Glass building table question

Hold out ffor some shower doors. Even the etched ones are smooth on one side, and they are thick enough that they will not disappoint.

When setting up a glass work table, it is essential that the surface be EVEN (not necessarily level). Squares and other reference gizzmoes work well off of an even surface.

Glass may be glued to directly: tacking ( sparingly) with even CA is easily cleaned with a razor. Thinner and windex then do the follow up.

Have fun!

See Ya

I currently have a 3/8" commercial glass sheet on top of a 1" thick granite slab on top of an old 6 foot long bathroom cabinet.

After getting the base and the granite for free, I was willing to spend $40.00 for the 5'X 30" glass sheet. Edging and delivery was free.

I wedge leveled the bench till the stone slab was flat and then dropped on the glass. Next time I build a wing I'll shim the glass with playing cards till its 100% flat and I'll be good to go.

You can use thinnner glass than I did but thicker is better. I'd LOVE to find a flat 1" sheet! Just remember many glass shops will refuse to cut old glass, so you'll need to find the right size. That might take a while.

That thin stuff from double pane windows is pretty useless. when you try to shim it, it just bends localy and you end up with waves instead of flatness.

1) Glass needs to be supported. In window thickness it will sag to follow your bench. Thicker stuff may not. But thick glass is not cheap.

2) Mine was a low E type window, and the pocket between the windows caused the window to bow in the middle. You need a single flat glass surface.

In my case I cut the glue and separated the glass (Without hurting myself, and shimmed it flat with strips of newspaper. It is a great surface to work on.

I have a 5' X 3' X 1/2" glass work surface that I ordered from a local glass dealer. Look in the yellow pages for someone who offers desk and table tops. It was a stock catelog item and I paid about $80 delivered. It's on top of a hollow core door and is dead flat as far as I can tell. A single thick piece of glass eliminates all the shimming headaches.

I put a piece of sheetrock on top of the glass so I can pin parts down directly over the plans and waxed paper. I've watched Windy's videos where he uses CA directly on the glass, but haven't tried it yet.

Now we've gone FULL CIRCLE.

I used to build on the dining room table, but upgraded to a basement workshop with a dedicated building board.

Latest thinking is to frame up teh model on teh glass dining room table and go eat at a resturant.

Done deal.

I picked up a free dining table glass top 30 x 60 5/8" thk.

I am still waiting for someone to tell me exactly how they check them for flatness tho--a staight edge can't do it since it wont reveal twist.

IF you are going to use a carpenters level and straightedge, you might as well use a piece of particle board and shim it by eye.

Even the 1" thick granite plates will sag some if not supported.

BTW, what do the group think is an acceptable flatness spec for a buildig surface?

Curt
Curt

The pool table Idea is excellent!

I have used the wire method. Alot of fussing to get it tight enough to not sag. Then it seemed to be difficult to really get much closer than 3-5 thou with the go gage because of the compliance of the wire.

even tight, the wire probably sags a few thou. I guess I could calculate that if I tried hard.

But, I guess I am in the camp now of: site in and if it is within 1/32 it is probably less than the wing will change with temp and humidity later anyway!

I'm planning on Huntersville. Lets hope for same weather we had last year--Watch yo back big guy, I'm flyin advanced now!

Sure it will. I have a long drywall ruler. If the table has not twists, the ruler will be flat on the table. Otherwise it will rock, or have a bow in the middle. String will work too. So will a cheap lazer, but it is a pain to set up.

Flatness spec. This will be intersting... I used less than a playing card thickness over 5 feet as my spec. But I think that is overkill

I disagree on the staightedge plan tho. Perhaps it will indicate gross defects (1/32 or in that vicinity)

I've watched guys check machine tables for flatness--and they don't use straightedges!

I just got a nice, new 6' x 4' x 1/2" glass building table.

Where can I get the glass magnets?

