housedad

I have been trying to figure out a way to build a large (30 X 80) building table that would be extremely flat, very strong, and still be light enough to pick up and lean against the wall or put in the garage. I have very little room in my basement at the moment, and I need the table to be out of the way when I am not using it.

I'm not getting any younger, and it must be light enough for me to lift and carry. The others I have seen are waay too much at 150+ pounds.

To top it all off, it needs to be easy to build, as I am essentially lazy about things like this.

I have seen the Torsion box designs that are shown on the DYN website, but they assume you are making this a permanent addition to youur shop space. It is heavy, but still a wonderful table. However, I doubt that any of our mocels would reach into the hundreds of pounds the the DYN table is built to withstand. We need the stiffness, not the weight or complexity.

A person could build one out of 1/2 inch and 1/4 inch ply that is in the area of 36 lbs, (I made a design of it). Unfortunately, it is rather complicated to build, and requires a lot of carefull planning and work and a GOOD table saw and blades.

Suprisingly, the design I came up with consists of using hollow core doors. Hollow core doors are high technology torsion boxes all on their own. The three main problems with using them as a worktable is:

1, They do not have a very stiff or even flat surface. The skins are typically 1/8 mahogany (luan) or birch. The interior of the door is honeycomb resin impregnated cardboard. This allows some fles to the surface when pressure is applied to a small area. The surface is able to flex from one side of the center line of the door to the other, but still staying the same thickness. This creates a uneven surface.

2. Used as a table, they will eventually warp. The doors are designed to operate in a vertical position. The honeycomb size is rather large, as all it has to do is support the skin and no other weight. The Thickness of the door is typically 1 3/8, Which is not a very large web to withstand loads, considering the span. Even leaning them against a wall will warp them as the seasons and humidity change.

3. They are already warped slightly by the time you get it at the store.


I found a solution that works so far. I have successfully glued two hollow core doors together and have a VERY flat surface to build on. These will be skinned top and bottom with 1/4 birch plywood, and then the entire thing banded with Oak. The birch ply will add stiffness to the top. and add skin stiffness.

As I do not have a vacuum bag system, The glue I used needed to be strong, waterproof, and have no water in it. Water in the glue migrates into the wood, and could create a warp on drying. It also needed to be fast and require no clamping. Contact cement was the glue of choice.


At this stage, only the Doors have been glued, with the skins going on tonight. As it is, the doors are flat. Very flat. The combination is extremely strong and stiff. After it is skinned and banded, I will suspend it at the ends and place weights in the middle to see what the deflection is. I will also weigh the entire thing. That will tell me if this is a success.

The support system that I used for building was nothing more than a couple of sawhorses and 2 X 4 's.

Pictures and a complete build sequence of events will follow over the next few days.

ecmiller

A little...ah no.. alot of overkill in my opinion. You must be a gearhead?

Mastertech

My Feedback: (31)

Watch what contact cement you use. Most of it is waterbased.

sscherin

My Feedback: (1)

I have a simple portable workbench..

It's a kitchen island counter top I got at the habitat for humanity re-store.

They are typically 1.5" thick, built to be a tough work surface and come in all sizes..
Mine is 60"x30"
I just throw that on top of my workmate and I have an instant building surface.

A bigger table like you want might take 2 workmates for support.

djr1007

My two cents,,,,,, I've recently gone to the magnet system of building, I'll NEVER go back. Now I did build a heavy table, 1/2" glass, 12 gage steal top, 4' by 6', Total cost about $500. But, before that I used a "Single" metal clad door! Very flat, without windows it was only about $80, and only required one. No ceiling tiles, no pin holes in your balsa, etc. I dry fit a stab recently the way you would normally, marked a couple of alingment marks, last night it took me just 30min. to glue, line up, and jig the entire assembly. Pulled it off a little while ago and with a machinist rule, and laser level I cannot detect any warp in any plane.

housedad

Well, here are the pics. It was a great success!! It is the weight I wanted at 53lbs. It is FLAT! It is even stronger than I figured.

housedad

The first two pics are the doors glued and ready to put together. Pic 3 shows the end or them laminated together. 4 and 5 shows putting in 2 inch drywall screws just under flush with the top.

Pic 6 now has the top and bottom 1/4 inch Birch pllywood skins glued on with contact cement and the trimming off of the excess with a flush bit in a router.

Pic 7 shows the Finished trimming with pic 8 showing all the laminates.

Pics 8 and 9 Show the prep of gluing on the oak banding (edging) around the entire table. I used Gorrilla glue and a brad nailer. After the banding was dry, I used a router with a flush bit to bring it to the level of the table top.

