The actual arc time on a typical driveway gate repair is a few minutes. A cracked corner weld is maybe ninety seconds of welding. A torn hinge plate with a doubler behind it might be four. Everything else in a three hour visit is preparation, protection, heat management and finish, and that ratio is the single most useful thing to understand about having a welder work at your house.
It explains why two quotes for the same crack can differ so much, and why a repair that looked perfect on the day can be bleeding rust at the joint by the following spring. The weld is rarely the variable. What varies is whether the coating was ground back properly before the arc struck, whether the steel was allowed to cool before anything was re-aligned, whether sparks were contained, and whether bare metal got protected again the same afternoon rather than left primed with a promise to return.
It also explains why one trip tends to cover more than the gate. Once a truck, a grinder, a cylinder and a welder are on site, the marginal cost of attending to a loose stair post, a bent window guard or the handrails on the front steps is small compared with booking a separate call for each. Most of the ironwork around a house was fabricated from the same stock, finished the same way, and is failing in the same places, so it makes sense to walk the whole property before the first piece of work starts rather than after.
What a mobile welder is genuinely there to fix
Field welding suits a specific class of fault: a local joint failure in steel that still has thickness in it.
That covers a cracked weld where the top rail meets the hinge stile, which is the most common structural fault on a swing leaf. A picket snapped at the rail, or loose and working its socket wider on every cycle. A hinge plate that has torn, or a hinge that has dished the wall of the tube it was welded to and needs an insert or a doubler behind it. A bent or sheared latch keeper. A snapped drop rod guide. A cracked operator bracket, which is extremely common because the arm applies a cycling load to one small patch of tube. A hinge or a frame bracket that has pulled its anchors out of a stucco or brick column.
What field welding does not suit is general thinness. If the bottom rail has lost most of its wall over a two foot span, laying a bead against it is welding to foil, and the honest answer is cutting out and replacing a length of steel, which is a different and larger job. A welder who taps along the member with a hammer handle and probes the suspect band with an awl before quoting is checking for exactly that.
Power and process decide what is possible at the curb
A welder's capability on site is limited by what is powering the machine and by the weather.
An engine driven welder or a generator gives the output to run heavier material and to weld continuously. A small inverter on a household circuit through a long extension lead is fine for ornamental tube and will trip or duty cycle out on anything thicker.
Wind matters more than people expect. Gas shielded welding relies on a column of shielding gas sitting over the puddle, and a steady breeze blows it away, leaving porous weld metal that looks acceptable and is full of holes. That is why outdoor repair work is often done with a self shielded wire or with stick electrodes, which carry their shielding in the consumable and tolerate moving air. If gas is being used outdoors, a screen or a blanket rigged as a windbreak is not fussiness, it is the difference between a sound bead and a decorative one.
One detail that almost never comes up and should: the earth clamp. Welding current takes the shortest path back to the clamp, and if that path runs through a hinge bearing, a slide gate wheel or an operator gearbox, it pits the bearing surfaces as it goes. Worse, an automated gate carries control boards, loop detectors, photo eye wiring and often a battery, and welding current near any of that can take out electronics. The gate should be powered down at the breaker and the operator disconnected and ideally unbolted from the leaf before the arc strikes, with the clamp placed on the same member being welded, as close to the joint as it will reach.
Paint, powder coat and galvanizing come off before anything else
This is the step that gets skipped when somebody is working quickly, and it is the one that decides whether the repair lasts.
Steel will not weld cleanly through a coating. Paint, powder coat, primer and galvanizing all break down in the arc and the products of that go into the puddle, giving porosity, inclusions and a bead that sits on top of the parent metal rather than fusing into it. Zinc is the worst of the group because it boils well below the melting point of steel, so a galvanized surface gasses off violently and leaves a weld full of voids.
So the coating is ground back to bright metal across the joint and for a margin either side, on both faces where there is access, and on the inside of any sleeve or plate that is going in. Grinding zinc also matters for a reason that has nothing to do with weld quality: zinc fume causes a genuine, if usually short lived, illness, and a welder who grinds the galvanizing off and works upwind is doing it partly for that.
Older ornamental iron brings a second hazard. Paint on ironwork from before the late nineteen seventies can contain lead, and grinding it produces fine dust. Sheeting under the work, containment of the debris and not simply letting it blow across a lawn where children play is the correct handling, and it is a reasonable thing to ask about on a house of that age.
