Knowledge You Can Build On — Est. 1998
Cracking problem
Alan Tolchinsky
>Hi All,
This is my first attempt at hollowing a piece of green maple branch. None too surprised it cracked the next day. I say none too surprised because I didn't treat this green wood after turning.
So I ask you: how do you treat these? Just like bowls made from green wood? I also turned a weed pot and so far that's been o.k. Thanks for any tips on this. Alan
Re: Cracking problem
John D Williams -oubaasjohn
>I don not think of this as green wood, wet perhaps but when it is as heavily spalted as this the tree was pretty long past its green stage. Spalted maple seems to work quite well when partly turned and then left to dry slowly (in shavings or in a paper bag or cardboard box to keep drafts off) Or alternatively it can be microwave dried. The crack also looks like it may have been caused by the bottom half shrinking more than the lid which fit inside? Another reason to partially dry before final turning the dry wood.
Re: Cracking problem
Brad Vietje
>Alan,
Making boxes from green, or unseasoned wood will require roughing out top and bottom pieces, drying them for a number of weeks - months, then re-mounting for finish turning. This is especially true for boxes with close fitting lids. Richard Raffan's box turning book covers this some, but the usual rules for drying wood carefully apply.
You are also swimming upstream a bit with branch wood, unless a vertical branch, because they tend to shrink unevenly on top and bottom side of the pith (tension wood vs. compression wood). Aslo if you are turning with the pith running through the piece, you are far more likely to get cracks. The only factor working in your favor is that spalted wood is somewhat weaker than sound (fresh) wood, but most Maples spalt unevenly, so some areas will have all the strength (and shrinkage) as the real sound wood.
I have had great success hollowing out branch wood for ornaments, but I drill the pith out, and once dry, I true up the globe, then attach a piece of contrasting wood to either end. Basically, for boxes, you'll have better luck with the entire blank on one side of the pith.
Safe spinning,
Brad Vietje
Thetford, VT
Thanks guys, appreciate it. I'll try again.
Alan Tolchinsky
>
Re: Thanks guys, appreciate it. I'll try again.
RonZ
>You could use black CA or blacken some epoxy and it should save this one.
