Painting cycle(mfr Carboline): Thermaline 450+ Carbothane 134HG under min DFT

[giuss73]

Hi I need an urgent help if possibile.
I need to get a DFT of 310microns (cycle: Thermaline 450/min req 260microns+Carbothane 134 HG/RAL7032/min req 50 microns) on steel structure made of CS. Measurements after completion of top layer gave back around 200 microns so it means that intermediate layer (Thermaline) is under the min required of 26omicrons. Can I restore the min DFT by using the Carbothane only (top layer) ?

 

[david339933]

You could....but if I was the customer, I would not accept it. The bulk of protection is coming from the high build epoxy. 134HG is used because it is easily tinted, and provides excellent UV protection.
This is why there are coatings inspectors/procedures....so measurements are taken prior/during/after each step of the coating procedure, ensuring proper thicknesses are achieved.

 

[Dhurjati Sen]

Dear giuss73,

Surely you can do that. But it would be highly unethical amounting to cheating.

Remove Carbothane using emery paper.

Increase the DFT of the Thermaline using approved repair procedure. Measure DFT after requisite drying / curing.

Reapply Carbothane.

Regards.

DHURJATI SEN

 

[giuss73]

Gents many thanks for your reply. According to SSPCA2 Appendix 2_A2.1 I've done n. 5spot readings per 10m2 of this platform(carbon steel structure). The average value is over the min required of 310 microns but some single readings are 150/200 microns then below the thermaline DFT. Is it acceptable based on SSPCA2 ? thanks again in advance Giuseppe

 

[Dhurjati Sen]

Dear giuss73,

From 5.2.1. "No single spot measurement in any 10 m2 (100 fi2) area shall be less than 80% of the
specified minimum thickness."

Your 80% is 248 microns. 200 microns is way below that. So you need to follow Appendix 1.

As you have followed that and the average thickness is above 80% of the minimum, you are good.

Do remember to take the specified number of spot and therefore, the average readings as per the Appendix.

Regards.