Pic 10 shows the strength of the table. That is me, pretty dirty from doing yard and gardern work, and dirt from the routing of the table parts. I am 250 pounds. The sawhorses are positioned at the very ends of the table. As I got on it, there was not a single creak or crack to be heard. It is solid as a rock! But a heck of a lot lighter.

Pick 11 shows the center deflection of the table with my weight on it. Measured to be 1/4 inch. Incredible for such a light table and that long of a span!! remember, it is only 3 1/4 inch thick!!

For those that think it is overkill, please remember that the requirements I had for a table is that is flat at all times for modeling, t will not twist or distort in storage, and It had to be light enought for me to haul around.

Additionally, it needed to be stiff enough to be self supporting. It does not need a level support structure to remain flat.


This table has fufilled all the requirements.

(on edit: I make no apologies about my messed up garage. I get to clean it up about once a month. It is not where I do my modeling!!)

housedad

By the way, I am going to the magnetic system. As I had so much leftover birch plywood from the build of the table, It makes it easy to make the fixtures. I just ordered the magnets. I am going tomorrow to get the steel. It will not be glued to the table, just layed on it.

Thanks to everyone that has shown interest!!

Kmot

My Feedback: (24)

Looks good!

tailskid

My Feedback: (34)

Lot of work done there....and it looks great! Wanna bring it over to my house and I can build something on it?

djr1007

Great job Housedad!,,,Your really going to like using the magnets.

housedad

Thanks for all the compliments!

I have finished sanding it now, and will start putting polyurethane on it tomorrow. The rest of this evening I'm gonna be sawing out blanks for the magnetic fixtures.

2 weeks ago, I bought a a Sears 10 inch table saw for $159 that I bought just for the hobby. Dang thing went on sale for $99 yesterday. I went back to sears and got a price adjustment. It should work real well for sawing the ply fixtures. REAL nice saw for hobby work. Get it now while it is on sale.

I need to find some handles to put on the sides of the table for handling.

This new table is only for assembly. I have a 40 year old oak drafting table that I use for everything else.

housedad

I just realized that I never posted pics of the table with the final finish on it. It is sitting on a couple of height adjustable sawhorses. It has 6 coats of Poly on all sides. Both surfaces are interchangable for a building area. Here are the pics:

There is a lot of sanding dust on it from other projects.

dhal22

drywall, sheetrock is pretty cheap again. you could always order a 4' pile of 4' x 12' sheets and have it delivered and stacked in your basement. that should be flat and stable.

david

flyingvranch

That's very nicely done! Great idea and I like the way that it can be stored away. I have found that with a surface finished like that, you can take a sharp chisel and pop off any hardened glue drops and keep your surface clean easily.

F4U Corsair

My Feedback: (22)

Nice job, you put some time in on it but the results were great! How much cash did this project end up costing you? Inquiring minds want to know! StikDude

housedad

Table, with glue and finish was about $140. Thanks for the compliments!

PlaneKrazee

My Feedback: (14)

Housedad,

Nice strong table you have there.

Old hollow core doors from the 60's are excellent quality. If you know of someone remodeling an older house see if you can get some. I was given a couple and they are perfectly flat. I will probably double them up like you did to make sure they don't move.

My first building table was a 12" hollow core door with two coats of Minwax poly. My H-Ray came out great! I use a piece of sheet rock as a work surface to keep the table clean and it holds pins well. Cheap, flat and disposable.

I thought of buying some cabinet magnets and a piece of 24 gauge galvanized sheet metal to make a magnet board but never got around to it.

I used two of these doors jointed together as a 46" wide shelf in my 4'X8' enclosed aircraft trailer. We ripped the doors to half the required width, removed the honey comb 1-1/4" deep, made a joiner spline from a 2X4 that we planed down to the proper thickness to fit inside the door skins. Glued the spline in with wood glue and secured with ring shank panel nails. The panel is very light and strong.

Broken Wings

My Feedback: (20)

It looks Beautiful. I wish I had the space to be able to leave a table that size set-up.

I bought a wood workers table with drawers from Harbor Freight http://www.harborfreight.com/cpi/cta...emnumber=93454 with a 20% off coupon. The shipping charge was like $12...I almost fell over.

I bought two of the large "purpose built" balsa building boards from Guillows so I can frame up both wing panels or build a fuse and rud/elev assy.

So far it's worked out real well and the Wife likes the way it looks so I get to build in the house. It's brutal here in Florida in the summers so working in the AC is a must.

Nice Job thinking outside the box.