Airless spray acrylic paint on trim
If you can master an airless or air assisted airless (AAA), you can do pretty much anything with acrylic paint that an HVLP can do, but much faster.
Ron Taylor has written this introduction to airless spraying acrylic paint. Ron Taylor first started using acrylic trim paints in 2004, and is now an authority in the UK on the application of water-based paints with brush, roller and spray.
Air Assisted Airless (AAA) for spraying acrylic paint
Air assisted airless or AAA may seem like a contradiction in terms. Surely, if it’s airless, why is it air assisted?
In reality, an AAA unit is an airless pump with an onboard compressor that enables it to be an airless pump for walls or larger areas, but at the flick of a switch turns into a very high powered HVLP type unit. I say type because it is not exactly the same. The power, as I said, is better and the finish is far superior.
These units are best just used for trim and fine work in the air assisted mode, occasionally switching to airless. You can spray walls with them in airless mode, but the combination of 2 hoses at the gun (one for air, one for paint) makes it more cumbersome than a standard airless. This is fine for the odd room, but not really a machine for spraying mainly ceilings or walls on a day to day basis.
I have used an AAA machine for about 30 seconds at the Graco factory. So the above paragraph is based in information researched and observed, not from prolonged personal experience.
Airless for spraying acrylic paint
An airless pump uses no air. A piston compresses and pumps the paint to the gun and atomises it at the tip.
This is by far and away my favourite way to apply acrylic paint. It’s fast, easy (well sort of) and gives a very good finish.
How much for a good airless spray unit?
Look to spend about £1000 on an entry level airless unit. This will be fine for interior painting of trim and walls. Graco, Titan and Wagner have excellent starter pumps at this level.
Your purchase will come with, usually a 50ft hose, gun and a 517 tip.
There are semi professional or diy units coming to the UK now. These should be ok but will have limited lifespan and you may struggle to get spares if they break down. The hoses are shorter, around 25ft and they usually only spray up to a 515 tip (more on tips later). They come in at between: £400-£500. To me that’s not enough of a saving to make me buy one of these over a pro unit.
Professional tips for using an airless spray gun
The force required to spray acrylic paint with an airless gun is very high, over 3000psi in some cases. And this gives you a number of things to be aware of:
Safety Because of the very high pressure that the paint is compressed to, an airless gun is a dangerous tool, and must be respected.
– You must never point the gun, even in jest, at anyone or any part of your anatomy.
– If your hand, or any part of the body, is sprayed with paint at close range (I won’t say how close, just don’t do it) it will tear the skin and inject paint into the cut. This is a serious injury and you must seek medical advice (at a hospital, not a GP) as soon as possible. Acrylic paint, because it is water based, will readily flow into your body and bloodstream, taking all the bacteria it picked up on your skin and in the air with it. One of the ingredients of acrylic paint is a toxic chemical called Titanium Dioxide and, apparently, this helps bacteria to grow inside the body at an alarming rate. This, if left unchecked can cause disfigurement, amputation or, in the most serious cases, death.
-Always use the trigger lock when changing or clearing the tip.
– Always turn off, depressurise the pump and lock the trigger when not in use. Never leave a pressurised pump unattended. Always be aware of this and you will be fine.
Using an airless
Once set up, the paint comes through fast, and the first time you use it, you will be shocked. You need to move the gun and/or yourself quickly to cover the surface. Too slow, and you will get massive build-ups of paint and it will run. This is a sprayer that you need to practice with a lot, before you become proficient.
-Using the gun 8-10” from the surface, try and move the gun a confident manner, without hesitation.
-Pull the trigger before you approach the work and release it afterward. If you stop or start over the job you will get build-ups and/or spitting.
-Try and keep the gun at right angles to the surface and don’t use arching movements of the wrist or you will get build-ups of paint in the centre.
– Overlap each stroke by 50%. The easiest way to do this is spray your first stroke then aim the horns or guard of the gun at the edge of the spray line. Then spray your second stroke. Continue like this and you will get good coverage.
– You want to be spraying at around 2200-2500psi with acrylic paint, but cheaper models don’t have digital readouts, so you won’t know what pressure you’re set at. So, as a rule, turn the pressure up just over half way and spray a little. If you get 2 lines either side of the main fan (tails) turn it up till this stops. Then you’re pretty much there, but test it first to see that you are happy with the pattern and finish.
