sealing butcher block counter w/sink
LynchPin
| Posted in Construction Techniques on
I just got an 8′ piece of butcher block counter (25″ deep, 1 1/2′”
thick) which I want to put in my kitchen with an undermount
prep sink. I know I should seal it with some sort of non-
toxic polyurethane, but I’m wondering if there are other
options? If not, what brand of polyurethane is recommended?
How many coats should I put on to ensure no rot around the
sink?
And if you’re in the market for butcher block, I got this stuff
at lumberliquidators.com for $184 (about 1/3 the price of what
my local retailer wanted).
Thanks,
John
Replies
I would not use poly. Poly is a plastic finish that coats the top and if you use the top to cut on you will cut through the finish and expose bare wood. I would try an oil finish that is food safe and expect some staining and movement around the sink. I would not use wood with a sink especially an undermount. The undermount exposes all of the end grain to water.
Rockler has some oil based finishes that are non-toxic. Also, Shellac in a dry form, is food safe as well. Both are reparable-Oil with oil and Shellac with Alcohol.
I like to use Shellac and Pure Grain Alcohol. The PGA works great, and if you get bored or p i s s e d off, you can drink it.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
Food grade mineral oil. Place that sold you the butcher block should have sold you some. They should have it.
Good luck!
skipj
Mineral oil is probably best (make sure it is food grade). A commercial kitchen supploer might have butcher block oil in quantity (you cna find smaller bottles in kitchen gadget stores). This is a mix of mineral oil & linseed oil. The linseed gives a bit better penetration.
Now, next to a sink, the exposed endgrain, is going to take up water from the sink, not matter what you do. For wooden countertops and undermount sinks, I make a frame (preferably of quarter-sawn matching the top) jointed up to present the least amount of endgrain in the sink area. (Then, most let them selves get talked into a pour-on acrylic close to 1/8 thick--but the kitchens are for show, not for use . . . )
Ok, so we like the bb top & the undermount, and the kitchen is not just for show--no problem, just keep some board oil by the sink, and treat the counter top like you would a good cutting board. After washing, just oil a bit.
Butcher block not a good choice around sink. If you use a nontox penetrating oil you will lose. Not enough protection. Forget the shellacs, tung oils, waxes, mineral oils or any other non film forming finish. If you want it to hold up you have to use oil poly or conversion varnish. Cured polyurethane film is nontoxic when the solvents have dissapated. Yes, if you cut on it you will break the film and the destruction of the finish is soon-come once water hits it. As a wood finisher for 30 years I have come across a dozen situations where wood has been used against a sink. I have applied finishes that were speced by architects and those paranoid that somehow they were going to poison their family if they used anything but a no-drier penetrating oil. All of those finishes failed in short order. They simply do not hold up to the repeated exposure to water. Having said that, If you are willing to apply oils ever few weeks you may have some success, but they will spot between finishings and who wants to be a slave to a kitchen counter surface. 2 months ago I got a call to finish a walnut kitchen counter, top-mount sink in the middle. It was polyurethaned with 3 coats about 5 and 1/2 years ago. Sink was well caulked. As you might expect there were some surface scratches and the joints moved a bit. A scuff-sanding and another coat made this baby sing. I have a customer that insisted I use pure tung oil on their butcher block kitchen island. It spots and rings weekly and I refinish it twice a year. They don't mind paying to have that look.
Jimbob
Couldn't agree with you more. Period.
Knowledge is power, but only if applied in a timely fashion.
I shoul;d have mentioned before don't forget to seal that endgrain before the installation! Oh yeah, I keep forgetting that most installers have a phobia about dipping a brush in anything. After all it adds time to the install and once it's in they rarely get the call back. It's becomes the painter/finishers problem.
For the love of Mike, WILL YOU BUILDERS AND INSTALLERS DO SOME BACKPRIMING!!!!!
jimbob
While we're mentioning oversights concerning your advice, you did forget to mention the need of equal amounts of finish on both top and bottom. But then again, I think someone already hit on that.
Wood countertops can be done, but you shouldn't expect to be able to use/treat them the same as if they were plastic laminate, solid surface or stone, especially around a sink. IME, only the most fastidious and anal of clients can use them, keep them looking good and holding together over the long haul......or those who don't use them at all.
