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Preventing Warping in Humidity Changes?

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Forum topic by Trucker posted 07-20-2015 01:37 PM 859 views 0 times favorited 25 replies Add to Favorites Watch
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Trucker

19 posts in 544 days


07-20-2015 01:37 PM

Topic tags/keywords: cherry maple walnut purpleheart zebrawood question

Hi Everyone,
I have been making a bunch of cutting boards over the past several weeks and I have noticed that some of them seem to warp a little between the time that I plane them to thickness and when I am finished oiling and waxing them. I do all of the cutting/assembling/planing/sanding in my non-climate-controlled garage and do the finishing inside. Is there anything that I can do to prevent/reduce the warping that I get in the finished product? I noticed with a few that they returned to being true after about a week inside, but this hasn’t happened will all of them. Any suggestions would be greatly appreciated.

Also, I do let the boards acclimate in my garage for at least a week prior to using them (but I am buying from local open-air lumber yards that are probably at the same temp/humidity anyway).

Thanks!


25 replies so far

View Bill White's profile

Bill White

4450 posts in 3422 days


#1 posted 07-20-2015 01:50 PM

Problem is that the lumber you’re using is not stable. Lumber yards are notorious for high moisture product.
Do you moisture check your wood, store it indoors, let it acclimate before use?
Bill

-- bill@magraphics.us

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Trucker

19 posts in 544 days


#2 posted 07-20-2015 01:52 PM

Thanks! I’m pretty new to working with hardwoods. Does that apply to legit hardwood lumber yards?

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Firewood

93 posts in 1096 days


#3 posted 07-20-2015 01:56 PM

Hi Trucker – This is one of the down-sides of having a non-climate controlled shop. Since this is an “indoor” item, I would recommend acclimatising the wood indoors for a couple weeks prior to machining. You want to keep the boards in an environment closest to what they will be kept/used in as much as possible. If the boards are too long, rough cut them to size before moving them indoors. Depending on the weather conditions, you may want to move the machined parts back indoors between machining and glue-up if it is not done the same day.

-- Mike - Eagle, WI

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Trucker

19 posts in 544 days


#4 posted 07-20-2015 02:26 PM



Hi Trucker – This is one of the down-sides of having a non-climate controlled shop. Since this is an “indoor” item, I would recommend acclimatising the wood indoors for a couple weeks prior to machining. You want to keep the boards in an environment closest to what they will be kept/used in as much as possible. If the boards are too long, rough cut them to size before moving them indoors. Depending on the weather conditions, you may want to move the machined parts back indoors between machining and glue-up if it is not done the same day.

- Firewood

Thanks for the info. I only have a tiny amount of indoor storage space (and an equally small level of tolerance from my wife for doing so). As an alternative, would it be advantageous to run a dehumidifier in my garage to try to maintain a more standard “indoor” humidity level (I live in North Carolina and we have humid spring/summer/fall) in my workspace (and main wood storage space)? I’m open to options if anyone has other suggestions?

Thanks!

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Firewood

93 posts in 1096 days


#5 posted 07-20-2015 06:58 PM

Unless your garage is well sealed, even an industrial dehumidifier will be working overtime to try and keep up. Temperature changes, soffit and roof vents will all keep your garage breathing in moist air from outside. Now, what you can try is sealing off a portion of your garage shop with plastic sheeting, etc and placing a dehumidifier in there to help stabilize the wood. But for this to work the area has to be well sealed and the wood stickered to allow good airflow. As mentioned by Bill, a moisture meter will be a big help.

-- Mike - Eagle, WI

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Trucker

19 posts in 544 days


#6 posted 07-20-2015 07:09 PM

Can anyone recommend a good moisture meter that won’t break the bank. I’m still new to this and have recently bought a decent amount of equipment, so keeping costs down would be a huge help. Also, I’m definitely an amateur, so I don’t need professional grade equipment.

View jumbojack's profile

jumbojack

1667 posts in 2086 days


#7 posted 07-20-2015 07:11 PM

Under beds. Behind the couch. Behind the entertainment center. Closets. Those are just a few of the places I store veneer and lumber. Wood rack in the garage is full. Outdoor wood lot is mostly full. Drying shack nearly full.
I gotta build more and acquire less.

