Some workbench questions

[omark]

Solid wood vs. MDF for the top:
laminated wood is easier to make flat afterwards (plane, straghtedge, winding sticks).
For laminated MDF I understand one need to do it dead flat from the start, using some reference surface and right clamping -- otherwise how to correct it later?

[PeteW]

For laminated MDF I understand one need to do it dead flat from the start, using some reference surface and right clamping -- otherwise how to correct it later?

Fair point, but not something that gave me any trouble. 3/4-inch MDF is pretty heavy and flat from the off. I did my glue-up on an old table top sitting on two saw horses and checked for flat with winding sticks and a straightedge. Then I predrilled for screws on a 12-inch grid, six inches from each edge, in the middle of the second board and sanded off any breakout to ensure flat. After glue, the second sheet was screwed to the first and the edges clamped with every small clamp I had available. Left it for three or four hours, then rinse and repeat for each subsequent board. Came out perfectly flat.

I don't want to come across as some MDF evangelist - one day I hope and plan to have a beautiful Roubo-style bench in quality wood. But I was under time and budget pressure when I built this one, and it's been nothing but great.

With regards to Hank's point about MDF and moisture, he's not wrong. I gave mine two coats of an oil finish that was left over from refinishing the maple countertops in our kitchen, which makes it easy to cleanup glue spills and WD40 overspray, but I wouldn't want to be spilling a lot of water on it.

Edit to add: The screws were, of course, removed between each layer!

[Admiral]

Matt, another way came to my mind; if you have a salvage yard or Habitat Re-store near you, seek out salvaged solid core doors (which may cost less than the sheets of MDF if you're lucky); two of those glued and screwed together will make a very solid top.  My first bench was a single hollow core door.

[frigator]

My bench has been soaked a few times, once when the roof went in a tornado and then two hurricanes when the garage doors were blown in and everything got wet.  Not to mention all the water I use raising the grain. MDF would not work for me at all. Love the look and feel of solid wood and think thats the way to go with a bench.

[MattP]

Matt, another way came to my mind; if you have a salvage yard or Habitat Re-store near you, seek out salvaged solid core doors (which may cost less than the sheets of MDF if you're lucky); two of those glued and screwed together will make a very solid top.  My first bench was a single hollow core door.

I just had a club sandwich at the pub right next door to the Habitat Re-store. Now you tell me. 


Solid wood v. Engineered wood:

CPutnam mentioned that my plan to paint the engineered wood would slick it, making it less useful as a work bench. My reply  was that I could dye it instead of painting it. About 10 minutes after I posted that, I realized that if I can dye MDF black, I can certainly dye wood black (I don't have the same objection to dying wood as I do to painting wood). So this discussion has led me to realize that I can use either engineered wood or real wood for the top. 

It seems that MDF is plenty strong enough to make a top, based on what Pete and Andy have said about their experiences. Baltic Birch is also an option. Pete's idea to reinforce the dog holes with CA strikes me as a terrific precautionary measure, whether or not it is actually required.

I forget who said it, but somebody suggested routing in a strip of maple for the dog holes. My idea was already to have a strip of maple as sort of a workbench-scaled inlay separating the black surface from the mahogany, so it would be a matter of tweaking the design so that the maple strip contained the dog holes.

I'm not overly concerned with price--I am planning a mahogany border, after all--but as a factor to consider, it's certainly worth noting that MDF and plywood would both be more expensive than using construction 2x4s from the big orange box. 

2 Foot versus 4 foot depth

The narrowness of traditional benches seems to be based on their use as dedicated hand tool surfaces. Mine is not going to be that. I only have a portion of a 400 square foot two car garage available as my workspace (most of it, but it's also where we put our storage), so my workbench is going to have to double as an assembly table and who knows what else. So I am settled on the idea of something in the neighborhood of 4 feet deep.

Next question: It occurred to me yesterday while I was thinking about this thread that a base constructed from black pipe would look pretty cool with the red/black motif I have planned for the top. A quick check online suggested that all you can get in the way of black pipe from the hardware store is the 1" gas pipe. So I have three issues with black pipe:

1. I'm not sure the 1" can do the job. What do you all think? Any engineering problems with supporting an 8' x 4' workbench top made of 2x4s with 1" gas pipe?

2. Even if it can do the job, it might look too flimsy and delicate compared to what is going to be a gargantuan top. Not sure about this, I'll try to play with sketchup (still learning that) to get an idea.

3. Moving up to 2" pipe would probably be stupidly expensive, and I'm about 80% certain I would just rule that out even if I could find a supply.  Anybody have knowledge about what 2" black pipe would set me back?

[Anji12305]

Consider a modular, and more portable approach.

If a move is in the near future, you could spend the nest few months building something you can't use.

http://blumtool.com/?page_id=56

http://www.finewoodworking.com/2010/08/0...-can-build

the-ultimate

[Steve Friedman]

No idea about whether a base of black pipe will work, but think about clamping.  I love having dog holes in the legs of my bench and sometimes .  I also sometimes secure handscrews to the legs to create an additional horizontal clamping surface.

Also, for hand tool use, consider the weight and stiffnees.  I know that steel is heavier than wood, but will the total weight of a pipe base be as heavy as a solid wooden one?  I guess you could always fill the pipe with lead shot.

Finally, my experience with black pipe is limited to pipe clamps, but they do bend.  I assume 2" think pipe would be more rigid, but so are my 4 x 4 hard maple bench legs and the 8/4 stretchers.

If you do this, you need to post pictures!

Steve

[MattP]

I was thinking modular last night, as a matter of fact. Mainly to address the issue of needing different work heights for different tasks, and not having room enough for dedicated tables for finishing, joinery and assembly in addition to the bench.

If the move is in my future, I won't be building until the move is done. Period. The last thing I need is to move another 300 pounds or whatever of workbench. I'll just get by until we get where we are going, and build it when we get there.

[Derek Cohen]

The idea of building a bench top from MDF is not new. Many consider this, and ply, to be a shortcut to a flat bench top. The problem with MDF and ply is that it does not endure - MDF is too weak for dog holes, and both cannot be resurfaced. It is not a shortcut; it is temporary. 

Paint or dye does not alter the structural components of benches like these. Do you want something that looks like a workbench, or do you want something to work on? 

The width of a bench depends on how you work. If you have a bench out in the middle if a room, and can work (or plan to work) from both sides, then you can make it wide. However, if like me, where the bench is close to a wall, and worked from one side (so I need to stretch across it), unless you have arms like a gorilla, keep it under 22". 

Regards from Perth

Derek

[Adnick]

Derek:

You need to look at Rob Cosman's mdf student benches, they have dog holes, that aren't temporary and totally stable. Never would have came up with that bench, but never would do an mdf woodworking bench for myself.

Regards,
Andy

mos maiorum