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Forum topic by BB1 posted 03-05-2018 01:44 AM 899 views 0 times favorited 16 replies Add to Favorites Watch
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BB1

1151 posts in 870 days


03-05-2018 01:44 AM

My husband has some pieces of cedar that he has turned some nice projects from. One area that he is having some problems is cracking of some of the wood. The problem occurs during and before use. The wood was cut a number of years ago. The question is how to stop the cracking from occurring. Would placing a piece that he has started to turn in a brown paper bag with some of the cedar chips be helpful or is this a situation where some type of sealer should be applied. This is an example


16 replies so far

View Wildwood's profile

Wildwood

2322 posts in 2157 days


#1 posted 03-05-2018 11:27 AM

Same thing has happened to me with woods from cedar species wood left unsealed along sap wood after couple years. Yes wood seemed dry or at EMC, but forgot wood absorbs and loses moisture content through out it’s life. Wood dries from outside in, (sap wood to heart wood), If there is a moisture imbalance will see cracking or splitting along the sap wood.

Good news is the heart wood still salvageable by cutting or turning away the sap wood past any cracking. You will have a skinier turning blank.

This has happen to me with other species of wood too thought was at EMC and didn’t reseal. Just not as much as cedar. Have also gotten away not resealing too!

I end seal my blanks using caning wax. Have a hot plate to melt the wax in a pot or frying pan and just dip each end in the melted wax. Use Gulf caning wax available at most grocery stores. Pot and frying pan old and ready for the trash. Have also used latex paint to end seal but prefer the wax.

-- Bill

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BB1

1151 posts in 870 days


#2 posted 03-05-2018 12:17 PM

Thanks Bill -I’ve passed along that information to my husband. The cedar is really pretty so hoping to salvage some for a few more projects.

View OSU55's profile

OSU55

1694 posts in 2011 days


#3 posted 03-05-2018 12:48 PM

Producr named Anchorseal can also be used as a sealer. Its a water based “liquid wax” that doesnt require heating. Seal the ends of logs.

Yes for the paper bag. I rough turn green wood (a log years old is still green), put in a heavy brown paper bag or wrap in brown kraft paper if too big, with handfuls of wet chips, tape closed, use a scale rated to about 5-10lbs to weigh the package, write wt on it, put it on wire shelves in the house to let dry. The paper acts as a vapor barrier to limit evaporation and prevent cracking (doesnt always work). Weigh the pkg occassionally. When it stops losing wt for a week its done. Depending on how green and size it can be one to several months. The rule of thumb is rough turn to 10% dia. This allows stock to be able to remove warping. Its worked well for me but I havent turned cedar.

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BB1

1151 posts in 870 days


#4 posted 03-05-2018 01:00 PM

Thanks OSU55 – I will pass this info along. Anchorseal sounds like a good option. I have only seen mention of sealing the ends. Would there be any value of sealing the “sides”?

View Lazyman's profile

Lazyman

2038 posts in 1409 days


#5 posted 03-05-2018 01:47 PM

One problem with Anchorseal is that it is a little pricey. A technique that I have been wanting to try is using detergent to prevent the cracking. See here. and here. Supposedly, this helps tremendously to reduce cracking when turning bowls at least, actually makes turning easier, doesn’t affect finishing and best of all is cheap.

Some cracking like that is mostly inevitable and some types of wood are worse than others. This happens because the wood shrinks as it loses moisture (more quickly from the ends BTW) and the only way to relieve the pressure is for it to split, usually in a radial pattern. The key is that you want to slow down the drying process. Sealing the ends as mentioned by others will help but may not prevent it completely. How you deal with it depends a little on what you are planning to turn. You will generally have less cracking if you can remove the center (aka the pith or juvenile wood) from the log or blank because it is more prone to crack because it usually shrinks faster than the mature wood. In some cases you can minimize the cracking by rough turning as soon as possible when green and then storing in a paper bag or cardboard box with the shavings from that turning. This is especially true if you are hollowing a vessel or bowl. It usually takes 3- 6 months but weighing is the only way to know if it has stopped losing moisture. You may want to sort of fluff up the shavings every week or two to prevent them from mildewing.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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Ripper70

1020 posts in 931 days


#6 posted 03-05-2018 02:45 PM


See here. and here.
- Lazyman

This is the kind of great information that you could live your whole life, wandering cluelessly about, and never stumble upon. Thank you for posting this.

-- "You know, I'm such a great driver, it's incomprehensible that they took my license away." --Vince Ricardo

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OSU55

1694 posts in 2011 days


#7 posted 03-05-2018 02:45 PM


Anchorseal sounds like a good option. I have only seen mention of sealing the ends. Would there be any value of sealing the “sides”?

- BB1


If the log has bark, no. I leave the bark on until Im ready to cut it into blanks. I usually leave bark on the blanks and turn it off. Ive had good luck putting the blanks in a plastic trash bag to eliminate evaporation until I rough turn them. Some end up in there for several months. Yes they can mildew some but it gets turned off. I dont tie the bag, just let the end fall closed. I rumage around and move the pcs every month or so in the bag so that probably helps.

Anchorseal is about $30/gal on ebay, and that gal will probably last several years. There are other similar products – search for green wood sealer.

View TheDane's profile

TheDane

5439 posts in 3685 days


#8 posted 03-05-2018 04:18 PM

Another option for sealing logs is PVA drywall primer.

