Large Building Board
#27
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Actually, there's a lot of room for tolerance if you don't mind having to fly your model with some aileron always trimmed into it. Really, though, you want your building surface as true as you can get it. It's not too hard to have a 4' x 8' worktable within 1/16" using regular shop materials. You'll likely put more warp into your wings when you shrink the covering.
I'm building a full-size RV-9 airplane, and the 12' wing panels are allowed to have up to 3/32" twist from one end to the other. That's not much, but it's easy to jig the wing so you have that or less. The same with models. You can use taut lines, lasers, good straightedges, and so on to check how true your worksurface is.
You can use 3/4" plywood, good both sides, as your work surface if you have a good structure below it. Mine has 2 x 4's held together with screws. A few shims under the ply from time-to-time keeps the worktop trued.
I'm building a full-size RV-9 airplane, and the 12' wing panels are allowed to have up to 3/32" twist from one end to the other. That's not much, but it's easy to jig the wing so you have that or less. The same with models. You can use taut lines, lasers, good straightedges, and so on to check how true your worksurface is.
You can use 3/4" plywood, good both sides, as your work surface if you have a good structure below it. Mine has 2 x 4's held together with screws. A few shims under the ply from time-to-time keeps the worktop trued.
#28
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Dick,
I either tack glue the parts to the table or use ziplocks with lead shot in them. When I tack glue them I use thin CA and build as much of the structure as possible including sheeting. When I can't do anymore work I just pop it off the table and finish up the other side. A quick scrape with a single edge razor and the table is as good as new. Plus you can mix epoxy, bondo, or whatever right on the table and it will scrape right off after it sets up. No more looking for paper plates or palets to mix on.
Hans
I either tack glue the parts to the table or use ziplocks with lead shot in them. When I tack glue them I use thin CA and build as much of the structure as possible including sheeting. When I can't do anymore work I just pop it off the table and finish up the other side. A quick scrape with a single edge razor and the table is as good as new. Plus you can mix epoxy, bondo, or whatever right on the table and it will scrape right off after it sets up. No more looking for paper plates or palets to mix on.
Hans
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Thanks, Bax, that answers my question.
Heavy Date, if you dont mind, how much did the glass cost, and can a guy find something like that at any old glass shop? Id like to work on a piece of glass.....
Heavy Date, if you dont mind, how much did the glass cost, and can a guy find something like that at any old glass shop? Id like to work on a piece of glass.....
#30
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I went to Lowes and got two counter tops, one 10ft and the other 6ft.
Built a good 2x4 frame, used drywall screws to secure the top to the frame, also shimmed between them to get it good and level, arranged in an L shape in the corner and can have something going in two areas at the same time.
Also use the tile for pinning down.
works great for me.
Del Johnson
Built a good 2x4 frame, used drywall screws to secure the top to the frame, also shimmed between them to get it good and level, arranged in an L shape in the corner and can have something going in two areas at the same time.
Also use the tile for pinning down.
works great for me.
Del Johnson
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sounds good to me. learn something new and worthwhile every once in a while. thanks. will have to try it on window glass with plan underneath for smaller parts. dick
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Im not trying to argue, Im just curious what tolarance is involved, because I think Im wasting a lot of time at home trying to achieve tolerances that I dont have to achieve. Examples: plywood (as stated above laid on a dining table) over its span is not going to be flat no matter what, an ironing board with something on top of it will also not be perfectly flat. Theres got to be perhaps a few thousands of an inch between the table and the straightedge. Maybe 1/4 to 1/2 mm millimeter. Im not saying these boards dont work, obviously they do, but on the flip side, obviously theres some point at which the boards are flat enough and minor variations dont make a difference. Im curious as to what is acceptable.
My torsion box building table shows no gaps between a straightedge and the surface of the table in any direction - lengthwise, cross-wise, or diagonally. By no gaps I mean I can't see any light from a flashlight held behind the straightedge passing under that straightedge. I was sort of surprised that it came out that flat over the length (6'), but I'm not going to argue about it.
You _could_ build a perfectly flat building surface, but it would entail having the building surface blanchard ground (meaning the surface is metal) at some considerable expense.
I can put you in touch with a machine shop here in hotLanta that would be glad to take your money.
"Flat enough" is however gap-free you can get it before you get tired of trying to make it flatter or get tired of spending money trying to make it flatter.
OTOH, "flat enough" is when the building surface can produce a built-up wing that can be made nearly perfectly straight by tensioning the covering.
Howzzat ?
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its all like the shine on a car. some guys are never satisified. its all in your idea of perfection. some like it Hot, some like Cold I just like it. dick
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ORIGINAL: Swager
Wait......the building surface has to be flat???
Wait......the building surface has to be flat???
Ya don't really learn to fly until you build a model on a surface with whoop-de-dos all over the place, and the model comes out cockeyed ever which way !
