dolphin

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

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

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

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
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.

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.

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

Thanks

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
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...