Pocket Book
for
Fabrications
Enquiries 0800 468 347
TIP
Hole Sizes
The larger the hole size the better the
drainage the better the finish
TUBE DIAMETER
HOLE SIZE AT EACH END
up to 50mm
2 x 12mm
51 - 100mm
2 x 16mm
101 - 150mm
2 x 20mm
151mm
2 x 25mm
(MINIMUM)
WARNING:
Inadequately vented fabrications
may explode when immersed
in molten zinc.
Enquiries 0800 468 347
Tubular Venting
Every sealed section of a fabrication must be vented for
reasons of safety and to allow the access and drainage
of molten zinc.
Each hole should be no more than 10mm from its
respective sealed end. The vent hole and drain hole
must be at diametrically opposite ends of the section
and the same pattern must run through the fabrication.
Hot Dip Galvanising
Shot Blasting
Grit Blasting
Transport
Centrifugal Spinning
(Auckland Only
Zinc Metal Spray
and Indusrial Painting)
Holes or Notches
Holes or notches must be
within 5mm of the sealed
end of the section.
Hanging hole
With hollow section fabrications, provision must be
made for venting and draining.
On vertical members a drilled hole or “V” notch should
be provided at each end of the section. There should be
holes/notches on opposite sides of the section.
Enquiries 0800 468 347
Structural
Steel
BRACKETS
Because the drain hole at the end of the tube is smaller
than the diameter of the tube there will always be an
amount of zinc remaining in the tube. This adds to the
weight of the tube. Ensure the hole in the base plate is
the same as the diameter of the tube - this will allow all
of the zinc to drain away.
TIP
This simple modification can:
- Improve quality
- Speed up the process
- Save you money
Hole in base plate
Hot Dip Galvanising
Shot Blasting
Grit Blasting
Transport
Zinc build up
Centrifugal Spinning
(Auckland Only
Zinc Metal Spray
and Indusrial Painting)
Structural
Steel
STIFFENERS
Stiffeners should have
corners cropped to
eliminate air traps. This
will lead to a cleaner and
more blemish free finish.
Welds must
be sealed
Notched corners
Drain/vent hole through plate
or hole through web.
Enquiries 0800 468 347
Base Plates
Hot Dip Galvanising
Shot Blasting
Grit Blasting
Transport
Centrifugal Spinning
(Auckland Only
Zinc Metal Spray
and Indusrial Painting)
TIP
Mesh
Due to expansion and contraction of the
steel during the galvanizing process
- only weld every other wire in the
mesh to minimise distortion.
Spot welds
Enquiries 0800 468 347
Surface Contaminants
Paint, oil, grease or palmer coat
A contaminant or coating of any kind on the surface
of items to be galvanized may interfere with the
process, requiring the coating to be entirely removed
beforehand. This results in time delays. While there is
no charge to remove ATM (palmer coat) there may be
extra charges to remove other surface coatings.
Distortion
TIP
Although CSP takes special care, distortion cannot be
ruled out during the galvanizing process. More usually
this occurs when galvanizing uneven sections or
sheet steel or when a component is fabricated using
different thicknesses of steel with large surface areas.
Hot Dip Galvanising
Shot Blasting
Grit Blasting
Transport
Call our Helpline on
0800 468 347 for free help
on how to reduce the
possibility of distortion
Centrifugal Spinning
(Auckland Only
Zinc Metal Spray
and Indusrial Painting)
Bath Sizes
The following tables outline the dimensions of
the baths available in Auckland and Christchurch.
Please call us if your work is close to or outside
of the bath dimensions.
Bath Size
Christchurch
Dipping
Dimensions
Christchurch
Length
Depth
Width
10m
2.6m
1.5m
Length
Double
Dip Length
Double
Dip Height
9.5m
12.0m*
4.4m*
*Double dip dimensions vary according to the overall
design. Please contact the branch to confirm.
Bath Size
Auckland
Dipping
Dimensions
Auckland
Length
Depth
Width
9.15m
2.59m
1.35m
Length
Double
Dip Length
Double
Dip Height
9.0m
13.0m
4.58m
Enquiries 0800 468 347
Surface Finishing
Surface Finish & Coating Appearance
TIP
The final galvanized finish will often vary from item
to item. The reason for this can range from bath
immersion times to surface profile, however, the
greatest influence is the steel composition. The
presence of both silicon and phosphorous in the
steel ‘make up’ can create what is commonly known
as a ‘reactive steel’. Reactive steels encourage a
greater zinc pick up, resulting in a thick, dull coating.
Unfortunately, this is beyond the galvanizers control
and is not evident until after the process. Steel
composition certificates can be obtained from the
steel supplier to help identify problematic steel.
Call our Helpline on
0800 468 347 for free help
on how to reduce problems
with surface appearance
Hot Dip Galvanising
Shot Blasting
Grit Blasting
Transport
Centrifugal Spinning
(Auckland Only
Zinc Metal Spray
and Indusrial Painting)
Rd
ilk
ins
on
Pa Elle
nm rsl
ure ie
Hw
y
W
Contact Details
So
uth
ern
AUCKLAND
Ga
vin
St
40-44 Gavin St, Ellerslie
PO Box 11165, Auckland
Ph: 09 579 0063
Mo
tor
wa
y
Symes Rd
Was
hbou
rne R
d
Rd
uth
So
in Hayton Rd
a
M
CHRISTCHURCH
23-27 Washbourne Rd,
Sockburn, PO Box 11183,
Christchurch
Ph: 03 348 8522
Enquiries 0800 468 347