Since I don't have the welding skills I need to make my next project happen I've come here to figure out how to find a welder with the skills I'm looking for. I've got a project coming up where I need to source and modify a pressure vessel about the shape of a LP holding tank, 8-10 ft long and 40-50 in diameter. I need to take one rounded end off and replace it with a flat steel plate. It needs to have various openings added to include ports for pressure gauges as well as inlet and outlet valves. The vessel needs to hold 45 lbs working pressure and withstand a structural integrity test of about twice that.
Although I don't personally know any welders who can do this kind of work, thankfully I have enough connections I could probably locate one with a little direction. Since getting this made could end up costing $$ I'd like to find someone who does this kind of welding professionally but is open to a side job. My best guess is that boilermakers or pipe fitters would be the kind of welder who could help me out.
Could anyone suggest how I can find a welder with these kinds of fabrication skills?
You are right about the "qualifications" being with Boilermakers. Depending upon your exact application, a truly certified welder should be your goal.
You don't list your area, so it would be hard to say how you can go about finding a freelance welder.
You don't list your area, so it would be hard to say how you can go about finding a freelance welder.
Pipe fitter or boiler maker, problem is most guys with the R stamp qualifications to do this know enough to not risk doing it on the cheap/ side because of liability. Pressure vessel work required paperwork, engineering, and third party inspection. It cost our company about 3k usd just to pull the paperwork for a repair, this would be a total rework so I’m guessing your going to be in the 7-8k range. Not including your end plates and materials will all need heat numbers and manufacturer documentation.
I have more questions than answers
Josh
Josh
There is a reason that the ends are rounded. Changing it to a flat end, will require some serious changes to the vessel. At 40 inches diameter, and 45 psi, you are looking at about 28 tons of force on the endplate. All of that force will be concentrated at the point where the the endplate meets cylinder.
With a dome end the total forces are the same, but they are spread over a much larger area.
With a dome end the total forces are the same, but they are spread over a much larger area.
No sense dying with unused welding rod, so light 'em up!
There's not that much more surface area in a dished end compared to a flat end plate. The difference is that a torispherical or semi- ellipsoidal end is joined to the shell with a butt weld static joint in tension. A flat end can and will billow subjecting the fillet weld to destructive torsion. In this case, a flat plate end is increased substantially to prevent weld failure. For this scenario the end plate would be (I guessing) maybe 1-1/2" to comply with asme.
The OP wasn't asking about this. He asking about sourcing a shop to do the welding. I recon he probably has an asme compliant drawing in hand.
The OP wasn't asking about this. He asking about sourcing a shop to do the welding. I recon he probably has an asme compliant drawing in hand.
Flat out like a lizard drinkin'
you need to talk to a place that welds and tests compressed air cylinders.toonces wrote:Since I don't have the welding skills I need to make my next project happen I've come here to figure out how to find a welder with the skills I'm looking for. I've got a project coming up where I need to source and modify a pressure vessel about the shape of a LP holding tank, 8-10 ft long and 40-50 in diameter. I need to take one rounded end off and replace it with a flat steel plate. It needs to have various openings added to include ports for pressure gauges as well as inlet and outlet valves. The vessel needs to hold 45 lbs working pressure and withstand a structural integrity test of about twice that.
Although I don't personally know any welders who can do this kind of work, thankfully I have enough connections I could probably locate one with a little direction. Since getting this made could end up costing $$ I'd like to find someone who does this kind of welding professionally but is open to a side job. My best guess is that boilermakers or pipe fitters would be the kind of welder who could help me out.
Could anyone suggest how I can find a welder with these kinds of fabrication skills?
start there, they will know welders who can do the work if they don't have anyone in house.
tweak it until it breaks