moisture

[sapling111276]

Here's a question for you experienced woodworkers. I have done a fair amount of read up on moisture and how it plays with the wood as it is drying. I understand cupping, warping, checking and twisting and I have several thoughts on making a relatively inexpensive kiln once I have the space to do so. That said, I don't have a moisture meter yet, so mostly I am flying blindly on the wood I purchase at my local supplier. I have a meter on order... What does mineral oil and beeswax do to the total dry out of a piece of wood? I have watched as people literally drop the entire board into a mineral oil bath. I know that the oil is more viscous than water but does the oil push the water out to some extent? Does it trap it inside?  Will the wood shift and warp as the oil slowly leaves the boards? What are your thoughts? 

  Also, I see people making boards at 1.5" thick. Is this not a concern at these thicknesses? Thanks, Bob

[lewisc]

When I first started making cutting boards, I had a board cup when sitting on a bench. I spoke to a cabinet maker I knew and he educated me on why timber might move that way. After that, I had it resting on sticks until it was oiled and the board equalised. Since then, I install rubber feet on the base to get air flow around the whole board.

That's about as scientific as I get though. I'm not sure about the whole moisture thing.

[difalkner]

In the mid 80's to early 90's I had a woodworking business where I designed and built furniture and accessories, we did restorations of fine antiques, refinishing, etc., at one point had about 8 employees (won't do that again!).  Anyway, I had a sign in my office for customers to see - There are two rules on wood movement; 1) Wood moves, and 2) You and I can't change rule number one.

It got a chuckle from some folks but it helped me to make it a topic when someone brought their own design in for us to quote.  In the last couple of years my wife and I have built about 40 end grain cutting boards ranging from 5/8" thick smaller boards all the way to much larger boards 2" thick.  None have warped.  All of the larger boards have silicone rubber feet and get air on all sides.  The smaller boards don't have that but I also don't think any of them get used for much other than kitchen decoration. 

Most of the boards we're making now, and fixing to gear up for more, are about 1.5" thick and I don't anticipate them warping.  The wood is dried to around 6% to 8% before cutting and we're in a climate controlled shop with humidity typically in the 35% to 45% range.  I'm also building acoustic guitars so I need to keep the tonewood in a controlled environment.  It just happens to help with the other things we do, as well.

David

[Isaac]

I feel that a cutting board is a utility object that only needs to remain visually and functionally flat, ie. you don't want it turning into a potato chip, but it also doesn't actually need to remain perfectly flat the way you need a component of a larger and more complex piece of furniture to be. If the side of a cabinet starts moving in a funky way, you might have issues closing drawers or doors, but the cutting board, on the other hand, isn't going to have 90 degree edge glued joinery intersecting with it, or similar demands, it can tolerate minor movement and still function.

[thatCharlieDude]

To (try to) answer your original question, I think the mineral oil baths and the beeswax are to help control/slow/regulate moisture loss during working. It won't push out the water but it will seal it in so the wood doesn't dry too fast and split.  A piece of aged or kiln dried wood shouldn't need sealing while you're working with it. After you're finished you can rub it down with mineral oil and beeswax to help protect it. 

[Wood Basher]

7 hours ago, Isaac said:

I feel that a cutting board is a utility object that only needs to remain visually and functionally flat, ie. you don't want it turning into a potato chip, but it also doesn't actually need to remain perfectly flat the way you need a component of a larger and more complex piece of furniture to be.

That is not my experience. A cutting board that rocks is annoying to use so to my mind it needs to remain flat, at least on the bottom.

[Brendon_t]

The mineral oil and bees wax on cutting boards has nothing to do with helping the cutting board dry. It's there as protection against being stained and holding onto the juices from food.

The lumber used for the cutting board needs to be completely dry already. If you are buying from a reputable dealer, ask them how the stock is dried. They will know. 

I have seen Cutting boards go wonky for 3 reasons.1 very thin end grain board 2. storing it on face instead of on side, Restricting airflow to the bottom long term. 3. storing a board on the oven when not in use. Constant heat and cool cycles = no bueno.

[sapling111276]

21 hours ago, lewisc said:

When I first started making cutting boards, I had a board cup when sitting on a bench. I spoke to a cabinet maker I knew and he educated me on why timber might move that way. After that, I had it resting on sticks until it was oiled and the board equalised. Since then, I install rubber feet on the base to get air flow around the whole board.

That's about as scientific as I get though. I'm not sure about the whole moisture thing.

Yeah, my boards all have rubber legs as well. Thanks for the info

[Isaac]

16 hours ago, Wood Basher said:

That is not my experience. A cutting board that rocks is annoying to use so to my mind it needs to remain flat, at least on the bottom.

I handle that with rubber feet, but I was really thinking more generally about tolerances. 

[Marmotjr]

17 hours ago, Wood Basher said:

That is not my experience. A cutting board that rocks is annoying to use so to my mind it needs to remain flat, at least on the bottom.

My girlfriend is a great cook, beyond what I would consider gifted in the home kitchen, and two of her brother's are head chefs in various restaurants.  I'm pretty sure none of them would tolerate a cutting surface that is not flat.  But, they are very particular about their tools, just like us, so they be in the 1% department there. 

[wdwerker]

I made a huge end grain cutting board for a chef/neighbor. 16 x 24 x 1 3/4 . He puts a kitchen towel on the counter under the board which keeps it steady and allows use of both sides. Meat on one side, veggies on the other. It stores vertically at the  backsplash .

[sapling111276]

Well, my moisture meter arrived today. I took it to my woodshop and started testing some nice 8/4 cherry, walnut and maple that I bought recently from my supplier. I was pleased to find that out of all 3 boards, the moisture was at 5 to 6% max. It will be interesting to see how that differs once I get to some inner cuts. That makes me happy to know that the supplier dries their stuff pretty good before sale. One thing I noted right off the bat when I was looking through their wood, was that all boards that were not previously cut, had a sealant of sorts on the ends. Like maybe paint or something else to help slow the drying and help prevent the ends from splitting.