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Butternut sapwood, drying

Started by TBrown99, August 13, 2024, 11:29:20 AM

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TBrown99


My neighbor recently told me I could take some poplar logs on his property because he couldn't use them for firewood. Turns out it was butternut! Yeah!!! So excited. 

I starting milling it and unlike the two butternut I've milled in the past this one is perfectly healthy. 

I have a 3' crotch section which I milled as live edge pieces, as shown here.  1" and the section yielded 11 amazing pieces.

I've read that sap wood must be removed to avoid huge drying warping issues. I get it with normal boards but what about live edge butternut? (I understand that black walnut and black cherry require similar caution.) Should I band saw it out? 

jimF

dry them more slowly than regular boards, since they seem to have some end grain in the surface.  The sapwood should not cause problems, as black walnut is commonly dried with sapwood with no problem; the sapwood provide a nice contrast.

mudfarmer

Good score on the poplarnut  :thumbsup: I have only sawn a few, did have some cupping issues with live edge sapwood pieces. In the future maybe, try to saw stuff that will probably dry wonky fat enough that they can still hit target thickness after they dry and are mechanically flattened. 5/4 or 6/4 instead of 4/4 etc. It's already cut-Strap it to a pallet and put a lot of weight on top  ffsmiley
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jimF

Structurally, there is no difference between sapwood and heartwood.  The only differences are the amount of extractants. And these will not influence moisture absorption and therefore will not influence the shrinkage.
What would cause warpage is the ring angle, grain angle, any end grain in the surface and uneven airflow between the two surfaces.

YellowHammer

The effect is commonly called "sapwood pull" and there is a definite relationship between bow and cup with inclusion of sapwood in walnut and cherry, and yes, to a lesser extent, butternut.

The NHLA is very lax on the criteria for bow, and it is true that many boards sawn with the inclusion of sapwood meets the specs for these species, but the reality of it is that when trying to get extremely flat boards, well down into the 1/8" per 8' range, which is our criteria, inclusion of sapwood and the generally increased stress it contains, is usually the kiss of death for a perfectly flat board in some species.  Butternut is related to walnut, but much softer, has less strength, so the effect of sapwood is less.   However, it is there, and whenever I saw butternut live edge slabs from butternut, I expect there to be enough bow that I will have to cut them shorter to get them dead flat in terms of bow. 

For these species, the stress of sapwood is generally evident while sawing, and the effect of a full sapwood one face, full heartwood the opposite face will make a board bow up off the mill like a carrot peel.  These stresses follow the board through the drying stage and the board will have bow.  When sawing live edge, if the sapwood is not balanced, edge to edge, the stresses in the board will cause twist.

Anyway, I measured some of my live edge butternut kiln dried boards after reading this post, and all had bow and twist of at least 1/4" per 8 foot, well within NHLA standards, but only suitable for charcuterie boards and such, and not suitable to meet the specs of the the flat lumber I sell.  However, for the product, the level of flatness is adequate, as charcuterie boards are generally cut into short pieces. 

I have discussed this issue with some big and well known walnut producers and distributers in the country, and the general consensus is that yes, sapwood in these species generally has increased levels of stress when sawn, and that stress is in some cases amplified when drying, but sapwood inclusion in a board generally will not exceed NHLA standards and to remove it to get flatter wood simply reduces profit margin while still making grade.  As one mill told me "I make my margin on sapwood, and if I make grade, why would I remove it?"  Steaming also helps to reduce walnut bow, and will produce flatter walnut lumber than unsteamed walnut, all things being equal.  I have proven that to myself and others many times, over the years. 

Anyway, I routinely show the effects of reading stress and sapwood pull in cherry and walnut in my videos, real time, as I mill quite a bit of both, as well as buy from "real" walnut producers for the purposes of comparing sawing and drying techniques for increased quality.

All that being said, butternut is a fairly mild mannered wood, and the sapwood ring is generally pretty small, so sapwood pull is not unmanageable.  However, through sawing, bark to bark, will result in bow and "not flat" wood.