Wow, they sure look handsome, sometimes charming when they're new and photographed for those magazines, tho. Most everything does.
Sanitation becomes a concern too, especially with those penetrating oils finishes. Did someone already mention that? I'd personally be much more concerned about harboring a robust colony of bacteria in the wood than the "toxicity" of a cured film finish. Time for some bleach.
I hope the manufacturer of that countertop used a water-resistant or waterproof adhesive. ????
Knowledge is power, but only if applied in a timely fashion.
Goldhiller writes...
While we're mentioning oversights concerning your advice, you did forget to mention the need of equal amounts of finish on both top and bottom.
Yes indeed, you are correct sir. I failed to mention that. And the point you made about bacteria--absolutely. We are most definitely on the same page here. I hope they used a waterproof glue also. There is a butcher block co here in the Northeast that uses epoxy for the glueup I'm not sure but I think that is the standard now.
jimbob
Thanks for all the advice. I'm now thinking I should, at the
very least, return the undermount sink and get a self-rimming
one. But the whole point of going with the butcher block is
so that the counter IS the cutting board. It may be somewhat
impractical, but we've all seen this done in many homes. I
should point out that this is not the primary sink in the kitchen,
i.e., it will not be used for washing dishes. It will be used for
washing vegetables and maybe an occasional glass of water.
Given that, I'm hoping I can avoid rot/water damage problems
with a little extra care (extra applications of a finish).
Jimbob -- you seem to have a lot of experience with this stuff --
is there a specific penetrating oil that you would recommend?
Mineral oil? Tung oil? A combination? How should I apply it?
How many "coats"?
Thanks again,
John
First, it sounds like what you have is not butcher block, but a laminated strip maple countertop. Butcher block is end-grain, you have edge. Semantics.
With this countertop being a working/cutting surface, and with the sink being a secondary sink, here are my thoughts:
First, the sink. You want undermount, go with it. An undermount will make it so much easier to wipe the maple down, which you'll need to do after each use to prevent standing water. With a self-rimming sink it's too easy to let a little water stay at the rim/wood interface, and that's a very bad thing.
Since this top will see many knife edges, I would not put a film finish on it under any circumstances. Simply use mineral oil or a food-grade butcher clock oil. The only mineral oil you want to use is a food-safe one, you can easily find it in the grocery/drug stores with the laxatives.
Give the slab several good rubdowns with mineral oil, but don't get it where the sealant will bond the sink to the bottom of the countertop. You want good sealant adhesion there. If you do get oil there, use acetone or something similar to remove the oil. Or, install the sink, then oil. Your choice. Oil the top, bottom and sides. Some warm the oil and claim better penetration, some rub it on with bare hands and claim the same. To start with figure three coats at a coat a day. If the oil absorbs quickly, more often is fine.
Mineral oil does not cure, though it will be absorbed a bit. Normally, in the first few days, if water droplets hit the oil, the water will displace the oil and you'll get horrible spotting. Sometimes, if left alone, as the water evaporates out of the oil the spotting disappears. Sometimes it doesn't. Still, a light application of oil on the spot will make it disappear. This may go on for the first few weeks. Eventually the top will get settled in and water won't spot much, if at all. Still, wipe off the wood and don't allow water to stand on the surface.
You can give the top a light wipedown of oil when it looks tired, when you notice water not beading anymore, or before company comes over to spiff it up a bit. Include the inside of the sink cutout when you wipe.
Cutting on edge-grain isn't the greatest thing to do, as you'll cut the wood fibers and the countertop can splinter. Remote, but it does happen. End-grain butcher block, on the other hand, is perfect for cutting, as the end grain self-heals like pulling a dart out of a bristle dart board.
If you want added protection on the end-grain in the sink cutout, give it a wash with thinned epoxy. Cure, then scuff sand, then another epoxy wash. The thinned epoxy will seal the end grain. Careful about getting epoxy on the top of the countertop. If you do, wipe off the spill with acetone. If you do the epoxy wash, do it before you oil the area to be epoxied.
Wood couintertops aren't perfect, but what surface is? Still, with a little extra maintenance, they can be worth the effort.
