What finish for hardwood bench top?

The suggested finishes have different moisture vapor transmission rates. Oil and shellac finishes transmit water vapor rapidly, polyurethane is slower, epoxy is very slow. The benchtop will stay flatter as the humidity changes if the top & bottom surfaces have finishes with the same MVT rate.

If you are just refinishing the benchtop with the same finish it had originally, you are probably ok just doing the top. But, if you apply a drastically different finish, it is best to use it top and bottom. This is especially true with epoxy finishes since no older finish chemistry comes close to them for low MVT.

Forest Products Lab did a thorough comparison study of MVT for wood finishes if you feel the need to look into this closer.
 
A lot depends on how you are going to use the bench. If it's lite work, a nice finish is appropriate. But if that bench is your primary work surface, forget the fancy finish. I use a sheet of hardboard cut to fit. I just nail it down with brads. With that as my surface, I don't care what I do to it. If I damage it, I just replace it with a new sheet. I just don't have the time to worry about what happens to my workbench, other than what to do about the natural clutter which keeps accumulating ;)

Randy
 
Used motor oil.

Unless that is you're making a countertop for the kitchen....

It's a Work bench after all, maybe you won't ever get it dirty but what's the point of that?
If you want it to look like it does now for a long time use West System epoxy, otherwise just start using it.

Here's my bench....

newoldbench1.jpeg

Cheers,

John
 
A lot of you experts will probably cringe at this, but depending on your use and if it's HEAVY butcher block style, you might want to consider no finish at all. Many years ago, I did quite a bit of woodworking as a hobby but had to quit because of allergies to sawdust. I made a workbench out of kiln-dried maple. I planed the boards myself to 2" x 4". Glued them up to a finished size of approximately 2' by 9' by 4" thick. Similarly made the base by making legs glued up to roughly 5" square, with 1" x 6" stretchers. (These are all 'finished' dimensions.) A friend of mine back then had a commercial cabinet shop, and we flattened the top on his Timesaver sander. Almost burnt that thing up because it was so long and heavy. I put a woodworkers vise on the end with maple faces made from the same stock. I NEVER put a finish on it. It is now over thirty years old and has not warped or separated and is still as functional as it was when I made it. It has oil stains, grease stains, nicks, scratches and all that stuff, but it's still FLAT. Admittedly, it has been in a temperature/humidity controlled environment all the time I owned it, but we live in Georgia - even glass warps around here! Since I got into metalwork as a hobby, it really didn't fit my needs anymore (didn't want to weld or use a torch anywhere near that table), so a couple of years ago, I traded out with a neighbor that needed it more than I did. His shop is not nearly as environmentally controlled as mine, but there is still no sign of warping on it.

If your table is anywhere near that heavily built and depending on its intended use, you might not even need to worry about a finish.

Guys, I know this is a bit of an unconventional suggestion, but it worked for my application. Be gentle on your criticism.

Regards,
Terry
 
Thanks for all the replies! This will be a general purpose bench for my machine shop. Based on the info y'all have given me so far, I'm leaning toward a polyurethane finish. Epoxy interests me, but sounds like a lot of work. I'm glad I posted the question here, because I honestly would have never thought to finish the bottom, but definitely will do so now.

I've attached a pic of what I've got so far. The base will consist of two tool carts I picked up at an auction. I have replaced the casters with leveling feet. The top is 1-3/4" thick. It was originally 2' x 6', but a couple boards were splitting off one side and the ends were starting to split. I cut all that off, winding up with a 21" x 5' top, which fits well in its intended space.

I've been flattening the top with a hand plane, stripping the remnants of the old finish in the process.
IMG_0843.JPG
 
Personally I would attack this with a belt sander and 80 grit (medium) sandpaper. Then clean up the bare wood with acetone, then paint thinner. Quick and easy. You could finish the stripping in an hour or two work and be ready for first coat of finish the same day.

You’ll be OK with polyurethane. Although I prefer old school marine varnish. It applies a little thicker and has excellent flow characteristics and longevity. Much better flow characteristics and leveling properties than epoxy. Actually, as an experiment I coated a mahogany plywood bench top with four coats of varnish couple of years ago, then mounted my old 1919 Dalton lathe on top. The way-oil that dribbles out of the oilers and through the headstock hasn’t discolored or penetrated the finish at all, near as I can tell.

