Any issues with glueing and clamping flat-grain hard maple 2×4’s for a countertop (96″ x 30″)? Top will be on a center kitchen island that has a flat top cooktop?
Can I use regular Titebond and standard clamping pressure (pipes, Besseys, etc.)?
Thanks,
Brian
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Replies
In most cases it is against sanitary regulations especially in commercial kitchens.
The top would be in residential kitchen and it is not for cutting; should I glue up edge grain and seal with oil?
I've made and installed many maple tops glued up long grain style.
use tite bond II or III and finish it up with a food grade oil finish.
Maple is very good for this as it has natural germ killing stuff in it, see tests by Forest Product Labs. Cheers
finish it up with a food grade oil finish
This should be tested on mythbusters. Contrary to popular belief, any finish could be used on your countertop.
http://www.popularwoodworking.com/features/finish3.html
The Folly of Food-Safe Finishes
"Despite what you've read elsewhere, almost every wood finish should be considered food-safe.
By Bob Flexner
It's a shame, but many woodworkers worry about which finish to use on objects that will come into contact with food or children's mouths. The reason for the worry is that woodworkers have been conditioned by several decades of articles in woodworking magazines to believe that ordinary finishes like boiled linseed oil, alkyd varnish and polyurethane varnish may leach poisonous ingredients like metallic driers. And other finishes, like lacquer, catalyzed (two-part) finishes, shellac and water-based finishes, may leach poisonous solvent.
The idea that some finishes are harmful is reinforced by a few manufacturers who label their finishes food- or salad-bowl safe, which implies that other finishes are not. "
A Non-IssueThe shame for woodworkers is that a lot of energy is spent on the issue of food safeness when none is warranted. Food safeness is a non-issue because there's no evidence of any problem. So far as we know, all finishes are safe to eat off of, and safe for children to chew on, once the finish has fully cured (the rule of thumb being 30 days).
Think About It• Have you ever heard or read of anyone, child or adult, being poisoned from contact with a cured, non-pigmented finish?
• Is it likely that any finish could be sold in paint stores or home centers without a warning if the finish were known to be dangerous for food or mouth contact? (Paint store clerks are rarely even aware that there might be an issue
• If there were any evidence that common wood finishes were unsafe for food or mouth contact, why is no mention made on the MSDS (material safety data sheets)? All unsafe uses of products are required by law to be listed on these forms, along with information about treatments for resulting health problems.
• Finally, does it make any sense that commonly available oils and varnishes that contain driers and solvents could be a health risk while the so-called "food safe" oils and varnishes, which contain the same driers and solvents, aren't a problem? (These finishes wouldn't cure without the driers and would be too thick without the solvents.)
"I learned this, at least, by my experiment; that if one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours."-Thoreau
Edited 7/21/2007 12:09 am ET by rez
Rez,
You asked:
"Think About It
• Have you ever heard or read of anyone, child or adult, being poisoned from contact with a cured, non-pigmented finish?"My six year old as a newborn used to sit on my lap as I tapped away on the computer (presumably this forum) and I thought it was cute that he would chew/teethe on the edge of my 1940's oak desk with a clear finish. At 9 months his pediatrician did some routine blood tests and his lead level was 21mcg/dl.This level of lead required the pediatrician to notify the county health dept who sent a nurse and a building inspector out to our house to both educate us and identify the source of lead.After examining our soil, exterior and interior finishes and a furniture the highest concentration of lead was found in my old oak desk with a clear finish. The inspector concluded that it was the source of our childs high lead levels.Needless to say this was a big eye opener for me as I had assumed clear finishes didn't have lead, only pigmented paint.I am just pointing this out as I could have stopped the chewing at any time, I just was misguided in my understanding that clear finishes were harmless.Karl
very interesting. I too have never heard of a lead based clear finish.
I once was involved with a HUD rehab project and spent about a week solid reading everything that was avaible on lead based paint. HEY, maybe that's it- everybody always refers to the lead problem as lead based paint instead of lead based finishes.
