solid welding

solid welding

OK, here is a photo of the sculpture, it is actually done but figured I would inquire before it goes up. Others have said I am fine. In the picture:
Red - 1.5" rod
Yellow - bulkheads
Blue - location of welds
The last foot of the rod (left) is welded to square tubing which slides into the mount.

Thanks


Rich Waugh's picture

I think you'll be okay on

I think you'll be okay on the bulkhead weld since they'r3e supported by the bulkheads themselves. My only concern would be the forces exerted on the rod at the point where it transitions to the square tubing for the mount.

If this piece is mounted horizontally as photographed, the weight of the piece will be focused on that junction. While that is probably fine, if you add any significant wind loading to the piece you may be over the tensile strength of the 1-1/2" rod at that point where the forces are concentrated. I'd want an engineer to do the calculations for stress moment due wind loading if this is being mounted in a place where failure could imperil any persons.

As I say, my instinct says you'll be fine, but where liability is a concern I'd want engineering calcs.

Rich


eligius1427's picture

You'll be fine, there is not

You'll be fine, there is not much flat surface area to catch any wind and the weight of the material itself isn't great enough to stress that 1-1/2" bar or the welds. That being said, if the bar is 4'long the total length of the scupture must be around 8'. Although i don't think wind will affect the sculpture structure, if the only contact point between the sculpture and it's mounting substrate is that bar coming out of the tail, the 8' of leverage stress might give that connection/joint a run for its money depending on how it's secured. Especially if people climb on it. With almost every sculpture I've built, the structural changes I've had to maker were not due to wind, snow, or ice, but the possibility that 3 drunk jack asses will climb on it at the same time.

Cool looking piece by the way, make sure to post some picts once it's installed.

Jake

Jake Balcom
Mettle Design
Lincoln, NE


Saltoh101's picture

rod welding

dolphindolphin

Thanks for all the responses. So you have the full picture, here is the model so you know what the final sculpture looks like. The dolphin and ball are about 7 feet long. This will be in San Diego where the winds are minimal except for the few winter storms where the wind can get to 40-45 MPH. Does anyone know how to find an engineer that would be able to make a determination. I am sure the 1.5" rod will hold it, I am just concerned about if the welding has compromised it, not sure if an engineer knows about that. Also, it it did fail, would it bend or just snap?

Thanks


Rich Waugh's picture

That will be just fine on

That will be just fine on the 1-1/2" rod. The welds will not be a problem as long as they are proper welds with no undercutting. You should do a solution annealing on the welded piece after welding is complete, both for stress relief and for rust protection. Just heat the piece up to a red-orange heat and quench in water.

45mph wind will not create sufficient wind loading to compromise the piece. You can look up the section modulus of the 1-1/2" bar in Machinery's Handbook or the ASME handbook and verify this, Should it fail, due to being hit by a flying projectile of sufficient mass during a windstorm for instance, the bar would bend, rather than snap due to the solution annealing.

Any mechanical or civil engineer could run all the calcs for you, but if you're in San Diego you might just go by the Engineering Department at San Diego State and see if a materials science professor will get one of his students to work the calcs for you. Gives you a good "in " later down the road when you need something really serious.

Rich


Saltoh101's picture

Rich, the welds are proper

Rich, the welds are proper but can't do the solution annealing without dimanteling some parts and removing the
clearcoat protection which is already applied, a real pain...
So basically you are saying that without the solution
annealing it will snap under load rather than bend?

Thanks


Rich Waugh's picture

No, I'm not saying that at

No, I'm not saying that at all. I'm saying the solution annealing is a good thing to do for both stress relief and for getting carbides back into solution that may have formed during the welding process. If you can't do it, then you can't do it and don't worry about it. You may note later rusting in that area since you're in a marine environment, but maybe not.

Since stainless steel is annealed by heating and cooling, the 360 degree weld may well have put enough heat into the bar to at least partially anneal it. The bar did not have any cold work done on it like bending, hammering, etc so it should be just fine. It will bend, rather than break, I'm sure.

Rich


Stephen Fitz-Gerald's picture

dolphin

Stephen Fitz-Gerald
Dear Saltoh,
This is polished stainless right?
So why did you have it clear-coated?
Another way is to simply use a good car wax on polished stainless.In San Diego this could be done probably 3 times a year and it would be fine.
The car wax keeps water stains from happening because the wax makes water bead up on the surface.


Saltoh101's picture

Stephen - it is not highly

Stephen - it is not highly polished, but has a light grind pattern in it. I know that a highly polished (mirror) surface will endure the salt environment, but it seems that once you put a bit of grind pattern in it, it becomes susceptible to corrosion. Since I will not have access to maintain the sculpture (i. clean, wax, etc) for a full year I decided to play it safe and try a poly clearcoat.


Saltoh101's picture

Rich - I found out that the

Rich - I found out that the stainless rod is cold drawn,
would that make a difference?

Thanks


Rich Waugh's picture

Since almost all stainless

Since almost all stainless is cold drawn, I had figured that was what you were dealing with. No sweat.

With that said, this brings up something that you might want to consider the next time you do something like this.

Whenever you're going to install something out in the public where it can possibly be damaged by wind, lightning, vehicles or idiots climbing on it, you place yourself in a position of vulnerability. If something happens and someone gets hurt, even if through their own stupidity, you may be looking at a lawsuit. For this reason, I recommend that you get an engineer involved at the beginning so your design will meet engineered loads - that way you share the liability with the engineer. It is worth the expense.

Rich


Stephen Fitz-Gerald's picture

good advice

Stephen Fitz-Gerald
Dear Saltoh,
I second this last advice of Rich.
It is to your advantage in the long run to WRITE THIS IN THE CONTRACT as an outsourced legal expense that your client is responsible for. Sometimes engineers can be a bit expensive but the legal coverage that this addition provides is like insurance...