FRANK BOND

INTRODUCTION

FRANK BOND is the Chemical used in the final rinse after Pre-treatment either by immersion

or spray process.

ADVANTAGES

Better corrosion resistance : Improved paint adhesion

FRANK BOND eliminates contaminants from the pre-treated metal surface and thereby increases

corrosion resistance and paint adhesion.

MINIMISED PAINT FAILURES

FRANK BOND counteracts the effect of hard water salts and acidifies the surface before painting.

It thus reduces the risk of paint blistering under humid conditions.

APPLICATION

FRANK BOND is used in the final hot rinse after treating work in FRANK PHOS or FRANK CHROME.

OPERATIONAL DATA

Chemical:FRANK BOND

Concentration  :50 ml FRANKBOND per 100 litres of water.

Temperature  :Upto 80°C.

Time  :30-60 Seconds

pH   :5.5 to 6.5

Chromium Titration  :1.6 ml maximum.

TA Titration   :Not more than 2 .0 ml.

This may be increased upto 100 ml where hard water is used or for use over heavy phosphate coatings which are to be oiled.

PROCESS

Frank Bond Treatment

Add the required amount of FRANK BOND to the final rinse of the Pre treatment  process. Rinse the

Work in the FRANKBOND solution for 30-60 seconds at as high a temperature as possible to aid drying Temperature upto 80 °C can be used except after FRANK CHROME Treatment when the temperature should not exceed 50°

DRYING AND PAINTING

Dry the work, preferably in an oven and paint as soon as possible if there is any delay between

processing and painting, the surface may become contaminated by condensation, hand marks

dust or fumes. Ideally Pretreatment should take place immediately before painting and no

Pre treated work should be left overnight before painting.

BATH MAINTENANCE

If soluble salts carried over from previous rinses are allowed to accumulate the FRANK BOND solution will deteriorate rapidly. It should therefore be made up fresh regularly, preferably once a day.

Check the pH  of the rinse  periodically, using a Universal pH paper. For a rinse containing 50-100 ml

of FRANK BOND  per 100 litres of bath the pH should be between 5.5 and 6.5. If it is over 6.5 add more FRANK BOND , if it is below 5.5 discard part of the rinse and replenish with fresh water.

In high volume production such as a converyorised  spray plant the rinse concentration is best

Controlled by chromium titration and total acid determination as follows:

CHROMIUM TITRATION

1. Measure 50ml of the FRANK BOND rinse into a clean Iodimetric flask.
2. Add about 1 gm Potassium Iodide crystal and agitate the solution until dissolved.
3. Add about 10 ml of C.P. Hydrochloric acid in the two equal portions to the lip of flask, raising the

 stopper slightly to allow the acid to run into the flask.

4. Rinse the tip several times with water and replace the stopper.
5. After the sample has settled for about one minute titrate with 0.1 N sodium thiosulphate until a

  straw colour is obtained.

6. Add several milliliters of 1% soluble starch solution to the sample, and continue the titration with

 0.1 N sodium thiosulphate ( without returning  the burette to zero) until the blue black colour

 disappeares.

7. Record the number of milllilitres of 0.1 N sodium thiosulphate used as the chromium titration.

TOTAL ACID TITRATION

1.Measure 50 ml of the rinse into a clean beaker.

2.Add 6 drops of Phenolphalein indicator solution.

3.Titrate with 0.1 N sodium hydroxide to a pink end point. The number of ml of 0.1N sodium

hydroxide added is the Total Acid Titration figure.

The total acid should be below 2.0; if it raises above this discard the rinse and make up a fresh one.

REPLENISHMENT

To raise the Chromium Titration by 0.1 ml add 3.2 ml of FRANK BOND every 100 litre of bath. The

Chromium Titration must not be allowed to fall below 1.5 ml.

EQUIPMENT

Dip tanks should be fitted with a heating unit. Water supply and a draining valve. Mild steel

equipment can be used for FRANK BOND.

PURITY OF WATER  SUPPLY

For best results the final rinse must be as clean as possible. In hard water areas the water is often the main cause of contamination and to be sure it will not affect the performance of the subsequent paint, the salts in the water should not exceed any one of the following limits:

1. a) 70 P.P.M total chlorides and sulphates ( Calculated as C1 and So₄)

1. b) 200 P.P.M total alkalinity ( Calculated as CaCO₃)

1. c) 225 P.P.M. of (a) plus (b) above

If the contamination of the water exceeds any one of these limits, deionised water or uncontaminated

steam condensate is recommended for use in the final rinse.

HANDLING PRECAUTIONS

FRANK BOND contains chromic acid and operators should wear safety goggles and rubber gloves, apron and boots when handling the concentrate, if any of the solution comes into contact with the skin, wash it off immediately  with liberal quantities of water. If it is splashed into the eyes, flush it out with water and obtain medical attention immediately.