Once read about an electrican with elevated lead blood levels. Nobody could figure out the source. Finally it was figured out that he always chewed on a scrap of wire (kinda like a toothpick), there was lots of lead in the insulation.
IIRC, years ago, lead was used as a drier in varnish. This practice is obviously no longer used.
This thread is about finishing a new piece. The issue of lead in a finish is no longer possible.
JMadson,
Sorry for hijacking the thread.You point out:
"This thread is about finishing a new piece. The issue of lead in a finish is no longer possible. "My intent was only to address the statement Rez made:"Think About It
• Have you ever heard or read of anyone, child or adult, being poisoned from contact with a cured, non-pigmented finish?"As it turns out I have personally experienced a child being poisoned from contact with a cured, non-pigmented finish.I concluded my post by saying:"I am just pointing this out as I could have stopped the chewing at any time, I just was misguided in my understanding that clear finishes were harmless."You are right though that contemporary finishes of all types are lead free.Having gone through the family drama of a lead poisoned child I opted to err on the side of sharing what I think is valuable information even if it is a bit off topic.My apologies if you felt it was inappropriate.Karl
Edited 7/22/2007 6:18 pm ET by karl
The post you referenced wasn't really from me in that it was a cut/paste continuation of the article linked by JMadson in post #24 right before my post in #25. My bad.
"In any weather, at any hour of the day or night, I have been anxious to improve the nick of time, and notch it on my stick too; to stand on the meeting of two eternities, the past and future, which is precisely the present moment; to toe that line."-Thoreau
As I get older, I'm learning to be more tactful. I obviously missed this time.
I was just redirecting back to the main point and clarifying history vs. current trends, but I didn't mean to imply that it was inappropriate in any way. Yours was a good addition to the post.
Any finish may be used but one would have to wonder when you smell a board where the oil has become rancid. I have never seen that happen with mineral oil.
What sanitary regulations are you referring to?
Using it as a cutting board.
That ain't what he asked.
And you are wrong anyway.
Ok - Thanks for the replies guys; I think I am going to glue 2x2's on edge grain and finish as suggested.
It'll be fine. Plenty of clamps, I hope. Might wanna do it in about 3-4 stages, IOW, glue up a plank, then another, then another..plane them flat and true, then glue them up into one, and scrape them even, then beltsand.
Piece of cake.
If using 1 inch thick boards, how deep would you cut the width of the boards on say a six foot counter?
be a counter offer
jlowe is the king lurker. Long live jlowe !
Do you mean rip to make up the lams for thickness?
If so, I'd rip to about 1 3/4. Glue up a slab as wide as my planer could handle ( 13") and make two that wide. Plane to flat and even on both faces, the glue them two togther into one @ 26" wide. Handplane the joint and sand a bit before Oil.
If that is what ya meant.
well ya.
How come 1 3/4"?
jlowe is the king lurker. Long live jlowe !
So, after finish planing you net 1.5". 34.5" cabs+1.5" top=36" from FF. Not always needed to be nailed exactly, but a common standard.
edit: even well drird lumber will yeild un-straight rips from the mother plank. If I need say 2" finish from a 1x10, I joint, rip at say 2.25, joint again and re-rip. Or if as in this case, Imay be inclined to plane a few rips at a time to a dimension that STILL allows planeing to final thickness after the glue up. To allow for misalignment or slippage while glueing.
The secret to getting dead nuts straight stock is a series of steps...rough milling, followed by finish milling. I even have two planers set up just for that reason, the first is for fast skip planing, and the other is kept as sharp as possible, for final passing stock thru. Or for other applications, I hand plane/scrape to final surface.
Edited 7/21/2007 7:06 am ET by Sphere
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
"I learned this, at least, by my experiment; that if one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours."-Thoreau
Before anyone goes to the effort of building butcher block I would suggest contacting American Wood Products in Horsecave, KY. I bought a top for an island several years ago. The price was good, they know how to pack it so it survives the trip, and the wood was beautiful.
If I am so wrong why do you think so many cities have required hospitals and restaurants to cover their maple blocks or replace them with something else?
