truly flat building table

[ozmo01]

Hi all,
For years I have built on the tried and true hollow door with a ceiling tile or 1/2" foam to pin into. I usually spray some polyurethane on the tile to keep it from dusting and crumbling.
I had an oportunity to redo a bigger table. It is a STOUT steel legged folding table that I retopped with fiberboard and added angle iron under to keep straight. I recently took the belt sander to it to remove years worth of drill holes, razor cuts and glue blobs. A close exam reveales age has caused some minor wavyness.

so here is my thought ( I know thinking can be SO dangerous :D)

Use some epoxy table coating (often used in restaurants ) with removable edge dams near the table edges (tape and rulers or watever) this would allow a liquid surface that would self level to perfectly flat before curing out. (thinning with alcohol would make it level out better) Its about 25 bucks for quart, dries crystal clear and would stay flat forever on my table. Any one tried this stuff? (I have used it on other tables but not dammed up) This would eliminate the hollow door. I would still use the ceiling tile or foam.

[tommyt]

If the table is level, not warped and just wavy, then a lot of people use a flat sheet of tempered glass from an old sliding glass door.

I use a counter made from sheets of 3/4" Virola plywood laminated to make a 1 1/2" thick counter on top of plywood & Formica cabinets as a building table.

Tom

[ozmo01]

Hi,
I like the idea of working on glass. I used to help my Mom in her stained glass shop and I will tell you glass warps more easily than most of us would suspect. I have heard glass is somewhat like a liquid in behavior. Any how I would think glass also would behave better on a flat suface. Level actually has very little to do with building a straight wing or fuselage as long as the building surface is flat. You could have the table at an angle and it would not matter. However level to the floor would discourage twist in the table top.
I suspect some of these guys build while they are a little "tilted" any how! :D

[lincoln]

Sounds like a good idea. I bet once you spread the stuff, you could warm it up to make it run out level.

If you want a wild idea, make up some low temperature concrete with lightweight aggregate and pour it on a piece of plastic over lake ice. (In Russia, they had some tricks for getting concrete to set at very low temps. Not sure what that does to the quality. Not sure if still in use after demise of five year plans. At least I assume their demise. )

[scaflock]

I think the stuff your thinking of is called "Bar Coat". Not much different than a good finishing resin.

As far as a pinning surface goes... I use a sheet of drywall. Holds pins great and when it gets too many holes in it you can fill them in with painters spackle and gently sand it back to flat. The one drawback to drywall is that your table has to be flat. Currently I am using a metal workbench that was picked up as surplus from the local Air Force base for $25. Perfectly good bench too. Your tax dollars at work once again!

Jeff

[ozmo01]

Yep
Thats the stuff.
I saw on This Old House that some company is making cement kitchen counter tops so why not. I have seen cement floors so smooth they're dangerous if just a tiny bit wet. My board has to be moveable so I will pass on the cement though.

[Ninjak2k]

Go for it! I'd love to see the results of this. Seems like you could turn any old table, even a crappy folding table, into a nice flat building surface.

~Dan

[lincoln]

If you did your homework it wouldn't have to be that heavy. There's a lot of odd technology with concrete. Some concrete floats. If I'm not mistaken, you can use bead foam as part of the aggregate!
Yep
Thats the stuff.
I saw on This Old House that some company is making cement kitchen counter tops so why not. I have seen cement floors so smooth they're dangerous if just a tiny bit wet. My board has to be moveable so I will pass on the cement though.

[ozmo01]

Lincoln,
Sure. I wasn't thinking about fillers. That might work well on my fixed bench I have in the shop out back.
The table is pretty stout as I said. I mean you could stand on it. It has four long ways lengths of 1" steel angle iron under the table top and the legs are 11/2" square steel. There is around 40 counter sunk bolts and washer holding the particle board top on. I used some left over Bar Coat to reseal it after sanding. I think I will stick a level on it and then go ahead and do the temporary edging and pour warmed Bar Coat on. It will cure faster warmed but this stuff is slow like a couple hours to set and 24 hours to hardened.
I really want it to be FLAT for the Bubble Dancer build. Well I think I will get to using the table as is for now to finish covering the Big Bird XL I have been SLOOOOWWLY working on :D

[OVSS Boss]

My bench is not straight, but that piece of 1/2" glass is perfect.

