Fea­ture: why paint when you can pow­der coat?

Pow­der coat­ing of­fers durable and long-last­ing pro­tec­tion for your au­to­mo­tive com­po­nents

Car (South Africa) - - CONTENTS - BY: Ni­col Louw Ni­col­l_­car­mag PHO­TOS: Peet Mocke Petridish_­mooks

The idea of restor­ing a clas­sic car or bike can seem ex­cit­ing until you spot all the rusted me­tal com­po­nents. The so­lu­tion is to give these items an in-depth clean to re­move the rust be­fore paint­ing them first with a primer and then a se­ries of base coats. Or, you could save your­self the ef­fort and have them pow­der coated by the pro­fes­sion­als. This form of pro­tec­tion of­fers a smooth fin­ish that is more hard­wear­ing than any paint layer. We spoke to Les­ley Christie, di­rec­tor at Castel­locote in Cape Town, to find out what the process en­tails.

01 clean­ing

As with con­ven­tional paint­ing, prepa­ra­tion is key for a good re­sult and a lot of ef­fort goes into clean­ing the me­tal com­po­nents be­fore­hand. This in­cludes dip­ping the items in a de-rust so­lu­tion for an hour (if needed) be­fore wash­ing them with a high­pres­sure cleaner us­ing a hot-wa­ter so­lu­tion. Then the com­po­nent is ei­ther shot- or sand-blasted to re­move any im­pu­ri­ties, af­ter which the threads and other ar­eas not re­quir­ing coat­ing are care­fully masked.

02 ap­pli­ca­tion

As the prod­uct is a fine, dry pow­der, colours can­not be mixed, as with con­ven­tional paint. There­fore, you need to pick a colour be­fore­hand. A pow­der-coat­ing shop usu­ally has a num­ber of spray booths al­ready set up with pop­u­lar colours. If you need an­other hue, a small setup fee is charged to pre­pare a booth.

The com­po­nent is sup­ported in the booth with hooks or a jig to pro­vide easy ac­cess for the spray gun. An elec­tro­static charge is added to the pow­der par­ti­cles by the ma­chine feed­ing the spray gun, which is then sprayed onto the com­po­nent at low pres­sure. Skill is re­quired to cover the part en­tirely. There is sur­pris­ingly lit­tle wastage be­cause most of the pow­der tends to stick to the com­po­nent. Any ex­cess pow­der is ex­tracted from the booth and re­cov­ered.

The cov­er­ing thick­ness achieved on a room-tem­per­a­ture (cold) com­po­nent is around 100-120 mi­crons but this can be upped to 300 mi­crons if the part is pre-heated be­fore the pow­der ap­pli­ca­tion.

03 cur­ing

An oven warmed up to 220 de­grees Cel­sius is needed to cure the pow­der layer. The par­ti­cles melt to form a sin­gle layer cov­er­ing the ob­ject. It takes about 30 to 45 min­utes depend­ing on the size of the items. Castel­locote’s oven is the size of a 20-foot ship­ping con­tainer, al­low­ing large ob­jects to be baked.

The com­po­nents are cooled nat­u­rally and are ready for use, with no dry­ing times as with con­ven­tional paint­ing.





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