Q on welding issue with 14ga steel - now cleat mounting system

[motoguy]

Ok...I need help.

I've got a wall hanging sign I'm making for a customer. It's approx 48" x 25", 2 layers. Being made from 14ga, it's pretty heavy (he wanted 14ga steel). I'm trying to put some large sawtooth hangers on the back, to adequately support the piece, as well as offer some mounting flexibility (should be able to put lags into 2 studs w/ 34" wide hanger. Below is an image of the backer plate and the sawtooth hangers.

Back Plate v2.jpg

The problem is welding these hangers to the back of the 14ga plate. I just turned one backing plate into a taco, due to warpage. I started with a single tack in each of the holes. Then 1-2" weld in the center, left, and right sides. Repeat on the other hanger. Go back to first hanger, and put more 1-2" welds midway between existing welds. So on and so forth. I placed my hand on the material, and made sure it was "comfortably cool" to the touch before adding additional welds.

Still ended up looking like a banana. I had the same issue with the backing for the "big clock" I made a while back http://www.plasmaspider.com/viewtopic.php?t=22277. Same idea, material thickness (14ga), and same sawtooth hanger parts. I taco'd the hell out of the first backing plate on that, too. I'm using a Lincoln Weld Pack 175, as in this photo:



It's a fixed-position knob, not infinitely adjustable. The panel on the side calls for D6 setting (definitely D, don't remember the wire speed for sure) on 14ga. I performed the above process on C4, so it's already turned down "a notch" from the recommended setting. Using 030 wire and 75/25 mix.

I -think- I may have went down to a B setting, to get the hangers on the clock (without warping). It seems to have worked fine, but I'm concerned about penetration on this one.

Anyone have suggestions? I may even end up just putting keyhole hangers in it, but I'd still like to know how to make this work in the future. I like the flexibility of these large "sawtooth hangers" on larger wall pieces.

[9er]

I think the sawtooth is a good idea to spread the load. But the design takes away so much material the heat has nowhere to go. And 14ga is actually pretty thick.
I'm not sure if you plan to brake or bump a bend in the sawtooth hangers, but if you have access to a brake, make a simple Z Bar mount (google it). It's basically a metal cleat system.
You lose basically zero material and you can use the same hole pattern for a rosette weld on your sign, and for a lag in to the wall. It'll absorb and dissipate more heat to combat warpage.
We've hung art as big as a 2 car garage door with the off the shelf Zbar and you really have a lot of flexibility. It's all shear strength so you can get by with 16ga as well.

[motoguy]

I do have a box and pan brake, which I've used to put a bend in the sawtooth hangers, so that they'll slide over a lag bolt. The side profile looks like this:

sawtooth capture.JPG

Which, now that I look at your suggestions, looks a LOT like this:



So I'd make two identical pieces, one goes to the wall, one is welded to the part? My main concern is having this 40lb piece fall off the wall and hurt someone. I'd like to put (6) 1/2" rosette welds on the bracket to securely hold the panel. If I leave the cleat plate solid, there would be much more material to absorb the heat (if that would help with the warpage).

[9er]

That's it. And you can make just about any size steel Zbar on your machine to fit your comfort level. We hang a lot of items. And this is all I use.

Program twice as many holes as you think you need. I also use a 4" center so I can hit a 16" and 24" stud spacing. Then I only rosette about half of them on the sign.

Plan your bump or offset to allow for lag head. IMO, a half inch rosette is pretty big. I generally run a 3/8" hole and use 5/16" lags. Less stud splitting.

[motoguy]

From Google. It wouldn't even have to be a "Z" bend...just a bend on each to lock together.

[motoguy]

That's it. And you can make just about any size steel Zbar on your machine to fit your comfort level. We hang a lot of items. And this is all I use.

Program twice as many holes as you think you need. I also use a 4" center so I can hit a 16" and 24" stud spacing. Then I only rosette about half of them on the sign.

Plan your bump or offset to allow for lag head. IMO, a half inch rosette is pretty big. I generally run a 3/8" hole and use 5/16" lags. Less stud splitting.

Ok, I'm liking this idea. I think a 2" tall design would be fine for this 40lb sign, split in the middle for 1" bend and 1" for the rosettes/lags. Line of holes on 4" center, for reasons you mention.

Here's what I'm thinking. Yellow line is bend line.

cleat mount.jpg

Weld a couple of these on the bottom, and you can offset the bottom of the wall with some 1/4-20 bolts. They can be bought from .5" through whatever, in .25" increments. So, get one close to the wall standoff you end up with (with the cleat), and thread it in to fine tune. Supported at the cleat on top, held off the wall on the bottom by a couple of 1/4-20 bolts with felt pads on the heads.

[9er]

I do suggest more of an actual Z. About 2-5/16" OA, with the 5/16" being your middle section. Bump it, flip it, bump again to regain your flat plane. you can determine how much of an offset by the degrees bent. It's actually stronger and more secure than the 1 bend cleat, get's it nice and tight.
Again, it's just how we do it. There's a million ways to skin a cat.

[motoguy]

I do suggest more of an actual Z. About 2-5/16" OA, with the 5/16" being your middle section. Bump it, flip it, bump again to regain your flat plane. you can determine how much of an offset by the degrees bent. It's actually stronger and more secure than the 1 bend cleat, get's it nice and tight.
Again, it's just how we do it. There's a million ways to skin a cat.

