th October 2011, 04:53 PM
When I rough out my bowls ,I also cut a recess on the inside, either with a skew or forstner bit . I can usually get a grip on one of them despite distortion . If all else fails just mount between centres and recut the tenon/recess on the bottom.
Ted

robo hippy
9th October 2011, 06:05 PM
Ron Kent started using the LDD (liquid dishwashing detergent) soak for helping sand out Norfolk Island Pine. I have used the soak for years. The only thing I can tell that it does is that it makes sanding a lot easier. I figure it is the soap that kind of lubricates the wood. Soak in a mix of half LDD (cheap brown stuff), and half water for about 24 or more hours. Remove and rinse surface soap off, then air dry for an hour or so, then wrap the rim. It does pull some color out of the wood, and can add some color to some lighter woods. I then switch it to soaking black walnut, then dump it on an ant hill (don't know if it kills them, but it does irritate them). I can't tell that it bothers any finish applications, though I never use a surface finish like spray lacquer.

I did one test where I dried several sets of bowls. Some air dried, some DNA (denatured alcohol) soaked, and some LDD soaked. No difference that I could see or measure. The DNA soaked bowls were harder to sand out, the LDD bowls were easiest to sand out.

A lot of people over here use the DNA method on twice turned bowls, and swear by it. They came up with the idea of wrapping the outside of the bowl and leaving the inside open. Theory being that the inside dries at a slightly faster pace, and 'pulls' the outside inwards. I figure there is some truth to that. I have never done a twice turned bowl, so don't know if it works or not.

robo hippy