Stair treads:
Does anyone have any ideas how to remove a very serious cup from 42″ Brazilian Cherry stair treads. 4 are in need of help. HELP???
Stair treads:
Does anyone have any ideas how to remove a very serious cup from 42″ Brazilian Cherry stair treads. 4 are in need of help. HELP???
Understand lumens, ceiling brightness, beam spread, tilt, and color options to make a wise choice on a common fixture that can range from $75 to $750 or more.
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Get home building tips, offers, and expert advice in your inbox
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial NowDig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now© 2025 Active Interest Media. All rights reserved.
Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.
Get home building tips, offers, and expert advice in your inbox
Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.
Start Your Free TrialGet complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.
Already a member? Log in
Replies
This will work but you better get them installed soon after you do it. Set them out in the sun with the convex side up and keep an eye on them untill they are reasonably straight (probably 4 to 8 hours depending on the temperature and time of day). Alternatively place them on a concrete floor with the concave side down, this will take longer and may induce some twist so try the sun method first. Good luck.
Mark
Are these already installed?
Excellence is its own reward!
They are not installed yet. New Construction.
Just pick up the cup and put it in the sink where it belongs!
Or
You can try wetting the concave side of the board and place that face down on the ground or floor. In sunny warm weather you can try it outside, allowing the sun to heat the unwetted side. Hopefully the wet side will expand and remove the cup. I've only seen this remove the cup in it's entirety in softwoods, but it is worth a try and the only solution I've ever heard suggested. You can re-plane the boards flat but you loose thickness you want for the treads and if the cup starts to come out on it's own you have another problem then...
Well I see that Goldhiller has already suggested this. That's what I get for sitting too long and not refreshing my screen. A much more technical explanation as well.
Edited 10/25/2002 8:46:03 PM ET by WFLATHER
42" deep or wide?
Tom
42" wide, 11.25 deep.
Did you cut these from stock or get them in pre-cut lengths?
If they were pre-cut, were they cupped when you got them or have they cupped since?
Did they cup after you put finish on one side only?
Is the convex side, the side with the finish?
Are we diagnosticians or courtroom lawyers?.
Excellence is its own reward!
The facts Madam, just the facts, please.
Gotta have info to give advice.
Knowledge is power, but only if applied in a timely fashion.
first he's gotta get sworn in.listening for the secret.......searching for the sound...
Hey, he said it's SERIOUS cup. This calls for serious info.
There's no time for foreplay at times like this.....or would that be floor-play in this instance?
Knowledge is power, but only if applied in a timely fashion.
New construction, home. Cupped when I received from builder. No finish applied as of yet, and they are not installed. Builder took delivery, so I don't know what condition they were received in. They are a solid piece of Brazilian Cherry, not joined.
I guess I'd do what 's been suggested prior. Add some moisture to the concave side as the cup has been likely caused by improper storage or drying technique. However, if these pieces contain really wild looking grain, you could have reaction wood on your hands and that's more difficult to deal with.
I'll assume for the sake of advice that this is a matter of uneven moisture content rather than reaction wood. More than likely the pieces were stored such that what is now the concave side was exposed to the air/sunlight/heat causing that side to dry faster than the other. It may be that these were the top pieces of four stacks of treads which sat around for a while allowing this uneven drying to occur or that they all came from one board that was stored this way prior to cutting it into four pieces.
The moisture can be added in a number of ways as all you're interested in at the time being is getting the moisture content even throughout the board's thickness to return it to a flat condition. The most expedient way to get this done would be to steam the moisture back in as this will cause faster penetration. You can use a wallpaper steamer or even a teapot on the stove to do this. Put on some heavy gloves and play the concave side of the tread back and forth in the steam plume for a few minutes and then lay it aside and do another while the first begins to absorb the moisture deeper into the board. Rotate your way thru the pieces this way until they all appear to be relatively flat and then get them clamped down so that they can be held this way for at least two or three days.
They need to be clamped so that the airflow is even on all sides this time. You can stack and clamp them all one on top of the other, but be certain to put some flat & true stickers in between the pieces about every 10" or so, as well as on the bottom. You're after even airflow and restraining force while the pieces even out their moisture content throughout the thickness. Then they should once again be flat. This should be done in a moderate temperatured place.
