Certified welding, rigging & structural steel · Dunmore Flats · Est. 2003
Every weld on a Tarspring frame has a name, a procedure and a page number.
We fabricate and set structural steel, crane runways and guards for the Flats’ mills and builders — AWS D1.1 procedures, certified hands, and a weld log that names the welder, the machine and the amp setting beside every joint we lay.
What we do
Three jobs that explain the shop
The crane runway
Forty feet of dual runway for the box mill, welded to qualified procedures and straightened to four millimetres over the whole span — because a crane finds every millimetre you leave in it, twice a day, for thirty years. The alignment sheet and the weld log live in one folder, and the mill keeps both.
The flood barrier gate
A six-metre leaf across the mill sluice, load-calculated for a head of water rather than a person. Hot-dip galvanized inside the frame where nobody will ever look — because the inside of a flood gate is exactly where the first thirty years of rust would otherwise start.
The mezzanine spine
A bolted-and-welded mezzanine frame for a binderie that outgrew its floor: stamped calculations, torque-controlled anchors, and a guard rail around the edge calculated to the 200-pound push before the deck boards arrived. The builder passed inspection on the first visit and rang to say so.
Dunmore Flats
The shop on Kestrel Row
Two structural bays, a plasma table, a rigging gantry and a crew of nine — four of them certified to AWS D1.1, all of them logged. The difference on a structural job is paperwork that survives the building: procedure qualifications, weld logs with amp settings beside the welder’s initials, and calculation sheets an inspector files in one sitting. We keep the logs because the steel will outlive every one of us, and somebody will eventually want to know whose hand is in it.
The folder is the promise
Every structural job leaves with a handover folder — stamped drawings, weld log, procedure qualifications, torque and test sheets. If an inspector ever asks for something the folder should have said, the re-inspection and the remedial work are ours.
Straight answers
The five the site managers ask
And the two their homeowners ask after them. The shop line at the bottom runs six to five; the person who answers owns the folder.
What does AWS D1.1 actually buy me?
A welder who passed a test on the procedure your joint uses, a procedure that was itself qualified by destructive testing, and a paper trail that says so when the building changes hands. It is not a mood or a sticker — it is the reason our weld log has never lost an argument with an inspector.
Galvanizing or zinc primer on exterior steel?
Exterior means the kettle, full stop. Zinc-rich primer is seventy-five microns of zinc-bearing paint — a legitimate shop finish for dry interiors and a false economy anywhere the Flats’ weather reaches. Hot-dipping fuses eighty-five to a hundred microns of zinc into the steel. We prime interiors and dip exteriors, and the quote says which is which and why.
Do you calculate the guards or copy a pattern?
Calculate — the 200-pound concentrated load at any point and direction on the top rail, fifty pounds per linear foot along it, and the sheet goes in the folder. Copied patterns are how a rail that passed in one building fails in the next one with a longer span.
Can you set the steel as well as weld it?
That is the rigging half of the name. Our gantry and crew set what we fabricate — crane runways, mezzanines, barrier gates — on our own rigging plan, so the welder who logged the joint is standing under it when it is torqued.
What amp settings appear in the log?
The honest ones. TIG on 1/8-inch wall runs 105–120 amps with a 3/32 lanthanated tungsten and 308 filler; MIG on structural laps runs 24 volts; sheet drops to 60 amps. The log records machine, range and welder because a number written down is the only one anybody can check in thirty years.
The Flats, 2025 — 2026
Steel we signed
Six fabrications from the last year. Every exterior piece in this gallery went through the zinc kettle before it went to site — the folder says so, and so does the finish.
How it goes
How a Tarspring job runs
The same sequence on every job — the only variable is your project.
Day 1
The measure and the load path
Tape, laser and photographs of every anchoring surface — and the load path sketched on the spot, on paper you keep before we leave site.
Week 1
The stamped package
Shop drawings, calculations where the structure asks for them, finish schedule — kettle or primer, named — and a fixed price. You sign the drawing and the schedule, not just the number.
Weeks 2–3
The floor
Plasma-cut parts, frames pinned square on jigs, MIG penetration where the load lives, TIG where the eye lands. Every structural weld laid to procedure and entered in the log with its amp range.
Week 4
The kettle or the booth
Exterior work goes hot-dip galvanized; interiors take zinc primer and two-pack. The finish follows the map and the schedule, never the mood of the week.
Set day
The rig and the folder
Set on our own rigging plan, anchors torqued to spec, guards push-tested with a gauge. The handover folder lands on your desk the same afternoon.
Their weld log is a better document than some engineering reports I have signed. When the assessor asked for the procedure qualifications, we opened the folder to the tabbed page and he closed his clipboard. Twenty-two years, and the folder has never once been the reason a job stalled.
They galvanized the INSIDE of my flood gate. I did not know to ask for it, they did not charge extra to discuss it, and eleven springs of standing water later the leaf still swings like a garden gate.
Mezzanine, guards, staircase, one folder, one inspection, passed first visit. The builder next door has since switched his steel packages to Tarspring and his inspections got shorter too.
Stamped packages inside five business days · (555) 019-7154 · rig@tarspringwelding.example
Bring the drawings, or the problem
Engineered drawings get a fixed price inside five business days; a napkin and a photograph get a measure and a load path. Either way, the folder follows the steel. rig@tarspringwelding.example