Alternatively, 5 or 6 coats of Formby Tung Oil will be nearly impervious to oil penetration. Surprising hard and durable. It penetrates well. The multiple coats fill the surface grain and mitigate staining and penetration by other substances. Glossy finish also... wipe it on, wipe off the excess in an hour so, do it again next day. You’ll have a superb finish after 6 coats.

Either way, your benchtop will inevitably become dipped, chipped, gouged and slopped on with glue, paint, maybe epoxy glue job bits. With oil or varnish finish you can just quick sand smooth these damaged areas and touch up with the original oil or varnish. Blends right in, without having to completely restrip and recoat everything,

FWIW, As this is a general purpose work bench, I wouldn’t worry much about creating a super flat surface, or take the time to recoat the underside. Wood absorbs as much as 15% moisture seasonally due to changes in humidity. Hence moves, swells, and heaves all over the place, every year, with changes in the season. It’s not a stable work surface. I’d work on just getting it into service quickly, and spend my time using it to make something!

Glenn
 
Last edited:
Glenn Brooks said:
Personally I would attack this with a belt sander and 80 grit (medium) sandpaper. Then clean up the bare wood with acetone, then paint thinner. Quick and easy. You could finish the stripping in an hour or two work and be ready for first coat of finish the same day.

You’ll be OK with polyurethane. Although I prefer old school marine varnish. It applies a little thicker and has excellent flow characteristics and longevity. Much better flow characteristics and leveling properties than epoxy. Actually, as an experiment I coated a mahogany plywood bench top with four coats of varnish couple of years ago, then mounted my old 1919 Dalton lathe on top. The way-oil that dribbles out of the oilers and through the headstock hasn’t discolored or penetrated the finish at all, near as I can tell.

Alternatively, 5 or 6 coats of Formby Tung Oil will be nearly impervious to oil penetration. Surprising hard and durable. It penetrates well. The multiple coats fill the surface grain and mitigate staining and penetration by other substances. Glossy finish also... wipe it on, wipe off the excess in an hour so, do it again next day. You’ll have a superb finish after 6 coats.

Either way, your benchtop will inevitably become dipped, chipped, gouged and slopped on with glue, paint, maybe epoxy glue job bits. With oil or varnish finish you can just quick sand smooth these damaged areas and touch up with the original oil or varnish. Blends right in, without having to completely restrip and recoat everything,

FWIW, As this is a general purpose work bench, I wouldn’t worry much about creating a super flat surface, or take the time to recoat the underside. Wood absorbs as much as 15% moisture seasonally due to changes in humidity. Hence moves, swells, and heaves all over the place, every year, with changes in the season. It’s not a stable work surface. I’d work on just getting it into service quickly, and spend my time using it to make something!

Glenn
Click to expand...


Glenn, I would like to respectively disagree with you on several points. First ,I am a retired carpenter, cabinet maker and woodworker turned Home shop machinist. A belt sander even in skilled hands is not a good option for leveling a bench top. Even with finer grits snipe is probably going to happen, especially near the edges. Hand planes will do the trick IF the person is capable. For a lightly abused top, orbital or palm sanders will be fine. Another way is to rout the top level. This requires a temporary rail on the long sides that are fixed at a precise height above the top. A router with a 1" mortising bit is mounted to a stiff and flat carrier. The router is traversed across the top .Takes a while but does flatten the top. The swirl marks are easily sanded out by hand or machine. Wide belt sanders are made for this but the average guy does not have access to them.
The top should have a finish top and bottom. As posted earlier the bottom does not have to be stripped of an old finish if their is already a finish on it. I do not know specifics of percentage of humidity wood changes but 15% I am sure is way to high. I believe 6% in a humid climate would be tops. Sealing the bench drops the percentage down depending on conditions.
Laminated tops as the OP has is quite stable, finish or not.

mike
 
mike44 said:
Laminated tops as the OP has is quite stable, finish or not.
Click to expand...
I can testify to the accuracy of that statement. (See my post on this thread.)

Regards,
Terry
 
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