-- Made in America, with American made tools....Shopsmith

View Ghidrah's profile

Ghidrah

667 posts in 684 days


#8 posted 07-21-2015 05:55 PM

You might consider locating a moderately sized furniture maker, the one I often use for maple, walnut and mahogany has their supply cooking in an air-conditioned warehouse, everything I bought so far is about 15% MC. The thinner your end product is the less it will shrink and or warp, the straighter the grain is before and after milling the less it’ll warp, flat sawn lumber is a basket case waiting to snap, rift sawn not so much.

This may sound counter intuitive, but maybe you should consider buying enough stock to allow for curing over an extended period, have a dehumidifier running, mine runs 24/7 April till the average temps drop below 45°

-- I meant to do that!

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Trucker

19 posts in 544 days


#9 posted 07-21-2015 06:02 PM



You might consider locating a moderately sized furniture maker, the one I often use for maple, walnut and mahogany has their supply cooking in an air-conditioned warehouse, everything I bought so far is about 15% MC. The thinner your end product is the less it will shrink and or warp, the straighter the grain is before and after milling the less it ll warp, flat sawn lumber is a basket case waiting to snap, rift sawn not so much.

This may sound counter intuitive, but maybe you should consider buying enough stock to allow for curing over an extended period, have a dehumidifier running, mine runs 24/7 April till the average temps drop below 45°

- Ghidrah

Any recommendation on a dehumidifier model/size? I have a standard two-car garage with a ~18-foot ceiling. Also, I took a look around my garage yesterday and it looks like it is pretty well sealed. The doors have rubber flashing all the way around them (I’m sure that it’s not the greatest seal, but not really any light coming through, so hopefully that means not really any air either), I insulated the walls and put drywall up a while back, and the ceiling is finished.

I’m receiving a humidity monitor today, so I will be able to determine the differences in RH between indoors and the garage, but ambient humidity this time of year is typically 50-60% during the day.

Has anyone else done anything like this?

View rwe2156's profile

rwe2156

2190 posts in 942 days


#10 posted 07-21-2015 08:58 PM

I have an unconditioned shop, too, and What about an air conditioner?

I keep my project parts wrapped in plastic celophane or in plastic bags.

You could also consider building a “dry box” with a big tub of calcium chloride crystals in there.

-- Everything is a prototype thats why its one of a kind!!

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Trucker

19 posts in 544 days


#11 posted 07-22-2015 12:23 PM

So, I got the humidity meter and the RH in the house is ~45-50% and ~65-70% in the garage (at least at the moment). I guess it’s time for a dehumidifier…

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rwe2156

2190 posts in 942 days


#12 posted 07-22-2015 02:06 PM

Trucker, you could be looking at >7000 cu. ft. with that ceiling height (why are the ceilings so high?).

First, I’m thinking ceiling fans to keep the air circulated.

Second, I’m thinking you’re gonna need a heck of a unit to dehumidify a volume like that.

There are some portable AC units that offer built in dehumidification might be worth checking out.

-- Everything is a prototype thats why its one of a kind!!

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Ghidrah

667 posts in 684 days


#13 posted 07-22-2015 08:43 PM

The one I have is a Frigidaire 50 pint per day and has a 2+ gal container, removable filter and MC settings. It sites in my shop yr round, I have my basement partitioned off, leave the doors open and it works the entire 768 sq ft.

-- I meant to do that!

View AandCstyle's profile

AandCstyle

2566 posts in 1719 days


#14 posted 07-22-2015 10:21 PM



I have been making a bunch of cutting boards over the past several weeks and I have noticed that some of them seem to warp a little between the time that I plane them to thickness and when I am finished oiling and waxing them.

Trucker, I wonder if there might be something about the way you store them since only some of them are warping. Do you store them so there is air circulation on both sides? You could try stickering the warped ones with a fan blowing on them to see if that helps at all. You might also dampen the concave side to see if that helps bring them back to flat. HTH

-- Art

View cebfish's profile

cebfish

129 posts in 2150 days


#15 posted 07-22-2015 10:37 PM

A harbor freight moisture meter works good for me awhile back there was a post about it. somebody said they checked out against a more expensive one and said it showed exactly the same mc

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