Building Board Suggestions ???

[atjurhs]

Hi All,

I'm about to get started on my Winter projects, and I noticed that the balsa board that I used last Winter (approx. 3/4"X18"X36" and had glued to a piece of formica counter top) has warped a bit, so I'd rather not use it. I now have a new very large build table with a plastic top that is flat. If I buy some more of those 3/4"X18"X36" balsa boards what can I do to keep them from warping so that my wing get built flat?

Looking for suggestions....

[Curare]

use something that stays flat.

think of all the nosecones and wing tips in that building board!

[aeajr]

I use a 2X4 Ceiling tile, working on the back.

[seanpcola]

What aeajr says.

They work very well, hold pins tightly and are very uniform in thickness. Cheap too!

[slozuke]

Better than ceiling tile is sound deadening board. You can get it a any BORG and it comes in large 4 x 8' sheets. Stays flat and holds pins very well and it's CHEAP!!!!

[Andy W]

I bought a piece of good quality 2x4' heavy plywood, to which I attached two ceiling tiles (with regular wood glue). I store it vertical, use it on a flat table, and it's lasted through several builds and about 4 years so far. I just check it with a straight edge before I start..
..a

[sleep4]

Todd:

Above will all work.

Something I have heard of recently is a product called Homasote. It's sold at most Home Depots, is light, flat, inexpensive and holds pins well. It comes in 2 colors and model builders are using the lighter shaded version. A search on "Homasote" on the sailplane and building groups will lead you to several threads about the product and people's success with it as a building surface.

John Mears

[kzimmerm]

I second John's suggestion here. I've used Homasote as a building board for many years now. I think it is a compressed paper product used as concrete block insulation. It is about 1/2" thick. Works well. One suggestion is you may want to mount it on a flat piece of plywood to keep it absolutely flat. You can use 1 1/4" wallboard screws to screw it to the plywood. Over time, as the surface gets worn, you can unscrew it flip it over and screw it back down.

Kurt.

Todd:

Above will all work.

Something I have heard of recently is a product called Homasote. It's sold at most Home Depots, is light, flat, inexpensive and holds pins well. It comes in 2 colors and model builders are using the lighter shaded version. A search on "Homasote" on the sailplane and building groups will lead you to several threads about the product and people's success with it as a building surface.

John Mears

[atjurhs]

Excellent suggestions! THANKS guys.

I will check out the Homasote option and keep the ceiling tiles option as my plan B.

[imack]

A sheet of drywall works pretty well too. Holds pins well and doesn't have any tendency to warp over time. It's cheap enough that when it get oily, etc. you can just chuck it and get a new one.

Ivan MacKenzie.

[OVSS Boss]

For a base board, a scrap piece of thick glass, tempered, is cats meow, the a layer of pinable surface on top. I had one that lasted forever and finally cracked in a move, will get another this fall.

Marc

[ecormier]

I screw a piece of drywall to an MDF board. I insert paper shims between the drywall and MDF and check with a straight edge to get a perfectly flat surface. Like Ivan, I chuck the drywall when it get too worn.

I'll have to check out Homasote next time. It seems easier to push pins into that stuff.

[kablair]

Based on all the great posts here, I went in search of some glass.

1/4" seemed too thin so I foolishly asked for 3/8" and was floored when I was quoted nearly $100 for a piece of 12X48x 3/8.

Then I went to Home Depot to find Homeasote. They never heard of it - can someone give me a different name, or use for it, so I may have better luck?

In an act of desperation, I bought 2 pieces of 3/4" MDF. The entire stack had been stored on top of 2 firring strips - of course they were on the short end - so there is a very slight bow in every single sheet!. I plan to put them back to back (concave side to concave side) and bolt them together to get a single level board.

Any other suggestions (economical ones!) ???

-Keith

[OVSS Boss]

Kieth,
I realize a C-note is not cheap, but take care of and it and it lasts forever and will not warp guarenteed. Glass is the way man, or a really solid piece of granite.

Marc

[sleep4]

Keith:

The following web address will direct you to Homasote in your area.

http://www.homasote.com/where.html

[kzimmerm]

Here is a suggestion. If you want to find some cheep glass, look for a store that is closing and request their glass countertop. I'm sure you can get it for a real good price.

Kurt

[kablair]

Thanks for all your suggestions.

Now I see why noone's heard of Homasote before, there's only one place listed in my area (Houston). Maybe the heat, humidity, and mold makes it less desirable as a building material in this area. Good grief, they even sell 'moss rock' (yes, moss/mold grows on these landscape rocks) for $0.20/pound! I grew up in New England and we never had to pay for rocks!

Good suggestion on finding glass at a closing store. I'll keep my eyes open, but it will have to be an 'opportunistic' finding - not one that's on my building schedule.

Looks like I'm starting my next plane (Yardbird II) on the MDF. At least it's smooth and flat. Not real easy to work with, but a straight wing is worth a $5 piece of MDF.

-Keith

[atjurhs]

I checked out the Homasote last night at HomeDepot, and decided NOT to get it but instead to get 2 ceiling tiles. The Homasote didn't appear to me to be as rigid (able to keep stick pins in place) as the ceiling tiles. The hollow door was $20, and each of the ceiling tiles was $4, so the out the door cost was $30.

Next question, do you glue the ceiling tiles to the door or just lay them atop?

If you just lay them atop, how would you know that they remain flat like the door?

[kzimmerm]

Instead of gluing the panels down consider using wall-board screws. I was also going to suggest that you take a 3-4' straight edge and run it across the surface of the door to insure there are no warps in the door. This trick I've learned long ago from a fellow long time modeler. My last building table was a fire-door, filled with gypsum. Yeah, it was heavy but it was absolutely flat.