Edited 7/20/2007 9:23 am by gb93433
why do you think so many cities have required hospitals and restaurants to cover their maple blocks or replace them with something else?Because, as often happens, well-intentioned government regulations are slow to respond to scientific knowledge. At one time it was thought that wood surfaces harbor more bacteria than others, such as plastic. But research has shown this to be untrue--in fact, as long as the wood surface is kept clean, it's more sanitary than plastic. That's a proven fact now.By the way, one thing to keep in mind when installing a maple countertop is that it will grow and shrink with the changing weather (among other factors), so you'll want to allow for the movement when fastening it down (slots instead of holes for screws underneath, for example). I believe most of the movement will be across the grain--but correct me if I'm wrong anybody.In installed a 4x5 maple countertop (made by John Boos) in my own kitchen and it's fantastic. By the way, make sure to oil it regularly (after a thorough cleaning) with food-grade linseed oil (http://www.triedandtruewoodfinish.com/danish.htm) or a mix of mineral and lemon oil (lemon oil has antiseptic properties and gives it a nice smell).
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Edited 7/20/2007 10:02 am ET by Megunticook
Edited 7/20/2007 10:07 am ET by Megunticook
Due to outdated or inaccurate information.
I had a commercially inspected kitchen, for my wife's catering bizness, and my processing of hot sauce. Never an issue with wood chopping block or cutting boards. I cut on wood vs. the Stainless steel counters and prep tables.
In 1979 I worked in a shop where we either replaced or covered all of the blocks in the commercial kitchens in the city. That was due to a health department regulation.
Long since rescinded ( at least where I was in NC).
There may be maany that do, but not with valid reasons, and it is far from being a universal truth as you seemed to imply. It is more the exceptiopn than the rule to find such a requirement
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Maybe wher your commercial kitchens are. But for years now there have been test results showing that maple cutting boards harbour fewer micro-organisms than the hard plastic tops formerly recommended.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Maybe so, but that is rather silly, especially in a residential application.The real problem is that meat inspection standards are at a 50 year low.I have a wooden counter top, and in 15 years have not had any sanitary problems.I treated my counter top with a high grade olive oil, and it is just now beginning to need a second application.
I don't like wood countertops near stoves or sinks. If you are installing near a cooktop, excess heat will tend to overdry and split the ends near the heat source. Others see no problems with this type of installation, however. I guess it depends on how hot the area gets and how close the hot pans get to the countertop. Wood will also get burn marks if you put a hot pan on it. If you are willing to live with these risks, your plan is fine. I suggest gluing up in 10-12" sections, using buscuits to keep things aligned during gluing/clamping. Poly glue works well, but Titebond II or III works fine as well. Run the sections through the planer to true up the subassemblies, then glue them together to get your final width. Even that out with a belt sander or take it to a place with a wide belt thickness sander for final leveling.
Use a foodsafe oil finish like salad bowl oil. Plan on repeating this every six months or so. Don't count on it looking like nice furniture. In fact, I suggest you don't baby it, but use it like a cutting board/countertop, not worrying about the dings it'll inevitably get anyway.
Mike Hennessy
Pittsburgh, PA
Maple tops have been used for a long time and with very good results.
I was always taught for oiling tops to use this rule ; once a day for a week, once a week for a month, once a month for a year and every year after that.
I'd glue it up in sections, maybe three of them, then I'd glue the whole thing up(wouldnt plane inbetween) then find a cabinet shop that you could take the whole thing to and have them run it through their wide belt sander. If you feel the need you could bisquet or make a spline for the full length of the top as it would save on your sanding waste.
Doug
I made a maple butcher block countertop for the island in my home -- got two maple block 25" counters, biscuits and lots of poly glue and clamped them together. It's been more than a year, and I can't remember or tell where the seam is. (I tested a couple pieces before the entire island piece, and the wood broke before the glued seam.)
If you don't want to go through the work of piecing individual pieces together, I got the counters from Lumber Liquidators at a good price. I think the entire counter top cost less than $300 for a 5' x 7' island top...with a good chunk left over to make some cutting boards.
