Woodturning Crack repair

KPG

Hi Guys,
What do you find is the best for repairing cracks in rough turned wood?:mad:

What is the best way to turning green wood or wood that has been lying around for a few months? I have a lad of cherry that was stored in a shed for over a year. I cut off the cracks in the end and rough turned a piece which proceeded to split badly:mad: :mad: Any suggestions?


KP

geofftulip

hi there,
there are many different methods used in drying out timber for turning, microwave, alcohol or soap soaking or traditional roughing out and air drying - which is my preferred method. for me it is the least time consumming and has a high yield of success - around 95% for me. the other methods are fine but take more time away from turning. It takes a bit of time to build up a stock of drying timber but once you have you can simply pick which piece you want to finish next and hammer or chip away..
there are a few things to consider apart from this :
1. the species of wood - some woods have a higher chance of splitting due to the difference in logituindal and tangential drying - unfortunately for you cherry and oak are some of the worst.
2. the way you process you timber - you must cut and process your blanks correctly to have high success rates. remove the pith, stay away from branches (unless you want natural forms)- by looking at the piece of wood you should be able to suggest its probability of splitting.
3. remember that splits open and close in wood - ie the splits can be already there just 'closed' when you turned it. look out for fractures from storm damaged trees etc - the fractures can cause splits well up the tree.
4. seal your wood after you have cut it

if you wish further info email me or call up to my workshop - i also offer a timber conversion course for those interested in processing their own blanks - check it out
www.geocities.com/tulipwoodcrafts

KPG

Thanks for that. Guess what wood I have the most of (Cherry and Yew):rolleyes: The problem I have I just don't have enough dried wood.
By the way I like the site the gallery has some lovely work in it !

Alun

Yew is usually pretty good when it comes to drying, but cherry, or any other fruit wood for that matter such as apple or pear will crack as soon as you look at it

If you're going to go down the route of first roughing out bowls from green, or nearly green, wood and then drying then you must take the precaution of sealing the exposed end grain to prevent too rapid drying which is the main cause of cracks. You can get special stuff for this, Anchorseal or Chesnut End-Grain Sealer, or if you're stuck either watered down PVA glue or latex based emulsion paint.

Minor, and I must stress minor, cracks that only get uncovered during turning can be repaired with CA glue (superglue), possibly with the addition of some sawdust / fine shavings from the wood itself. You can get this in several different consistencies from ultra-runny to thick from woodturning suppliers (don't bother with the titchy little bottles of superglue from DIY stores).

KPG

I think one place I'm going wrong is that I don't have a Bandsaw and roughing pieces is generating too much heat on the wood. How long have you found it takes to dry out Yew in a shed say before you could be in a position to turn it say 8" by 4" rounds?

Alun

The vast majority of the Yew I use is branchwood for making small items such as boxes. Irish Yew doesn't tend to grow into large trees, but is more like an overgrown bush, so large pieces aren't that common. Yew is also very prone to "heat checking", tiny, almost invisible surface cracks, but this is usually only an issue when sanding where you have to be pretty careful not to build up too much heat.

I normally get most of my bigger Yew pieces either as fully kiln-dried blanks or rough blanks (usually from Geoff!), so I've no real experience of drying large-ish Yew pieces from green. Maybe Geoff could give some figures?

KPG

OK Thanks for the advice. Back to the drawing board!:D

geofftulip

yew is alot easier to dry than cherry but the same applies for both - for branchwood which i think you have make sure you seal the ends as suggested with something suitable (wax or pva are my choice). i take it you are planning on doing spindle work with your wood.
for most timbers in our climate air drying outside and under cover from the sun (allowing for air flow) - the rough guide is 1" per year so your 4" diameter logs should take 4 years. however this in practice this seems a bit long, and bu keeping the timber indoors in a dry airing shed the time can be reduced to apprx 1 year. this seems a long time but these are the joys of woodturning - if you are drying traditionally like me then you find 50% of your time is cutting , collecting or sealing timber and it takes up a bit of space. if you dont have any dry timber then collect more and dry more eventually you will have a pile od drying stuff to select from. if you dont have the space - go on tghe scrounge from joinery shops etc who will give or sell you their offcuts of mahoganny, cherry, elm etc - not great sizes of pieces and with no real exciting grain but it is cheap and kiln dried.
for your yew branches - if you have enough experiment with a microwave - set to defrost and give 30 sec at a time - if you can weigh them until there is no real difference in weight then you know when they are dry.
yew tends to split a few cms through the sap wood especially when the bark is missing but it should stop shortly after it reaches the 'red' wood.
cherry is simply hit or miss - it will dry perfectly or you will loose the lot - it sometime depends on the time of year or the species of cherry etc - not always your fault !!
for branchwood and spindle turning it is not always necessary to be completly dry - i have turned yew 12" diameter spindles which have dried for a few years - they are dry on the turning surface but deep in the heart still damp - it simpply didnt matter when making the lamp....

good luck
try visiting a few local turners and see what their set is for timber drying and storage

KPG

thanks Geoff loads of food for thought! I'll start working on the Yew. Thanks again!