THE LIMITATIONS OF WATER
This month we will look at the â€œlimitations of waterborne paintâ€, but the difficulty is that there arenâ€™t that many limitations outside of the changes in techniques and work patterns to which you have already become accustomed.
Anything that you can do with a solvent paint you should be able to do with water. The processes may be different, but the outcomes will be the same.
An example is the painting of engine bays. Some of the industry short cuts which have been employed with solvent wonâ€™t be available to you with water. The hardening of solvent basecoat – instead of applying your basecoat and a matt clear – to achieve a higher level of gloss canâ€™t be done. Some companies have a converter for that process, and Glasurit has a product to achieve a similar result, but it is a limitation.
The view of â€œlimitationsâ€ will also depend on your definition of the word. For example, if yours is a high production shop then you are going to need some form of retrofitted ancillary air movement/drying system in your spray booth, such as a set of Junair QADS, and that will come at a cost. Without this the paint will dry, but it will take longer than a solvent-based paint, especially if itâ€™s cold or humid. If you have a shop which does not depend on rapid throughput of work then this will not be an issue for you, and there will be no â€œlimitationâ€ on that score.
â€œSome waterborne systems have limitations in regards to colour,â€ explained Glasuritâ€™s Technical Sales Support Manager, Ian Johnson. â€œGlasurit isnâ€™t one of them â€“ any colour which can be mixed in our solvent line can be mixed with our waterborne line – but there are some limitations with some waterborne technologies in terms of colours. This would mostly apply in metallic and â€˜effectâ€™ type colours.â€
Johnson continued, â€œThis whole topic of â€˜limitationsâ€™ is often brought up and discussed. Thereâ€™s an expectation that there will be limitations; that water canâ€™t be as good or as efficient as a solvent paint. The only real problem is one of education, and the body shops just need to be educated that there are no real limitations to waterborne.â€
One of the expectations of a change to waterborne is that it will cost more: A new technology will cost more is the belief. And pound for pound, gram for gram, litre for litre it will cost more, but if used correctly you will use less paint per job and thus you will save money.
While jobs will vary, and brands will vary, you should use up to only half as much paint per job, and while the price per litre might be up to 20 to 30 per cent dearer, the net saving is significant. This might only become apparent once you have properly adapted to the product, technology and the volumes required per job, as the common response from painters new to the paint is to prepare too much paint per job initially until they become familiar with the requirements.
â€œThe change to waterborne is all about mindset,â€ said Johnson. â€œForget about what youâ€™ve learned in the past, this is a new technology. You need to accept and adopt that technology and techniques and move forwards or else youâ€™re going to have problems and limitations in the way itâ€™s used.
â€œThere are more advantages in using water than solvent these days. With the majority of OEMs painting their cars in waterborne itâ€™s preferable to be refinishing cars in water.â€
Johnson pointed out that a lot of waterborne paints have a limited shelf life, with a lot of the tinters having a limit of 12 months, though some, like Glasurit, have a limit of five years, because itâ€™s a true waterborne system as compared to a water-based system. Ancillary products, such as reducers or viscosity adjusters have a limit of 12 months. True waterborne primers which can be used with these systems have a life of 12 months.
Water-based paint systems can have troubles with cold weather â€“ a potential problem in colder regions during winter â€“ that will require heated storage and warmed air systems. Similar problems can apply in extreme heat, where the paint can start to thicken through the rapid loss of water, requiring the use of a lot of viscosity adjuster.
Issues such as the required use of different paint strainers or masking tapes are not limitations but more points of difference.
On the issue of masking tapes, Johnson pointed out that while most masking tapes on the market today are suitable for use with waterborne paint, there are still some around which will start to lift if they are used with water-based paints. Make sure you choose an appropriate brand.
Most equipment will require no change.
Attending training with the manufacturer of your chosen brand of paint is a significant and necessary step in adopting waterborne paint. The whole shop needs to be prepared for and enthusiastic about the change or itâ€™s unlikely to be a successful move.
While you can use any spray gun, HVLP is preferred simply because it will limit the application of too much paint and result in excess drying time, as discussed previously. HVLP has been around for years, and some older painters donâ€™t like it because it requires a change in techniques and they prefer to continue to stick with what they learned decades ago. This attitude is the very problem which will limit the successful adoption of waterborne paint, which requires a similar preparedness to accept change in a number of areas.
â€œFor a conversion to waterborne to be successful, everybodyâ€™s attitude needs to be right,â€ reiterated Johnson, stressing a point heâ€™d made to ABN before. â€œItâ€™s not just the body shop owner, but also the painters and technicians who must be enthusiastic for the change, and to achieve that it is all about education. There are different methods that all paint companies employ, but education is the key and is very necessary.â€