As for sanitary, I don't cut on the counters...just the cutting boards I made. But I do heat up a pan of mineral oil on the stove every couple of months and sponge it on. You can also seal the counter with beeswax.
Should turn out just great.
Make sure you use the same amount of finish on the bottom of the countertops as you plan to put on the top. Also allow for the countertop to move when you install it. Those seem to be two of the biggest reasons why people end up with cupped or split wood countertops. Also make sure you get the end grain sealed nicely.
I use oil finishes so that they can be renewed easily (although it takes a committment on your or the client's part to keep it up) If I do an undermount sink I make sure to really finish the exposed sink-side end grain and do so every few-several months.
I use foil tape on the underside of the countertop over the dishwasher as a moisture barrier, and I use foil tape over the edge grain and underside of the countertop around stoves as well. I know it helps with the dishwasher, as I've seen the negative results with no protection, but I use it around the stove just as an added measure, and I can't guarantee that it makes a difference. It only helps me sleep a little better at night.
After I've glued mine up I take them to a local woodworking shop and run it through their giant belt sander. I find it turns out more even than when I hand belt sand it, and the $50 or so in cost is usually well worth the time saved.
Paul
Make sure you use the same amount of finish on the bottom of the countertops as you plan to put on the top.
Yet another myth in need of busting. There's no need to finish both sides of a piece...
http://masterpiecefurniture.com/design_notes/flexner/antiques_roadshow.html
Tabletops and the need to refinish
by Bob Flexner
IT’S A WIDESPREAD MYTH among woodworkers that the way to reduce, and maybe even prevent, warping is to finish both sides of the wood. I don’t have any objection to finishing the underside and inside, but doing so isn’t going to have any significant impact on warping; the moisture content of the wood is going to adjust to the surrounding atmosphere anyway. It’s keeping the finish on the exposed side in good shape that makes the biggest difference.
Have you ever noticed that warps in tabletops, deck boards, siding, floor boards and even cutting boards are almost always concave on the top or exposed side? And that this is the case no matter which side of the wood (heartwood, sapwood or quartersawn) is up or out, or whether one or both sides of the wood is finished?
The explanation is that the top or exposed side was wetted and allowed to dry repeatedly over a long period of time, and the finish (or paint) wasn’t in good enough shape to prevent the water from getting to the wood.The continued wetting and drying of just one side caused compression shrinkage (or “compression set”).
Compression shrinkage is a technical term used by wood technologists to describe a condition in which the cylindrical cells of cellulose in wood are not allowed to expand when moisture is absorbed, so they get compressed into oval shapes. Compression shrinkage explains how screws work loose in wood and wooden handles become loose in hammers and hatchets. It also explains splits in the ends of boards and checks in the middle of boards in addition to warping.
When water enters wood, the cellulose cell walls swell. If the wetting is only on one side and the thickness of the wood prevents the cells from expanding, they become compressed into oval shapes.When the wood dries, the cells don’t resume their cylindrical shapes and that side shrinks a little. Each time the one side is wetted and dries out it shrinks a little more. Repeated wetting and drying of one side eventually leads to that side cupping, and if the cycle continues long enough, the wood splits and checks.
Tabletops are commonly wiped with a damp cloth to clean spills and sticky dirt. If the finish is allowed to deteriorate to the point where it no longer prevents water penetration, warping and eventual splitting result. More than any other furniture surface, the finish on tabletops needs to be kept in good condition.
Compression shrinkage has been well understood by wood technologists for decades, but none of them carried it to its logical conclusion to explain warping until Carey Howlett did so in a paper he presented to the Wooden Artifacts Group of AIC (The American Institute for Conservation of Historic and Artistic Works) in 1995.You can read the paper at: http://aic.stanford.edu/sg/wag/1995/WAG_95_howlett.pdf.
(Interestingly, understanding the cause of warps in tabletops leads to the counter-intuitive but effective method for correcting warps. Hold the board in clamps across the grain to keep the wood from expanding.Then wet the convex side, usually the bottom side of tabletops, many times, letting it dry thoroughly after each wetting.The convex side will slowly shrink, bringing the board flat.)
