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Moisture in SYP for Workbench

51K views 31 replies 12 participants last post by  allpurpose 
#1 ·
Questions first, details second:


  1. Is 8-10% and 12-15% MC SYP dry enough to use for a workbench in a non-insulated garage shop in Austin, Texas?
  2. Given that the MC ranges across a board, which figure should I use? Max? Average? What about small wetter spots?
  3. My cheap moisture meter states "Measurement accuracy: ±4% for both hardwood and softwood". Does that mean a reading of 10% could actually be 6% or 14%? Does that make it almost useless for determining if wood is dry enough for woodworking?
I started building a Roubo-inspired workbench during my vacation which has 1 week remaining (back to work on 1/14). I was really hoping to have it done by then. The plan is to build a 4.25"x28"x6' top by gluing up 8/4 Southern Yellow Pine. The base will be made from doubled up 8/4 SYP as well.

I chose SYP because it is pretty darn cheap here in Austin, Texas and is recommended by Christopher Schwartz in his book on building workbenches. I was sourcing from lumberyards when I found my local Big Box store sells construction grade "kiln dried" #2 prime SYP for dirt cheap. I picked through the stacks and found some decently straight and clear 2x10x12' flatsawn boards that I could rip in half.

I wasn't considering moisture content because it was advertised as "kiln dried". When I got home I could feel that one of the boards was noticeably damp to the touch (not sure how I didn't notice at the store). I bought myself this cheap $45 pinless moisture meter to check it out. I moved the meter over the face from one end to the other. That board ranged from 35-40%... Luckily, that board was from a different bunk/stack than the rest. Of the others, about 1/2 read between 8-10% across the board with spots at 11% and the other half 12-15% with spots at 16%.

This is my first large furniture project so I started reading up on acceptable wood moisture content. I learned a lot but was also inundated with often conflicting information lacking context. Some put a dead stop on figures like 9% or 12%. My case may be atypical since I am building a beefy workbench and not fine furniture. As such, I don't mind cosmetic flaws like small cracks that might result from the wood settling as long as they are not detrimental to the integrity. Also, the bench will not be indoors and instead in my non-insulated garage shop and exposed to the changing humidity. This site states "In most of the U.S., when wood is outdoors but protected from the rain, the wood will attain an EMC of 12% when the RH is 65%" "in more humid locations ... wood outdoors can attain 16% EMC." So maybe the wood is actually about were it should be for outdoors in Austin? Idk

It seems quite a few people have built workbenches using construction grade SYP from a Big Box store without reporting any issues. Am I overthinking and over-worrying?

Let me know what you guys think and I appreciate any input.
 
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#5 ·
For those like me who have to look up terms to understand the post:

SYP = Southern Yellow Pine
MC = Moisture Content
EMC = Equilibrium Moisture Content
RH = Relative Humidity
Idk = I Don't Know

It would be very nice if people would have the consideration of others of spell out acronyms the first time they use them in a post. Exceptions are well know acronyms like FBI, CIA, etc.



George
 
#4 ·
I built mine from big box SYP 2x10’s & 2x12’s ripped to size. I didn’t check MC. I just rejected the boards that didn’t feel dry. I followed Schwarz’ book rather meticulously, have had no problems. I’ve had it a few years now.
Since you are building the Roubo, you’ll be mortising the legs into the top. There should no expansion/contraction problems.
I suggest you glue up in three or four sections. I used Titebond Extend for longer open time.



Sent from my iPhone using Tapatalk
 
#9 · (Edited)
Dry or Green...It does not matter...

...Is 8-10% and 12-15% MC SYP dry enough to use for a workbench in a non-insulated garage shop in Austin, Texas?
...
Hello Yo1dog,

If you put work benches in the search line of this forum, there is a lot of good discussions covering all of this...

I didn't really need to go past your first question...If wanting to get into all the other stuff you asked about...Plenty out there that covers it, and many here that can discuss it...