Someone previously asked abut the adhesive. You may want to find out what it is. Epoxy would be best, but that's doubtful. If it's a simple titebond-type, you may have trouble with water, especially on the endgrain. In that case definitely do the epoxy wash. Still, I'd think that with these slabs being intended as a countertop of some sort they'd have a water-resistant glue at the least. I wouldn't bet money, though.
You could also buff on a light coating of food-safe paste wax. Look for a wax with no turps or spirits.
Enjoy the top. When and if it gets too scarred for another coat of oil to purdy it up, break out the belt sander and give it a facial.
Incidentally, good advice from Mongo.
Thanks very much for your detailed advice, Mongo and
Jimbob. I'll let you know how it turns out.
John
Small add-on...
If you use tung oil like jimbob mentioned, make sure, as he also mentioned, that it's 100% tung oil. It should also have 'food safe' on the container. Read the application instructions and see how long after application it will be before you can use your top.
Thanks for all the advice Mongo. About your previous post:
"If you want added protection on the end-grain in the sink cutout, give it a wash with thinned epoxy."
Can you give me some more details on this. What kind
of epoxy? I looked at the local big box and they just have
the usual epoxies in the little tubes -- is that what you
mean? And thin it with what? And what exactly does
"give it a wash" mean? The only way I've sealed end-grain
is by rubbing a little silicone caulk into it. Not exactly
pretty, but it gets the job done.
Thanks again,
John
Oh and one more thing -- does anyone have any advice
on getting a nice clean cut out for the sink? I have a good
jig saw and some nice new blades, but whenever I've cut
through something this thick (and this hard especially),
the saw blade invariably gets out of plumb or comes off
the line a little bit and you end
up with an uneven cut. Any hints?
John,
I use West System epoxy. It's a 2-part that comes in cans with premeasured pumps. Any good 2-part will work. Use a solvent, lacquer thinner or acetone, to then thin the epoxy out so it's less viscous. It'll soak up into the end grain better, and will go on thin instead of looking like a thick film coating. That's why it's bettter to do a few thinned 'wash coats' instead of one thick coat. My opinion. It'll blend in and look more natural. Watch the drips.
Best way to get a clean sink cutout is to use a jigsaw to cut the rough opening within 1/8th to 1/4" of the finished size. Then make a template of the sink opening. Some sinks come with templates, or you can make one by inverting the sink on a piece of MDF. First draw around the outside of the sink, so if it shift you can easily move it back to where it's supposed to be. Then pencil in hand, put your hand through the sink's drain opening and draw a line tracing the inside edge of the sink. Keep the angle of the pencil constant.
Figure you what you want for a reveal, and either use the line you made as the actual template cut line or make your final line slightly inside of outside of that line, to make the countertop openign larger or smaller.
Cut the template to within 1/8th inch with a jigsaw, then sand to the line and to get a smooth edge.
Put the template over the rough-cut opening on the countertop and use a router with a straight pattern cutting bit to get the opening primo.
To radius the top edge, remove the template, put a roundover bit with bearing in the roouter, and run that along the inside edge of the sink opening.
West System makes a "penetrating epoxy" that is designed to soak into porous wood. I bought the last stuff I got at the local marine supply store (one local marine supply store had it, the other didn't). You can also find suppliers on-line. Previously, I used a penetrating epoxy from Rot Doctor. The list price on Rot Doctor was cheaper but the shipping costs made them about equal in final price. Both of these products seemed about equal in quality, although the Rot Doctor stuff may have been just a little thinner (thinner being better for my purpose). West System has a discussion of thinning epoxy resin at:
http://www.westsystem.com/webpages/epoxyworks/14/ThinningEpoxy.html
Old, dried out wood can soak up an amazing amount of penetrating epoxy, but with tight grain and good wood, I doubt that you will need very much.
http://www.rotdoctor.com
http://www.westsystem.com/
Casey, thanks for the tip.
I wasn't aware that they had a product like that. I'll certainly look into it, as I'm doing a run of teak outdoor furniture and I use thinned epoxy on the end grain of the furniture legs.
Mongo -
I just checked on the West epoxy container and I was mistaken. The last penetrating epoxy that I purchased is from West Marine, not West System. I guess that is why I only found it at a West Marine store in Portland. I don't know if West System makes a penetrating epoxy. Anyway, the West Marine penetrating epoxy seemed to be pretty good stuff, in contrast to some unknown brand of penetrating epoxy that I bought at a lumberyard in Berkeley, CA.
