What is the best sticker material

[Jjoness4]

Still learning the trade.  What is the best sticker material out of the following possibilities- Red oak, poplar, southern white pine, ash.
I am having staining issues with really all of these.  Perhaps I am not spending enough time preparing stickers for service.  How dry do they need to be?  Any help and advice is greatly appreciated.

[beenthere]

Dry is the best... of all of those choices.

[bkaimwood]

Dry, dry, dry,...most important!!! White pine is my choice, ideally, you'd have stickers cut and dried of the same species you are stickering... Grooves cut in the stickers can help airflow and sticker stain...you have to be specially careful on whitewoods and others like cherry...check and move them often, and get the surface MC off quick, to minimize risk...fans...

[GeneWengert-WoodDoc]

There are more oak stickers for hardwood lumber drying than any other species.  Apitong is also popular.  Both a strong so they resist breaking and compressing.

For softwoods, various species are used, mostly all softwoods.  Plywood stickers are popular too, along with aluminum.  For large softwoods operations, the stickers must be very straight so they feed through the automatic stackers.

[YellowHammer]

I am having staining issues with really all of these.  Perhaps I am not spending enough time preparing stickers for service. 

As you are finding out, stickers make or break the lumber.  They are boring, unexciting, and mundane, but good stickers make good lumber, bad stickers ruin it.  Stickers have to be bone dry, preferably just unstacked from the kiln and put immediately back into service.  Personally, I plane and "H" cut all my stickers, and its been a long time since I've seen zebra wood. 

 

[GeneWengert-WoodDoc]

I would like to clarify the term "bone dry" used by YH.  We do not want the stickers to be really dry, like under 6% MC, as they can dry the wood right under the sticker too fast and create two issues.  First, drying really fast, including right under the sticker, means white colors.  So, if the rest of the lumber is dried slightly slower, the color of the rest of the lumber will be slightly darker and the stickers will leave a white streak.  Second, with oak, really dry sticks will dry the wood right under the sticker too fast and create checks that will likely become honeycomb or internal checks.  So, it is often the best idea to use 10% MC sticks for oak.  For white woods like maple, dry sticks are great, but then make sure that the initial drying is as fast as it is suppose to be without rain wetting.  Avoid warmer temperature initially as well.  Basically, differences in drying rate mean differences in color of the wood.

[Compensation]

Sounds like a "breeze dried" style might be beneficial. I am thinking about trying some out.

[YellowHammer]

Sounds like a "breeze dried" style might be beneficial. I am thinking about trying some out.

They are relatively expensive.  I make my own version and they work well.

[Compensation]

Hmmm Do you just cut your grove with a dado blade?

[longtime lurker]

I'm curious about the H grooves.

Do they lead to compression indentations because of the reduced bearing surface?
In multi pack stacks, do the bottom rows of stickers ever collapse due to the weight?

NB: I dont have much if any sticker stain issues but I'm always interested in learning new tricks.

[GeneWengert-WoodDoc]

I would also be curious if these stickers violate the patent rights that Breeze Dried has.

We do know that such a design has about 2-1/2 to 3 times more weight or psi at the contact area which does result in compression or indentation.  To minimize this, avoid sticker spacing more that 16" and tall stacks.

[beenthere]

Long as he doesn't sell them to others... can't be a violation of Breeze Dried pat.

[Jjoness4]

Thanks to all for your helpful input.  I am amazed continually at the wealth of experience and knowledge on the Forum.  One more question:  I have an abundance of 1" MDF (medium density fiberboard).  Just wondering if this might be a suitable sticker material.  What do you think?

[Denny]

"I would also be curious if these stickers violate the patent rights that Breeze Dried has."

That was my thought too. I don't know much about patent laws, but I think if you're making your own BD style stickers and you're a business, you might not be able to use that design. And if I recall, the company who holds the patent has been known to be litigious on the subject.

[Compensation]

The breeze dried I've seen have small humps going at an angle. His shaped like an "H" are not even close to their designs that I've seen. I have their trifold on my lap right now. They are rounded small humps that touch the wood. I believe if you copied it and made square humps you would not violate this particular patent. Maybe they have that square humped patent hidden in a safe somewhere but he is far away from any of it on his design.

