How about making the work surface out of 2 ply 3/4″ OSB. I like Advantec because it is quite flat, relatively smooth, and OSB because it will hold it’s shape better than plywood – less warping. Stagger the joints 4′ between the top ply and the bottom ply. Glue and hail the pi$$ out of it with 1 1/4″ nail gun finish nails from the bottom side. putty the joints on the top side and sand smooth. So that would be 5 sheets at $30 or $150. If you want it to be more smooth, add a top layer of 1/2″ MDF. This could be screwed from the bottom and be considered a sacrificial work surface – might be better for cutting on to since there would be no wood grain to “mess with” your knife cuts. Maybe edge band the whole thing with 1×4 with smooth routed corners since I guess they would be leaning against it all day.
Maybe some type of scaffolding could be used to make the base (legs). That way it would be semi-portable…
My neighbor has a sign business. He is doing very well: 450+k house for 2 people, 5+ garage bays, drives a Hummer, collects domestically made V-twin motorcycles$$, employs full service landscape company, car wash service, etc, etc. The service part is what I’m jealous about… Plus, I like MCs, but one nice one would be good for me 🙂 He has some artistic talent too – saw a way cool Big Dog motorcycle that he custom painted himself. He uses CNC machines to do a lot of his work… I think CNC is the right term…
Another bud/childhood friend has a sign business. Barely gets by. Lives in small town environment. Works maybe 3 days a week. Likes living that way. Very artistic also. Seems very happy.
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We built work benches in a shop that I worked in using metal legs and two layers of MDF,overlap the seems. the metal legs were just square tube steel. Cant remember how the apron was done though.
We sprayed them with lacquer but you could roll some sort of finish on them.
Solid as a rock.
Doug
Large torsion box
Here's a link to the basics
http://www.diynet.com/diy/ww_materials_products/article/0,2049,DIY_14442_2278181,00.html
Not the simplest way to come up with a 20' table but you can up with a damn strong and flat surface using 3/4" plywood.
Are "pounces" still used in sign making? An electric pencil that perforates the pattern?
If so, allow for a metallic top to be laid up..
Spheramid Enterprises Architectural Woodworks
HOW ABOUT THAT REZ GUY? UH HUH? ...He ain't Silesien I bet....wimp
I haven't built one near 20 feet long, if I had to I'd imagine I'd build two 8x4 sections and one 4x4 section, then bolt them together well.
They are not very "hard" to build but mildly time consuming, Good luck.
How smooth is Advantech? Wouldnt some birch plywood be a better surface?
I would think masonite would be the best, it's cheap, smooth, and easily replaceable
Good call. I was just thinking there must be somthing smoother than OSB.
Tempered masonite my brother..tempered. Spheramid Enterprises Architectural Woodworks
HOW ABOUT THAT REZ GUY? UH HUH? ...He ain't Silesien I bet....wimp
Way back there were games. Strategy games. Weinies played Stratego while the real gamers worked more demanding games. From AH's simple fare to monster games like War in the East. Rule books that resembled the Manhattan phone book and half-inch square cardboard playing pieces by the thousands. This was waay before computers made it easy.
You needed room. A two-car garage works well if it can remain undisturbed for weeks. The tables had to be relatively smooth, sturdy and resistant to being jarred. What worked for us was tables made with two 4' by 8' pieces of 5/8 B-C plywood glued together 'B' sides out. A few brads used keep the sheets from sliding. Clamping was accomplished by piling on concrete blocks. These were finished on both sides with poly sanded between coats. As I remember it three coats.
The thickness, sealing with the poly and symmetrical construction limited swelling and warping. They lasted for years. Long after we stopped using them they were pressed into service with a local church where the hefty stability was, I heard, appreciated at the wild parties and heated family gatherings.
To these folding steel legs, the heavy version of standard folding table legs, were screwed. As I remember it these were rated for 250# each. These made for solid tables that fit the bill. To make them even more stable we fitted simple steel cables with swaged eyes. These were used, with a short length of rebar as a toggle, to hold two concrete blocks at each set of legs. Four blocks per table.
The weight of the tops and the blocks made for tables which didn't move when bumped. Originally we wanted sandbags, and they would have been ideal for damping vibrations and impacts, but the blocks were cheaper. Deep five-finger discount at midnight construction supply. Who knew you could carry sixteen concrete blocks in a CVCC. The tires ground in the wheel wells and the sounds of mechanical suffering and the smoke of overheated rubber filled the air but the deed was done, the sin committed. I shall now go off and flog myself.
We used four tables and each pair was screwed together end to end with a piece of half inch plywood to keep the ends flush and the gap near zero. The tables set up on a flat concrete floor worked well.
I suppose that if four of something similar in idea to these tables were set up they might serve. You might consider laminate or melamine for their smooth surface but you might want to be careful to do the same on the bottom as the top to limit warping.
This may sound too simple, and it is simple, but torsion box legs and top would have zero movement, be dead flat if built with moderate attention to the process, and be easy to build. The following will structurally be drastic overkill for your purposes, but that's not bad.
For a commercial quality table I'd make it in three pieces using dry and straight 2x4's, 12" on center lengthwise, with a 2x on each end for secure joining of each section (bolts) and 3/4" AC ply for the top and lower skin. Polyurethane glue and staples every 3" is quick and makes it bulletproof.
Legs of the same construction, only slightly more narrow, are a perfect base for this type of top. The legs would only need to be placed on the ends and two in the middle where the sections join. The legs don't need to have skin as thick, but it's nice since the 3/4" ply holds screws well and makes attaching future undertables or whatnot very easy. A few ply triangle gussets would eliminate any movement along the length axis.
As much as I hate MDF for other uses, a 1" layer stagered over the torsion box joints would be smooth, firm, easy to work on and easy to form a smooth edge on. Ideal.
As an example of how stable the above construction is, a 2' wide by 8' section will show essentially no deflection in the middle with a 200 lb person. With 600lbs evenly distributed it will deflect about 1/4" over a 6 month period. Remember, that's for an 8' span.
A 2' x 8' section made from 2"x3"s and 3/8" ply deflects about 1/2" with 300 lbs evenly distributed. This is my favorite toolbox storage shelving since it's inexpensive, lightweight and easy to assemble.
Best of luck!
Don
Zbalk, I build a set of 22' wide tables to frame walls on every job. Our needs aren't so demanding but I've learned a little about big tables.
The flatest and stiffest tables are made of TJI joists. I'm currently using 4 joists that are 9 1/2". The table is 8' x 22' and there is considerable flex in between the well spaced joists (32" oc), so I would recommend using more. I use two rim joists that are of manufactured product (rim joist or microlams would do fine).
Cap this framework with a high quality surface and the only thing you'll need to do is dampen the thing with solid legs like 4Lorn1 mentioned. I agree, the concrete blocks have made our table very solid. I only block up the four corners, but you might want to add a mid span support.
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