Difference in drying/seasoning time for bowl blanks?

[LancsRick]

I wasn't quite sure how to title this thread, so I'll explain a bit more.

Having just got my hands on the somewhat rare bowl turning attachment for my Coronet Major, the headstock is now at 90degrees, and my entrance into the world of bowls over 24cm can commence!

Given that bowl blanks of large diameter, even thin ones, tend to be very expensive, I was going to start paying more attention to scavenging trunk slices rather than old logs. Given that these are thin but wide, any tips for drying them? If they were logs/spindles I'd be going the PVA or wax route and waiting many years, but I'm hoping that discs might be faster?

(Please be faster, I'm tight).

 

[marcros]

alternatively, you could obtain logs and turn them green. then allow to dry for a while and finish turn them.

This would allow you a lot more scope than discs would, and be less likely to crack.

 

[CHJ]

.....Given that bowl blanks of large diameter, even thin ones, tend to be very expensive, I was going to start paying more attention to scavenging trunk slices rather than old logs. Given that these are thin but wide, any tips for drying them? .....

If you are a drying novice don't bother, even if you are experienced at drying green wood the chances of drying a slice without it forming serious splits is somewhere in the minor miracle region.

Slices of any log timber are the quickest route to lots of firewood.

Unless you are into the expense of lots of resin filling and gluing and producing stuff with artistic pretentions forget normal bowl turning from slices.

 

[Random Orbital Bob]

Are we understanding you correctly....you want to turn end grain bowls out of a slice horizontally across the trunk (like tree surgeons normally produce so they can easily carry away the tree)?

If I'm reading that right then Chas is spot on, you'll never have one survive and the risk of mounting it, end grain on without any support in its length would be suicide.

The right path for you is to scavenge green logs with up to as large a diameter as your new setup will allow. Cut them longitudinally like a normal bowl blank ie cross grain (face grain) but turn them rough straight away and then store them wrapped in newspaper in a paper sack for 6 months. The thinner rough turned blank will dry in that time, you then remount and finish turn them, being careful to true them before finishing up.

 

[LancsRick]

Sorry, I realise my first post could be very misleading! When I mean slices I don't mean spindle slices, I mean with grain running across the face.

6 months I can cope with, thanks! Guessing since they'll be wet it would be wise for me to treat for worm if I go down that route?

 

[Random Orbital Bob]

not usually necessary because once you rough turn them (typically to around 10% wall thickness ) you'll have turned past the worm as it's typically only in the sapwood. If it's in the heartwood then the blank is probably too punky to turn safely/give a decent finish.

 

[CHJ]

Sorry, I realise my first post could be very misleading! When I mean slices I don't mean spindle slices, I mean with grain running across the face.

6 months I can cope with, thanks! Guessing since they'll be wet it would be wise for me to treat for worm if I go down that route?

If you are talking about thick Plank format the normal nomenclature is a Slab, how are you intending acquiring such, time is of the essence for end grain sealing if someone else is doing it for you.
Are you converting them yourself (slabbing) on a bandsaw or with a chainsaw mill.

Stacked in the dry with spacers to encourage airflow will see a year+ per 25mm thickness to get into a safe turning to size region.

If turning green, leave wall thickness (this must be as even as possible over whole of form) at least 10% of expected finished diameter. I.E. 250mm bowl-25mm wall thickness.

Expect the blank to distort considerably dependant on wood species, expect some so prepared to finish with a wall thickness no more than 10mm from such.

Drying of green turned can be quite quick given ideal conditions and wood species but can be many months, in fact many turners put stuff on store for several months to keep a stock backing and easy rotation without having to worry about it..