i have not dune alot of work for a long time the wood sculptors i have dun in the past ar very small mostly worked in local stone . i have aquired 4 logs of douglas fir and 1 large log of willow i dont know if they ar any good for carving i have never tried anything this size before 20in across and 4 ft high i dont have a carving saw no cash. one question i wont be.able to finish a piece in one go is there any thing i have to du to the half finished piece. like sealing it to stop it cracking before i return to finish it or will it be ok hope you can help thank you tony
Many things to consider. Wood Species, Green or Cured, Temperature and Humidity level, will it be stored indoors or outside between carving sessions, etc.
First of all I can not speak from experience using the particular species you mentioned, but I'm sure someone will. Myself, I carve a lot of ERC (eastern red cedar), walnut, cottonwood, and elm. But all logs, no matter what species will eventually check, or crack from ring shrinkage. Here's is a very good article about moisture movement in wood as it dries.
http://www.woodweb.com/knowledge_base/Ive_Got_that_Shrinking_Feeling.html
Each situation will dictate the level of protection that you would want to give an unfinished carving.
This is how I evaluate when carving freshly cut logs:
High temperatures an lower humidities= fast drying= quick cracking
this would call for a high level of protection especially if outdoors and exposed to the sun.
short periods--- a wet burlap covering over the entire carving or wrap it in plastic to help retain its moisture. this doesn't work well for long periods because the burlap will dry out fast and need to be soaked down again and the plastic can hasten the growth of mold.
longer periods= get it in the shade if at all possible and if the carving is only a blocked out version and you still need to remove large quantities of wood then you can apply a coat of poly or similar to lock the grain to prevent rapid drying of the outer layers. It will carve right away when you start up again and doesn't soak in very far. This works very well but can be a bit expensive with a large carving.
When carving even a so called cured log there will still be a large amount of moisture that will exit the wood once it it peeled of the bark. Hence there will still be some shrinkage and degrade but on a much smaller scale than with a freshly cut log.
Other pros and cons are green wood is easier and faster to carve and your chain will stay sharp longer. Dry, cured logs are a little harder to carve, take longer and will dull your chain faster.
Note: I always put a relief cut in the back of any sculptures that I do if it has a base where I have removed none of the layers of growth rings.
It will prevent the inevitable checking from taking place in the front and of course you can't see it in the presentation side of the sculpture.
Hope some of that helps you out and be sure to post up some pics of you work on this thread-
http://www.arboristsite.com/showthread.php?t=121402- when you get around to it!
