Safer & excellent value compared to ferric chloride Excellent stability Etching time is 5 to 10 minutes at 45anddegree C1kg makes 5 litres of etch solution This sodium persulphate based etch powder has been specifically developed for etching copper laminate used in the electronics industry. The product exhibits excellent stability in use leaving surfaces clean even & free of staining.1kg will make 5 litres of etch solution or 200g per litre.4.5 litres of water is heated to between 40 to 50anddegree C & the powder is slow stirred into the water. When dissolved top up to 5 litres with water. The solution should last between 4 to 8 weeks but is dependent upon the volume of copper in solution. BN.BB To prevent premature breakdown of the solution do not operate in excess of 50anddegree C. Supplied in 1kg tubs.