Here are a few pics. The first is of a not overly flat butternut, live edge, with maybe 1/4" bow, end to end.  The second is of a picture that another Forum member took many years, on the same subject, showing a typical result of sapwood inclusion on his cherry boards.  You can see how the all heartwood boards around it are very flat, many with similar and changing grain angles, and how the sapwood on the board really "pulled" and deformed the part of the board.  This is an extreme case, but clearly shows the discontinuity between the sapwood and heartwood interface.  At the time, I advised him to adjust his sawing techniques to eliminate sapwood and he reported remarkably flatter boards.  The post is somewhere here in the archives, I assume.   Although not shown in the picture, the part of the board that was heartwood both faces was flat, the only part of the board that cupped up was the sapwood edge.  This same sapwood pull that causes cup also causes face bow.

   

     
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

doc henderson

That is a phenomenal piece if you like rustic chaotic beautiful grain.  In general, you can do all you can do, but warping and cracking is somewhat in the hands of the wood Gods (not necessarily a reference to Robert ffcheesy).  Good luck.
Timber king 2000, 277c track loader, PJ 32 foot gooseneck, 1976 F700 state dump truck, JD 850 tractor.  2007 Chevy 3500HD dually, home built log splitter 18 horse 28 gpm with 5 inch cylinder and 32 inch split range with conveyor powered by a 12 volt tarp motor

jimF

extractants > extractives  Sorry, the grammer part of my brain was not working.

Yellowhammer; in the second picture I only observe cupping not bowing. This is a result of the inclusion of tangential and radial grain direction in a board, which is typical of any flatsawn lumber of any species close to the surface of the log. Not a function of sapwood inclusion.
The first picture I can not see close enough to comment.
You may interpret your observations as sapwood pull. I maintain inclusion of sapwood of itself does not cause any distortion.

jimF

Another factor that just came to my mind: often walnut and cherry and well as the butternut that was pictured above includes crotch wood or non vertically grown material.  These would include growth stresses which would have higher longitudinal shrinkage rates and therefore would distort off the saw and in the kiln. But again the cause is not sapwood inclusion.

TBrown99

Wow! Thank you for the many thoughtful responses. Awesome!

As I process these pieces, which have been sitting stickered inside with a fan trained on them for a couple days, they are already snowing signs of mold... small blackish-blue spots. Mild temps in Vermont now though a bit humid. They were quite wet as I hosed them off to take photos but stickered immediately. Others from a smaller sample cut as straight lumber and simply leaned on a wall for a week show no mold. Perhaps my 3/4" stickers are too narrow. Or maybe it's just from initial water oversaturation. Not sure if I should be concerned.   

I expect that the problem is due to stickering it in semi-humid conditions before the surface moisture has dissipated, ie. very soon after milling. So, perhaps it's always best, except during winter or cold periods, to let sit a day or two depending on conditions, semi-shady area with breeze.





jimF

TBrown99; it certainly depends on the weather and species. i would never let oak, beech or sycamore sit in the sun and breeze immediately after slicing boards. They will check very badly. Many mills destroy their lumber by stacking off the green chain onto a cart in the sun open to the breeze. The time involved going from one cart to another to sort the boards or the stacker stops and helps someone else is enough time to start surface checks.
I was at one operation that had this setup and the boards were badly checks but the owner did not want to hear any of it.  To make matters worst, they pumped the steam into the kiln to initially get the temperature up causeing the surface to swell and enlarging the surface checks.

The first day of two protect any species. Than let the breeze go to it. This is the purpose of shade-cloth. The high humidity and initially wetting the surface certainly set you up for problems. One inch stickers would also help. Your likely beyond the initiation of surface checks, so high breeze or fan will help get the surface dry to stop the mold.

YellowHammer

Cool thing about this forum, everyone has their own opinions.   

If grain change caused the cup, then the board directly under with no sapwood has as much or more grain change and is dead flat.  Same with the board to the side.  Although the right side of the edge cupped board was not shown in the photo, it was flat.  The only part of that board that moved, and moved badly?  The sapwood portion.

So I'll say it, and people can do what they want and believe what they want.  They can look at the picture and make their own decisions.  Look at the boards in the photo.  Look at the grain changes of each, and look at the flatness relative to each other.  Do they want the flat wood, or the one with sapwood on the edge?

So FWIW, include sapwood in walnut, cherry and a few other species and the boards will cup, bow and warp more so than if the sapwood is stripped off during the sawing process.  It's easy to prove, simply saw, dry and sell some.  Run an experiment, strip sapwood off some boards, for others, leave some on, dry it and compare. 

The difference will be obvious.



YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

TBrown99

Nature provided a line to easily follow there so I'll trim sapwood from half of these, leave the others, and compare...  :thumbsup:  

If the bandsaw works fairly well, I'll trim 7 out of 11 of them based on my intuition that it will help. 


YellowHammer

Take the sapwood off before they dry, immediatly off the mill, a twisted, crooked board will not straighten after it has dried and taken it's "set", I have tried many times.  You can't unwrinkle a sheet of paper...   

Your flattest boards will be zero knots, zero sapwood, and sawn away from the pith, and your boards with sapwood, pith and knots will be the worst.

The thicker the sapwood band the more it will cause deformation.  The thinner the band, the less effect it has.  Butternut generally has a relatively narrow band, less than an inch, walnut and cherry can be a couple inches wide and will cause more deformation.  Look for cup and especially long bow down the length of the boards.     

Butternut is a pretty forgiving wood to dry, has a high daily allowable moisture removal rate similar to walnut, so if you are getting mold you not getting enough airflow though the pack, so are drying it in the wrong place if you are using 3/4" stickers and your packs are four foot wide or less.

The approach I use is to not wet them with a hose, (never a good idea) immediately sticker them outside under roof, with 3/4" sticks every 16" or so, preferably on a very flat concrete surface, under an open sided roof, with substantial weights on top, even a layer of concrete blocks will make a difference.  Do not block the sides of the packs to prevent airflow on butternut.  Also, especially with sapwood live edge, of any species and thickness, stack them "counter cup" to each other, like this:  ( )( )( ) to get higher loads on the edges of the boards that want to deform, to try to force them flat, and do not stack them like Pringles (((((( or they will settle and dry like Pringles.  Then let them do their thing, that's about the best you can do to keep them flat.             
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

TBrown99

The jigsaw worked better than bandsaw to trim sapwood from the 3' crotch pieces. Though I didn't try the scroll blade. These don't look as interesting without the sapwood. Perhaps rounding the edge with router when they're dry will improve...

Thanks for mentioning the drying properties for butternut. The species isn't mentioned in Nyle's four species type drying schedules. It's a hardwood yet quite soft. I expect it's close to white pine / hemlock / etc, so the first category.

The mold formation seems to have been an one-off. Never happened here before. I need to always let surfaces dry superficially before stickering unless it's cold out. I'd spent some time hosing these down to take photos and then I left out in rain.

I recalled that I saved several 1.5" butternut live edge cut-offs in the back shed one approaching 14" wide... They are currently at 12% and there's minimal warping (cupping). The sap bands were not more than 1" at the most. I'll try to do a closer look with photos later...

Does degrade occur only during the drying process or also lots of movement once dried? If it's only during drying, maybe just cut thicker and plan for extra flatting efforts prior to finishing. With live edge products like table tops perhaps it doesn't matter but fine furniture perhaps it's impossible. We see lots of live edge walnut and cherry table tops.

The two 8' lengths of sound butternut still await, as well as two not so nice ones.

But first I'll need to mill a few drop-off logs for a one-time lumber dressing customer. They only have a bucket to lift logs with so they arrived covered in gravel. Hmm. And I learned that they are all limb sections. I have to stop assuming customers know something about milling. Anyways. He wants to proceed even though I explained that limbs aren't used for lumber. I guess he has projects where it doesn't matter.

He said they are maple, soft or hard he's not sure. They look like ash to me but sometimes maple bark looks like ash. I can provide pics. I'd guess they're ash but maple tricks me more than any other bark. The base "tree" section was quite large so it's not exactly young bark. Maybe I'll show with a pic later. 

Thanks!





 



 

SwampDonkey

Great score. Definitely butternut. I've not ever seen much for sapwood on butternut after sawn up and edged, mostly gone once squared up. Very thin sapwood. Of course live edge will have it. I've never seen more than 3/4".

What's the dry schedule for basswood? Butternut would be similar in hardness to that. Butternut is rarely come by these days. Basswood is like weeds some places. Growing all around.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

YellowHammer

Here is a document and if you look Table 1, of the maximum allowable moisture removal rates per 24 hour period for some major species.   Since you maybe getting into maples and other species this would be useful to you.  You can see how much walnut can lose and how forgiving it is related top other woods, and since butternut is related to walnut, but not as dense, I just use walnut drying schedules for butternut, it's been working good so far.