We can control the rate of moisture exchange by what finish we choose to put on the wood and how many layers of it. This is why we want to put the same amount of finish on the bottom of a solid wood dining room table, for instance, as on the top. Without it, the tabletop will cup as the moisture content of the environment changes.
Make certain that the "excess" moisture has escaped from the steamed sides of the boards before you put finish on them or it could cause finish failure.. I'd recommend even amounts of finish on both sides.
Edit....When you clamp these boards down, make the clamps snuggish, sort of, but not so tight that as the board cannot move from flutuating moisture content, or it could split itself apart. The wood needs to be able to slide between the stickers as it seeks equilibrium.
Knowledge is power, but only if applied in a timely fashion.
Edited 10/25/2002 9:49:50 AM ET by GOLDHILLER
Edited 10/26/2002 9:17:28 AM ET by GOLDHILLER
Please explain the "free water" and "cell bound water". I thought all cells are pretty dead after the tree is cut and the wood dried. Shouldn't all moisture flow through the dead wood and achieve equilibrium with the surrounding?
Tom
Yes, all moisture will eventually pass thru wood until that wood "reaches" EMC. EMC is not a static state though, because relative humidity isn't static...... and so it's a relative condition rather than fixed state. This is what the authorities of wood technology tell me. I've never seen evidence to the contrary.
The difference between free water and bound cell water goes something like this according to those who look at it under the microscope.
Wood is comprised of cells. The moisture contained within the cell wall sac is known as free water while the moisture contained in the cell wall membranes themselves is known as bound water. The free water is quite easily and rapidly removed. Once all the free water has escaped, the wood has reached FSP; the fiber saturation point. What is left in terms of moisture is known as bound water. Bound water is called that because it's bound by physical attractions within the cell wall membrane and is not nearly as easy to remove because of this. Both the free water and the bulk of the bound water must be removed in order for the wood to reach EMC (equilibrium moisture content) with the environment surrounding it, and attain the characteristics of strength and relative dimensional stability that makes it useful to us as a building material. When we're in a hurry to use the wood, we turn to kilns to help extract both the free water and the bound water more rapidly.
IME, kiln dried lumber is more dimensionally stable than air-dried lumber because those cell walls undergo changes during the "rapid" kiln drying process that leaves the wood in a state that is not quite as welcoming or receptive to atmospheric moisture. But....I prefer working air-dried stock as it's much creamier under a sharp hand plane and cabinet scraper. Knowledge is power, but only if applied in a timely fashion.
To remove cup from wood...
Using saws, chisels, rasps files, etc... remove everything that does not look like cup.
Once all "not-cup" is removed, all that will be left is cup.Political discussion on this forum = The blind insulting the blind
Quittin' Time
Darn, you guys are fast. I was going to reply to Fred's posting and when I post it two postings already got in front. I hope I can get this one posted before anybody butt in. Thanks for the explanation Goldhiller, does free water include extracellular water as well?
Tom
I'm in trouble here. I've no idea what "extracellular" water is and my ignorance is now apparent, or............I'm missing something here that's going to make me embarassed anyway.
You're pullin' my leg, right? Knowledge is power, but only if applied in a timely fashion.
You are not in trouble, you are not missing anything and I am not pulling your leg. I understood everything you said until I hit
>>the moisture contained within the cell wall sac is known as free water while the moisture contained in the cell wall membranes themselves is known as bound water.
I remember my plant biology that a plant cell has a cell wall which gives the plant the rigidity because they don't have a skeleton. The cell wall is fibrous and non living. Inside the cell wall is the cell which is bound by a cell membrane. Anything inside the membrane is intracellular and anything outside is extracellular (this is not where you cannot receive your cell phone signal). When you said "the moisture contained within the cell wall sac is known as free water while the moisture contained in the cell wall membranes themselves is known as bound water." to me the "moisture within the cell wall sac" is intracellular and "the moisture contained in the cell wall membranes" is membrane bound water so it is just logical that I asked what happened to the extracellular moisture. Also when the cells die the membrane becomes permeable to water and moisture so the cell cannot control the migration of moisture/water anymore. By the way I don't believe in "feeding" dead wood with oil.
Your observation on kiln dried vs air dried, can I make the similarity that kiln dried is like washing your hair frequently with a strong shampoo without conditioner and blow drying the hair with high heat?
