cracks in logs

[mick59wests]

I got some cedar logs with the intention of using them primarily for bowls. However, even after cutting off a couple of inches there are still many cracks - some in the centre, some on the outside and some both.

What I have currently done is painted the ends. I have a few questions:
Is it worth even painting/sealing the ends when there are still cracks? I just wanted to get them stored so I can later deal with them one at a time.

Where there are cracks in the centre (but not going through to the edges), I figure if I split the log down the worst of the cracks and make this the top of the bowl (ie: a standard bowl - not a live edge one) then I effectively turn out the cracks. For these areas I was thinking of using a forstner bit as much as possible before any gouges.

Where the cracks are around the edges I am thinking I can turn a live centre bowl but am a bit worried about using my gouges on the cracks.

Or do I need to get to completely crack free before turning?

Perhaps what i really have is firewood :weeping2:

Any help/thoughts/suggestions most appreciated.

thanks in advance

Mick

[tea lady]

Usually the logs need to be split in half for drying to relieve the stresses. WHat you say about turning away the cracks is right. I'm doing that currently with some birch logs I got. Green turning them to rough shape then letting them dry before finishing! :cool:

[mick59wests]

TL,

thanks for that. I'm still worried about the cracks on the outside of the wood and trying to turn them out - nice and slowly I am guessing

cheers

Mick

[TTIT]

It all depends on how deep the cracks are Mick. If they are only just through the sapwood ,as long as you mount the blank securely just turn the sapwood away until you're happy with what's left. If the cracks go well into the heartwood or right into the pith, it is probably best to split the log along the cracks and work with what is left - eg: spindles!
As you're sealing the ends I'm assuming the logs are still green in which case you really should split them in half anyway to minimise any further cracking. Cracks in the centre of the log are a sign of a timber that will need splitting in half or even quarters if you want anything useable left once it dries. Hope this helps :shrug:

[orraloon]

Mick
We all have trouble with drying wood. Some woods are better than others but general rule is cut the log down and remove the center pith or hart. Do this as soon as you can after tree is cut down. In hot weather this is as soon as tree is cut down. As wood shrinks a log in the round will crack somewhere. Sapwood will shrink faster than the hard wood center of the log. The actual center is also a main source of cracking so should be removed as soon as possable.Around the Woods: Contents (http://aroundthewoods.com/contents.html)
This bloke shows how to cut turning blanks and there are many others on line.
Even doing all the things as listed wood is a natural material and so we somtimes end up with the bits between the cracks and a new plan for turning them.
Regards
John

[mick59wests]

thanks very much for the tips and help. I am glad to see the tips were consistent so I was not confused even further. Looks like its back to the chainsaw for me to start splitting the logs ASAP. In my previous readings I had learnt about sealing the ends but not about splitting the wood.:2tsup: Also thanks for that link - I had not seen that site before.:2tsup::2tsup::2tsup::2tsup:
cheers
Mick

[Paul39]

A couple of splitting wedges and a 3 or 5 pound hammer will quickly split most wood.
Start the wedge in the biggest crack.

If you have a crotch and want to use the feathery grain, cutting through the center of the three piths with a saw is necessary.

[mick59wests]

I spent most of the morning splitting logs and re-sealing the ends where I had cut the logs.

A question on sealing - now that I have split the logs, assuming I am not going to get around to rought turning for many months (at least for some) do I need to seal the exposed long-grain? They will be kept out of direct sun and rain.

thanks again

Mick

[BobL]

A question on sealing - now that I have split the logs, assuming I am not going to get around to rought turning for many months (at least for some) do I need to seal the exposed long-grain?

No.

[rsser]

Agree. Sealing the end-grain is the most important. And 25mm or so up the long grain.

Use a dedicated product for this (emulsified wax), not just paint. Double coating as soon as poss. after cutting.

Best of all is to turn the half logs exc. pith into octagons with the CS and then rough turn them on the lathe. Wall thickness about 1/10th of the diameter. Then seal the end-grain with dedicated sealer. If you don't have that, put all the rough turned bowls into a cardboard box or a big plakky bag with plenty of shavings. Check progress every couple of days. But the risk there is with fungal infection.

You can get end-grain sealer mail order from The WOODSMITH Pty Ltd Home Page,Woodturning Supplies, Woodturning Timber, Woodturning Tools, Woodturning Accessories, Woodcarvers Supplies (http://www.thewoodsmith.com.au/thewoodsmith/)

HTH.

[BobL]

I know turners don't usually use much end grain sealer but as I use it by the gallon I've found it is very easy to make my own using a parafin wax house candles and turps. The proportion of each depends on the size of the candles but I use about 1 candle per litre of turps. Melt the wax in a large sauce pan, mix in the turps, let cool, and bottle. When it cools it eventually does sort of gel into a large blob but a 30 second shake gets it mixed up again.

Safety tip - for a heat source I use an old electric frying pan and place another 5L saucepan inside that.

Cost works out to about $3/L

[rsser]

Thanks for the recipe Bob.

I actually use a lot of paraffin wax, plain (without stearate) and bought in bulk, in an electric frypan. In my book this is more reliable than commercial end-grain sealer but you can't treat big lumps this way and is a bit more of a fiddle.

Mail order source: click (http://www.australianwaxco.com.au/)

I've experimented with adding some beeswax to this in small proportions, to improve adherence/flexibility and it hasn't helped.

No connection etc.

[mick59wests]

Ern and Bob,
interesting about you both strongly recommending a proper end-grain sealer. I have very limited experience but a number of sources say paint will do. I do double coating on each end.

Perhaps this should be a separate thread, although it is still related to cracks in the wood. I'd be interested what others do and how much better using a proper sealer is. Also, if others seal the end-grain on rough turned bowls as I do not remember seeing this written before.

cheers

Mick

[rsser]

1. No, paint won't do. It's designed for a very different purpose.

2. Google sealer, blanks, bowls, rough turned, end grain. There will be plenty to read.

[BobL]

I also use paint, when 20 logs come into the milling yard and I know it will take me 6 months to get around to milling them there is no way I'm shelling out for 20 logs worth of end sealer. Paint is less effective because it does not penetrate as far as the turps/wax mix. On the other hand the paint dries hard so very little will stick to it, unlike the wax which will pick up grit and small rocks when the logs are moved around the milling yard. What I do in that case is dock off the first 100 mm or so of the log before milling. There is another good reason for doing that on some logs in that the ends become case hardened within a few months of felling and the destroy most of the effort put into sharpening a chainsaw.

In a few cases where the length of the piece was critical and a few cracks penetrate into the required length of piece I'd much rather be dealing with wax than paint.

Anyway now that I have the home made end sealer recipe working I'm fairly happy with it. I looked around for cheap sources of parafin wax (bees wax is generally more expensive) and unless one buys at least some 10s of kg at a time I haven't been able to find it for less than about $6/kg. For kg amounts the unit price of the wax is less than the unit price of the turps so buying turps in bulk would be the first thing to focus if one wished to save money.

[rsser]

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]

..........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!


........... 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 :U

[rsser]

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]

In pottery we cut the wax with kero or diesel. For brush on resist. Prolly work for sealling ends as well. :shrug: Proportions are terribly unscientific. :U

[dai sensei]

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]

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]

.............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 :U

[dai sensei]

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