Framing Flat Techniques

Ech725

Active Member
I've framed multiple flats with different carpenter's over the years. They all had their own tips/techniques in framing. I wanted to know how you guys go about framing. Once you have examined the drawings and cut all your pieces from the cut list. (HARD FLATS) How do you proceed? Checking squareness? Handle seams on large flats? Slight imperfections? Screw or staples and so on? Plus any tips you've picked up over the years. It's always good to get a fresh perspective. :grin:
 
Flats should always be stapled and glued. Medium crowned staples are best, though 1.5" narrow crowns do work. I always build the frame then square to the luan. Doors/windows are then routered out.

When I build steel flats, the entire thing is jigged on a wooden table with jig blocks. After its welded up, a skin is t-nailed or aerosmithed on.
 
aerosmithed ? Not a term I am familiar with.

Then you have not lived. Think of a T-Nailer..... but much, much better. These things can go through 3/4" ply and 14 gauge steel without issue. If you build with steel, its the only way to go. VersaPin ST4100 Pneumatic Tool by Aerosmith

Back when I used to weld, it was probably one of the most used tools in the carp shop after I chucked out a piece.
 
Then you have not lived. Think of a T-Nailer..... but much, much better. These things can go through 3/4" ply and 14 gauge steel without issue. If you build with steel, its the only way to go. VersaPin ST4100 Pneumatic Tool by Aerosmith

Back when I used to weld, it was probably one of the most used tools in the carp shop after I chucked out a piece.
Never seen or heard of one, interesting tool though.
 
If you don't know it, here's one neat trick: after you've stapled the lauan to the perimeter (squaring the frame to the sheet as you go) you need to staple to the toggles (interior frame). I take a 4' drywall square and line it up with the staple holes connecting the toggle on the side of the flat, such that I can run my stapler down the square and shoot staples into the toggle without missing, and without having to have marked anything.

As for seams between sheets: here are my three techniques in ascending order of effort (and quality),depending on the demands of the build:

1-sand the seam flat and use joint compound

2-sand the seam flat and use bondo or water putty

3 -use the drum of a belt sander to create a slight valley along the seam. Spread some wood glue into the seam to lock it together. When dry, apply a layer of water putty. When dry, sand and apply a layer of joint compound with a 4" putty knife. Sand with a flat block laid flat on the surface. This seam will be invisible, and shouldn't open a hairline when transporting the flat.
 
I use the same sort of technique as Nicholas and it's the same on Horizontal or Vertical seams. I use a 4.5Inch Angle Grinder with a flapper disc in it to make a slight valley between the two sheets. I then run a palm sander over the seams to catch any splinters. I then go to town with the bondo
I prefer using Painters chaulk between flats and on floor seams that don't come out perfect.

Oh, and for the record. I NEVER square to the Luan. I use a squre and go from there. I once recieved an entire shipment of luan the was off-square by 2 degrees. Doesn't sound like much till you span 40' and your lfats are 3 " off the ground .
Old buddy in the filmindustry used to have a saying, " If you route, your out." He meant that you need to cut your covers to size first then attach them never attach then route.
 
Wow, Van, thanks for the cautionary tale. I don't think I've ever run into that. Perhaps at the least, one should measure the diagonals of the sheet before squaring to it.

Incidentally, I certainly go along with cutting the covers first, especially on a flat that's oddly shaped. Lay out the shape in full scale on the sheet, cut it out, then build the frame to fit.

One more tip: if I'm building two custom flats that will go together, I temporarily attach the frames together before sheeting them, so that I can make the seam between the sheet super tight.
 
Old buddy in the filmindustry used to have a saying, " If you route, your out." He meant that you need to cut your covers to size first then attach them never attach then route.

Why should you never router the edges? Does this include window and doorway openings?



Another trick, I have picked up, using a chalk line to secure the luaan to toggles. Line up with the staple/screw holes on both sides and snap. Full line that virtually gaurantees hitting all toggles even on 8 foot wide flats.
 
Why should you never router the edges? Does this include window and doorway openings?



Another trick, I have picked up, using a chalk line to secure the luaan to toggles. Line up with the staple/screw holes on both sides and snap. Full line that virtually gaurantees hitting all toggles even on 8 foot wide flats.
I agree, if you have a bad batch of luan that isn't square, why can't you cover then rout it off? I don't personally do it either but I don't see the taboo. I am a firm believer in not making absolutes unless it involves safety. I can do something one way and it work great but not at all for somebody else. I worked for a guy that insisted it was done his way to the point that if I was doing something and somebody else came up, saw what I was doing and duplicated it, he would change the method.
 