Edited 12/8/2003 1:32:20 PM ET by CaseyR
I appreciate the follow up.
After your first post I did look at my epoxy setup and ordering manual and came up dry regarding info about a West System penetrating epoxy, so I went online and found this:
Thinning Epoxy
There are epoxy-based products specifically designed to penetrate and reinforce rotted wood. These products, basically an epoxy thinned with solvents, do a good job of penetrating wood. But the solvents compromise the strength and moisture barrier properties of the epoxy. WEST SYSTEM epoxy can be thinned with solvents for greater penetration, but not without the same compromises in strength and moisture resistance. Acetone, toluene or MEK have been used to thin WEST SYSTEM epoxy and duplicate these penetrating epoxies with about the same effectiveness. If you chose to thin the epoxy, keep in mind that the strength and moisture protection of the epoxy are lost in proportion to the amount of solvent added.
There is a better solution to get good penetration without losing strength or moisture resistance. We recommend moderate heating of the repair area and the epoxy with a heat gun or heat lamp. The epoxy will have a lower viscosity and penetrate more deeply when it is warmed and contacts the warmed wood cavities and pores. Although the working life of the epoxy will be considerable shortened, slower hardeners (206, 207, 209) will have a longer working life and should penetrate more than 205 Hardener before they begin to gel. When the epoxy cures it will retain all of its strength and effectiveness as a moisture barrier, which we feel more than offsets any advantages gained by adding solvents to the epoxy.
http://www.westsystemepoxy.com/West_System_User_Guide.asp
Again, thanks.
Mongo thanks for the post
a little heat always feels good this time of year!
Use a router with a top bearing straight bit to clean up the saber saw cut. Make a template from the sink pattern.
John,
Although I don't recommend penetrating oil in this situation, If speced and forced to do it, I would simply use 100% Tung oil or Mineral oil. Do a test on scrap and see which you like the appearance of better, they are about the same in terms of protection, it's arguable that the tung oil will provide better protection but is harder to work with. The mineral oil flows out better.
As for the application, you need to sand the surface (obviously) down to say 220 grit (some would argue finer than that). Get rid of all the dust. Tack it down. I am assuming you know how to sand down to a finish of 220.
I apply tung oil using the flat of my hand. I flood the surface in small areas and rub it in. Work quickly and in small areas. If you get too much material on or get too far ahead, the material will gum up and be difficult to remove. Elbow grease and speed is key. You need to let the material soak in say 5-15 minutes. You need to then remove the excess with clean lint free rags. 100% cotton is best as it is absorbent. It may leave some lint behind. If so you need to find a better quality rag. I always look for rags that are t-shirt scraps, they are almost lint free.
To clean the tung oil off your hands I lather up dry with dish soap then use a clean rag to wipe the soap/oil slurry off my hands. Then follow with bar soap and water. Or if you are not health conscious, use mineral spirits. But note that most solvents will penetrate your skin and get into your bloodstream. Then your liver has to deal with detox. Years of this type of behavior will certainly create health problems, at the least, a case of dermititus.
Back to the Block,
After the excess is removed and the material soaks in you will find that there are dead spots where penetration is incomplete. Leave it overnight. If gritty,Lightly sand and remove dust. Repeat the process. During the process of removing the excess, If for some reason you get too far ahead and the material gums up you can get rid of the excess with a rag dampened with deoderized mineral spirits. I always use deoderized mineral spirits as the fumes are considerably less noxious than regular paint thinner. I wear nitrile gloves for this step.
Mineral oil is applied by prepping as above then flooding the surface and removing the excess. Repeat after an overnight soak-in. Mineral oil has a thinner viscosity so is easier to work with. It also won't gum up the way the tung oil does. I forgot to mention that you can cut the first coat of tung oil with some of that mineral spirit if it seems too thick. I put the gloves back on for this and rub the oil in with a rag.
When in doubt, the application directions will be on the can. Follow them. Don't forget that these oils can sponteneously combust in rags if they are not laid out to dry. Never pile them up or put them in plastic bags. If you are nervous about this fire hazard put them into a metal paint pot full of water. I just lay out the rags over the rungs of a step ladder and let them dry. then discard them on trash day.
