I wanted to call this, "When it all goes horribly wrong!" but on reflection "Paint…
Spray acrylic paint
Ron Taylor has written this introduction on how to spray acrylic paint, and goes on to focus on HVLP for 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.
Spraying acrylic paint is a mindset You need to go into spraying with your mind and your wallet open. Be aware of what you need and what extras you want, before taking the plunge on the unit. Make sure spraying is what you want to do and budget accordingly. Buying the machine is only the start of the costs. In fact, spraying will not make you any money, or more likely, it will cost you money, without all the extras.
You may need extra needles and tips (fluid sets) for HVLP
and you will need extra tips for airless.
None of this gear is cheap, so check before you buy what else is required.
Also if you want to airless spray walls with 12” fans or exterior masonry paint, make sure the machine can handle this. The cheapest models usually won’t.
Masking machines, tapes, films, plastic sheeting, extension poles (for ceilings, etc), lubricants are all extras that won’t come with the initial purchase. And freebies with machines, in fact any freebies within the spray industry are generally rare.
If you are wondering how I know so much about not being prepared, it’s because I took none of the above advice on board, and ended up with a bit of a shock when I came to spray for the first time.
You will see many articles and advertisement extolling the virtues of spray painting. You will see HVLP (high volume low pressure) spray machines from as low as £95. These products are of absolutely no use to a professional painter, in fact they are probably of no use to anybody at all.
HVLP machines need power to spray paint;
The more power the unit has the more expensive it will be. The power comes from a turbine graded in ‘stages’. These stages start at 2 stage (the lowest power) to 5 stage (currently the highest output possible). They work like vacuums in reverse, converting air into power. More power is created by more stages. You can add onboard compressors to the larger stage turbines to increase power further.
Best HVLP for spraying acrylic paint
To spray acrylic (or latex as it may be advertised on US sites) you will need a minimum 4 stage turbine, but in reality you would be better with a 5 stage. Paint thinning is pretty much always required, even with 5 stage units.
Most of the cheap units are 2 or 3 stage units. With this kind of low power, you will struggle to spray anything that isn’t the consistency of water, so acrylic paint will be so thin as to be unusable. The more expensive models of these lower powered units (Graco/Apollo/Capspray) are designed for thin oils and dyes, which have little or no viscosity to them.
Setting up an HVLP spray gun
Setting up an HVLP gun is a hassle and you will require patience. But get it wrong and you could end up re-spraying the lot or, even worse, sanding and re-spraying the lot.
The paint will usually be in a cup under the gun. The air is forced to both the pressurized pot and the gun separately. When you pull the trigger the paint is pushed to the gun where it meets the air going to the gun. This can be regulated to atomise the paint into small particles to enable it to spray.
A 4-stage turbine will spray thicker paint, but you could never use product straight from the can with any HVLP gun. To spray more viscous material you will also need to increase the air, which will create more overspray.
Overspray is the bounce back of some of the paint from the surface, and is your worst problem, especially in occupied houses, and more air in the mix adds significantly to the problem. So thin the paint right and set up the gun correctly.
How to thin acrylic paint for spraying Thin the paint with water and Floetrol to the point where, when you lift the stir stick, the paint dissipates into itself immediately, ie when you swirl the stick around you can’t see the swirls lying on the paint.
I’m talking Graco here, but nothing smaller than a #4 needle will really be large enough for acrylic paints, occasionally a #5 will be required.
Too much overspray can, and will, get everywhere, leaving any uncovered carpets and furniture covered in a very fine talcum powder-like dust in the colour you are spraying. Cover everything methodically with sheets or plastic.
Trial and error As the air and material has to be regulated by the user it’s a trial and error process. The settings you make today won’t necessarily be the same settings you need tomorrow, even for the same paint. There are too many variables: ie: humidity, cold or paint consistency. So get the thinning right, water and paint conditioner is best, and get the settings correct before you start the job.
As I mentioned, these units can be difficult to set up for the beginner. Don’t expect any indepth help from any US manufacturer’s spray manual on actual spraying – it is assumed you know how to do it.
Technique for spraying with HVLP
Don’t learn to spray on a paying job. Get an old door or have a go on something that isn’t going to be scrutinized too much.
Don’t spray light, fast coats, this will give you a rough patchy finish because the paint will dry too fast and (in some cases) before it even touches the surface.
Apply a full wet coat moving the gun slowly and methodically across the surface. It’s all about practice, don’t expect to be able to do it straight way.
Cost of good HVLP
To get an HVLP unit to spray paint to any sort of standard, you will need to spend a minimum of £1000. But if you are looking at consistent high class finishes you will need a 5 stage unit with the option of an onboard compressor. This set up will cost you nearer £2200.
I know that some people reading this will say ‘I have a 3 stage turbine and it sprays just fine’ and that’s ok if you’re happy with the finish. But if you used this next to a Graco TurboForce 9.5 plus compressor you would see a marked difference in both performance and finish quality.
HVLP speed and control
HVLP is slow, though not as slow as a brush and roller, but if you’ve had any experience with an airless pump you will be a little disappointed with HVLP, performance wise.
HVLP has more control than airless though and it’s not as easy to get into difficulty.
To follow: Spraying acrylic paint with airless
This is a guest post from Ron Taylor, a member of the Traditional Painter network working from south of Birmingham to Evesham, specialising in painted kitchens and furniture. 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. Ron uses acrylic paints on all his private residential work and can be contacted on………..07905 895502 firstname.lastname@example.org
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