Is a string any better? I just do the best that I can with the tool I do have, and know that there will be some change due to the airplane and bench wood dring out swelling, dope shrinkage and all that. For what we do a good long straight edge carefully used is going to be within limits of what is real.

I think you are correct, flat glass is an overkill. Working on glass is nice even if the table is not machine flat. It is a very consistant surface. The surface is smooth, and glue bumps don't get in the way. It's so much easier to clean up.

I guess some like the string or wire but I found it sagged too much for consistent use.

THe machine guys use a flat sliding base with a horizontal arm that holds a vertical dial indicator onto the surface about 6 to 10 inches from the base. As you move around the indicator shows the bows or bumps.

Problem is, with the glass, you have to shim it if it is low--the machine tables get scraped.

I glue sanding strips it directly to my work surface. That makes it really easy to true-up sheet wood, motor mounts, flaps and so forth.
It's the same surface I use to assemble crutches and fuselages.

Lastly, we want a flat surface upon which to align and assemble the completed components.

In my workshop, everything begins with flatness and hopefully ends with trueness.

I suppose, in the end, the higher your standards get the more finicky you become.

Hey Ted! How you do it?

those 1" thick granite or marble plates are heavy enough.

I do have a 18 x 24 cast iron, webbed surface tooling plate I use for engine measurements, etc. but it isnt big enough to build on.

For my foam wing stuff, where a flat is critical, I use a 1-1/4 thick modular office work surface that is about 30 x 60 and as flat as we can sight it.

Stabs and smaller items like crutches get built on smaller 1/2" thick aluminum tooling plate. Then I always put the engine mount pads on and mount the whole unit to the bridgeport to true up the mount area.

FWIW

Well, moving the granite was a real problem, so I had to get Donna to help me.

When we moved the granite from the cabinetmakers reject pile, she picked up one end of the slab while I picked up the other. Then we put it in the back of the S-10 and drove home.

To get it up on the table, we did the same thing. It was a little heavy for her, so we had to put it down once so that she could rest but all in all the job lasted three or four minutes.

The marble slab that we picked up at the same time was placed on top of my tool bench. It was smaller and lighter, so installing that one went much faster.

In exchange for her hard work, I made Donna a fresh lemonade and installed hooks for some new hanging plants and bird feeders!

Are you sure it is not something to do with Old dawgs and new tricks? No, I sure that there are a ton of flyers still using glass or sheet rock, Luan doors or anything flat to turn out their needed parts, heck I included myself into that group, it's the American way to be different!

I have found a product that was easier for me to use. I build wings, engine crutches, true sheeting, build fuses, straighten warpped balsa, heck I use this thing for all sorts of work, besides it is almost as big as most glass surfaces and it is covered with formica, it is hard to beat for a building surface because it is FLAT.

As far as quality is concerned if the guy behind the Exacto knife doen't have a clue then the best equipment in the world will not help him to build the first thing straight.

Mike Clark, Uh not to be confused with Mr. Clark

Lets see a picture of the wing building jig.

I use parallels to build my wings. I have no idea how other people do it. Parallels are nothing more than several boards all exactly the same thickness and height. It takes me almost a hole 10 seconds to setup to build a wing. The parallels can be used on any wing no matter what size or shape it is. I am happy with what I have but I am always open to new ideas.

Who is paying $60.00 for glass. I paid $1.00 a sheet for 60 sheets of 26" x 74" tempered safety glass. The local trash dumpster is a good place to get it. The man that works the trash dumpster sets things to the side and sells them to make a few extra dollars. I don't think he is suppose to do that but no one is complaining.

What do you guys use your glass for? I use it to keep my airplane plans clean and flat on my work table. I put the glass over the plans and build my airplane right on top. I can take measurements real easy on top of the glass. I don't attach anything to the glass I just use the glass as a hard flat see through surface.

So now the dumpster at the Hobby shop, glass company and the local XXX rated print shop was secure!

All you guys look the same around here!