Other things I do with penetrating oils:
Wet sand them into the wood with 400 grit silicon carbide sandpaper (make sure it is wet or dry brand paper or you will end up with abrasive fragments all over your surface) I have also burnished the wet material in with 3/0 steel wool, again removing the excess oil and fibers with clean rags. If you screw up somehow remove excess with the spirit dampened rag.
You will have to maintain this surface on a regular basis. I wish I could convince you that cutting on this is not a good idea. I have had customers that are charmed by cutting on the block but usually end up hating the fact that there are scratches all over the place. It complicates the refinish process as well as you will need deep sanding. Please consider a cutting board instead unless you really want that patina.
Rudimentals of penetrating oils: The wood will absorb only so much oil before it pools on the surface. Once it pools, it will take forever to dry. Maybe months, maybe never. The idea is to get the wood to that saturation point but not to exceed it.
Drop me an email if you come across any problems. I'll be on vacation for the next 2 weeks starting today so don't expect a reply before then.
Best of luck
Jimbob
My suggestion is to install laminate, granite, tile or whatever and have removable butcher block cutting boards laying on top of the finish top. You can pick them up, scrub them, sand them, clean them and then just lay them back on top.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
Good idea with the cutting boards right up there so you don't have to dig them out when you need one. Big ones would give the nearly the same advantage as the whole thing being a cutting board.
The restaurant that I worked at during my tender years, had huge hardrock countertops for food prep. Open 20 hours a day. But the worker bees (us) were instructed to wipe up moisture on an hourly basis if possible and everyday they received a bleaching with a powdered product. They held up great. Food grade mineral oil finish renewed after counters had dried from the bleaching/sanitizing. But no sinks in these counters.
A sink in a wood countertop may be theoretically possible, but as Andy would say..........."be anal retentive"....... or lose the battle.
The last folks for whom I custom fabricated and installed a maple countertop with sink were given the lowdown on care numerous times. They chose the 4-coat oil-poly finish and assured me that they would care for it as if it were a new born baby. They wouldn't dream of using it for a cutting board. Not to worry.
Within 6 months my phone was ringing. They had indeed used it for cutting ( aand quite a bit from appearances) and put slits in the finish. Water entered those slits, finish was separating in a localized fashion particularly near the sink. That's the moment when the first thing you want to say is........"I told you so".
And so I did. :-)
Knowledge is power, but only if applied in a timely fashion.
Edited 12/3/2003 9:41:33 PM ET by GOLDHILLER
Edited 12/3/2003 9:43:44 PM ET by GOLDHILLER
Many of the butcher shops mix mineral oil and paraffin wax 50/50 and dissolve the wax into the oil over low heat. Wipe it on the bock, rub it in, and let it dry. Then scrape the excess wax off the top with a flat spatula and rub the remainder into the wood.
The wax bridges the large and small micro-cracks in the wood and prevents water and bacteria from getting into the wood.
Still, I wouldn't use block around a sink.
Billy
I love wood & I love butcher block - but I would never put butcher block next to a sink. (too many years with boats & brightwork) I currently (my second kitchen) have a 50 inch piece of butcher block countertop that terminates 6" (trying to get the max BB in a short kitchen) from my sink - then tile surround at sink. now that I've lived with it for a year, 6" is a little close - the kids are always putting wet stuff at the edge of the sink and puddles get on the BB. I treat it probably twice a year with hot (heated up in a pan to about 100) olive oil. I puddle it on the BB and let it sit over nite. usually it soaks it up by morning and I wipe off any excess. I wipe BB regularly - when-ever I use it (2xdaily) with a regular sponge. never have any bacteria problems and the wood itself is in great shape. no water spots or stains.
have used a rubbed tung oil finish on dining room table . looks great - but isn't as durable as I expected - no water problem, but kids do homework on it & ink will soak right through finish. bummer.
anyway - hope this helps. I wouldn't have a kitchen w/o butcher block - but keep it away from water!
No updates on these comments in a long time but I'd like to throw in Waterlox as a recommendation as it is used for Marine applications. They have specific "How-To" section on finishing an underside of a wooden countertop for an undermount sink.
In case someone doesn’t read the whole thread and flies over your response…
Use only FOOD SAFE oils / treatments on the top of a wood kitchen countertop.