The point has already been made...Wood Moves...period.

That is all you really have to keep your mind focused on. Dry or green and how much moisture is in it doesn't really have a bearing on all this...especially for a work bench that is following any semblance of a traditional version...

I would also close with, that "Work Benches" and/or the majority of them ever made through history (and the ones we make) where not made with air dried wood (and certainly not kiln dried!!??)

The woodworker dropped a tree, hewed/rived the parts and assemble the bench...What they understood was that the joinery must compensate for movement...
 
#16 ·
How do you know that you need a moisture meter? Most of the woodworkers I know have gone their entire lives without one. I do not own one.

-> Before you buy anything, including a moisture meter, tell us more about the kind of wood you will be working with and the kind of woodworking you would like to do with it. It might help if you share the area where you live, too.

From your post, I assume that you have some green (fresh) wood that needs to be dried. It would help if you share more details so that others can give you better advice. There is more to processing freshly cut wood than just drying. Sealing the ends is but one example. Dealing with insects is another.

Imagine if someone had asked about the "wood cutting process" in their first post without providing any other information. What would you tell them?
 
#14 ·
@Thomas_Z

To make a long story short, there are two main forms of lumber drying. One is open air drying and the other is kiln drying.

Open air drying is exastly what it implies. More or less lumber is stacked in the open with a cover on top and left to dry naturally. Normal estimate is about 12 -14% final moisture content (MC) based on one year for each inch of thickness.

The other is kiln drying. Again , this is the short of it. The kiln is exactly as implied, a relatively low temp oven. drying time depends on the set-up usually under a month. Normal estimate is about 7-8% MC.

8% MC is about right for furniture grade wood.

Can you use normal lumber from the lumber yard for work benches? certainly.
Do people use normal lumber yard lumber for furniture? Some do, but I'm sure it is the minority. I personally would not.

Will you need fans and de-humidifiers? Most woodworkers dont use them. They will probably help but to what degree is unknown.
 
#15 ·
@Thomas_Z

As a side note, there are what we call the big box stores such as Lowes and Home Depot. Us old timers do not consider them as legitimate lumber yards. If you want quality lumber for furniture, you will have to find a hardwood lumber yard.

If you go back to your profile, add the town you live in as your location. it will appear on here with your posts and we will be better able to assist in things like this if we know where you live. There will be other questions you will ask such as where to get furniture grade lumber, hardware, etc.

BTW, Welcome to the forum
 
#18 ·
Purchasing Hardwoods

One more thing...............when you buy hardwoods they do not come in standard dimensions like 2X4's or 2X8'sor any set size.
Hardwood is purchased by the board foot and comes in random lengths and widths - just like it came from the lumber mill. It is more or less a slab. It has rough surface and rough edges. You can have them plane it and straighten one edge or you can do it yourself at home. They charge extra for that. My commercial shops always had planers and rippers but I always had the lumber supplier do it mainly because it was not cost effective to do it myself. Working in your home shop it would pay to do it yourself once you acquire the equipment - mainly a planer. A straight line rip jig is easy enough to make yourself

A board foot is the equivalent to 12" x 12" X 1". So when you pick out a piece, they will measure for you, or you can measure yourself and do the calculations. Most places sell the slab and wont cut you just a small piece. You have to buy the whole board. On the brighter side, they have a scrap area where you might be lucky enough to find exactly what you want.
 
#19 ·
12-14% is the number for air dried wood where I live.


Acclimation to the environment it going to live is really the objective. For example, wood acclimated to an open air shop in a fairly humid environment & will live in a climate controlled house will shrink considerably.



The wood you have there sounds ready to live in your shop, but I recommend sticker it for a week or two in the shop just to let it totally acclimate.
 
#30 ·
I believe DrRobert's post is worth some focus, especially the Acclimation part. Very dry lumber were it will be living in a humid place isn't good where "wet" material going into a dry home isn't good either.

