Everything you need to know about transfer efficiency
By Clive Wilden
Everything you need to know about transfer efficiency
As a professional tradesperson, efficiency is no doubt pretty important to you. We work hard to make sure we’re doing our job in the most efficient and economical way while striving for an excellent finished product. So how would you feel if you were to learn that when it comes to spray painting (or any other type of liquid spray atomisation for that matter but here we’ll focus on paint), you could be losing up to 75% of the paint you use to the air and surroundings? That doesn’t sound particularly efficient does it? Here, we’ll look at everything you need to know about transfer efficiency and how you can improve yours.
What is transfer efficiency?
First things first, what exactly is transfer efficiency? The technical definition is something along these lines:
Transfer efficiency is the proportion of paint solids deposited on the intended surface vs the proportion of paint solids that are lost in the painting process.
So, the more efficiently the spray gun coats the item being sprayed, the lower the wastage and thus, the higher the efficiency.
What is considered “normal” for spray efficiency?
It may surprise you to learn that the normal range for spray efficiency is anywhere between 25%-95%; where 95% is a highly efficient spray machine and 25% is, well, the opposite end of the scale. As you can imagine, losing 75% of the paint you use to waste is a big problem. Most people accept that spraying saves tradespeople time and results in a better finish but is a costly process. So, when you learn that a big portion of that cost goes to waste, you might want to do something to change it.
Why should I strive for better transfer efficiency?
All of this wasted paint has to go somewhere. It ends up on the floor, in the air, around the applicator and clogs up spray booth filters meaning you need to change them far more regularly than you should.
As well as wasted paint and the subsequent rise in cost, paint overspray can lead to a dangerous work environment, raise your bills expenditure and lower productivity. In contrast, a well set-up and efficient spray gun can transfer up to 95% of the paint onto the intended surface.
How do different spray guns fare on transfer efficiency?
There are a huge array of spray painting guns on the market. These guns vary greatly in price and the transfer efficiency of each varies just as much. Take a look at the spray guns below and assess which is the best option for you and your paint shop,
Entry-level spray gun such as the Golden Eagle – it’s possible to get your hands on a spray gun for less than £100. These spray guns certainly won’t break the bank. They’ll likely be gravity fed or use a suction cup and obtaining spares won’t be easy. Such guns could be a great option for DIY and non-professional spray painters who want to try their hand at spraying without the worry of low transfer efficiency.
Low pressure spray gun – Low pressure spray guns such as the DeVilbiss FLG-5 will usually come in at less than £150. These guns give the user more control over the gun and so are great for detailed work. The lower pressure results in less wastage and overspray. If you’re working on a small area and don’t require a thick paint finish, this could be a great and affordable option with positive transfer efficiency.
Conventional spray gun – Conventional spray guns such as the DeVilbiss Advance HD Spray Gun – Conventional will usually cost around the £250 mark. This type of gun will generally be suitable for use with a wide range of accessories meaning that it can coat wood, metal, plastic, ceramic and composite substrates. These guns can instantly improve the finish, are suitable for small operations and high volume spraying and are a serious upgrade on the entry level equivalent.
Trans-tech spray guns such as the DeVilbiss GTi Pro Lite Spray Gun – Trans Tech usually come in at around £300. They use lower pressure which can improve transfer efficiently. Like with the conventional spray gun, there are an array of suitable accessories (such as specific aircaps) which can improve transfer efficiency even further. They’re user friendly, require low maintenance and are the perfect choice for professional painters carrying out routine maintenance work.
Airless spray guns such as the Graco XTR 7 are typically used for painting metal. No air is used which can improve transfer efficiency. This type of gun can save users huge amounts of time and can be used to apply even the highest solid paint coatings.
The Electrostatic Spray Gun sees a leap in initial cost outlay. These guns come in at between £2,500 and £5,000 with various manufacturers having their own twist on the technology. This is a big jump from the others we’ve covered but for good reason. These professional spray guns are designed to maximise a businesses profits and actively work to create a high transfer efficiency for less wastage and more cost saving. Compatible for use with a number of different paint types including automotive, base coat, clear coat, enamels, high solids, metallics, plural component materials, primer, solvent borne and urethanes, these highly effective spray guns use less air to help lower your energy bills and improve efficiency.