[Compensation]

www.breezedried.com

They look good

[YellowHammer]

I'm not a patent attorney, but I have a some experience with patents and did a reasonable investigation some time ago into the Breeze Dried patent, as well as several others, both to become familiar with the state of the art, as well as the prior art, in order to push my techniques as far as possible.

The patent in question is Breeze Dried Patent RE3818, Lathe for Lumber Stacking, May 13, 2003
The Breeze Dried Patent claims many things, but the common claim is "a plurality of grooves extending transverse to the length of the separator to permit air circulation within the grooves, and a plurality of ridges between the grooves to support the pieces of lumber. In another embodiment, a second plurality of grooves extending. transverse to the length of the separator and the first groove to form a cross-hatching of grooves to permit air circulation within the grooves, and a plurality of protrusions to support the pieces of lumber over the grooves."

In other words, it claims multiple transverse grooves across the sticker, at varying angles.  It also claims a crosshatch pattern, transverse to the length of the sticker.

The common "H" style sticker, grooved with an axial cut down the length of the sticker is discussed in the patent and considered a relatively common industry standard, and prior art, i.e. a point of departure and improvement for the new, improved patented configuration which incorporates the same transverse grooves across the sticker, whether it is solid cross section, "H" shaped, or whatever.  The patent specifically states how the Breeze Dried sticker is an improvement over the conventional axial "H" design, therefore the Breeze Dried patent doesn't apply to my sticker, unless I cut angled grooves across its width. 

Quoted from the patent, "a plurality of grooves extending transverse to the length of the separator to permit air circulation within the grooves, and a plurality of ridges between the grooves to support the pieces of lumber. In another embodiment, a second plurality of grooves extending transverse to the length of the separator and the first groove to form a cross-hatching of grooves to permit air circulation within the grooves, and a plurality of protrusions to support the pieces of lumber over the grooves."

Later in the background text of the patent, the "H" style sticker is discussed, its advantageous and disadvantageous, relative to it being "prior" state of the art, in other words, "state of the art" prior to the invention of the Breeze Dried patent, which is the "new state of the art", and its subsequent improvements and advantageous.

Again, quoted from the patent "Nevertheless, the lengthwise groove design to reduce contact area was adopted in the industry, but in wooden separators. It is not uncommon now to find wooden separators cut with top and bottom lengthwise grooves forming an "H" shaped cross section. The "H" separator reduces contact area and utilizes the wood resources of a mill but suffers the same disadvantage of poor air circulation along the long narrow grooves. The manufacture of such wooden separators may use equipment ordinary to a mill, but cutting lengthwise grooves requires close tolerances and straight separators to maintain the alignment of a groove to the long axis of a narrow separator. Further, manufacturing many separators may require many tools or many runs through the same tools.  It is an object of this invention to provide an improved separator for separating lumber that provides reduced contact area between the separator and the lumber, improved air circulation and permits simple manufacture without close tolerances using equipment commonly found at a mill."

In the diagrams of the patent, the prior art "H" groove sticker is identified in Figure 5, as compared to an "H" grooved sticker with the new, patented transverse grooves, Fig 6.




So its my conclusion that I'm not infringing on any patents with my conventional "H" shaped, "prior art", sticker.  Also, Despite Breeze Dried's claims to the disadvantageous of an axial goove cross section, the sticker is still a definite improvement over the common solid cross section sticker, and makes a significant difference drying wood.

Incidentally, the Breeze Dried patent will expire in a few years, as American patents have a limited life. 

I cut the stickers on a dado blade with a power feed at 100 feet per minute, which is pretty fast.  I've got a video on YouTube showing me making some. 
https://www.youtube.com/watch?v=jcrfH66gBI4
They are all kiln dried, planed to correct height, then grooved.  I can reuse them many, many times, and have thousands of them.  The current width of the legs of the "H" don't cause any compression, although it will manifest if they are significantly narrower.  The highest I've stacked is 12 feet high, and I use 16 inch spacing.

[GeneWengert-WoodDoc]

The adhesive used for MDF will not standup to the moisture in the kiln.

YH has indeed done a great job describing the patented sticker.  It does look like there is no conflict to me as well.  One advantage that figure 5 has is that there is more wood in the sticker than the "H" design shown earlier, so the sticker should be stronger.