Thin wall tube, and why burn through is the real skill
Ornamental frames are usually light wall tube, and a repair joint is frequently at a spot that has been corroding, which means the metal there is thinner than the gauge it started as.
Heat runs away into pitting rather than building a puddle, so settings that would be right for sound steel punch a hole straight through. The techniques that keep this in hand are all forms of patience: lower current, short stitches rather than one continuous run, moving around the joint so no single area soaks, and stopping to let the work cool. A backing sleeve slid inside a tube gives the weld something to fuse into and stops the puddle dropping through. Where a hole has already opened, a plate welded over it is legitimate if the surrounding metal measures sound, and it is a cover up if it does not.
A repair done fast on thin tube looks heavier and shinier than a repair done properly. A lot of weld metal piled onto a thin section is a sign that something kept blowing out, not a sign of strength.
Heat moves steel, so the sequence is measured
Welding shrinks metal as it cools, and a bead run along one face of a frame pulls that face shorter. On a twelve foot leaf hanging on two hinges, a small pull at a corner becomes a visible misfit at the latch.
The practice that avoids it is to measure both diagonals before any work starts, so there is a number to return to, clamp or tack a temporary brace across the leaf before cutting anything out, and alternate the welding around the joint rather than finishing one side and then starting the other. Then wait. Steel that is still warm is still moving, and judging alignment or resetting operator limits on a hot leaf produces a gate that fits beautifully at four in the afternoon and binds the next morning.
Hot work on somebody's driveway
A grinder throws sparks a surprising distance and a cutting disc throws them further, in a flat fan that bounces off concrete.
The things that catch on a residential property are all ordinary: a mulch bed against the gate post, dry turf, artificial turf, which does not burn so much as melt into hard black scars, a cedar fence returning into the gate, composite decking, a stack of patio cushions, irrigation tubing, pool chemicals in an unlocked cabinet. The usual answer is welding blankets over anything combustible within range, a hose run out and charged, and cars moved well clear. Vehicle paint picks up spatter as permanent embedded specks, and window glass pits, both of which are far cheaper to avoid than to fix.
Grinding dust deserves its own mention because it is the complaint that arrives a week later. Fine steel dust settles on everything downwind and then rusts, which shows up as orange freckling on a white car, on light coloured stucco, on a pool coping or on a freshly sealed concrete drive. It is removable while it is loose and a staining problem once it has been rained on.
A fire watch after the work matters more on hot work than during it. A smouldering mulch bed or a bit of dry thatch can take half an hour or more to show itself, which is why the last part of a competent visit is a slow look around with the hose still out rather than packing up the moment the gate swings.
The finish is part of the repair, not a tidy up
Every weld leaves bare steel and a heat affected band either side of it where the original coating has burned away. In Gulf Coast humidity, bare steel will start to bloom overnight, so protecting it is a same day job and not something to come back for.
The sequence that holds is to dress the weld flush and knock off the spatter, because weld toes and spatter peaks are exactly where a coating sits thinnest, then a zinc rich primer or a cold galvanizing compound over the bare metal, then a matched topcoat once that has flashed off. Dew point governs the timing: coating steel that is below the dew point traps moisture under the film.
One honest limitation. A powder coated gate cannot be repaired with powder coat on site, because powder needs an oven. A repaired patch gets a liquid finish matched as closely as possible, and it will usually read very slightly different in sheen in low sun even when the colour is right. Asking for the match to be tried on a hidden face first is reasonable, and so is asking whether the whole leaf would be better refinished in one pass.
What the truck cannot carry
Abrasive blasting to bright metal needs containment that a driveway does not have. Hot dip galvanizing needs a zinc bath, and a closed section with moisture in it is dangerous in one, which is why vent holes matter and why some galvanizers decline used weldments. Oven cured powder coat needs the oven. And pulling a racked leaf back into square properly needs a flat table with stops, because straightening it in the air just moves the twist somewhere else.
Everything else on an ordinary gate fault list is driveway work, and the measure of whether it was done well is not how the weld looks on the day. It is whether, a year later, the joint is still bare of rust bleed and the two diagonals still read the same.