You can get it for about $10 a gallon at the big box.

I put 2 coats on.

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

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LesB

1748 posts in 3465 days


#9 posted 03-05-2018 05:37 PM

I’m surprised that there was cracking on wood that was dried “for several years”. Was it stored outside?
I’m intrigued with the idea of using a detergent soak and may give it a try.

I have had good success with microwaving turnings while they are still in the rough turned stage. This method also uses the brown paper bag trick and works like a steam kiln with the microwave generating heat internally in the wood to drive the moisture to the surface. The paper bag contains the “steam” or water vapor so the stress between the interior of the wood and the exterior are more closely balanced. I usually microwave the wood until it is almost too hot to hold then let it cool (in the closed bag) and repeat as many times as needed to dry the wood. Let it stabilize in the bag for a few days. During this process I check regularly for cracks and if I see small ones developing I treat them with medium CA glue which usually stops their expansion.

-- Les B, Oregon

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BB1

1151 posts in 870 days


#10 posted 03-06-2018 12:45 AM

Thank you to everyone for the additional options to try. Passing this info along to my husband who is the one working with the lathe. The logs/branches were stored outside and then were cut into manageable lengths. The wood was not fresh cut when turned (my understanding was the tree was cut years ago). I’m guessing sealing as soon as possible after the wood is cut is ideal for in the future. Thanks again for all the insights.

View Wildwood's profile

Wildwood

2322 posts in 2157 days


#11 posted 03-06-2018 11:21 AM

Had same problem pieces of cedar stored under my work bench in my shop unsealed for couple of years. That same batch of cedar already couple of years old before started turning Xmas ornaments. That’s why didn’t bother to reseal ends.

Most woodturners of do not usually end seal after turning unless dealing with really wet wood. I never seal rough turned bowl blanks and hardly ever end seal a spindle blank. Have a couple different speice of spindle blanks stored under my work bench end sealed and not.

End sealing isn’t always going to guard against drying defects! Doesn’t matter what product you use to end seal. Splits along sap wood isn’t that bad if hasn’t started deep cracks in the heart wood you can still salvage something. Might be able cut away minor end checking if left blank little long.

End sealing only slows down the drying process doesn’t stop it! If dip a turning blank completely in wax you will! Vendors selling wood usually buy their blanks completely sealed in wax and sell it that way and have no idea of MC. We have no idea of MC of those blanks before processors dip in wax. Completey sealing turning blanks in wax stops water vapor transfer regardless of temperture or humidity that why its done.

Storing rough turnings in paper, plastic bags, or carboard boxes with or without shavings has its place in woodturning. None of those procedures are foolproof in preventing drying defects or mold growth. Lot depends upon where you live, time of year, wood species, temperature & humidity.

-- Bill

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BB1

1151 posts in 870 days


#12 posted 03-14-2018 04:22 PM

Followup question…would shellac on the ends (for logs with bark still on) be of any value? I’m guessing not…

View Steve Peterson's profile

Steve Peterson

377 posts in 3104 days


#13 posted 03-14-2018 04:49 PM

The picture shown in the original post shows a section of the center of a log including the pith. This is almost guaranteed to crack because of the way the wood shrinks as it dries. Anchorseal or brown paper bags can slow down the shrinking, but they do not eliminate it.

All wood species shrink less between the growth rings (tangentially or tangent to the rings) and more around the rings (radially or along the radius). This is why you will often see cracks in the end of a log that look like someone was cutting pizza slices. The cracks in the photo are typical of normal shrinkage while drying.

If your husband can split the wood down the center and seal the ends, the wood might be able to continue drying slowly without cracking. The other option is to rough turn the shape oversized while it is green and finish it 6 months later. Look up “twice turned bowls” as an example.

-- Steve

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BB1

1151 posts in 870 days


#14 posted 03-14-2018 05:22 PM

Thanks. He picked these up from a friend. Couple of cedar and walnut. The walnut was cut about a month ago. Trying to prevent cracks in that walnut – looks like it should be interesting turning


The picture shown in the original post shows a section of the center of a log including the pith. This is almost guaranteed to crack because of the way the wood shrinks as it dries. Anchorseal or brown paper bags can slow down the shrinking, but they do not eliminate it.

All wood species shrink less between the growth rings (tangentially or tangent to the rings) and more around the rings (radially or along the radius). This is why you will often see cracks in the end of a log that look like someone was cutting pizza slices. The cracks in the photo are typical of normal shrinkage while drying.

If your husband can split the wood down the center and seal the ends, the wood might be able to continue drying slowly without cracking. The other option is to rough turn the shape oversized while it is green and finish it 6 months later. Look up “twice turned bowls” as an example.

- Steve Peterson


View Wildwood's profile

Wildwood

2322 posts in 2157 days


#15 posted 03-14-2018 07:34 PM

Have to learn how to read a log. Not every log will give large bowl blank, so have think about some smaller bowls or spindle turning too as process a log.

The pith doesn’t always run straight thru the log. In top left log looks like the pith is off set, so splitting down the middle won’t work. While won’t hurt to split the log want to remove as much as pith as you can.

After a month would not be surprised to see some end checking in ends of log. If split your logs and remove the pith & any end checking; would end seal to slow down the drying process.

Removing the bark helps prevent insect infestation & some rot. Have done it both ways (bark on/off). Have turned away live larva and sometimes leave their home they laid in as decoration or simply turn away.

-- Bill

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