steel frame flats? Thoughts?

[curtis73]

I've been saving my pennies in my budgets and I think the time has come to start replacing some of my hollywood flats with steel. Am I nuts? I'm tired of repairing and rebuilding wood flats, and I'm not keen on sending a bunch of wooden flats 50' in the air on a pipe. Hollywoods also take up max storage space, and stage flats are a pain to fly, and a pain to make into a rigid wall that doesn't sway with every breeze.

How would you attach lauan to the steel? I'm thinking I could do some flathead self-tappers, but it should be bonded as well, otherwise they'll get pretty wavy when painted. I'm trying to think of a glue that will hold well, but also not be a complete pain if I need to replace the lauan in the future.

I'm thinking 1.5" square cold rolled. Could be hot rolled, but it's a bit more malleable.

Think me through this.

 

[bobgaggle]

I've built many many steel framed flats. 1x1 16ga steel square tube is great. Luan skins with screws just like you said. I haven't used an adhesive, wavy luan isn't really a problem if you use enough screws. Totally worth it to pre drill a standard bolt pattern in the stiles on your drill press before you weld them up into frames. Then whenever you need to attach them together you're not trying to drill bolt holes by hand. Also worth it to weld on some D rings for rigging. I typically put the D ring on the inside and drill a 1/4" hole in the top rail to run aircraft cable through. That way you don't see hardware above the flat

 

[gafftapegreenia]

@bobgaggle hit the major points.

The busier shops have what’s called a Concrete T nailer or an Aerosmith nailer.
Makes attaching Luan to steel quick and easy. It is rather loud tho. I myself would adhere the sheet goods with PL construction adhesive.

Also I’d frame your steel with horizontal toggles instead of a single vertical stud. The frame will end up more rigid this way and better support the Luan face.

 

[bobgaggle]

T Nail at your own risk. We tried it on two different jobs with two different tools, couldn't get the thing dialed in just right. Luan is thin enough that you have to be very precise on how deep you're setting the nail, else you just blow through and there's no wood left for the nail to hold. Too little psi in the tool (we shared a compressor with the painters) and the nail doesn't have enough energy to pierce the steel. It goes all cattywampus and you gotta dig out a crumpled up nail. Not to mention if you hit the factory weld in the square tube it gets all weird again as well. And yeah its louder than a waffle nailer.
We couldn't get consistent results and just went back to screws.

Agree with @gafftapegreenia on the horizontal toggles.

 

[jayvee]

Maybe pre-paint the luan with a junk paint base coat on both sides before attaching might help the wavy gravy. Thereafter just paint the fronts until you need to replace.

 

[TimMc]

As someone who has to handle them, I F'n HATE STEEL FRAME FLATS. Heavy, awkward and prone to mis-handling.

 

[Footer]

@bobgaggle hit the major points.

The busier shops have what’s called a Concrete T nailer or an Aerosmith nailer.
Makes attaching Luan to steel quick and easy. It is rather loud tho. I myself would adhere the sheet goods with PL construction adhesive.

Also I’d frame your steel with horizontal toggles instead of a single vertical stud. The frame will end up more rigid this way and better support the Luan face.

Aerosmith is the way. Had one years back when I ran a metal shop at a rep theatre... things are essential if you are doing a lot of steel work and way better then a t-nailer.

 

[gafftapegreenia]

Aerosmith is the way. Had one years back when I ran a metal shop at a rep theatre... things are essential if you are doing a lot of steel work and way better then a t-nailer.

Around chicago it was at the new, more forward thinking scenic shops I encountered the Aerosmith. At established operations, it was T nails. Aerosmith is certainly superior.

 

[HollyRawls]

I've built many many steel framed flats. 1x1 16ga steel square tube is great. Luan skins with screws just like you said. I haven't used an adhesive, wavy luan isn't really a problem if you use enough screws. Totally worth it to pre drill a standard bolt pattern in the stiles on your drill press before you weld them up into frames. Then whenever you need to attach them together you're not trying to drill bolt holes by hand. Also worth it to weld on some D rings for rigging. I typically put the D ring on the inside and drill a 1/4" hole in the top rail to run aircraft cable through. That way you don't see hardware above the flat

100% what this guys said about everything! There is no need for adhesive on the luan and totally second predrilling bolt holes for easy assembly. We have a grip of 4x8s, 2x8s and 3x6s. We've used them indoors and out with no problems. We also made movable interior rails so windows or other openings are easy to frame- 1x1 steel with a flange and a predrilled hole on each side made to the interior dimension of the different flats. I love how straight they stay when flown, especially if you put a 1/4" flat stock along the bottom of the "wall." Nothing wrong with steel flats!

 

[curtis73]

As someone who has to handle them, I F'n HATE STEEL FRAME FLATS. Heavy, awkward and prone to mis-handling.

These will actually be a few ounces lighter than my wood flats. Wood flats I build with stiles 24" OC. These will have stiles every 32" OC which is just a tad lighter than wood.

