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Ask Joe Powder

"Ask Joe Powder"
"Ask Joe Powder" is a question and answer column authored by Kevin Biller of the Powder Coating Research Group. Mr. Biller has over 30 years experience formulating and manufacturing powder coatings. He welcomes your questions regarding powder coating technology. Please write to: askjoepowder@yahoo.com 

Kevin Biller
The Powder Coating Research Group
15 W. Cherry Street, 3rd Floor
Columbus, OH 43215
614-354-11988
www.powdercoatingresearch.com 


Dear Joe,

We are in the process of establishing an assembly plant here in South Africa. One of the topics on my agenda is the question regarding the following:

Can an e-coated vehicle shell (body) be shipped overseas and painted at the destination? If so, what would the processes be to implement something like this i.e. paintshop

Kind regards,

Deon J. van der Merwe
General Manager Assembly Operations
Naledi Assembly Plant of RSA (PTY) Ltd

Dear Deon,

Indeed this process is quite feasible. In fact it is a very good idea. It would be essential to thoroughly clean and prepare the electrocoated surface before applying the next coating. You would need to clean the surface to remove any soils deposited during transit and handling. A simple alkaline cleaner followed by a tap water rinse then a deionized water rinse should suffice. Sufficient drying before the next coating is applied would be the final step. This will provide a clean surface that will readily accept a powder coating.

Please let me know if I can be of further assistance.

Best regards,

Joe

Hi Sir, How r u?

I need your help.......... What type of chemistry one should use for below absolute temperature i.e. 0°C up to -30°C? Should I go with Pure Polyester, or Hybrid? Will Super Durable PP work? Or should I go for some higher percentage of resin, around 80%? Please Reply when you get time.

Thanking you,

Rahul Dusane, Mumbai-Nashik, India

Dear Rahul,
I would start with a 50:50 hybrid with minimal (but some) filler such as blanc fixe or perhaps mica.
Is there a gloss or colour specification? A 50:50 (polyester to epoxy) hybrid will provide toughness,

adhesion and thermal stability at a relatively low formulation cost. I would be careful not to incorporate too high a concentration of filler. Some filler is good, however excessive amounts will compromise flexibility, toughness and corrosion resistance.

Sir,

It is a glossy and semi-glossy. Could not I use PP Super Durable? Sir, I want to request to you about some literature which relates to powder coating formulation, which will help me to get me help in resin and filler selection. Thanking you.

Dear Rahul,

The 50:50 hybrid still makes the most sense. It can be formulated easily in a gloss or semi-gloss product and will provide the best flexibility and toughness for the price. Super-durable polyesters provide excellent resistance to sunlight and intense UV radiation. They typically possess significantly less flexibility than other powder chemistries including epoxy, hybrid and pure polyester types.

As for a really good book on powder coating formulation I recommend: Powder Coatings Foundation for the Novice Formulator, BNP Media, 2004. You can order it at: this link

Kind regards,

Joe Powder