[georgeg]

Then I went to Home Depot to find Homeasote. They never heard of it - can someone give me a different name, or use for it, so I may have better luck?


Any other suggestions (economical ones!) ???

-Keith


I think its also known as celotex. You should be able to find it at Home Depot or Lowes.

[atjurhs]

I did think of the screw it down option after I wrote the post - dhooooope

But I hadn't thought of the straight edge idea. I'll check it when I get home....

Thanks

[Peytr]

I use ceiling tiles and glue two of these back to back. The double board is stiffer and can be stored standing vertical for short periods of time. After a while it can be turned over to get a fresh board once the first side gets worn.

Longer pins can be used without scrathing my desk :p

[seanpcola]

You can also use thin double sided carpet tape to hold the ceiling tiles to your door.

As kzimmerm suggested you really need to check the door to be sure it is flat. I have purchased them in the past from Home Depot and had to go through several in the store before I found a flat one.

I now use a building board made from solid pine, 3/4" T x about 16" W x 6' L with three rows of 1" square aluminum stock screwed to the bottom lengthwise to hold everything flat. So far it has stayed that way 2 years even when stored on end.

[Dennis Everett]

I use the celetex also , but i first lay a piece of plywood down on 2 - 4 foot levels (i think 8 bucks a piece ), then the celetex , makes it perfectly stright that way...Dennis

[Curare]

I'm a big fan of the ceiling tile, worked for me:)

[kablair]

Just finished building my building board :confused:

Didn't want to spend $100 on a pieces of glass, still couldn't find Homasote, and I've found ceiling tiles to change shape over the course of building a wing.

Therefore, I took 2 pieces of 2'x4'x3/4" MDF (~$5 each) and bolted them together with 1" carriage bolts. A 1/4 hole was drilled through both boards and then a spade bit was used to allow the bolt head and nut to be recessed. It is at least as flat as my 4' level since there is no light shining underneath it at any point.

Not very easy to push pins into, but neither is glass. I'm coating it with wax paper and moving forward.

[thermal]

You can build a torsion box with much lighter material and it will stay straight and level moreso than a solid board. Just to throw in another variable...I've been using galvanised steel on a level surface and building with magnets. You can make lots of different holding jigs and never put a hole in your balsa.

[Curare]

I used a peice of slate from a pool table under my ceiling tile with a large frame underneath supporting it. take your time to make sure it's absolutely flat, and you'll thank yourself later. I also drew a grid on the tile to give me some reference lines for scratch building later. if you're worried about pushing pins into your mdf, use metal headed pins and tap them in with a jewellers hammer.

It worked for me for the best part of 20 years.

[apage]

My building table is made from 2x4's joined with those galvanized framing brackets. The top is a SOLID core door, 30x80. I'm not sure why people use hollow doors - seems like the thin skins would become wavy. I also like being able to use it as a hard surface for things like laminating spars under weights, or for the occasional build that requires some sort of jigging, which can be tack glued right to the solid door. Again, I just don't see how a hollow door would work well for this - the ones I've seen inside of are just 1/8" skins and minimal cardboard 'honeycomb' core.

Make sure the door is well supported with straight 2x4 aprons all around the perimeter (get the straightest dry ones in the pile and joint them if possible) and at least one cross member. A torsion box is nice but not needed in my opinion. Screw some big lag screws in the bottom of the 2x4 legs. This allows you to adjust to an uneven floor, and to take out any twist the top may otherwise have. Sight along the table's length and judge the twist by two parallel 'winding sticks' placed across the ends. Adjustments are easy with an open end wrench, without moving the table. Mine has stayed flat for over 5 years.

As others have said, ceiling tiles work well as a building surface. I've seen Homasote and I think it would hold pins a bit better. No need to glue them down, they will lie flat. I do attach them to a sheet of 1/8 ply (doorskin or paneling) by taping around the edges with duct tape. This keeps the edges from crumbling and allows you to remove the tiles if you need a hard surface, while keeping the two tiles tightly together at their ends so you aren't building across a moveable gap. If I used Homasote, I might still tape it to a backing sheet of doorskin, just to keep pins off the table surface.

When the tiles get dented from elbows, and full of holes.... it's cheap enough to buy two more, but I've kept mine alive for years by scraping a thin layer of drywall mud across them with a wide taping knife - just enough to fill the depressions. Sand any little ridges left by the knife with a long sanding bar. A few quick passes is all it needs. Pins don't know the difference between the tiles and the mud fill. Of course, I happen to have the bucket of mud on hand.... it would make more sense to buy new tiles otherwise.

[rpd]

I use ceiling tile, too. My "bench" is the cast iron top of an ancient Craftsman bench saw (it was my dad's and I am 56) with two pieces of 3/4" X 2' X 4' particle board on top that are glued together. The ceiling tile tops it off. If you use an exacto knife, don't use it over ceiling tile. It will dull the blade very quickly. I have a small piece of plywood that I use under wood that I am cutting.

[bobby legue]

Take the time to seal the mdf against moisture as a simple spill will swell the board out of shape.
Bob

[Dinkus]

For several years, I've been using an internal (core filled) door (2040mm x 720mm x 45mm). Cost me AUD $10 from my local hardware supply as it had a door handle hole already drilled into it and couldn't be sold as new ...and most importantly - it is dead flat. (ask for a "damaged" door) The door is then fastened to a solid table base. I then lay over the door, a sheet of Canite board - which pins press into very well. I use clamp mounted Dremel & lighting which clamp onto the far side of my workspace and a small clamp mounted vice on the nearside. Once the project is complete, I then use the Canite as sandwich packaging material for a soft wing container bag. (i buy fresh Canite for each project)

Works very well for me ...and is cheap as chips :)