How to skin steel flattage with ply

[solex]

Hello all,

 

I'm about to build some steel box section flattage. While I've made wooden framed ply skinned flats before, and also make things from welding box section together, I've not yet skinned a metal box section frame with ply.

 

Whats the best way to attach one to the other? Were this a wooden frame I would glue and screw, is that the same for wood to metal?

 

Best,

 

Sol

[ImagineerTom]

Pop rivets

 

It's worth getting the larger, flat-head versions, make sure you also get just the right length ones for your task (ie if it's 3mm ply and 2mm steel wall thickness don't buy 20mm long rivets) and above all get yourself an hydraulic/pnumatic pop-rivet gun. Trying to do more than half a dozen rivets with any kind of hand-operated riveter is absolute hell on every level.

[solex]

Cheers Tom,

 

Some how I had totally not thought of pop rivets, much obliged!

 

Sol

 

Forgot to ask, how spaced apart would you use them? Don't want to go over or under board :)

[ImagineerTom]

On 20mm steel box with 3mm ply we use them every 30cm. Go to somewhere like screwfix/toolstation and you'll buy hundreds of rivets for a few pounds. Go to anywhere retail and you'll pay £5 for a dozen rivets.

[solex]

Cheers, A couple of questions loosely on the topic if you know:

 

What paint would you suggest to protect the box section, it won't be sat outside but would rather not leave it fresh from the depo.

What thickness and size of box would you suggest for an 8by4 flat (we are actually making them slightly smaller) and how many cross beams within the outer rectangle of the flat would you suggest?

 

Sol

[ImagineerTom]

Paint - red oxide primer it; cheep and durable

 

Structural questions really depend on exactly what you're attaching to the flats, how they're going to be moved/handled etc

 

Assuming you're making something akin to a traditional canvas flat then 20mm thin wall box tube would be fine, I wouldn't want more than 1m unsupported so 2 horizontals.

 

It's incredibly easy to make this sort of flat "not square" - even the slight deformity created by welding heat adds up to quite a deviation across the frame so it's well worth investing in a large set-square to ensure all your right-angles are perfect 90deg; you don't find out you've messed up until it's all built and you try to butt two of them together and discover a 2 inch gap.

[solex]

It will mostly be buttons and light switches on it, the most weight would be a computer monitor. But the flats will be attached at each end into a frame on their long side down to make a hexagon corridor flats. (its for a scifi corridor)

 

Thanks for the tip on square-ness, we have magnetic right angles but they aren't too big so will get in a bigger set-square to check it with too :)

 

Sol

 

edit: photo pf the model: https://www.dropbox.com/s/uqw25y8narcvdjy/2015-02-09%2015.18.56.jpg?dl=0

[Dmx512]

Bond and seal works really well and is slightly elestic where as rivets and screws etc can rip out when the flat is transported

 

Dave

[abbotsmike]

To keep the square, erm, square, using a tape measure to check the diagonals are the same is a quick and easy method as well. If you do this at the point where only the outside is welded up it's pretty easy to tweak it back to shape as well!