Figure 13: Spiral after the process is complete
Filing down. When both the housing and the suction tube segments
are arc-welded together, the end result will have burring and small
protrusions caused by the welding bead both inside and outside the
housing and suction tube. This must be removed. Removing any
burring and proud seams on the interior is advisable in order to reduce
water friction, thereby limiting any loss in the area, while on the outside
it serves an aesthetic purpose.
The filing process involves using a hand grinder with grinding discs and
circular abrasives (for the grinder), followed by files and abrasive paper
as required, beginning with a coarse grain and finishing off with finer
grains.
Painting. The surface should be completely cleaned before painting,
using a clean rag and thinners or any other substance to remove any
build-up of dirt and grease.