Waterborne Paint: The Beginner’s Guide – Part 6


It has to be said right at the beginning that kilo for kilo, litre for litre, waterborne paint is more expensive. However, like all things there are other factors that work to make it cheaper, especially once you’ve had experience with it and know how to use it.
Every manufacturer’s paint will vary, and one way to assess it is by theoretical spread rate. Each manufacturer’s spread rate will be different, but in essence waterborne paint, with its higher level of solids, will cover more area per litre, and the reality will be that to paint a given surface area will require less paint. The result is often that the cost is about the same or even less for any given job. It is also advisable to ask your paint manufacturer to demonstrate the product so you can get a first hand look at what water can really do.
As stated in this series of articles before, it’s a common problem for a painter, when first converting to water, to still mix his paint in the proportions he’s used to with solventborne and to end up with paint left over, which he throws away.
“Also note that many water-based systems are 100 per cent product usage, meaning, 100% tinting base is used when mixing formulation, so they could be quite expensive if you don’t get your quantities right,” said Glasurit’s Technical Sales Support Manager, Ian Johnson, “but a true waterborne paint, such as Glasurit, you convert to water and you’re only using 30 per cent tinting base in the mix and your costs should be lower.”
If you’re not putting through a lot of work, or you’re in an area of a lot of temperature change you can add cost because there are factors related to shelf life limitations with waterbase paint. Most waterbase tinting system have a shelf life of 12 months. Glasurit waterborne tinting bases, have a shelf life of five years, but like all ancillary products such as the viscosity adjusters or the reducer shelf life is limited to 12 months, but since these are used in everyday applications,they are in constant use and are quickly consumed.
This compares to a solvent paint shelf life of three to five years.
When it comes to equipment it will pay to have your current set-up assessed by someone who knows what they’re looking for. There are several areas which will need to be addressed.
Your current compressor and attachments will need to be examined. Is it large enough to meet the needs of the extra air which might be required for spraying or drying? If the compressor seems large enough but the supplied volume is struggling you could be losing air though fractures or faulty fittings in the hoses, or have air lines which are too small. Is the supplied air clean enough, as waterborne paint is more prone to defects related to unwanted oil or other foreign material in the air.
Is the filtration system of your spray booth adequate to provide you with clean air? Is the booth air flow adequate? Does it need to be upgraded? You will need a minimum drying system such as a hand held or air diffuser type.
“To keep costs down and to suit the characteristics of waterborne paint you would be strongly advised to go to HVLP spray guns, if you don’t already have them,” stated Johnson. “This will mean the transfer efficiency of the gun is at a premium, therefore getting the most out of the product.”
There are other drying systems, such as the Junair QADS or the Garmat systems, which can make a big difference in terms of the time a job is in the booth, and your decision on these will be based on throughput or how many painters or booths you have.
“If you’re only doing small jobs, and your average repair is two to three panels or small rapid repairs your hand held blower or air diffuser will probably be sufficient,” Johnson continued, “but if you’re pumping the work through, or you’re in a cold climate area, or you have a lot of painters and only one booth then you can improve your drying time with an air movement system. Some claim efficiencies in drying time for solvent paints and clearcoats, and reductions of up to 10 minutes in bake cycles, and if you’re putting through five cars a day that can add up to another car through the booth each day.”
You may find that with waterborne there will be happier customers with better paint jobs, and even happier painters, because approximately 70 per cent of vehicles today are painted in water-based paints by the OEM factories, and blends or matching paint will become easier. There will be a reduction in problems associated with using solventborne paint for a repair on a water-painted vehicle, including solvent sensitivity caused by the solvent biting into the waterborne coating causing “ring-up” and “fry-up” and similar issues. As more manufacturers switch to waterborne it will become a basic requirement to repair their vehicles.
Also look at the cost of training: Is it part of the package or will it be charged? What down-time might it cause in the shop? Normally with a change-over there is some training involved, partly in-house and partly in a training centre. It is advisable to speak to your paint supplier in relation to this.