Has anyone used paper bag drying technique?

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Forum topic by UncleDave posted 02-26-2015 05:25 PM 886 views 0 times favorited 9 replies Add to Favorites Watch
View UncleDave's profile


36 posts in 607 days

02-26-2015 05:25 PM

Topic tags/keywords: drying turning bag maple

This is my first post to Lumber Jocks.

I have had some experience with green wood, and when working with it I had major problems with cracking. Currently I have a large maple bowl blank that came with wax on it. I removed the wax except for the coating on the end grain, but it started to check a little bit almost overnight. So I put this Anchor Seal stuff on it to help prevent further checking.

I’ve done some looking and obviously the best option for properly drying pieces is to just be patient and let time do its thing. Of course the problem is that waiting a year or two for a piece to be ready just stinks.

So I did some looking and found this link with information about drying pieces in paper bags.

Based on the page, it looks like this should be a good way to dry the wood that will help prevent major stresses and let the wood dry evenly. But I’m just looking for feedback from others if they’ve tried it.

- Has anyone roughed a bowl to bag dry themselves?
- Did you have a problem with the piece cracking in the bag?
- How long did you wait for the piece to reach EMC?

Any other insights or comments regarding this are welcome!

9 replies so far

View pjones46's profile


986 posts in 2063 days

#1 posted 02-26-2015 05:46 PM

Very interesting. I have never heard of this method but it makes some sense. Hope others who have experience with this method comment on the process.

-- Respectfully, Paul

View TerryDowning's profile


1052 posts in 1537 days

#2 posted 02-26-2015 05:53 PM

I use the paper bag method for drying rough blanks. It works for me (There is some loss due to cracking though.)

The trick is to keep the wall thickness at about 10% of the diameter. 10” bowl = 1 inch wall thickness. This allows for warping and shrinkage and provides enough mass/material to turn to final shape when dry.

I place mine in the bag with the shavings from the rough out process. the shavings and paper bag slow the drying process enough to reduce checking. Write the date and weight on the bag and put it on the shelf. Each month, weigh and and mark the date and weight. When the weight stays the same, for 2 weigh ins, it’s ready for final turning.

My last few bowls I turned the green wood to final shape and wall thickness and let nature takes it’s course. I just flattened the bottom after a couple of weeks to stop the bowl from rocking.

This was my last one.
Click for details

-- - Terry

View Tennessee's profile


2410 posts in 1934 days

#3 posted 02-26-2015 06:07 PM

I’ve used the paper bag thing before. Terry is exactly right when he adds the shavings. They not only slow down the drying a bit more, they will absorb some of the moisture from the larger piece.

-- Paul, Tennessee,

View LeeMills's profile


268 posts in 721 days

#4 posted 02-26-2015 06:26 PM

I use a combination of DNA and bagging. I soak in DNA first, allow the most DNA to flash off (about 30 minutes) then coat the endgrain and then into a bag. Of course this is for roughed out turnings, not whole blanks. I do use a pin type moisture meter and just push it into the foot (never had to hammer it in as the article stated). Equilibrium where I live is 12-14% so anything lower than 15% I consider ready. I do try to remember to bring them into the house for a couple of weeks where it lower than the shop before the final turning.
If you have a whole blank, and like it sounds like you did, don’t leave it unprotected. If stopping for lunch hour wrap a plastic bag around it. If you are not sure how long it will be go ahead and recoat the endgrain.
I have had new cut logs start cracking on the ends in a 20 minute drive.

Starting about page six is an equilibrium chart for most any area of the country. If you live in a very dry area you may need to coat the entire roughout. Some folks can use shavings in the bag but for me they promote mold.
I still get up to 10% that develop a crack but that depends on the wood. For me holly is the worst, for you it may be a different species of wood.

-- We cannot solve our problems with the same thinking we used when we created them. Albert Einstein

View TheDane's profile


4934 posts in 3083 days

#5 posted 02-26-2015 06:37 PM

- Has anyone roughed a bowl to bag dry themselves?
Yes. Quite often … sometimes I use a cardboard box instead of a bag. The box is slower, but can I stack them on a shelf in my storage room.

- Did you have a problem with the piece cracking in the bag?
In a few cases where I got impatient and finish-turned them too soon. I check the moisture content every week or so and write it down on the outside of the bag/box. I also fluff the shavings when I check MC and leave the bag/box open for an hour or so before I close it up.

- How long did you wait for the piece to reach EMC?
Depends on the moisture content of the wood, size of the piece, etc. There is no good answer to this other than to keep checking it.

Unsolicited advice: If your rough-turned piece has a tenon on it, put a steel band-clamp (plumbing department) on it and keep tightening it during the drying process. It will reduce the chances of the tenon cracking and warping.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View gwilki's profile


119 posts in 893 days

#6 posted 02-26-2015 06:58 PM

Like the others, I do this with all my twice turned bowls. I do not add shavings to the bag, though. In my case the shavings are very wet – dripping sometimes – and they have caused mould on my blanks. The mould turns off, but they also mean the blank takes much longer to dry out. So, now, I simply coat the end grain with sealer so that the end grain and the side grain lose moisture at a more even rate. I use the weight method to determine when the blank has lost all the water it is going to. I have good luck with this. Some woods/blanks are going to crack no matter what you do, but the bag method gives you good odds. In my climate and my basement shop, the average time to “dry” is 6 months.

-- Grant Wilkinson, Ottawa ON

View Nubsnstubs's profile


810 posts in 1150 days

#7 posted 02-26-2015 07:21 PM

You’ve gotten good advise. The only thing I can add is wood species varies with what happens during drying. If you think you’re going to match up a lid with your green wood bowl, box or other object, don’t bother because it will warp differently than the bowl. Give both that 10% thickness mentioned earlier. .............. Jerry (in Tucson)

-- Jerry (in Tucson)

View UncleDave's profile


36 posts in 607 days

#8 posted 02-27-2015 01:31 AM

Thanks for all of the feedback folks. Lots of useful information. Too bad I didn’t gain any patience :)

I’ll be turning this piece to rough size within the next week or so and then I’ll toss it in a paper bag using the 10% rule as mentioned by Terry Downing. I have a small piece of olive wood that I bought wet the other day. I turned it to a spindle and now have it drying in a bag of shavings. I’ll see how that goes. Thanks again everyone.

View Wildwood's profile


1850 posts in 1554 days

#9 posted 02-27-2015 02:02 PM

Yes, rough turning a bowl blank and putting it into a paper bag to slow down drying process is a viable solution. Already stated not entirely fool proof, so not really a set it and forget it procedure.

You want to check from time to time and remove the blank from the bag to allow for better air circulation at some point. When to remove blanks from a bag will come with experience with different species of wood.
Have done this for years only after rough turning to a uniform thickness first. I do not always bag rough blanks. Whether to bag not bag rough blanks depends upon time of year and how wet, and species of wood I am dealing with. Lot of times just rough turn and store blanks on the floor in back of my shop. I never put any sealer on rough turned blanks like some people.

You can improve drying wood procedure if get wood to turn locally if possible. Easiest way to find EMC is weigh bowl blank on a scale after rouging. When blank stops losing/gaining weight for week or two probably at EMC. This could take as little as three months depending upon species & density of the wood to almost six to nine months.

An inexpensive moisture meter will also get you in the ball park.

-- Bill

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