One of the great things about metal yachts is the ease of making structural connections in a totally watertight fashion, by welding. When this takes place on a completed vessel certain cautions need to be observed.
- All equipment with electronic circuits on them should have their breakers turned off.
- Sensitive electronics, like engine CPUs may need to be totally disconnected.
- The ground connection for the welder must be kept close to the point of welding.
- Flammable materials must be removed from the welding area.
- A fire watch should be maintained, with an extinguisher close at hand.
- Finished surfaces must be protected.
- A remote sensing temperature gun can be very helpful in watching for hot spots.
These photos were taken while while we were having several pieces of awning track stitch welded to the starboard corner mullion. On the inside of the mullion the highest temperature near a weld was 170F/77C. By the time we were four inches/100mm away with the infra red sensor the temperature was down to 90F/31C.
Posted by Steve Dashew (November 18, 2011)
November 18th, 2011 at 7:25 pm
Steve,
Good thoughts.
When I had some metal steps added to my boat last week, the welders asked to have the battery power disconnected. What that necessary? They ended up using the TIG welder because the standard rod welding with argon was just not hot enough to handle the heavy plate (Strongall).
Thanks
November 18th, 2011 at 7:41 pm
Hi Victor:
I don’t know about disconnecting the batteries. We have typically not done this, but perhaps your welders have had an experience where it was necessary?
November 21st, 2011 at 1:54 pm
Automotive circuits nearly always use the chassis as the ground to complete the circuit and so disconnecting the ground is good practice to prevent the rectifiers in the alternators cooking and the batteries getting a fizz. On a closed circuit boat this is less of a problem but easier to leave the training as part of best management practice and allow the welders to disconnect the batteries.