cracks in logs

**rsser** · 26th February 2012, 04:32 PM

Horses for courses.

We turners usually end up with half logs ex pith. All sorts of factors affect how likely they are to check, externally and internally.

There's two big English Elm of such in the backyard in the shade and they're checking more than a chess Grand Master. They have two coats of emulsified wax on the end-grain. But they were cut down last Spring so have high moisture content and the EMC down here in Melb. is lower than it is for you Sydneysiders at this time of year.

They were too big for the plain paraffin wax bath. I'd much prefer to have that on it than the tinned stuff as it's thicker and more flexible. Bob's recipe is bookmarked.

Why turners need flexible is that we deal with shorter lumps in general, for faceplate work. And when rough-turned the bowls are heading for oval the moment they come off the lathe.

We only seal end-grain (and a bit up the side in the case of a block) to as to equalise drying rates, reduce ovaling and minimise checking.

Another option is to green turn to finish in one session. Even if you step out for a cuppa, you have to bag the piece. You're likely to get an oval form out of this anyway. My best ever in this mode was a bowl of NIP, 25cm wide. It only went out of true by a mm or so. Why so little distortion? I blocked the lumps down just after a winter felling here in Melb. and did this piece straight away. 2nd reason possibly is that NIP is stable for a soft wood. (Fully dry, it's such rubbish it supplies extreme test pieces for tool edge treatment experiments).

**TTIT** · 26th February 2012, 10:59 PM

Originally Posted by rsser

..........I actually use a lot of paraffin wax, plain (without stearate) and bought in bulk, in an electric frypan. .............
I've experimented with adding some beeswax to this in small proportions, to improve adherence/flexibility and it hasn't helped.
..........

Can't agree Ern! I was having trouble with paraffin on it's own due to it's rigidity and it would fall off in a sheet on timbers that shrank a lot. I added beeswax to the pan and haven't had a problem since - the ratio would be about 20:1 or maybe even 30:1 - not a lot but it does the trick!

Originally Posted by rsser

........... But the risk there is with fungal infection. .........

While on the subject, if the bark will come off without too much effort - DO IT!! I lose too much much timber to fungal stain from leaving the bark on and it's a pain! I love finding logs where the bark will peel away with just a few taps with the back of the axe - no stain, no dirt in the saw blades etc - worth the effort

**rsser** · 27th February 2012, 07:38 AM

Curious. May depend on timber type. My mix was less durable than the straight stuff and more likely to be knocked off during a blank sort and pick exercise.

Was your paraffin-only brew free of stearate?

**tea lady** · 27th February 2012, 08:01 AM

In pottery we cut the wax with kero or diesel. For brush on resist. Prolly work for sealling ends as well.

Proportions are terribly unscientific.

**dai sensei** · 27th February 2012, 10:01 PM

Originally Posted by TTIT

Can't agree Ern! I was having trouble with paraffin on it's own due to it's rigidity and it would fall off in a sheet on timbers that shrank a lot. I added beeswax to the pan and haven't had a problem since - the ratio would be about 20:1 or maybe even 30:1 - not a lot but it does the trick!

Interesting, can't say I have ever had a problem, perhaps depends on where you get your wax. But adding a bit of beeswax is easy.

I have an old giant wok half full of wax, the shape allows for green bowls of up to ~600mm to be dipped along the edge bit by bit (depending on shape of course).

**rsser** · 28th February 2012, 05:39 PM

Way to go Neil.

I'm sure you're wary of flame + paraffin fumes.

...

FWIW for paraffin wax newbies reading this thread, my advice is to use a lekky frypan. Heat 'til the smoke is almost visible (you sense it before you see it) and then fry the endgrain. There'll be fizzing (water? air?), and when the end comes out it should dry clear. A big lump will drop the temp of the mix so take your time. No harm in redipping a cloudy end.

**TTIT** · 28th February 2012, 10:36 PM

Originally Posted by rsser

.............Was your paraffin-only brew free of stearate?

Yup! Got a 25kg monster bag of the pure stuff from our host (Ubeaut) and a big block of beeswax from the Kuranda Honey house. Should last me several lifetimes

**dai sensei** · 28th February 2012, 11:12 PM

Originally Posted by rsser

I'm sure you're wary of flame + paraffin fumes.

Actually no

, I do now, but it is an electric wok too scratched to cook with

. I also double dip my blanks for stuff I know are bad for cracking, single for stable stuff.

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