FREIBOND 8 chemicals are formulated to provide dense crystalline zinc phosphate coatings on steel surfaces prior to painting or rubber bonding. Zinc coated material can also be treated in mixed production with steel. FREIBOND 8 can be applied by immersion or spray.
This excellent product has a built-in phosphate crystal refining agent. It is of particularly importance that it significantly enhances the detergence resistance of the paint film and has found wide acceptance in the appliance industry. Freibond 8 has excellent rubber-to-metal bonding capabilities. Freibond 8 operates at higher temperatures that Freibond 6, but with less sludge generation.
- materials required
- process sequence
- testing and control
- general maintenance
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- Ordering Information
FREIBOND 8A Make-up Chemical
FREIBOND 8B Replenishing Chemical
FREIDOX 2 Accelerator Chemical
FREICLEAN Alkaline Metal Cleaning Chmical
FREICON Non-chrome final seal rinse
Stainless steel, mild steel, and high temperature acid resistant plastics are suitable for processing equipment.Utilizing 300 series stainless steel equipment will significantly increase the service life of the equipment. Full cone spray nozzles, such as Spraying Systems WhirlJet® nozzles, are normally used in spray applications to ensure uniform application of FREIBOND 8.
Spray pressures should be maintained at 15 psig for optimum coating. Spray pressure above 20 psig will create inconsistencies and voids in the iron phosphate coating.
Utilization of deionized or reverse osmosis water in the system will reduce both chemical consumption and sludge generation. Application equipment should be cleaned or a regular maintenance cycle with PICKLE 2 to remove sludge and scale deposits that may interfere with application and subsequent performance.
The typical process sequence for FREIBOND 8application consists of the following steps:
1. FREICLEAN treatment
2. Hot water Rinse
3. Water Rinse
4. FREIBOND 8
5. Cold Water rinse
6. Cold Water Rinse
7. FREICON post treatment seal
To charge the tank fill to the three quarter level with water and add 36 gallons (450 lbs) of FREIBOND 8A for each 1000 gallons of working solution. Top up with water to working level and bring solution to operating temperature range 180-200°F. Once the optimum temperature determined, it should be maintained within 5°F. A processing bath built up according to these recommendations will result in 20 points of Total Acid. Immediately before processing any work add 1¼ pints (600 mls) of FREIDOX 2 per 1000 working gallons. Processing times usually range from 2-5 minutes.
To charge the tank fill to the three quarter level with water and add 21.5 gallons (270 lbs) of FREIBOND 8Afor each 1000 gallons of working solution. Top up with water to working level and bring solution to operating temperature range 155-165°F. Once the optimum temperature determined, it should be maintained within 5oF. A processing bath built up according to these recommendations will result in
12 points of Total Acid. Immediately before processing any work add 1 liter of FREIDOX 2 per 1000 gallons of working solution. Continuous addition of FREIDOX 2 is recommended for spray applications where steel is being processed. Processing times are usually 1 minute for spray applications.
An appropriate FREICLEAN product, followed by a rinse stage, should precede FREIBOND 8 phosphating application.
To maintain the bath’s performance it should be regularly tested and adjusted to within operating parameters. Normal processing time with FREIBOND 8 is 60 seconds to 2 minutes for spray and 2 to 5 minutes for immersion. Processing parameters can vary widely based on individual processes and performance requirements. Typical operating parameters are listed below. Your Freiborne representative will help develop the proper operating parameters for your specific needs.
Indicating Paper 17 can be used to perform a quick test to ensure the bath is running on the nitrite side (Freidox 2 value is greater than zero).
The FREIBOND 8 treatment is typically followed by a rinse stage and a chrome free final seal rinse such as FREICON RSX.
Total Acid Test:
Pipet a 10 ml sample into a suitable beaker or Erlenmeyer flask and add 5-10 drops of Indicating Solution 3 (phenolphthalein). Titrate with Testing Solution 11 (0.1N NaOH) to a permanent pink endpoint. An addition of 1.25 gallons (15 lbs) of FREIBOND 8B per 1000 gallons will raise the Total
Acid by 1 point.
FREIBOND 8A is used only for make-up or in replacing points lost due to mechanical loss, such as leaks, etc. FREIBOND 8B is used for normal replenishing of the bath.
Freidox: (This is only required where steel is being processed)
Dip a strip of Indicator Paper 17 into the working solution. If it turns pink Freidox 2 must be added, as above, until a fresh piece of paper does not change color. This is typically performed at least once per shift during operation. If it does not change color continue on to the titration, but if it turns pink the
bath is on the iron side and Freidox 2 must be added in the same increments as for a new bath, until the iron is cleared.
When no change in color occurs, determine the FREIDOX 2 concentration as follows: Pipet a 25 ml sample into a 250 ml beaker or Erlynmeyer flask, add 10 – 20 drops of Testing Solution 44 (50% H2SO4) and titrate with Testing Solution 15 (0.042N KMnO4), swirling vigorously until a persistent (10
second) pink is obtained. Maintain the FREIDOX 2 concentration between 0.5 and 3.0 points.
An addition of 1¼ pints (600 mls) of FREIDOX 2 per 1000 gallons of working solution will increase the concentration by about 1 point.
During the phosphating reaction, sludge is formed as a by product of the reaction. This residue collects at the bottom of the tank and should be removed regularly so that is does not deposit on the work. The sludge is generally removed by allowing the sludge to settle to the bottom of an auxilliary
tank, then the clear solution is pumped back into the processing tank from the top of the auxilliary tank. A cone shaped bottom with a bottom valve is convenient for discharging the sludge into drums for disposal. Filter pressing the sludge will recover most of the solution and lower disposal costs.
FREIBOND 8A Make-Up Chemical should be used to replace any points lost during desludge.
When the FREIBOND 8 solution has been heated for some time, scale will build up on the heating coils. Periodically the coils must be removed from the tank and the scale removed by immersing in muriatic acid or by mechanical means.
Carbon Steel, Galvanized Steel
Paint Pretreatment, Rubber-Metal Bonding
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