Interior welding of hull

Once the hull was upright, tempoary tarpaulins went up to keep the rain out and the sun off. Sheets of roof iron covered the bow and stern deck areas.

Then a corrugated iron roof was attached over the deck beams for longer term protection of the hull. Any rain at this stage could cause corrosion. (NB: prior to hull plating, the stringers outer edges, were treated with wirebrush, phosphoric acid and zinc primer.)

 

The stringers were again treated with phosphoric acid and zinc primer. This does take a bit of time, so getting the flat bar stock block blasted and zinc primed before delivery to site is always the better option.

Now the hull was rolled, downhand interior welding proceded in a similar pattern to the outer hull welds. Before a weld was done the seam was ground out to remove any slag from the outer welds. The back-step method with short 2-3" runs was used.  3.2mm rods were used for the 5mm plate seams and 2.5mm rods for the chine/3mm plate seams.

The welding pattern was similar to the outer hull.  Once the welds were done..the tempoary 1" flat anti-distortion bars on the outside were removed. Interior welds were ground slightly to clean them up but the convex weld profile was kept for maximum strength.

For safety and comfort electric fans and ample ventilation are needed to blow weld fumes away. It could be worth wearing a welders respirator under the weld helmet at this stage.

Exterior grinding and staircase

The exterior double chine welds were ground down. A 9" angle grinder was used. It's a heavy and dangerously powerfull tool, so to suspend the weight, it was hung off a chain with rubber strap.  The top was a hook over the gunwale which could be moved along . A lightweight 4" grinder finished the seam.

Old highset house stairs from the house wreckers provided much easier-safer access into the hull than a ladder would. The stairs allow hands to be free and used for carrying tools and materials up safely.