Tony B mentioned working with rough sawn hardwoods. I learned the hard way years ago that once surfaced 2 or three sides, it's very important to allow the material to "rest" a week or so in my climate controlled shop. it's not unusual to have to plane and/or joint stock a second time after it "rests" the first time.

I happen to like buying dimensional lumber for finished type projects from the big boxes. The quality isn't as good as my local lumber yard but the trade off is the big boxes keep their stuff inside where the lumber yard stores their lumber outdoors, under cover. Pick your poison.
 
#20 ·
I was going to work with red oak and the idea was to store it in the attic with dehumidifier and fan placed withing, periodically monitoring the humidity. That won't be outside storage or something like that to be worried about the wood origin. You, however, suggest me to purchase lumber from lumber yards for start, right?
 
#21 ·
I'm lost here with all the side notes, including my own.

Anyway, for your workbench, you can use the SYP, just try to use the drier ones.
Red oak is nice to wrk with, but dont think it is necessary. Thats a choice thing.

I'm lost in your first sentence "I was going to work with red oak and the idea was to store it in the attic............."
Store what in the attic, the red oak or the SYP?

Anyway, I would not recommend storing wood in the attic. As wood dries, it has a tendency to move a little. This may not be a problem in itself however, but when wood is normally dried - air or kiln - it is stickered when it is stacked. Stickered means placing 1" square strips between the layers of drying wood and also some weight is resting on it to prevent moving. This could possibly create a collapsed floor in the attic and the wood ending up on the dining table.

So here is what I think...use the dryer SYP boards, return and swap out the wet ones. If you cant do that, put the wet ones out of your way and if they warp, they can always be used when short pieces are needed.

The work bench staying in an unheated garage and no AC in the summer is just fine. When you make Mortise and tenon joints, the shrinking boards will actually end up with tighter joints.

You work bench top when glued up as one solid unit with opposing grain structures and different MC, will help tend to help keep itself straight. Kind of like averaging it out. On the other hand, it could bend up like a pretzel over night - just kidding.

like i said, take the really wet ones back and swap out for dryer ones. the go ahead with your project.

I am not a pine person, never was - EXCEPT for work benches.

So, get the work bench started and keep us posted - with pics if you can.

Remember, this is supposed to be fun. So go have some.
 
#22 ·
Perfect timing for this thread to get necroed/hijacked :grin:. I am finally getting back to this project.



While I was all gung-ho about getting the bench finished during the break last year, I actually only got as far as gluing up 4 boards into 6 beams. These beams and the rest of the SYP sat in my garage shop all year. Beams sat on top of my old work bench. Other boards were in a haphazard pile on the shop floor (no stickers).


The beams did not move that much. They were certainly twisted, but when I pushed them next to eachother I think the biggest gap was ~1/8". I wish I would have taken a picture. When gluing the beams I was careful to arrange the boards to have opposing stress, which you can see by looking at the endgrain.

Some of the boards in the pile were warped pretty significantly. Those were probably the very wet ones. For the most part it was nothing drastic.

I re-jointed the 6 beams, glued up 3 beams each into the two halves, then glued the two halves into the final top. I flattened the bottom using a sled and a router. This method worked really well and got it dead flat (less than 1 card thickness at lowest point). I wasn't careful enough on my first attempt and quickly realized I was cutting too deep and taking off more material than I wanted. You can see this mistake in the pictures bellow. I'll flatten the top the same way once I get in on legs.
 

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#23 ·
Dressed the legs and cut the tenon dovetails and shoulders. One leg is shorter because I attempted to hand cut the tenon... I don't have near the handsaw discipline required to cut hand cut tenons that large. Luckily I purposely made the legs ~12" larger than needed so I just chopped it off.

For the dovetails, I ran the legs through the table saw at 45deg with a stop block to ensure I cut to the right depth. I clamped a block to use a reference surface at the desired depth and used a flush cut saw against the block to establish the bottom. Then I used my miter saw cut some kerfs into the excess and paired it out with the chisel. Worked great.