Tom
Yeah, I think it's similar to that analogy. I think of it kinda like two pieces of pasta. The one that's immersed in boiling water right from the package will absorb the water and become eatable in "x" amount of time while one that was dried to an extreme in an oven first just won't respond the same to that boiling water. It may never be useful for anything but the sole of a shoe or maybe you could make a saddle from it in a pinch. IME, kiln-dried stock is like that force-dried piece of pasta...it just isn't as receptive to moisture and consequently is more dimensionally stable. Since furniture grade stock is dried to a lower moisture content than construction grade lumber is, the resistance is more pronounced in that grade of lumber.
And yes, I'd agree with you that there should be some water that is "extracellular", but folks like Bruce Hoadley in his book "Understanding Wood", I don't think make any mention of this in particular; neither does Ernest Joyce in his book " the Encyclopedia Of Furniture Making". However, both he and other authorities on this matter, will tell you that the moisture you refer to as membrane bound water is indeed bound by physical forces whether the cell is "dead" or not and is more difficult to remove……… I dunno.
A certain amount of technical info is and has been very beneficial to me when building anything of wood as it gives me an "edge" of understanding the how's and why's of choosing lumber, (be it for the lowly wall stud or for a credenza) storing it properly for later use, and engineering a piece to last for generations without ever tearing itself asunder, BUT………………at a certain point the technical info becomes irrelevant to my efforts and results. For instance, if I know how to recognize the best pieces of lumber because of grain structure and can recognize a piece of case-hardened wood caused by too rapid of drying in the kiln…… I benefit. But I can't conceive that staring at wood cells under the microscope would be helpful to me and so I don't do that.
I remember having many (read that as "too many") of these "wood cell" discussions years ago when I still lived and worked amongst a large community of professional furniture and cabinet makers on a day to day, decade to decade basis. The beer flowed as the discussions progressed and nothing ever came of it….except that we all had a good time. I concluded that this was the most important thing about all those "the nature of wood cells" discussions…….it provided a suitable topic around which we could converse, enjoy each others company and drink beer. It beats the heck out of centering social discussions around politics, which is never fruitful either and frequently leads to fist-a-cuffs, especially when mixed with alcoholic beverages. Long live the great debate of wood cell physics. It's probably kept many a tooth in its socket.
Knowledge is power, but only if applied in a timely fashion.
well taken
Tom
Even though this discussionb might seem to have been too cerebral for some, it is exactly the reason that this place has value. In the midst of practical advice we find a wealth of educational material interspersed with jocularity. Now I have something to ponder all day while I work my little butt off.
As beer in the can is known as extra-cellular ethyl and once consumed and assililated, it is known as intra ceellular ethyl. And the potential hangover is post-cellular ethyl.
Excellence is its own reward!
Well now. If you've got an abundance of extra cellular ethyl around, you could bring it over and we could then discuss the matter.
Knowledge is power, but only if applied in a timely fashion.
Why don’t you take the boards back? Instead wasting the contractor’s time and your Money. It is one thing if you are doing this project as hobby and don’t care if you waist your time just to save some money. That contractor can’t be cheep to have him standing there steeming two stair treads.
New treads have been ordered. Too much time and $$ to fix. Thanks.
With all the valuable information already presented I would go with the above advice, return those boards. First of all the contractor shouldn't have accepted those boards in the first place thinking that the stair builder would take time and effort to correct the shortcoming. It sounds like a pretty impressive stair so why chance it.
Tom
i always thought hardwood stair treads were made out of three pieces of laminated wood
plane
plane the wood, perpendicular to the tread,hand plane or electric, then hit with beltsander, just do one side, deal with the other side.
listening for the secret.......searching for the sound...
I dunno but it could be a grain problem, the blanks could have been taken from the outside of the tree instead of the more stable heart of the tree. I'd have to see the endgrain to be sure, but that isn't going to help you now. Another " fix " for this problem would require you to rip the stair treads into four pieces, invert every second piece and re-assemble the treads using biscuits or dowels. I'm sure a cabinet guy could do it for you or explain the process, but you'll need some shop equipment to do the job properly.
sometimes board sometimes knot
2 words, just 2 words: Power Plane
Hope this helps