Slowing down drying of green wood

[Prashun Patel]

Does anyone use a washcoat of shellac or varnish on their green rough turned bowls to allow them to dry at a more even (albeit slow) pace after roughing?

I read a lot about packing pieces in shavings or paper bags, but never this...

[Steve Schlumpf]

Shawn - I have not tried it, so have nothing to back this up - but the idea of drying a green bowl is to slow down the drying process. I would be afraid that the shellac or varnish would seal the wood and trap the water inside instead of allowing it to escape slowly. As mentioned - nothing to back it up - just a hunch.

Plus - putting those finishes on green wood - it may be a challenge just getting the finishes to cure/dry. Could turn into a gummy mess.

[Prashun Patel]

Shawn - I have not tried it, so have nothing to back this up - but the idea of drying a green bowl is to slow down the drying process. I would be afraid that the shellac or varnish would seal the wood and trap the water inside instead of allowing it to escape slowly. As mentioned - nothing to back it up - just a hunch.

Plus - putting those finishes on green wood - it may be a challenge just getting the finishes to cure/dry. Could turn into a gummy mess.

I'm talking about something like shellac, which could be washed way down. It's basically the equivalent of a prestain conditioner, which partially seals the pores - but not so much that a stain can't absorb.

[Wally Dickerman]

Why not use a commercial wood sealer which is made to seal wood and still allows it to dry at a slower rate. When you buy turning blanks from wood dealers they are nearly always sealed with a sealer. Most woodworkers stores such as Woodcraft stock the sealer. When I cut blanks I always apply sealer at least to the end grain. I seldom have trouble with cracking wood. Using other products with the hope that they might work just doesn't make sense to me.

Wally

[Bob Bergstrom]

I would suspect shellac would suffer the same faith it does it the flat world when exposed to moisture. It is my opinion that the shellac will fail. It may slow down the evaporation process but not near as effective as wood sealer. A paper bag would probably be better.

[Prashun Patel]

Thanks, All. That's why I posted here!

[Bernie Weishapl]

I have to agree with the others. I would think shellac or varnish would seal the wood to good not allowing it to dry at all and if you wash it down it would dry way to fast with cracking. I have never seen a blank or purchased a blank sealed with either. All I have ever seen is wax or anchorseal used. Maybe latex paint in a pinch.

[Reed Gray]

I have used Deftoil Danish oil on some Madrone hollow forms that I wanted to shrink, and warp and would not be able to sand after without removing all the crinkles. It took it longer to dry, but it is a penetrating oil, not a surface finish. I also used some old oil finish to end seal some logs. Seemed to work fine. I would be doubtful that a surface finish would work well.

robo hippy

[Leo Van Der Loo]

I'm talking about something like shellac, which could be washed way down. It's basically the equivalent of a prestain conditioner, which partially seals the pores - but not so much that a stain can't absorb.

Shawn
A nicely controlled kiln would work best, but I can't afford one, so my Brown Paper Bag kiln is what I use, not a real kiln maybe, but it works with the same principles.

The green turned bowl is put into the BPB (Brown Paper Bag) and closed, nothing else added.
The bowl will start drying and the air inside the bag will get saturated with moisture from the bowl, at which point the drying would stop, but now the BPB will absorb some of the moisture of the air inside the BPB, so the bowl can again loose a bit of moisture.

Now the air around the BPB will absorb moisture from the BPB, and the BPB will again absorb moisture from the air inside the BPB, and again the bowl will be able to loose some moisture, and so it continues until the air inside the BPB is equal to the air outside the BPB.

And now here's the problem, if you live in a hot and dry place this process of drying will go faster than if you live in a cool and damp place, or I should say the place where you keep the BPB
For me this is fine inside my home in the summer (no AC) but not in the winter as the air gets pretty dry and the whole house stays warm.

So if you can keep that BPB at a cool place without a draft then you have a good working kiln, I have always used this system, tried a few of those to good to believe other ones and come back to this every time, as I haven't found anything else that works better, short of a real kiln.

It is maybe too simple for some, or too slow for others, but it works for me