Hemming THICK material...

[MatBirch]

I know my client is nuts, I think the contractor is nuts, and I'm guessing my boss is nuts! But hey, maybe it's just me...

The client wants a detail on the trim for his home (mostly steel construction, many exposed steel elements) which could basically described like a roof drip edge with a hemmed edge. Trouble is, he wants it out of 3/8" plate!
Does the equipment even exist to hem 3/8" plate?? I know we can't do it, and I know my former employer with far larger equipment couldn't do it.

Other than individually fabbing each piece in sections (240+ LF), with maybe the legs welded to a pipe, anybody have any thoughts?

 

[bradpac]

More details of the exact application would help. It would have to be done hot on something that thick. I can't think of a reason to use actual plate on a house. Look into aluminum composite panels, thin aluminum skin with a rigid foam core for thickness and no oil canning. Cut out the foam and hem it over on the edge.

If it really has to be plate, probably best bet is welding a thin piece on the edge and grinding it round.

 

[MatBirch]

More details of the exact application would help. It would have to be done hot on something that thick. I can't think of a reason to use actual plate on a house. Look into aluminum composite panels, thin aluminum skin with a rigid foam core for thickness and no oil canning. Cut out the foam and hem it over on the edge.

If it really has to be plate, probably best bet is welding a thin piece on the edge and grinding it round.

ya... details on the application are- the client has more money than sense. Although this will be many feet in the air, and nobody would ever know whether is was 3/8 or 16ga., I guess he needs to spend the money...

The welding and grinding is likely what will have to happen.

 

[MatBirch]

duplicate- sorry

 

[sz0k30]

Sounds like they're all idiots.

 

[matt_i]

As stated I don't see any way other than hot bending.

Have to make a set of cam rolls that gradually forms the hot sheet as its sent thru the process (custom machine) and some hot work forging die steel guides. I have this pegged in my head as S7 or D2 but its escaping me right now.

If welding is allowed, machine the U-shape out of 1" square/rectangle stock with roundover/radius cutters and weld that to the flat 3/8" sheet. Do you even need the equivalent inside-radius or can that just be square corner?

I don't know if you are working with A36 or Cor-Ten or some other pre-coated material.

 

[EdT]

You can buy steel half rounds in 3/4" wide. So, if it really has to be/look like a hemmed edge, you could stack the 3/8 and then put the half round on the 3/4" edge and weld it. Probably a lot less work that building up the edge and grinding it back.

 

[jkeyser14]

That's doable, but would need to be done hot. Talk to some local blacksmiths/ironworkers.

 

[dr_clyde]

Other than that being a really dumb part, I think it is possible.

You'll need a pretty big press brake, but I would think that is a do-able part. I would think you'd need 300 tons, minimum. I would go out of my way to convince the customer that this is a dumb idea, and will be very expensive.

First bend is to 90°, then switch dies to acute dies. Bend as far as the machine will allow, then switch to flattening dies. Finish the bend down to the finished hem.

The trick will be keeping the outside of the bend from cracking. You'll want something pretty soft.

Not a lot of shops out there with brakes this big, but if you can find one, I think this is bendable.

 

[PCustoms]

Am I reading that print right, 8"x18" chunk of 3/8" steel as a fascia?!!!!

How the hell is that going to get installed...

There's got to be a way to form this from more reasonable sheet but still make it look bulky.

 

[MatBirch]

Am I reading that print right, 8"x18" chunk of 3/8" steel as a fascia?!!!!

How the hell is that going to get installed...

There's got to be a way to form this from more reasonable sheet but still make it look bulky.

Yep... it will be craned into place if it happens. It looks like the general contractor may throw in the towel on the project. In the meantime, our suggestion is exactly what you’re thinking. Make it look big without being big.

 

[Bodj Built]

Other than that being a really dumb part, I think it is possible.

You'll need a pretty big press brake, but I would think that is a do-able part. I would think you'd need 300 tons, minimum. I would go out of my way to convince the customer that this is a dumb idea, and will be very expensive.

First bend is to 90°, then switch dies to acute dies. Bend as far as the machine will allow, then switch to flattening dies. Finish the bend down to the finished hem.

The trick will be keeping the outside of the bend from cracking. You'll want something pretty soft.

Not a lot of shops out there with brakes this big, but if you can find one, I think this is bendable.

