Best practices .... Start to finish

[Ribsy]

Yellowhammer,

Can this metal contamination permeate deep into the board as sticker stain can or can it be planed off with little consequence?

[WDH]

What I have experienced planes off. 

[GeneWengert-WoodDoc]

There are three stains in red oak...
1.  Blue stain caused by a blue colored fungus (dark blue).  This stain or fungus only goes in the sapwood, but can quickly go deep,into the lumber if temperature is warm.  This is also called sap stain.  Borate does not control this well as the fungus moves quickly into the wood, more quickly than the borate diffuses.  Any fungicide must be applied prior to the development of the fungi...that is, once it starts and goes beyond the surface, it is hard to control.  The stain cannot be removed easily.
2.  Iron tannate stain develops from the interaction of iron, water and tannic acid.  The iron can come from iron hardware touching the lumber or even from iron in the water used for cooling the saw.  Commercial treatment of water to eliminate the iron is easy and inexpensive.  The stain is a surface phenomenon.  Once it forms, it can be instantly removed by treatment with oxalis acid, even with dry wood.
3.  Chemical stain, that includes grey sap color and sticker stain, results from the oxidation of sugar and starch naturally in the wood.  This oxidation can begin in the log or in stored lumber.  Oxidation is controlled by faster drying, as the oxidation takes time.  This gray can be removed by oxalic acid, compared to fungal blue stain that cannot.

[WDH]

Has anyone had any experience removing sticker stain with oxalic acid?

[GeneWengert-WoodDoc]

Oxalic acid will remove much, but not all, of sticker stain.  Similarly for the other chemical stains...most but not all.  However, the oxalic acid can also turn a light colored wood a bit pink in some cases.  Another name for oxalic acid is wood bleach.  In the old days, using oxalic acid or wood bleach as part of finishing was commonly done.

[longtime lurker]

I'm going to be a little contrary here.

I agree that having a whole heap of stickers ready can make for improved workflow, and I agree that every sticker should be interchangeable with every other sticker. Mostly.
But here's a couple thoughts for when you should Reach for that mostly, because there's always an exception right?

I cut stickers every day. Shorts, out of grade boards, edgings - anything and everything that can make a sticker goes onto a separate pallet that gets put through the #3 bench when I need more stickers, the pallet overflows, or during Saturday morning cleanup, whichever comes first. It's great having piles of stickers but because you need them all the time you should make them all the time too. Make them at the start true... But you don't need ginormous piles of the things because once wood is going through a mill there's ongoing supply of low grade stuff to make more from.

Keep them all the same size, generally. But sometimes you need to change sizes too... The thickness of your stickers determines the maximum airflow through your packs of timber. Want faster drying, then make a thicker sticker, want slower make them thinner. Some species you want to dry fast to keep mould out, some need slow drying to reduce checking. Rather then having bigger fans and a bigger electric bill, just changing sticker sizes can have a huge impact on this. Mostly here we use 7/8 stickers, but sometimes wel use a run of 1 1/2" . What you need to be aware of though is that airflow through multiple packs depends on having even decks of boards ie when you stack packs together you need packs to have pretty much the same thickness of board and the same thickness of sticker. Stuff here that gets those thick stickers often needs to be restacked onto standard stickers after the initial air drying is done or it'd screw up the kiln loading.

One of the things we do with the high value stuff, or with species prone to stain, is put like with like. That is we'd use oak stickers with a stack of oak, walnut with walnut. Or at least white stickers into a stack of white timber. There are chemical reactions that can occur between the extractives in the wood and cause staining too. There's one species here that's very prone to a chemically induced stain like that and the best solution is to make sticks from each tree to stack it with...PITA, but it works.

A dry sticker is always better, until it hits the borax tank. Then it's a wet piece of timber again. Try and keep your stickers to species of similar shrinkage rate because if the timber gets wet and they swell from KD size you can induce a wave in your stack. Or if they're green and some shrink more them others you can get the same result. The difference between 2% and7% shrinkage in a 7/8 sticker isn't much... Until you've got 40 lots of that difference piled one atop the other.

Google "Australian hardwood drying best practice manual" and you'll find some interesting reading. Some won't apply because of the different species obviously, but I think the 101 stuff doesn't change much regardless of where you are. Gene gets cited in the bibliography several times also.

[tule peak timber]

longtime,,,very interesting...Rob

[Ribsy]

Excellent comment and a new way of seeing things, Longtime. Thats what I love about this business. When you think you're getting things figured out, someone throws you a curve ball and it turns into a strike. 😅😀😅😀

[Ribsy]

I'm in a quandary! Why, if Timbor is not labelled for mold does its treatment prevent it? From my limited experience, when I treat with Tim-Bor, I get no mold and when I don't, I do. Pine and oak, SE USA.

[tule peak timber]

fauna and flora...

[YellowHammer]

As said, some sticker stain planes out, some will only disappear when it gets loaded on somebody's truck as low grade....  ;D
Several types of stain, several types of cures, and unfortunately, several types of severity.  I have to admit to one or two bad afternoons where there was some cussing in New Market when I pulled a load of lumber and it was zebra wood.  A learning curve for sure.  Poplar and maple are tough in the summer, some folks around here won't even saw it when it gets hot and humid in July and August.  The nasty stain is the one that shows up when the wood gets planed, and gets worse the deeper it gets. 

I generally don't keep much of a stockpile of stickers, I don't like keeping them idle because they pick up moisture and possibly bugs.  I'd much rather pull a load of wood from the kiln, unstack it, then use those same stickers immediately. 

I also don't TimBor or otherwise wet any white wood anymore, unless it is noticeably bug infested. Since I use fans to quickly dry the surface of the boards to prevent sticker stain, it seems I get a little head start when I don't wet the stickers or the boards with spray.

I only use one thickness of stickers, 3/4" thick, because all it takes is one of the wrong size stickers in the stack to really cause problems, and I've had it happen more than once when helpers got tired, or lost their concentration.  Having stickers only one thickness means they don't have to think, just do.
YH



 

[GeneWengert-WoodDoc]

Mold is a fungus, but it does not eat wood.  So, when you use a fungicide on and in the wood, the mold, which is eating dust, dirt and microorganisms in the air, is not affected as you did not poison the mold's food supply.

Sticker thickness and pile width go together.  With narrow piles, you will get the same speed drying with 3/4" and 1.25".

When two stacks are adjacent side to side, in the kiln keep at least 4" space between them so the air can adjust for differences in sticker openings.  In air drying 24" is best.

[bkaimwood]

Book on drying lumber for dummies via a dry kiln in the northeast/PA?