 

[curtis73]

Progress so far. I have an older work table that has a 4x8' ply top. I added some 2" angle on the corners and some flat plates on the sides to make a jig. It's really close, but not close enough for me. The tiny radius inside the angle iron holds the steel perfectly, but it requires measuring and adjusting to make it square and perfect. It also doesn't help that the thing has multiple coats of paint, it's at least 15 years old with cuts on the corners, dollops of epoxy on the surface, and generally imperfect. I dropped the first set of steel into it and I was within 1/32" of square (which is super easy to tweak while adding lauan), but the overall width between the jig stops isn't perfect. It's basically relying on the tiny inside radius of the angle steel to keep things snug, which means that each piece still has to be set up by squidging things around. I'm going to replace the corners with steel plate leaving a gap at the corners and might build a new ply top to have more control over the dimensions.

Tomorrow I'm taking a flat strap of steel to make a jig for drilling the mount holes and I ordered some dedicated 5/16" grade 8 hardware for rigging. More this week as I start welding.

 

[curtis73]

I've built many many steel framed flats. 1x1 16ga steel square tube is great. Luan skins with screws just like you said. I haven't used an adhesive, wavy luan isn't really a problem if you use enough screws. Totally worth it to pre drill a standard bolt pattern in the stiles on your drill press before you weld them up into frames. Then whenever you need to attach them together you're not trying to drill bolt holes by hand. Also worth it to weld on some D rings for rigging. I typically put the D ring on the inside and drill a 1/4" hole in the top rail to run aircraft cable through. That way you don't see hardware above the flat

Good to know I bought the right stuff

For rigging, I prefer to rig as close to the center of mass as possible. If I rig to a D-ring on the back, the whole wall tends to tilt forward. In the space where I rig, the pipes are 6" OC which means I have a lot of pipes to play with, but it also means that if the next pipe is an electric or a border, I have VERY little thickness to work with.

For these I can pass the aircraft all the way down through to the bottom and put a bolt through the swaged thimble inside the tube. That way, it's not only rigged the whole way to the bottom, but it's closer to the center of mass and I have next to zero potential for "jacob's ladder" collapses. The upper flats (if used) would simply be carried by the bottom row

 

[curtis73]

Also wishing I had made a 5x9 welding table more of a priority.

 

[gafftapegreenia]

Also wishing I had made a 5x9 welding table more of a priority.

I’ve worked at several shops with big 8x12 welding tables made up of two thicknesses of 3/4” plywood. They staple all the jig blocks down with medium crown staples, and remove them with a hammer when done. Most fabricators put a dedicated rail along two sides of the table so they always have a 90° point to start from.

Thanks for the progress pics, looks like you’ve got it well in hand.

 

[curtis73]

I'm thinking I might scrap the old blue table idea and make a new top with fresh ply. Problem is that I'm kind of expecting wood to be as precise as the resulting precision I want in the flats.

 

[RonHebbard]

I’ve worked at several shops with big 8x12 welding tables made up of two thicknesses of 3/4” plywood. They staple all the jig blocks down with medium crown staples, and remove them with a hammer when done. Most fabricators put a dedicated rail along two sides of the table so they always have a 90° point to start from.

Thanks for the progress pics, looks like you’ve got it well in hand.

@gafftapegreenia When you install your two dedicated rails at 90 degrees, leave a small gap in the corner to keep debris from accumulating.
Toodleoo!
Ron Hebbard

 

[curtis73]

Rigged up a simple jig today. The bed is just a scrap 2x8 with some plywood screwed in the end as a stop. The jig pattern is an unused section of angle steel that is 2" on one side and 1" on the other. It's a pre-fab leg from one of those bolt-together utility shelves. I screwed it to the 2x8 and marked the holes at 4" and 44". Slide the piece in, drill the top wall with a hand drill, then finish the bottom wall with the drill press to make sure it's straight. Easier than trying to fit a jig and an 8' stick of steel in the drill press.

The downside is that the jig is only 4' long so I'll have to make absolutely sure all my 8' lengths are, indeed, 8' long. Holes will be 5/16" with 1/4" hardware and 1" fender washers, so there will be some wiggle room. Not overly confident that this will be accurate enough for my tastes, but I load the show in three weeks. I don't really have time to sit around and think about it.

 

[curtis73]

I also ordered a self-centering dowel jig. I don't have high hopes for it lasting when the drill bit snags some steel, but I always wanted one anyway. Tomorrow I'm hoping to finish the cut list and start making sparks.

 

[derekleffew]

These will actually be a few ounces lighter than my wood flats. Wood flats I build with stiles 24" OC. These will have stiles every 32" OC which is just a tad lighter than wood.

Did you perhaps mean toggle rather than stile?

 

[gafftapegreenia]

I also ordered a self-centering dowel jig. I don't have high hopes for it lasting when the drill bit snags some steel, but I always wanted one anyway. Tomorrow I'm hoping to finish the cut list and start making sparks.

Love those things. If it’s the Dowl-It jig the body is steel so they hold up all right. Best thing to do is get a set of transfer punches to mark center, then remove the jig and drill on a drill press. Do all this before you weld it up, of course.