Why not use a sacrificial top layer for a bench top?

[Rick Cicciarelli]

I am planning on building a bench using the Roubo design as inspiration. I was wondering
why I never really see these nice benches incorporating a sacrificial top layer? I imagine
the wood alone is more traditional and looks better, but it would seem like a good idea to
incorporate a layer of MDF on the top of the bench to add weight and protect the wood
below from accidental tool marks. One could still drill holes for bench dogs ect. through the
MDF. Is there any reason NOT to incorporate a layer of MDF on the top of the bench in
my design?

[Matt Radtke]

The biggest advantage to a real wood top is that you can flatten it. Over time, the wood will move, warp, get dinged, etc.

While a sacrificial top itself will be flat, what about whatever is under the top? Also, I find real wood grippier--work pieces are less likely to slip around.

[John Coloccia]

I thought the work bench was the sacrificial top. LOL. You should see mine. When it gets bad, I'll take it to my local mill and have them flatten it on their wide bet. Should cost me about $20. :)

[Chris Griggs]

My first bench/the bench I am currently using until I finish my half complete Nicholson Bench was/is MDF with a sacrificial top. Actually I very quickly got rid of the sacrificial top as I has a hard time getting it to stay flat against the MDF with only screws. Would work better with glue but then it wouldn't be sacrificial. I also don't love the MDF as a bench material. If it gets even a little wet it will swell. Also, I've had problems getting the MDF to hold up under the stress of mounting vise hardware. I build a wagon vise and the "track" that kept the moveable blog/chop in place literally ripped out of the MDF fairly soon after.

I can't wait to get my Nicholson done... The top will be made out of large, laminated, God knows how old, yellow pine beams that came off an old church. I will not miss my "sacrificial" top or the MDF in least.

[Rick Cicciarelli]

Just to clear up...I was going to use 4x4's glued together to form the top. I was then going to use 1/2" or 3/4" MDF on top of the 4x4s AS the sacrificial top. I figured if somehow the 4x4's started to tweek, I could remove the MDF top layer and plane the 4x4s flat again, and then replace the MDF top layer (sacrificial layer).

[Chris Fournier]

If you place a sheet good on your solid wood top and you don't treat the underside in a similar matter you are going to cup your bench top in short order especially if you are going Roubo and using a single heavy slab.

My one bench is now 12 years old and the top has some scars but nothing major. I've been careful but not paranoid/psychotic about taking care of it. If you're going to do something really nasty and intend to use your bench then haul out a chunk of scrap for the task at hand.

Your bench will need to be flattened, spring/fall for the first few years as it moves about and this process takes out many of the finer dings and scratches.

Would you put plastic over your upholstered furniture? We all laugh about that now.

[Tim Null]

I have a laminated maple bench top. I was anal about it at first, like a new car. After the first few dings, I relaxed. When I am going to do things that would possibly really mar it, I use a piece of scrap or a plywood cover that is held by 3/4" dowels in the dog holes to protect it. But you need to have a good, flat bench as your reference when doing most work. You can always plane it down and put a new coat of finish on it.

[Michael Titus]

A lot of woodworkers use their bench appliances (shooting boards, bench hooks) as a "sacrificial top". You can saw and chisel on one with abandon, and then just replace it when it's worn out.

[Erik France]

Just to clear up...I was going to use 4x4's glued together to form the top.You might want to reconsider using 4x4s. Most of the 4x4s I see aren't very clear, and the majority of them have a pith running right down the middle. You will get a lot of movement with wood that has characteristics like that.

[David Weaver]

There are a lot of reasons I wouldn't use it, but first and foremost, I wouldn't use it because it is dark. If you get metal dust, dirt or grit on it, you will not be able to see it, it will end up on the surface of your boards and it will bum the edge of a smoothing plane in one pass leaving lines all over your work.

In addition, everything that would end up on it would come off of it via tearing out unless you glue sized and waxed it.

And as well (i have a router table with MDF), over time, it will absorb ambient moisture once you start to abrade the top and it will get lumps all over it. You can plane MDF, but you can't plane it long. I have planed the top of my router table exactly twice. Both times I had a dead blunt handplane after doing it, even with a plane with high speed steel. I found out the router table went out of flat a couple of weeks ago by ruining two quartersawn maple blanks that I was slotting to make beading planes. It sucked!!

And while i'm at it, what are you going to do for dogs? the MDF would have marginal holding power, if you have some dogs with short posts, they are going to rip it apart around the dog holes.

If it was a good sacrificial surface, you would see it more often on benches.

[Stew Hagerty]

I have a hardboard "sacrificial top" that I put on my bench when doing glue-ups or finishing. The rest of the time it sits in the corner.

[Matt Meiser]

I have a hardboard top I put on my welding table when I'm not using it for welding. I use that as my general work table and try to avoid doing non woodworking tasks on my bench. When I do glue-ups, I just put down some kraft paper which is cheap at Lowes (plus I jut learned that you can also use it to rub any dust nibs off a finished piece, so it does double-duty!)

[Chris Fournier]

I have a hardboard top I put on my welding table when I'm not using it for welding. I use that as my general work table and try to avoid doing non woodworking tasks on my bench. When I do glue-ups, I just put down some kraft paper which is cheap at Lowes (plus I jut learned that you can also use it to rub any dust nibs off a finished piece, so it does double-duty!)

Ah welding and woodworking - what finer blend of activities could you have in one shop? I mix these two up under one roof as well. I draw the line at using angle grinders in the shop - outside for that. The clean up drives me crazy but we do what we have to!

[Matt Meiser]

I try to do the same whenever possible Chris. I also make sure the shop gets a thorough cleaning before welding. Shavings burn too easily!

[Jeff Wittrock]

My bench to is just laminated 2X4s laid on edge, but even so, I pampered it for a while when it still looked so nice and "white".
When I was making some concrete vanity tops, I didn't have a good place to pour them, so I put the form on my bench top after covering it with plastic sheeting.
The sheeting tore of course, and concrete juices soaked into the top. Lets just say it gave the top a pretty rough patina. Now I don't worry so much about it.

I do use some bench hook type things when I want to avoid cutting into the bench top though.

[Andy Margeson]

When I first began woodworking a decade ago, I built a bench in one day. I took one piece of baltic birch plywood, cut it in half and glued it together to make a 1 1/2 inch top. The bottom is made from 2 x 4s and metal simpson brackets. Ten years later I have graduated to a better bench and the bench is my assembly table. It remains dead flat and, though the top is dinged up, it is eminently usable. I think about this often because it seems to violate the rules. Meanwhile, I've just finished flattening my maple laminated benchtop because it warped. The main disadvantage I see is that it is only 5 feet long.