That makes sense. I'm always one to listen to someone's building science.
But I will add a disclaimer that in my opinion the undersides around the sink cut out and especially above the dishwasher still need several coats of finish as actual moisture protection, even if not for moisture content equalization to control wood movement.
You didn't by chance read the referenced study by the Colonial Williamsburg Conservator of Furniture?
Don't know where Flexner is coming from, but the paper he references says:
"Warpage from compression set shrinkage is common in panels and boards where the presentation surface is relatively stable-shielded by an effective moisture barrier (paint, varnish) or held rigid by a physical addition (perpendicularly laid veneer)- while the reverse uncoated surface is open and responsive to relative humidity fluctuations. In such panels, the stable presentation surface acts as a restraint, causing the uncoated moisture-responsive surface to undergo compression set shrinkage. This shrinkage affects the entire panel in the form of a pronounced warp, convex across the width of the presentation surface."
The paper is actually about how to deal with warped pieces left subject to those uneven MC changes. There's even a drawing illustrating the warpage from uneven surface treatments. Difficult to miss the point.
R. Bruce Hoadley in "Understanding Wood" says: "If there is anything worse than no moisture barrier at all, it's an uneven moisture barrier, which would allow moisture to be adsorbed or desorbed unequall in different areas of the wood. ... It is crucial that all sides of every board receive equal finish."
I read the paper as it came out 15 yrs after Hoadley's book. There's no contradiction. Who's Flexner? Apparently he never read the paper he referenced. I'll refrain from commenting on Flexner's other inaccuracies. He's seemingly never read "Understanding Wood" (Taunton Press). Hoadley, BTW, has a degree in forestry from Univ of Connecticut and a doctorate in wood technology from Yale.
But J, thanks for bringing this into the light. PAHS Designer/Builder- Bury it!
I actually spent a week with Flexner at the Marc Adams School of Woodwork in Indiana - just a couple of weeks ago. He's forgotten more about finishing then I'll ever know. Check out his book Understanding Wood Finishes, great reference to have.
We actually talked about this in class one day. My take on it is there are two phases when wood will change shapes. First is the initial loss of moisture left over when it was a tree. The second is repeated "watering" of a surface over the years, i.e. cleaning or spilling. He's talking about the later. If you keep getting one surface wet and not the other, it will keep cycling wet/dry until the cells on the wet side go oval from repeated compression and the wood stays that way. It doesn't matter if it's finished or not, water and moisture will still creep through any finish over time.
I'll need to re-read his references before I can comment on what he wrote. Write now, I'm just going on what I've heard him say.
It doesn't matter if it's finished or not, water and moisture will still creep through any finish over time.
Actually, aluminum paint does a pretty good job of stopping moisture travel. <G> But the issue is not that moisture goes into and out of wood, but the differing rates between sides of a board that's finished (or cross-banded) on one side, raw wood on the other. Warpage results.
Glad to hear Flexner has some background, but referencing a paper he apparently didn't read and using conclusions not found in the paper for his own ends is inexcusable. He didn't even see the one illustration! I'd repost it here but have no idea how to get it out of "clipboard". I'm inept with pdf.
Flexner, and you, would have a better understanding about compression set after reading Hoadley (1980, ISBN 0-918804-05-1). I copied the relevant paragraph from the paper Flexner referenced. Clearly contradicts what Flexner wrote, doesn't it? Amazing that he didn't see it.
I have a lot of respect for anyone good with finishes. I'm mediocre at best, but I do understand how they perform. Not just what I've read (motivated by my own past failures) but from my 30 yr progression of furniture-making.
Met Hoadley just after his book was published, at a national woodworkers' conference in Utah. He was the one presenter that virtually every woodworker presenter (names you'd recognize) made it a point to sit in on his lectures. That's why I wanted to see who (CW Conservator of Furniture) was correcting Hoadley's studies. Turned out there was no correction, just Flexner's misuse of the paper.
I'll need to re-read his references before I can comment on what he wrote.
Surely that was a typo (re-read). You didn't really read the referenced paper and come away with Flexner's conclusions did you?