This. Also, the maximum width of each piece will need to be taken into consideration. There's going to be a LOT of seams

 

[gmwelder86]

If time and money are no object. Find a pipe or tube size with the radius the client wants. Split the pipe in two use each each for your radius and weld plates to either side to get dimension required. Don’t see any way of bending 3/8 plate like this hot or not. Would easily weld, finish with flap disk and paint

 

[BigMike782]

Dumb it may be but to the owner or the architect it's pure genius. It's as simple as bending some steel.....how hard can that be?

In the years I worked at the lumberyard I saw some awesomely stupid stuff.
Custom made interior doors from imported hardwood that once finished and installed didn't look right so they were taken out and remade.

Sign post installation. Dig a hole with a 48" excavator bucket, set the pole in the hole and brace. Then fill the hole with concrete.

There are people in this world writing checks for things they want and have not a clue as to how it is supposed to get done.

 

[metlmunchr]

Gonna need at least a 250 ton brake to air bend the 90 on 10 ft of 3/8 plate across a 3" die opening. That's based on A36, and most HR plate out there today has a yield much closer to 50 ksi than to 36 ksi, so you could be looking at a 350 ton brake. And that corner is going to have a big radius, nowhere near the square corner shown.

The chances of hemming the edge without cracking to the point of broke in two pieces would be near zero. To create something similar to the drawing, I'd use 1" HR round stock, space the two 3/8 pieces with a 1/4" shim, and let the intersection where the round butts to the plate act as the weld prep. Running spray transfer, and with a little fiddling with travel speed, the weld could be made in a single pass with little excess buildup to grind away.

I learned a long time ago, when someone wants something like this and supposedly money is no object, you throw a price at it that'll show real fast if money is talking or hot air is blowing. Sometimes they really don't care about the cost, and you can smile all the way to the bank. Most shops run from anything out of the ordinary, so you often have no real price competition.

 

[Bodj Built]

If time and money are no object. Find a pipe or tube size with the radius the client wants. Split the pipe in two use each each for your radius and weld plates to either side to get dimension required. Don’t see any way of bending 3/8 plate like this hot or not. Would easily weld, finish with flap disk and paint

For the length the customer is looking for, screw cutting the tube in half. Leave it as a whole tube, set spacing apart (as said by metlmnchr), and burn it in. Also, screw cleaning it up that much material with a flap disk. It'll take forever and you'll end up with a wavy, non-uniform surface, especially over the length the customer is requesting.

A corded belt sander like this makita (below) running parallel with the weld, will eat up the buildup and leave a uniform, level finish across the length. the 36grit belts work really well, and then you can work up grits with whatever other sanders you choose.
https://www.homedepot.com/p/Makita-...ive-Belt-80G-Belt-and-Dust-Bag-9403/203162056


@jonathanprincesculpture on instagram has some great techniques for making uniform finishes on various materials.

Picture number two from August 15, 2019 is kind of what I'm thinking. A large belt grinder with a 'floating' platen.

 

[tarbellb]

Gonna need at least a 250 ton brake to air bend the 90 on 10 ft of 3/8 plate across a 3" die opening. That's based on A36, and most HR plate out there today has a yield much closer to 50 ksi than to 36 ksi, so you could be looking at a 350 ton brake. And that corner is going to have a big radius, nowhere near the square corner shown.

The chances of hemming the edge without cracking to the point of broke in two pieces would be near zero. To create something similar to the drawing, I'd use 1" HR round stock, space the two 3/8 pieces with a 1/4" shim, and let the intersection where the round butts to the plate act as the weld prep. Running spray transfer, and with a little fiddling with travel speed, the weld could be made in a single pass with little excess buildup to grind away.

I learned a long time ago, when someone wants something like this and supposedly money is no object, you throw a price at it that'll show real fast if money is talking or hot air is blowing. Sometimes they really don't care about the cost, and you can smile all the way to the bank. Most shops run from anything out of the ordinary, so you often have no real price competition.

Listen to this guy-

My company was doing 600+lf of 2" radius roof edge detail out of 3/8" plate.

As the foreman/ lead install told my boss to do it out of aluminum and not steel, the install cost would be cheaper, and safety with steel plates (10'x3') hanging off the roof edge would kill us.

Long story short, we had ours rolled, crazy expensive and time consuming, the 3rd party roller had lots of trial and error with 10' plate being rolled consistently.

I realize this is not what you are talking about, but lots to be learned in that project. I think you would be better off welding to achieve the look, unless its going to be clear coated? If painted, weld, grind, filler, finish grind, not to terrible at 240' :]

This was all in the most expensive westside area of LA, ie money was no object. Job got completed, but not sure if we made any money.