Picking a metal finish

Side by side

Powder coat

• A dry powder, sprayed on and baked hard
• Powder maker TIGER Drylac recommends at least 2.5 to 3.0 mils
• One PPG powder passed 2,500 hours of salt spray. That's a lab test, not years outside.
• Protocase allows 0.003 inch of powder per side when sizing holes

Anodizing

• For aluminum and titanium only, never steel
• Type II: 0.00007 to 0.001 inch, at one Ontario finisher
• Type III, hard coat: 0.0005 to 0.0045 inch there
• Colour adds time at SendCutSend: clear and black add 1 to 3 days, red, blue and gold 5 to 7

Hot dip galvanizing

• Steel dipped in a bath of molten zinc
• Heavy structural shapes get at least 3.9 mils of zinc under ASTM A123
• The American Galvanizers Association's example: 72 to 73 years before first maintenance in an industrial setting
• First maintenance means 5% of the steel shows rust
• Right on the ocean, it can rust within 5 to 7 years

We found no hot dip plant in Ottawa. Corbec runs one in Lachine, near Montreal, with a 48 foot kettle. Trylon in Elmira, Ontario advertises 48 hour turnaround.

Zinc plating or galvanizing?

• Zinc plating is a thin layer, about 0.0003 inch per side at SendCutSend
• Hot dip galvanizing is far thicker: at least 3.9 mils on heavy shapes
• Plating suits bolts, brackets and parts kept dry
• Galvanizing suits steel that lives outside for decades

How long finishing takes

• Outside finishing adds 7 to 10 business days at one Quebec fab shop
• One Quebec plater: about 5 working days, 48 hour rush
• Powder coating at one Ottawa shop: 5 to 7 business days

Sources

• Silver Fox Manufacturing on powder coating, Ontario
• TIGER Drylac on film thickness
• PPG ENVIROCRON data sheet
• Protocase finish tolerances
• Precision Plating anodizing, London ON
• Caswell Canada titanium anodizing
• SendCutSend anodizing, plating and finish thickness
• AGA: time to first maintenance
• AGA: galvanizing in coastal climates
• Corbec facilities
• Trylon, Elmira ON
• Laseo lead times, Quebec
• Placage Boucherville, Longueuil QC
• Ottawa Powder Coating services