This information brochure is adressed to the technicians who are operating in the industrial maintainance fields.
The final purpose is to halp in the resolution of the many problems connected with the protection of rusty metal surfaces.
the cycles proposed have been developed and tested in our lab with the specific aim to facilitate the choice of the most suitable protective treatments.
Frequently, during industrial maintenance, one has to completely remove all rust from metal surfaces, sometimes even when the machinery is still in operation. This creates considerable difficulties irrespective of what treatment will ultimately be adopted.
It may be that the metal surfaces to be treated are in enclosed spaces, close to moving parts or close to easily pllutes raw materials or are awkwardly shaped or are inaccessible and so on, making sand-blasting impracticable. In these cases the traditional methods of hand-brudhing, scraping, chipping or more often the simple use of abrasive papers will only partly eliminate the existing surface rust and certainly cannot penetrate deeply into the porosity of th metal. The use of Fertan in these situations represents the most efficient process to ensure the best resistance to corrosion after the chosen painting cycles. To prove this proposition, in our laboratories we have used some of the traditional industrial maintenance painting systems on a series of differently treated rusted panels, following treatment, the panels were subjected to mumerous chemico-physical tests and a comparison was made of the relative resistance to rusting.
The folowing is a reprot on the cycles of treatment and tests carried out together with the results obtained.
Tested samples
A. Shotblasted panels
A serie of hot laminated panels, having a thickness of 1 - 2 mm and being 130 x 200 mm in size, were shot blasted eith metal grit to Sa 2.5. grade in accordance with the Swedish standard.
B. Shotblasted panels followed by rusting
A serie of panels treated in the same way as in "A" above and then placed outside in spring and subjected to the local atmospheric conditions for a minimum period of 30 days.
C. Shotblasted panels rusted and then treated with Fertan
A serie of panels treated as in "B" above and the fertanized assording to the following procedure:
Hndbrushing to elimate superficial rust
Application of Fertan rust converter
Spraying with water to thoroughly wet the surface followed by a second spraying after two hours
24 hours reaction time at romm temperature (20°-22°C)
Final washing using plenty of tap water to eliminate the excess of the reations and relative salts.
Each series panels was then sprayed with paint in the following manner.
CYCLE ONE (1)
1st Coat:
Medium lead - long oil synthetic primer to a thickness of 60 microns - air dried.
2nd Coat:
Medium oil enamel red oxide in colour applied to a mean thickness of 60 microns - air dried.
CYCLE TWO (2)
1st Coat:
Red oxide solvent based epoxy primer cathalysed with polyamide applied to a mean thickness of 60 microns.
2nd Coat:
Yellow oxide coloured medium oil synthetic top coat applied to a mean thickness of 60 microns.
CYCLE THREE (3)
1st Coat:
Yellow ocher winyl primer applied to a mean thickness of 30 - 40 microns.
2nd Coat:
Gray semi-matt vinylic enaml (RAL 7032) applied to a mean thickness of 80 - 90 microns
CYCLE FOUR (4)
Single coat:
Epoxy tar cathalysed with epoxyamine compound applied to a mean thickness of 120 microns.
CYCLE FIVE (5)
1st coat:
White solvent based epoxy primer cathalysed with epoxy-amine compound applied to a mean thickness of 50 microns.
2nd coat:
White semi-matt solvent based enamel cathalysed with epoxy-anime compound applied to a mean thickness of 70 microns.
CYCLE SIX (6)
1st coat:
Long oil red lead sytetic primer to a mean thickness of 60 microns.
2nd coat:
Red polyurathance enamel applied to a mean thickness of 60 microns.
In each of the above cycles the instructions dor application and drying of each coat was strictly followed and the painted panels were then left for 30 days befor carrying out the accelerated corrosion tests.
NB:
The results of the above mentioned tests my be more easily seen in the enclosed photographs.
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