As the thickness of the wood increases, the max allowable moisture rate drops somewhat proportionally, so thicker wood must be dried slower.  At some point, as wood species get thicker and thicker, the daily air drying conditions will exceed the max allowable moisture content removal rate and defects will happen.  However, you can sue the table to judge the species and thickness and the danger of exceeding the rate.

As a general rule, it's a good idea to cut slabs thick and plane them, or better yet, face them flat then plane the other side.  I prefer to do the final flattening after they have been kiln dried, but if you don't have a kiln, you can't do a lot about that.

We saw a lot of 8/4 live edge of many species and I have found that sawing no less than 2-3/8" will generally clean up a 20" wide slab both faces, but milling to 2.5 inches will give you just a little more margin.

It would seem that just cutting excessively thick would be the answer so you will have lots to take off later to get flat pieces, but remember the max drying rate table, the thicker you cut, the less moisture the board can loses per day to avoid drying defects.  So it's a trade off.

Anyway, in my experience, live edge butternut is pretty well behaved, maple starts to get a little cranky, and will move some.  Walnut is pretty easy, but, even air drying, it will many times develop wet pockets and "stall" and if the slabs are made into furniture at that point, as the wood which you thought was dry, continues to dry, and it will move.  Many of our competitors don't know about this or don't care and will sell "dried" lumber but with wet pockets, and when the customer builds furniture and asks us for help, we call it "dog leg" furniture, because if its a table or chair, as it continues to dry and move, it will lift a leg off the floor like a dog peeing. 

If you are going to do this, I would highly recommend a good moisture meter.

https://extension.oregonstate.edu/catalog/pub/em-8612-air-shed-drying-lumber

     
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

TBrown99


I'm geared up with a Nyle L-53 chamber (Stan approved!), Lignomat 3-probe pin system with optional flat scanning, as well as Delmhorst pin reader. Very nice products. 

YellowHammer

Sweeet.  I started with an L53, and still use one, for specialty wood cuts like live edge slabs, it is very good for that, it is a wood drying machine.  So when you finish in the kiln, and sterilize to 150F (or whatever you go to), you should be at 7%, and you will have subjected the wood to more than anything your customer will ever do. So for all practical purposes, yes, the live edge wood is done moving and cracking, and you can flatten it and it will stay that way.  

If you watch my videos, some time ago I made one or two about live edge slab flattening using a facer to get a flat skid mark (no need to flatten the entire face, just get about a 6 inch wide flat streak) then put that piece in the planer, skid mark down as a reference face and the pieces will start coming out dead flat.

YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Stephen1

YH Always great to read form other sources.  I really like how the information does not change over time. There really is no quick and dirty method of properly drying wood. 
You really do have to take it down to the 6-8% to properly dry the wood. 7% okay . 
So many people I come in contact with feel the thick slabs 8-10% is good enough , because its only going to go back to 10-12% is what I am always told. I find getting it all down  to the 7% hardest part. 
IDRY Vacum Kiln, LT40HDWide, BMS250 sharpener/setter 742b Bobcat, TCM forklift, Sthil 026,038, 461. 1952 TEA Fergusan Tractor

SwampDonkey

You'll be lucky to maintain 12% unless you have climate control. A lot of dried hardwood up here is set out in unheated sheds where it's 16-18% air. That'll never be no 7% when you get it. I've seen 'shed wood' move 1/16-1/8" on a 6" wide board and even want to cup on a glued up table top. Because the shop is probably 8% when the heating season is on. By December the shop is very dry once the summer moisture is driven out with a few wood fires.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

jimF

Stephen1: are you talking about average MC or all the way though to 7%?
What are you using to measure it?

YellowHammer

All you can do is the best you can, and the customer has to do their part.  If you look at an Equilibrium Moisture Content table, then you can see why it so so important to dry to 7%. I don't like to get to 6%, that's too low, but I won't stop until it's under 8%.  Why?

Most people in this area run their houses at 70F between 40% and 50% humidity, especially with the new high efficiency air conditioners and heaters, which make rooms "feel cooler" by reducing relative humidity even less than the systems just a few years old.  As a matter of fact, when questioned about it by costumers, I simply tell them to look at their thermostat when they get home and they can easily tell what their house EMC actually is, since most new thermostats display both temperature and relative humidity.  Most times, in this area, homes are between 7% and 9% EMC, so it's important to dry to that level.