Similar process for the outer shoulder. I had to make cuts from both sides due to depth restrictions of the table saw. I used the table saw to cut the kerfs this time. Also, the tenon face was a little larger than my chisels could reach so I used a hand plane to help cut out excess and flatten.
 

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#24 ·
Again for the center, I first used the table saw to establish the cheeks. Then I used the drill press to hog out material above the shoulder. Next I used a hand saw to cut out the middle while making sure to keep the blade on the inside to ensure I didn't cut into the cheek. Finally I used a chisel to pair it out.
 

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#25 ·
For the mortises, my idea was to position the tenon on the top and outline it with pieces of hardboard thus creating a perfect template of the tenon. I would then use a router with a trim bit inside the template for a perfectly sized mortise. Finally I would square the corners with a chisel. However, this did not work out as well as I would have hoped. I ended up with an oversized mortise and a fairly loose fit.

Looking at my pictures, you can also see how far off it was from the pencil lines in some places. You can also see gaps between the hardboard and the tenon. So it could be that I was not careful enough to ensure the hardboard was flush against the tenon. Or it moved while I secured it down. Or perhaps the hardboard was cut at an angle somehow. I will do some testing.

I haven't taken the mortise all the way through yet as I was just testing the fit. I was able to get ~3" deep using a combination of a 1" top bearing trim bit, a 2" straight bit, and a router template bushing. I started with my straight bit and a bushing making ~1/4" deep passes until I was just over 2" deep. Next removed the bushing and used the 1" trim bit to remove the top 1" of excess from the sides caused by the bushing. Then I switched back to the 2" flush bit and ran the shaft of the bit along the template like a bearing on a trim bit (1/2" shaft and 1/2" diameter bit) to remove the rest of the excess from the sides. Finally I continued to lower the bit and make ~1/4" passes until the router bottomed out.

My plan for the last ~1" is to route from the opposite side. I am tempted to use a bottom bearing trim bit but there is no guarantee the top and bottom surfaces of the benchtop are parallel planes. This would result in the mortise not being straight. It may be close enough though. Safer approach would be to remove most of the material but leave some excess around the edges that can be paired away with a chisel, but I worry about tearout.
 

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#31 · (Edited)
I work with quite a bit of yellow pine since it's so dirt cheap and I don't have a big pile of cash just sitting around the shop waiting for the wood yards. I make bench tops, occasionally a table top depending on what kind and lots of side pieces for shoring up certain hardwood projects. I also use it for work surfaces especially and all of my work surfaces are SYP with one exception, but I'll also make the occasional piece of furniture as well especially for stuff I intend to give away. I have been known to build tables and even chairs to give to local charities with SYP.. Hey, beggers can't be choosers.. is it perfect? Of course not, but it's tough to beat for the price and its a great way to get your feet wet learning new skills.
Where the moisture really bugs me is with the resin it'll leave on saw blades and the like. I really need to get busy cleaning pitch and resin off my blades more often.. I also have a deal going with a local rabbit raising operation to come pick up my sawdust on fairy regular basis. They raise show rabbits or else I'd be eating lots of rabbit stew..
 
#32 · (Edited)
I will make one comment on SYP.. Look for the tightest possible growth rings you can find. At least 10 per inch of end grain is pretty good..more if you can find it. It'll be a lot heavier than that with a lot fewer rings, but it'll be a lot stronger as well. Not long ago I had two 2x8s about 4' each. One had really tight rings and the other only had a few, maybe 8 in the entire board. The one with the tight rings was at least 30 pounds heavier..
This is from a 2x10. The first 3" on the left (bottom maybe in the image? Edit: Ok, the top) Is just about equal to quarter sawn lumber. The pith kind of ruins that, but it's a good straight board, nice and heavy and strong as hell for what it is, SYP.
 
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