Marc

[ozmo01]

Where do you get 1/2" thick glass? Plate glass is 1/4 thick such as in store fronts etc.

Well while I'm at it I also need to make a portable building board. Our club is having winter build nights every Thursday. ( need not be a club member if by chance you are close by)

[TRC]

Just a comment from an old glass guy..........Spent 45 years in the business. Tempered glass is not flat. The thinner it is, the more warped it is from the tempering process which is a re-heat and an air quench. Annealed float glass is flat. It is floated over molten tin while in a liquid state, hence the name "float". If you're going to use glass, use float glass and the thicker, the flatter. There is no such thing as plate glass made anymore. It refers to an old process of casting the glass then twin grinding it to a polished surface. Now obsolete.

[TheNightowl]

I almost hate to point this out, but the liquid resin topping is technically only perfectly flat while in a liquid state. Once hardened, whatever deformations attack the underlay will be applied to the hardened resin. Whatever warps your base eventually acquires, so will the surface. So, actually, it's no better than any other flat surface. I'm happy with my ceiling tiles laid over 1/2 inch plywood laid atop any surface that will evenly support it.

Nightowl

[seanpcola]

I'm about to build a new table for my shop. I have not settled on a size yet, maybe 30" x 8' . All pieces will be 3/4" MDF. Plan is to make a top and bottom surface then a series of upright bulkheads all cut to maybe 4" height and run through a joiner to ensure they are all of exact dimension. I will lay down the first work surface on an old prop table we have, it's made of 6" steel, machined to exact tolerance and is perfectly flat. Them the uprights will be glued to that piece in a checkerboard pattern. After curing, I'll flip that over on top of the other work surface and bond it. This will form a type of honeycomb structure. The MDF should remain dimensionally stable and the design will be ridgid enough to remain flat over a long period. All edges will be open and one side will have holes located in various patterns for clamping. Other side will remain whole for ceiling tiles to lay on.

[Batmanwpg]

Where do you get 1/2" thick glass? Plate glass is 1/4 thick such as in store fronts etc.

Well while I'm at it I also need to make a portable building board. Our club is having winter build nights every Thursday. ( need not be a club member if by chance you are close by)


One of the guys in our group got a glass door while a building was being demolished and it was about an 1" thick. Very flat but weighed a ton! Maybe try a place that re-cycles building materials.
My building surface is an old metal business desk. Very heavy and surprisingly flat.

[Windependence]

Another thought would be granite. You could go to just about any granite countertop fab shop and pick up a piece of granite 30x8. They throw away pieces larger than that. It is usually at least 1 inch thick and is about as flat as one could want.

I picked up a big piece this past fall and am going to build a new table from it this winter.

Wayne

Edit: They might just give it to you because they need to pay to get rid of the off fall.

[OVSS Boss]

I was lucky enought to get the glass, ~48"x18", from a glass store here in town that had some shelves that had been ordered with a mistaken dimensions. I take a ruler with me to check it, and the three pieces I have had were always perfect. i do very little built up work anymore, but I like ot have it around just in case.

Marc

[TRC]

Go to a glass shop that does commercial work, not a small shop or hardware that just cuts window glass. Ask for a 6mm float glass "cutoff" the size you want; you should get it for less than $2 bucks a square foot or they're ripping you off. Most of the time they don't want to fool around with a nickle/dime sale and will give it to you. Have the edges "seamed" so they won't cut you. Most glass shops are friendly and accomodating.

[ozmo01]

I almost hate to point this out, but the liquid resin topping is technically only perfectly flat while in a liquid state. Once hardened, whatever deformations attack the underlay will be applied to the hardened resin. Whatever warps your base eventually acquires, so will the surface. So, actually, it's no better than any other flat surface. I'm happy with my ceiling tiles laid over 1/2 inch plywood laid atop any surface that will evenly support it.

Nightowl

YEP, without a good base the surface won't matter :D

[chipgibbs]

If your going to dam the edges for the epoxy, another option is "Self Leveling Embosser" for flooring. It is a cement product used to level floors befor tile etc. Its cheap at about $7. a 10 pound bag. the only down side may be cracking if the foundation is flexible.

ChipG