So at 70F, 40% RH the EMC numbers is 7.7% and at 50% RH the EMC is 9.2%.  So if a person buys lumber that is properly dried and builds a piece of furniture it in a shop that is conditioned to that level, and sells it to a customer who lives in an air conditioned house, the piece will be very stable, simply because the EMC will have barely changed throughout the entire process which results in a Happy Customer.

Don't believe "what everybody says" when it comes to drying and selling your wood, go to the literature, research it, and figure out what is best for you and your situation.  Then make sure your wood can meet the conditions required to maintain the highest levels of quality.

Oh, if you want to do a sanity check, which is always good, take your moisture meter into your house, look at your thermostat, go to the EMC table, then start measuring stuff in your house.  I prefer the inside of hardwood cabinet face frames.  Then check the reading against the EMC table, they should be very close.  If not, then there is most likely a problem with your meter.

Of course, the better meters can be sent back for NIST traceable calibration, and some have internal shunt calibration systems as well.
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Larry

Quote from: YellowHammer on August 19, 2024, 09:40:58 PMOh, if you want to do a sanity check, which is always good, take your moisture meter into your house, look at your thermostat, go to the EMC table, then start measuring stuff in your house.  I prefer the inside of hardwood cabinet face frames.  Then check the reading against the EMC table, they should be very close.  If not, then there is most likely a problem with your meter.

I've only been doing this for 30 years now. In my house in north Missouri summer time MC would be right at 9 percent. I had central AC (heat pump) but on cool summer nights I opened windows. In winter we liked running a big wood stove in the great room. MC would drop to 6 percent come late February which is too low, especially for hardwood floors. I solved that problem by adding a humidifier which kept the wood around 7 percent.

I built a new home in north Arkansas about 12 years ago. Heat pump 24/7, and I never open the windows due to my allergies. It also has a woodstove but I only burn it in power outages. MC runs from 8-9 percent late summer to 7 percent late winter.

My target MC in the kiln is 7 percent. I think this is too low but it seems I always have a wet spot or a few boards that are a little higher. After the wood comes out of the kiln this will even out.

Ok, now as a furniture maker for I guess 60 years now, for most projects I like the wood to be at 9-10 percent MC. The reason is that I know absolutely which way the wood will move in its final environment. Never have a problem with sticking drawers or doors. I know my live edge tables will shrink and know exactly where to put the attachment holes in the "C" channel. On the flip side I have made wood for floors and that should be at 6 percent or as low as possible.

Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

YellowHammer

@Larry 
Why do you like to get the flooring so low? So it will expand a little after the install and tighten up? 
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

SwampDonkey

Most houses up here are 60% plus RH in summer and can be RH 12% in winter without a humidifier. MC will be 16-18% in summer. You gotta open a window or have an air exchanger of some sort, isn't healthy otherwise. I keep the house around RH 30 % in winter. Your airways get too dry. Who wants a bloody nose all winter? Rural vs urban dwelling is a 50/50 split. Never seen it below MC 12% here with wood fire all winter.  Most people aren't even running a humidifier. We burn a lot of wood where I live. There are 3 mini-splits around on this road, most used as AC, some for winter backup. You have to have alternative heat for insurance purposes, as a backup plan. The one guy I know that heats with his has to use the wood stove when it's below 20F, in a trailer. Hardly a house here with an A/C unit in them, 2 or 3, not used much. I have one, and it isn't a 24/7 operation. 12 hrs on the hottest day maybe. July mostly, the odd day in August. Taking mine out this weekend in fact. 60's here this week until Friday, then 70's. Probably 16 houses out of 22 burn wood on this road. Some burn oil and some on baseboard. On another note the firewood pile goes down to MC of 12% beside the wood stove. Wood splits apart as it dries in the pile.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Larry

Quote from: YellowHammer on August 20, 2024, 12:29:19 AM@Larry
Why do you like to get the flooring so low? So it will expand a little after the install and tighten up?
Yes
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

YellowHammer

Hey! I guessed right!  
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Larry

Your really good at figuring out those things, or maybe Chip told ya the answer. ffcheesy ffcheesy ffcheesy

Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

YellowHammer

Yes, Chip is the brains of the outfit, Martha is the muscle, and I'm the eye candy.

I'm like the Col Sanders of Hobby Hardwood, I just stand out in front of the building and wave at people. 
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

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