Ask the Expert Question-and-Answer Archive

by Ron Joseph

Spray Efficiency

Q. I am the CEO of a small startup in Palo Alto (also a Saratoga neighbor). I’ve tried unsuccessfully to contact you via Linkedin recently, perhaps this email might work better.

I am very impressed with your domain expertise on spray, I wonder if you might be kind enough to answer a couple of newbie questions? We are trying to understand how a factory can stay in business when the maximum spray transfer efficiency is only 60%!

A. A transfer efficiency (TE) of 60% for spray application is wonderful for most applications. I see applications where the TE is in the 20-30% range. The key is to try to apply the coatings more efficiently by selecting the most appropriate application technology. If spray application is the only feasible method, painters can be trained to improve TE dramatically, since most painters do not know the basics of how to set up a spray gun to produce the least amount of overspray.

Q2. Thanks Ron!

Let’s say I have an automated line doing spray coating. If my TE is 30% then does it mean there is a 70% loss of the material? That is pretty bad yield.

In your travels, have you seen technologies out that can improve the total yield (e.g. material recycling…etc)? If someone really works at it, do you think it is possible to get above a 95% yield?

A2. Yes, if you have 30% TE you are wasting 70% of the material. If you have an automatic line you must fine-tune it to give you the highest possible yield. That could be 35%, 50%, or whatever depending on many factors, and especially on the part configuration. Depending on the type of coating resin system you are using you may or may not be able to recycle. On the other hand you mighrt be able to recycle the solvents in the coating and dispose fo the resin/pigment portion.

Regards,

Ron Joseph