Construction of a Stern Platform using TIG Welding
In this article, we want to briefly tell you about one of our TIG Welding Course participants who actively collaborated with a Tuscan company in the nautical sector.
Specifically, we are referring to Black Sail of Grosseto, a company that for 6 years has been actively dedicated to producing nautical accessories and equipment (for both recreational boaters and port activities) using 100% made-in-Italy materials, all rigorously assembled by hand.
In this instance, the task our student-welder undertook involved the construction of a stern platform using TIG welding; a brief description of the manufacturing stages that led to the completion of the nautical accessory will follow.
Construction of the Stern Platform
First of all, however, here are some clarifications!
The stern platform is one of the most requested nautical accessories; it particularly serves to provide more space on the boat. In fact, many people mount the life raft directly under the stern platform to avoid occupying a locker on board. It is especially useful for boarding and disembarking from pontoons, and it also provides excellent support for taking a shower when re-boarding the boat after swimming, to avoid wetting the interior.
It is also useful for supporting a gangway or attaching a boarding ladder and proves to be a functional and aesthetically appealing item, especially when made with quality materials; typically, mirror-polished AISI 316 stainless steel tubes are used for their construction.
For this type of fabrication, the TIG welding method was used; this is an arc welding process performed using a non-consumable tungsten electrode, under the protection of an inert gas. This welding methodology is particularly widely used (and was already developed in the first half of the 20th century for wartime production in the aeronautical industry) but requires the employment of highly specialized operators, in addition to excellent quality of the materials used (let's remember that they will need to be cut, cleaned, and trimmed).
Below are the steps for manufacturing the stern platform
DESIGN
To proceed with fabrication, it is first necessary to study and understand how to interpret a design, taking into account potential issues that may arise during the welding phase.
PART PREPARATION
After studying the drawing, the next step is the fabrication of the parts to be welded, which must then be degreased from the emulsified cutting fluid of the cutting machine, trimmed of burrs caused by cutting, and drilled according to the requirements specified in the design.
ASSEMBLY AND WELDING
It is crucial to always start with a suitable work surface to ensure that the parts to be joined are square with each other. Once the ground clamp is connected and the parts are positioned, a "tack welding" process is performed, which helps compensate for the thermal expansion that occurs with the high temperatures of welding (the twisting effect during welding is significant, and it becomes more pronounced the longer the welded section).
Once the parts are tack-welded, their correct inclination is checked with a square, ensuring they have not undergone excessive "torsions," which will be adjusted before performing the final weld.
Welding will be performed in alternating sections so that any potential distortions are compensated, maintaining the desired inclinations.
The welds thus obtained will already be firmly joined by fusion, but it is advisable to always add filler material to increase their solidity.
PICKLING AND CLEANING
Once the welds have cooled, pickling can be performed. This is a chemical process that removes the discoloration immediately from steel subjected to high temperatures.
The reaction with these chemicals is highly aggressive and must be carried out with appropriate clothing and protection in well-ventilated areas.
Application and usage times must always be respected, even if it appears not to have worked properly, as the actual result will only be visible after a final rinse.
FINAL CONSIDERATIONS
Given that we work with AISI 316 stainless steel, which is the preeminent steel for marine applications, this type of steel loses its qualities once heated if not properly treated (pickled and polished).
Polishing involves applying additional chemical reagents that restore the characteristics of 316 stainless steel deteriorated by high temperatures.
Once these products have also been used, it is advisable to rinse thoroughly with water to eliminate any traces of the aforementioned agents.
If the part we intend to fabricate requires it, the entire surface can be polished to a mirror finish using specific brushes and polishing pastes with progressively finer grits.