Airless tip sizes
You regulate the fan and amount of paint sprayed, not by the pressure, but by using different tips in the gun. The tips come in various sizes and take a bit of figuring out for a beginner.
The first number(s) on the tip is the fan size, the higher the number(s) the wider the fan. You must double this number for the fan size. So if the first number is 4 you will get an 8” fan. The second two are thousandths of an inch. The higher these two numbers the more paint is released.
The tips come in 2 different types for spraying paint, standard and fine finish (FF). I always use FF tips for trim as the finish is better. You only really need a couple for trim and I’d go for a 210FF (4” fan, 10 thou) and a 310FF (6” fan, 10 thou). As you do bigger projects or walls, you will need larger tips. Don’t use FF tips for walls or ceilings.
If it’s a new machine it will come with a 517 standard tip. This is for ceilings and walls. Don’t even attempt to paint doors and frames with this or you will make a very large mess.
Maintaining an airless
Always use the lubricant for the piston every time you use it. This will prolong the life of the pump and make for less problems.
If you intend to store the sprayer for 2 weeks or more run pump saver though the unit. This is very expensive and I’ve heard that it’s only car antifreeze anyway. I’ve seen internet sites for and against using the cheaper antifreeze. It’s your unit so only you can decide if it’s worth risking it but I used expensive Titan LS10 and Graco Pump Armor for years. I don’t anymore.
Best acrylic trim paint for airless spray
To get to know which paints perform best on trim, it is best to experiment, as some will perform much better than others. My favourite trim paints, in no particular order are:
Glidden Trade Acrylic Eggshell & Gloss: Both are nice, affordable, products that spray very well. I wouldn’t go for the eggshell on trim, but if you have ornate coving that requires this finish,it’s worth a try.
Neither of these products will give you any issues when sprayed. They don’t want to sag or run unless seriously over applied. And both level out to a smooth, good looking finish when dry.
Sikkens Rubbol BL Satura: Will give silky smooth, oil like, finishes when applied to the best prepared surfaces. Can be very unforgiving of over application or a bad spray technique though, as it has a tendency to build up on edges and run. The slow drying times can also give issues with sagging, again if too much paint is on the surface.
This product, more than any other acrylic product I’ve sprayed, can be challenging. But done right you will get a superb finish.
Mythic Classic Semi Gloss & High Gloss: As an American product I would have expected this paint to spray well – and it does. No issues at all with application and levelling. This product is very forgiving if slightly over applied (I did say slightly) and gives an extremely good finish on trim, cabinets, etc.
Paint coverage with airless spraying
Don’t let anyone selling you the gear tell you that it will only use 10% more paint than a brush and roller. This simply isn’t the case. You will lose at least 20% to overspray and flushing the system. You will save on labour, so it’s not really an issue in that regard. But what is an issue is the amount of paint you will need in the system to do a simple job.
To spray a couple of doors, both sides, you may need a litre of paint. But you will need another 2 litres in the system to move the litre, plus another litre behind it to replace the paint in the pump, as you spray. So, to spray those doors, you really need 5 litres. You will get 4 back when you clean the unit, but it’s something to be aware of. American paint manufacturers sell paint in 5 gallon buckets, this is why.
Masking up for airless spraying
The key to a good spray job is masking. Mask anything you don’t want spraying. Buy a good masking machine, 3M Scotch do the best I’ve seen, and learn to use it. These will dispense Masking tape and poly film at the same time. Bought new they come with a good instruction DVD.
They are not cheap at around £60 and the film, depending on length, will cost between £10 and £20. Sounds a lot of money, but not as much as replacing items of furniture or carpet caught by accident with an airless gun.
Videos on airless spraying
You can do research about spraying on the internet. Some of it’s very good, some of it dire. But have a look on YouTube at the guy above demoing the masking tape applicator, Chris Berry of Idaho Painters. He makes some excellent videos on airless spraying and is a real master of the equipment.
This is a guest post from Ron Taylor, a member of the Traditional Painter network, specialising in kitchen painting. He covers from Birmingham down to Evesham. In 2004, Ron took the plunge ahead of the rest of the UK pack, and he is definitely now an authority on brushing acrylic paint, using a roller, spraying acrylic with HVLP and spraying acrylic paint with airless.
If you have any further questions about this topic, please check out the Traditional Painter spray gun forum
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