You've been there, I haven't. I'll take your advice. Thanks for the info!

[AndrewMawson]

Alternative is to use a stud welder to weld short threaded studs onto your backing plate, and fix the saw tooth that way. With 18 gauge my stud welder would leave no sign on the 'fair' side that it had happened, and certainly no distortion.

[KM Koncepts]

Just a suggestion. If you can get your hands on some thick aluminum flat bar you could use it as a chill block for welding. Clamp it behind where you intend to weld and the aluminum will help pull out the heat (heat sink). I use scrap pieces all the time to help prevent heat distortion. I haven't tried it but I do have other welder friends put there aluminum chill blocks in the fridge to get them cold and then Clamp behind what they are welding to help pull out even more heat.

[2015cmax]

To prevent the warp, I clamp my work to a 1/2in plate welding table which acts as a giant heat sink. The more clamps the better. Just let it cool while clamped

[motoguy]

Just a suggestion. If you can get your hands on some thick aluminum flat bar you could use it as a chill block for welding. Clamp it behind where you intend to weld and the aluminum will help pull out the heat (heat sink). I use scrap pieces all the time to help prevent heat distortion. I haven't tried it but I do have other welder friends put there aluminum chill blocks in the fridge to get them cold and then Clamp behind what they are welding to help pull out even more heat.

I've got a partial sheet of 1/4" AL. Would it help to clamp the part I'm welding to that?

[KM Koncepts]

Just a suggestion. If you can get your hands on some thick aluminum flat bar you could use it as a chill block for welding. Clamp it behind where you intend to weld and the aluminum will help pull out the heat (heat sink). I use scrap pieces all the time to help prevent heat distortion. I haven't tried it but I do have other welder friends put there aluminum chill blocks in the fridge to get them cold and then Clamp behind what they are welding to help pull out even more heat.

I've got a partial sheet of 1/4" AL. Would it help to clamp the part I'm welding to that?

Yes anything to help pull the heat out as your welding. I just suggested flat bar because I do a lot of welding that I gotta slip a piece of flat bar behind something thin I'm welding whether I'm mig welding or tig welding. You can also cut up scrap 1/4 inch plate you have and stack them just make sure you have it clamped down good and flat to help transfer the heat.

[Gamelord]

Yea, just clamp it to your welding table or some thick steel to take the heat. Also, just tack weld it in areas instead of trying to run long beads. A good firm tack in multiple places will hold up just fine. Test it on another scrap piece and I am sure you will be surprised at what force you need to break it off.

[Dana gear]

A good, thick steel (at least 3/8") clean surface welding table, and clamps trust me you can't have enough of them around.
Clamp the material you are welding down. Don't remove clamps till material has cooled down somewhat, generally just a few minutes after welding 14 ga .It's not that thick of material and short weld beads you should be doing would dictate faster cooling anyway.
Of 14 ga hot roll carbon steel we probably use around 45 to 55 thousand pounds per year in product building, of that less then a couple hundred pounds get scraped due to distortion , most of that is due to improper jig clamping as most is done in fixtures here.
And just as Gamelord states in above reply never run long beads in 14 ga. It creates line heat distortion.
With .030 that is most likely ER70S6 or something close to it and 75/25 shielding gas even a small rosette weld or butt will most likely exceed the tie in to the parent 14 ga metal.

[little blue choo]

I don't understand why you are running 1 to 2 inch welds and then keep coming back and splitting the difference between them. We're not building a battle ship here, we're attaching a hanger. I attach all my metal hangers with 1/4 inch tacks and have had no problems with warping or coming loose. I rarely do anything less than 16 gauge so I never have to use anything as a heat sink but will if doing anything thinner. Sometimes less is better. Oh well back to my hot chocolate and snow watching.

Rick

[motoguy]

I don't understand why you are running 1 to 2 inch welds and then keep coming back and splitting the difference between them. We're not building a battle ship here, we're attaching a hanger. I attach all my metal hangers with 1/4 inch tacks and have had no problems with warping or coming loose. I rarely do anything less than 16 gauge so I never have to use anything as a heat sink but will if doing anything thinner. Sometimes less is better. Oh well back to my hot chocolate and snow watching.

Rick

Just my paranoia at these 40+ lb guillotines falling off the wall on someone's foot. You are probably right. Several rosettes are probably plenty to hang from.

[Gamelord]

Get a piece of scrap, tack weld it good and firm and then try to bust it off. I think it will solve the paranoia thing. A couple good tacks and I bet you could hang 200 pounds off of it no problem. The hanger itself will probably get destroyed before the tacks break loose.

[ovrrdrive]

I modified the sawtooth file and added holes on each end and I just spot weld inside the holes to attach. As mentioned above it doesn't take much. Doing hangers as long as the one's you're making I might add another hole every 9 or 12 inches and do another spot weld on it. It's plenty strong.

[tnbndr]

Just my paranoia at these 40+ lb guillotines falling off the wall on someone's foot.

I worry more about how the customer attaches the wall hanger!!!!!! I stress you must anchor into studs but who know what really happens.