What is the preferred building board these days?

I have a door that I've built on over the years, but I'm not 100% sure it's flat anymore.
What is a good way to check a board to see if it's buildworthy?

Thanks
Bob

Easiest way that I've found is a couple of thumb tacks & a string. Put a tack on one side of door & go directly across from it & check if there are any " low spots". Do that all the way around untill you check it from all angles.No high spots or low spost = a good building board.

Nice idea, thanks!

Is there any way to use a laser to do the same thing?

That's a bit drastic. I would just use a straight edge and lay it across the board to see if there are any gaps.

Wouldn't the straightedge have to be the entire length of the table to give useful information?

Another way is to use a florescent tube and roll it across the surface in both directions. They tend to be pretty straight.

How flat is flat enough for a building board?, considering that balsa swell and shrink as the humidity content in the air changes? I'm building on a 6 mm thick laminated glass sheet on a 50 mm thick (kitchen top sheet from hardware store) for many years. Never had problems with skew wings or fuses.
You build a plane on a laser levelled board, but by the time you come to cover it, the wood may have swollen or shrinked abit due to moisture in air. Then, when you cover the plane and shrink it eneven, you have a skew plane. Their are tolerances we have to accept and something like a length 50 mm kitchen top is a good,stable base.

Cheers

Bundu

Since most wings are in the 72" range or smaller, a 36" straight edge would be long enough.

I would like to see less than a 32nd inch gap anywhere. Less than a 64th even better.

The fuse I'll build is a 73" long profile and it don't want any warpages built in.

MinnFlyer,

I don't disagree with those dimensions and tolerances, but have always felt that bigger is better for when you get to rigging and setting angles etc. You could build two really nice and straight wing halves and then screw up on dihedral because both won't fit on the building board. As I think of it though, i suppose you could center the wing section and calculate height 15" or so out from center to get the right angle. Is that how you would do it?

My hobby activities progress very slowly so some may remember my pool table slate idea. Well, I got a nice piece of slate free from a local billiard store....finally. Finally! It only had one small corner broke off where the "corner pocket" would be but outside of that it is complete. I am going to cut it lengthwise to square it off and build a table on wheels so I can move it around. Just something I am playing with at this point and I am planning on covering it with metal and move toward magnets.

Anyway, no question that pool table slate is totally and perfectly flat. Also, no question that pool table slate is totally heavy! .

Did I say heavy?

Tom

I checked my old doors and they are not flat at all.
Don't know what to do now?

I hate when this happens...

I really liked building my last two wings on my a-justo-jig. Everything is as straight as I can measure.

My wing was one rib too big for the jig, so I extended the rods out past the end. The risk of the last rib not being perfectly in-line was very minor.

I also had to be able to remove one rib brace from each wing when the aileron ball-crank was installed. I cut two of the jig rib braces in half, and rejoined them with a backing plate. Next time, I'll use those two braces in the place where I'll need to remove a brace.

As long as the table is RELATIVELY flat (less than 1/32 over 36 inches) it's really not going to hurt the dihedral over a 73" wingspan

Is there a way to build a long flat fuse on an Ajusto Jig?

Sheetrock on a metal desk. Has worked for 36 years. Still straight and level.

Do you adhere cork or something on the sheetrock to stick pins in?

Hey Skip,

I am assuming you used the rib alignment template of the Adjusto Jig to make the holes in the ribs...any issues with using that part of the system? Any "if I did it over again" tidbits?

I recently picked up an Adjusto on ebay and plan on using it on a large bi-plane; but just don't want to become proficient with the jig by the 3rd wing half!

I plan on using my slate table, and magnets to lay up the fuse, tail etc. I have done a lot of reading here on RCU as well as the Airfield Models site and I am very intrigued by the magnet system and the fixtures that are used to get something all together, lined up and double checked before glue! Plus that system caters nicely, in my opinion, to building with CA adhesives. I can understand the joint being properly fitted, tight and secure while the thin CA wicks into the balsa to hold everything together....nice!

Thanks,

Tom

I too had the magnet system years ago.
Still have one of the metal magnet grids, but the board I glued it to isn't true now.
What are you doing with your metal grid to keep it straight?

Thanks
Bob

$9.00 at Menards, Sheathing board, near the foam insulation, comes in a 4x8 sheet, pins go in easy, pins come out easy, and don't move around at all. The best stuff in the world, flat, and cheap! Its black with a different core.

Jason

I have several surfaces I work from, I have a fold out table mounted to a wall i my shop, a 4x8 pressboard sheet sitting on a old dining room table and my machine area is a bench top of 2x12 planks

but when I need to build a wing or something strait I work off my 1 3/4 solid core door I have sitting on some saw horses its been strait and level for a few years now after checking it with a strait edge a few times there doesn't seem to be any warping at all

Just to be clear, I don't have the magnet system in place yet.

Grid reference?

Tom

I agree with the magnets system - have one and love it - 16 ga metal on Ikea kitchen center Island (2000) bucks plus metal

[link=http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/tools/magnetic_building_board/order_magnetic_fixtures.htm]Magnetic Building Board[/link]

The "grid" system I referred to is the way the metal surface is laid out that the magnets hold to similar to the one in the link.

It looks like sheathing comes in insulated, gypsum and exterior.

Which do you use?

Thanks
Bob

$2,000 for a table to build on?[X(][X(] A good door and some ceiling tiles, we aint building the space shuttle. $50 max for the door and tiles.