PAHS Designer/Builder- Bury it!
Tom,You and Madson are talking about different situations.You are correct that single sided finishing will cause wood to warp from environmental moisture.He is correct that double side finished wood will still warp from the repeated application of water to one side.I use a 15yo, 3/4" x 8" x 10", cutting board that gets oiled once in a great while. To prevent warping I always wash and rinse both sides the same even though I mostly use the same side when I cut on it.SamT
Not quite Sam. Madson posted a column by Flexner, which I read with interest. Enough interest to follow the link. The subject of this thread at the time was if both sides needed a finish to diminish warping.
Here's Madson's post, responding to hipaul:
Make sure you use the same amount of finish on the bottom of the countertops as you plan to put on the top.
Yet another myth in need of busting. There's no need to finish both sides of a piece...
Then he quoted Flexner:
"IT’S A WIDESPREAD MYTH among woodworkers that the way to reduce, and maybe even prevent, warping is to finish both sides of the wood. I don’t have any objection to finishing the underside and inside, but doing so isn’t going to have any significant impact on warping;"
Not quite what the article Flexner referenced said. Was a very interesting article about 2 methods to deal with warped wood in casegoods. One of which was "Induced Compression Set, shrinks a convex surface to the narrower width of the concave surface using moisture and physical constraint".
No myth, as you know. PAHS Designer/Builder- Bury it!
Now I need to re-read the article (you were right about my mispeak above)
At the initial impression, it does sound contradictory. The only thing that I can think of is that Flexner's point could be that, regardless of finish on one or both sides of a piece, it will "eventually" warp either way - which I think we all agree on.
That being said, why wouldn't you finish both sides just to be safe?
(I'm so confused)
The warping is best managed in the traditional manner: quarter sawn boards, with the grains opposed, and a "floating" installation. It also helps that the slats be rectangular ... and glued on the 'broad' faces. If you apply finish to one side only, the warping is likely to be pronounced. At least the original coat ought to be applied to all faces. Later on, it's OK to just renew the finish on the exposed face, but that's another matter. I don't like the idea of "any" finish or varnish .... but perhaps that's a design choice. I would prefer a finish that didn't flake off or scratch. Mineral oil is one such finish. It will show off the wood grain, is perfectly edible, and will repel minor amounts of moisture.
On my counter, I used ordinary cooking oil as a finish. I have been persuaded that mineral oil will not go rancid - a risk with cooking oil. In either case, to 'refinish' one need only scrub the top with a strong soap (as in an SOS pad), rinse, and rub in the new oil.
Actually, the USDA has absolutely no problems with wood cutting surfaces, in any place where food is handled.
Around 1990, there was a sudden, widespread belief - a belief that had no basis, but suddenly appeared in some press releases - that wood was inherently less sanitary, supposedly due to the wood having pores.
By 1992, there was plenty of actual research done that showed wood no more septic than plastic ... indeed, the data suggested that wood might even be slightly more sanitary than plastic. It was speculated that tanins in the wood may have some antiseptic properties.
That false belief led to a considerable expense, as everyone rushed to replace all wood in their facilities ... from knives (handles) to counters to serving trays. It is a good example of false 'science' causing us to waste resources that could better be used elsewhere.
As for a wood counter: They have worked fine for centuries, especially where cutting is performed. They need to be wiped with mineral oil on a regular basis - the more so if they get wet. They are not suited for use around a sink for this reason. They are reasonably heat resistant, but will char or discolor if you try hard enough. They have more 'bounce' than most materials, which means glassware is less likely to break if knocked over.
Care should be taken in mounting the counter so that it 'floats' in place; this will allow the wood to shrink and expand with changes in humidity. A top mounted too rigidly will warp, and even split. This is also something to conside with large, or irregularly shaped counters.
"Around 1990, there was a sudden, widespread belief - a belief that had no basis, but suddenly appeared in some press releases - that wood was inherently less sanitary, supposedly due to the wood having pores."
One of the pleasures of eating in Montreal used to be the steaks which were served on round wood platters with a groove around them to hold the drippings. They were victims of the scare you mention, and never returned.