Why should you never router the edges? Does this include window and doorway openings?

Another trick, I have picked up, using a chalk line to secure the luaan to toggles. Line up with the staple/screw holes on both sides and snap. Full line that virtually gaurantees hitting all toggles even on 8 foot wide flats.

I agree, if you have a bad batch of luan that isn't square, why can't you cover then rout it off? I don't personally do it either but I don't see the taboo. I am a firm believer in not making absolutes unless it involves safety. I can do something one way and it work great but not at all for somebody else. I worked for a guy that insisted it was done his way to the point that if I was doing something and somebody else came up, saw what I was doing and duplicated it, he would change the method.


One of the best reasons I can give you is this; Have you ever been routing something and you hit a 'Hard patch' of the wood? What happens when you do that " it increases the pressure against the bearing. if you increase the pressure against the bearing and you are in the middle of a stile or rail where there is no framing support, chances are the Stile or Toggle is going to flex. As soon as it flexs you nice straight line is gone. When your're done routing you'll wonder why the one section on the outside of the flat doesn't quite line up with the framing anymore.
 
I think another reason not to route, especially in film, is that even a slightly warped piece of pine (those of us building in humid areas know how hard it is to find straight lumber) would result in a door or window opening that is slightly off between the toggles.

Noticing all the suggestions seem to be for hard covered flats, is anyone still building classic Broadway flats?
 
is anyone still building classic Broadway flats?

I have not for awhile, but when I used to work at Music Theatre of Wichita, we always built Broadway flats. However, instead of wooden framing we went steel. The reason we did not build Hollywood flats was for truck pack reasons. We could pack an entire 4 portal set in a 4'x20' hole. Hollywood would take up the entire truck.
 
My current show has Both Studio Flats and Broadways in it. We have such limited space that Broadways are often the only way we can get sliders, or fold outs to store backstage.
 
In undergrad the shop always ripped 1x6 to 2.5" and built flats using narrow crown staples & glue for the entire flat.

However in grad school the local #2 pine was not as straight and knot-free as we preferred and the higher grade pine was cost prohibitive. We actually had alot of success using a "primed pine" product that came painted white and was actually built out of scraps of higher quality boards that were dovetailed together. We built flats 16-20+' high with no problems. Since the wood was preprimed and was glued up it stayed as straight as an arrow.

The assembly technique in the shop at the the time was actually using a pair of 2" finish nails in each joint with a drywall screw in the center. It took a little longer but the flats could take quite a beating. The finish nails didn't have the tendancy for little ends to pop out the way the longer NC staples did at times, especially if they hit a hard spot in the wood. We usually squared to the lauan and attached with glue and satples, however we would be checking diagonals as well.

We also tried to back up lauan seams with ripped down 2x stock whenever possible which helped keep our seams (usually joint compound) from cracking. Water putty shrunk less, but having the bucket of premixed JC ready at all times won out in the end. Windows and doors were typically routed out and we usually did a quick 1/8" round-over on the back side of the flat to make for easier handling. People would joke that the sets looked as nice from the back as the front.

What is people's stance on using glue on the endgrain of 1x? I have heard people insist that it was required, as well as those who thought it was a waste of time.

What about spacing of toggles in a flat? 24", 32"?
 
We actually had alot of success using a "primed pine" product that came painted white and was actually built out of scraps of higher quality boards that were dovetailed together. We built flats 16-20+' high with no problems. Since the wood was preprimed and was glued up it stayed as straight as an arrow.

Where we are it's referred to as finger-jointed pine.. it is the nicest stuff I've worked with. I use it when we are building stock units that I know will be around awhile. The higher cost is offset by the fact that all of my units will be very uniform.
 
Where we are it's referred to as finger-jointed pine.. it is the nicest stuff I've worked with. I use it when we are building stock units that I know will be around awhile. The higher cost is offset by the fact that all of my units will be very uniform.

The "technical term" is PFJCVG Primed,Finger-Jointed, Clear-Vertical-Grain. Though typically in a dimensional engineered lumber product the 'cvg' part would be implied as no one would waste the time to finger joint #2 common or less.
and I'm the same I typically only use it for specialty pieces, it's too dang expensive. You'd think with the housing market being in the dumps that prices would have come down, but the haven't, if anything lumber prices have increased.
 

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