Ya gets to practice yer trimmin' skills thataway, bub !!
I finally got a flat building surface so's my head doesn't roll off, when I've been in the shop too long and needed a little lay-me-down . . .
#37
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Walsh..Melamine comes finished both sides. As for supports or tables, if you use construction materials, such as 2 X 4 and then glue, screw or nail the MDF or Melamine to it, it will warp in high humidity or changing humidity. If you want a stable table you should use, Redwood, Spruce, Cedar or Honduras Mahogany (called Genuine Mahogany by some) or you must let the top float and occassionally shim it to make it level, as Bax mentioned. Use a string line to check it. 1/2 inch block at each end, string tight and check it with another 1/2 inch block. In furniture construction, good tables are made with a floating top, if the top is glued to the base it will eventually warp or worse, split. If you are going to use plywood, put a sheet of tempered hardboard (masonite) on top and shim that. Drywall will soak up humidity so if you are going that way use green board, drywall used in bathrooms and kitchens. If you are going to use plywood, do not use construction D.F. Ply, the edges will soon begin to curl, use Birch Ply and soak it down with Watco oil or Maloof oil and then use Thompson's water seal or CWF to seal it from moisture. BTW You guys that are using ceiling tiles, you can buy celotex in 4 x 8 sheets.
#39
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Homasote board works very well, strong, flat and pins will push into this material very well. The pins will not bend over or pull out to easy. You can pick up a 4x8x1/2 board at most big box home centers (homedepot etc). I cut mine into 20"x96" pieces, lay it on a flat surface and it makes a perfect building board. Hope this helps.
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Prop Nut, what is homasote board? Is that like celotex or the foam insulation board builders use to cover the exterior of new homes with before siding or brick is put up? My home depot people don't know what homasote is, and I don't either. Help me, please.
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E V E R Y O N E is right on! On the other hand - hah! How many hands do we have? LOL from the rediculous to the sublime.. If all else fails, the best know flat surface is one that will require a man an a few small lads to move it. --- try GRANITE. I think the best amswer I read is true to all that read this -- you really don't need it DEAD FLAT That's what trim is for!
Best of luck
Best of luck
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safebet,
I use homosote for my train layouts, and Home Depot nor Lowes has it near me. I have a smaller lumber yard near here that carries it, you may have to seek out one of the smaller lumber yards to find it.
When you do though, it is cool stuff. Its a pressed paper board. It sort of looks like fiber cement in color but its smoother, and it kinda looks like MDF from the side, but its made of paper rather than wood fiber. Its kinda heavy too. When you cut it, I found you may have better luck with a knife blade in a jigsaw, in my experience it dulls saw blades pretty quick.
I use homosote for my train layouts, and Home Depot nor Lowes has it near me. I have a smaller lumber yard near here that carries it, you may have to seek out one of the smaller lumber yards to find it.
When you do though, it is cool stuff. Its a pressed paper board. It sort of looks like fiber cement in color but its smoother, and it kinda looks like MDF from the side, but its made of paper rather than wood fiber. Its kinda heavy too. When you cut it, I found you may have better luck with a knife blade in a jigsaw, in my experience it dulls saw blades pretty quick.
#45
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I use solid doors and hollow core doors. Depends on what I can get. Some one is always changing doors and giving a few away. I weld up steel. May be different tools then what the R/C rs generally have but steel is about $11 for a 24' section at a steel supply yard:
![](http://www.rc-tech.net/MGB/sand/table.jpg)
![](http://www.rc-tech.net/per/shop.jpg)
I weld them up with a mig welder. I realize not all R/C rs have a mig welder but it works great for me. If the door gets buggered up, turn it around or turn it over.
![](http://www.rc-tech.net/MGB/sand/table.jpg)
![](http://www.rc-tech.net/per/shop.jpg)
I weld them up with a mig welder. I realize not all R/C rs have a mig welder but it works great for me. If the door gets buggered up, turn it around or turn it over.
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and I thought that I had a big model shop. what I have is so cluttered with the remenents of my ex 14,800 sq ft shop, that the ceiling of the living, dineing and 2 bed rooms is where my planes are hung. so far my bride of 54 years hasn't complained too hard. just let her know before the club decides to come over. will have to get busy soon and fill up the back yard 2,500 sq ft shops. dick
#49
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My plan for the ultimate building table...
http://homepage.mac.com/mikejames/rc.../rcmovies.html ( at the bottom of the page)
http://homepage.mac.com/mikejames/rc.../rcmovies.html ( at the bottom of the page)
#50
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this is my winter time drawing board, on top of the dinning room table. currently the new plans for the 61" wing span, 2 passenger 1919 Fokker D-7. the fuselage is only 54 1/2". everything is ready for when the wife says clean it out, company coming. Have a MERRY CHRISTMAS. dick