Bloodwood moisture content

[Wayne Minami]

I just bought a rough 5/4, 6'5" long 4" wide bloodwood board.
It has a moisture content of 8.5% and was being stored in an unheated warehouse.
I want to mill it to 4/4, 6' long, and 2" wide and glue it between two walnut boards. The walnut has been in my shop for weeks at room temperature and the MC is 4.5%.
My question is: should I wait before milling it and should I wait to try to get the MC down closer to the walnut.
Or, what are the consequences of not waiting?
I am relatively new to woodworking.
Thanks.
Wayne

[Harvey Pascoe]

Bloodwood is much harder and denser than walnut and as a result does not give up moisture readily. You could wait another two years to get down to 4.5, if ever. I use bloodwood quite a bit and most of my stock runs 10 -12 and though I cut it into 0.100" strips, they do not warp, so I'd say 8.5 is about as dry as its going to get.

[Brian Tymchak]

Wayne,

Personally, regardless of the MC, I would let the board acclimate in my shop for a couple weeks, as I do with all new lumber. Maybe some would consider that overkill but I've experienced how much newly purchased lumber can move when being cut.

My standard method is to wait a couple weeks for any new boards to acclimate to my shop, then mill close to final dimension, maybe to within a 1/16th in all dimensions, sticker it for a day or two to finish moving, and then do the final milling. Use the board immediately after that final milling. As you mill the board, particularly if you are removing a lot of material, the fresh surface is typically higher in moisture content than the surrounding environment. As this moisture comes to equilibrium in the shop, the board can move (warp).

Brian

[Wayne Minami]

Harvey and Brian
Thank you so much for the advice.
I will wait to do the milling.
I am just using a thin, 2" strip in the middle of a tabletop as an accent. I hope it is attractive.
I was advised to get a moisture meter and it seems it was a good buy.
Wayne

[Bill Davis]

It's tough to argue with one who has had direct experience with that particular wood but.... (actually I'm not arguing just offering my view based on my experience)

My guess is that you paid a significant price for that board or at least treasure it highly. And of note (to me at least) in comparison to what Harvey said, you are not cutting your piece into thin strips therefore your situation is quite different.

The experts, Gene Wengert (http://www.woodweb.com/Resources/RSAboutWOODWEB.html#gw) et. al. provide a lot of wood science and wisdom on this very topic at WoodWeb (http://www.woodweb.com/cgi-bin/forums/sawdry.pl) and has stated that when wood is glued together the separate boards MCs should be within 1%. IMO there are times to believe and follow their advice and there are times to do my own expermenting or deviating from wisdom beyond mine. You have to decide that for yourself given the risks involved. What is the risk and how big of a hurry are you in and what would happen if .....

I am currently working on a small table for which the top is to be glued up Ebony (very dense and hard and slow to change MC) and Narra (Paduck) which is very different. I don't really feel like taking the chance with the possible effects of moisture difference at the joints so am being perhaps overly cautious in this regard. I do not want the table top, the most visible and potentially striking part of the table, to suffer from my not doing it right. I let the rough wood stabilize in my dryer before initially machining it. Cut to rough dimensions, and observed any tendencies to change due to any possible residual internal forces, re-machined and am now allowing more than ample time to do more stabalizing. Much of the 'letting it set time' is not necessarily for the stabilizing purpose but rather my schedule of time available to get back to it. But it won't hurt.

Harvey is correct that hard dense woods change slowely in MC but I would add they DO change and I have had smaller pieces of ebony (1" x 1" x 5") down to 0% MC and watched how slowely it returned to EMC in the shop. Very different than the rate of the Narra. IMO all the more reason to be sure to allow ample time for the two woods to achieve near the same MC and hopefully at the EMC of the final location where your project will find its home. I think that is as important or more important when gluing up woods with such differing characteristics.

There are some relatively easy ways to get the MC where you want it for any piece of wood and you apparently have a moisture meter so have an invaluable tool to help you in that.

[Scott T Smith]

I just bought a rough 5/4, 6'5" long 4" wide bloodwood board.
It has a moisture content of 8.5% and was being stored in an unheated warehouse.
I want to mill it to 4/4, 6' long, and 2" wide and glue it between two walnut boards. The walnut has been in my shop for weeks at room temperature and the MC is 4.5%.
My question is: should I wait before milling it and should I wait to try to get the MC down closer to the walnut.
Or, what are the consequences of not waiting?
I am relatively new to woodworking.
Thanks.
Wayne

4.5%???? A moisture content that low is unusual. If the room temp in your shop is 60 degrees F you would need a relative humidity of less than 20% inside to dry the walnut down that low (based upon it reaching equilibrium moisture content).

It is usually best if your shop can imitate the temp and RH of the environment that your project will ultimately reside in. Usually the wood needs to be between 6% - 8% MC.

Rather than drying the bloodwood down lower, you may be better off using a humidier to increase the RH in your shop so the walnut raises up to 7.5% or so.

[Wayne Minami]

I made a mistake.
I forgot to adjust the meter for the spec grav of bloodwood, which is 95, acc to the internet.
So, the MC of the BW is 5.5 and the walnut is 4.5.
I just got the meter, and this is the first time using it.
The shop is cold, at around 60 degrees, and low humidity, since it is winter.
I just downloaded the EMC chart from FWW, and the EMC for 60 deg and 20% humidity is 4.6, which sounds like my walnut.
I guess I will let the BW sit for a while and take another reading to see if its MC comes down.
The table I am making will be exposed to big temp and humidity variations.
Thanks to everyone for the advice.
Wayne

[Damon Stathatos]

I used to see Bloodwood all over the place a few years back. I haven't seen much of it around and whatever I have seen seems to be more of a grey, muddy tone than the good-stuff that used to be around.

Also, how much does it go for now?

It used to be one of my favorite trim woods, when I could find it in a good color.

[Wayne Minami]

I got mine at Colonial Hardwoods, 7953 Cameron Brown Ct., Springfield, Va 22153.
It was $7.50/bd ft. They had probably 20 pieces to choose from, most 6' plus in length and various widths. Most were 5/4.
My piece looks a little lightish red, but it is rough and I have only seen one other to compare it to.
It is nice and straight, no knots, etc. It is 6 1/2' long, 4" wide, and 5/4 and cost me $22.