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HOW TO APPLY THE PRIMER,INNER TAPE AND OUTER TAPE ?
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XUNDA TAPE Application Instruction
1.Steel pipe pretreatment
1.1 Keeping the pipe external surface clean and dry. Remove the dust,
oil, welding slag, burrs, grease and dirt on pipe surface.
1.2 Pipe surface prepared up-to a level of Sa 2 or 2 ½ or St 2/st by sand blasting.
1.3 After the pre-cleaning operations,the pipe surface not smooth
which may sharp the pipe coating should be burnished , the abrasive
dust attached on the pipe surface should also be cleaned clearly.
1.4 If flash rusting occurs, the surfaces must be re-cleaned by blasting as above.
2.Coating &Wrapping application
2.1 Coating &wrapping application consist of primer application, inner
tape coating ,outer tape coating .
2.2 weather condition
2.2.1 When the wind&sand was strongly, when the sand and dust covered
on the surface of pipe, primer ,tape etc., should not be brushing primer
and wrapping the tape if there is no reliable preventive measures.
2.2.2 When air humidity is greater than 80%,or when the pipe surface is wet from any precipitation, should not be brushing primer and wrapping tape.
3.Brushing primer
3.1 The brushing time should be control within 6 hours between the pipe surface treatment and brush primer.During brush primer ,pipe surface should be free from damp and pollution.If the pipe surface rust return,should be re-pre-cleaned.
3.2 The primer should be mixed evenly in the container before brushing.
3.3 The primer should be applied uniformly, without any sags,floods,runs,drips,bare spot and over spray, such as leakage brush, clot , streaming. The primer coat DFT shall not be less than 25-50micron(1-2mils)
3.4 After the primer dried, then wrapping the tape(It usually takes 3to 5 minutes.).
3.5 Consumption:
machine application approx. 0,1 litre/m²
hand application approx. 0,2 litre/m²
4.Wrap tape application
4.1 Wrap tape application consists of hand application and machine application.
4.2 The tape applied temperature must be above 5 degrees,the coating construction temperature shall be more than -5 degrees as better .
4.3 The tape shall be spirally applied ,minimum overlap shall not be less than 50%.
4.4 When a new roll of tape started ,the ends shall be located to ensure the continuity of wrap tape using the same method of application.
4.5 Outer tape applied method is the same as above.
5.Cutbacks
Cutbacks shall be a minimum 6inches(150mm) from the ends of each
pipe.The cutbacks may be tapered or straight edge for the total thickness
of the coating.
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