Tell me ab out HVLP spraying

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Selwyn

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Ok I want to get into this. Partly because my other half wants to upcycle some stuff, I want to finish off some of my wood projects and maybe with an eye on painting some emulsion and external walls on a house I'll be doing up (don't worry it will be just first coat emulsion not all over the carpet!).

So I already own a 2hp 50l compressor. But I can afford an independent system up to the price of a Earlex 5500 if I need to.

What do I need to be looking at? A good spray gun and then filter on the compressor, or something on its on which is a bit more easily movable?
 
I think it would work well for finishing your wood projects. I would suggest using water based paint for both clear and paint finishes. Ive not used the earlex myself but have seen some positive reviews on here.

You may be able to spray a mist coat for emulsion on walls. However Im not convinced it will be quicker than a roller. I think spraying walls is more common in the US and from what Ive read professionals that do, it will go over the wall with a roller after spraying whilst still wet for the best finish. So it probably isnt worth it by the time you factor in masking. Emulsion spraying is done with an airless pump sprayer which can pump 4 litres /minute. An Earlex will be pretty slow by comparison and I cant see it spraying emulsion unless it is thinned.
 
TBH why are you after an earlex? A 2hp 50l compressor is far more versatile as you can then add specific spray guns for different tasks.

Having separate guns (and possibly air lines too) for different setups - like oil and water based paint for example is an absolute must - or you will risk cross contamination and I can absolutely assure you from years of experience that having to totally remove a paint finish because it's contaminated in some way is just awful.

HVLP guns are cheap - £25 will get you a starter user (anything cheaper will be chinese crap).

The earlex is for basic DIY people who may paint a few bits now and again - a shed, a fence - , and possibly use it indoors - which BTW I seriously don't recommend unless you are a professional who has done it before; actually painting the walls and redecorating / replacing EVERYTHING and I mean EVERYTHING else in the room after. There is no such thing as "no overspray".
 
Hi rafezetter. I'm also completely ignorant on the spraying thing. I'm looking to start off by spraying some primer and then paint on an mdf cabinet. Then build up to spraying finish (water based probably) on various furniture project St in the future.
I currently already have a compressor. Would you recommend going that route instead of HVLP and if so can you point me in the direction of a decent inexpensive spray gun?
Thanks
 
I too would be very interested in suggestions for HVLP guns. I'm in a similar position to noddy, looking to spray with my existing compressor (3hp 150ltr). Probably Morrells water based finish, as acid cat looks nasty and not suited to a DIY setup without a professional spray booth. There is a bewildering array of guns from the likes of DeVilbiss and Iwata, and to be honest I don't know where to start!
 
I have an earlex. I bought it to spray a massive desk (10m x 2.5m). It got the paint on ok, but couldn't achieve an even finish. I think it might have been because it was a very hot day. It was fine on the smaller pieces like the legs and rails.
And yes. There is stil a lot of overspray.
 
I have an Earlex Gemini which will take a whole 5L tin of paint (including the tin) which I bought for painting a whole house myself.

It would have cost about £1500 in P&D fees which I would rather have spent elsewhere, so £140 on the Earlex seemed like a good investment. My opinion is positive but mixed.

If you have a new home or a refurb job you have to paint from scratch I would recommend it. You can just blast our white undercoat on all surfaces (once woodwork is masked) and you can breeze through a house. Although you can't use trade paint which is too think all other standard commercial paints spray fine with no dilution.

I have also used it for painting doors and you get a brilliant almost powder coated type finish, very smooth. Although for furniture I would buy the 1mm needle for finer droplets (it comes with 2mm).

Where all domestic HVLP systems fails in my opinion is the top coat. Firstly you get ALOT of overspray, its unavoidable, I would never use one in a finished house. Even on a project house you have to mask all your ceilings with that masking tape that have a 500mm plastic sheet attached which negates a lot of the time savings.

You also can't get an even finish, so if you spraying dark colours or a fall with a window that shines light down it your going to see unevenness at an angle.

It's also impossible to touch up. Because of the flat texture less finish of HVLP if you touch up any marks or chips you will always see them because the brush or roller leaves a different texture.

My house looks great but I think if I did it again I'd just spray the undercoat and roll the top coats.

If you do spray furniture make sure you create a "box" out of dust sheets everything for meters in whatever direction you spray will get covered in droplets. Personally I'd just use a foam mini roller.
 
True HVLP paint guns use a lot of CFM. 12-18 CFM is quite common, this means you will need a large capacity compressor (not so much the receiver/tank size but the compressors actual output ).
If you want a quality gun look at the DeVilbiss range, quite costly though.
There are cheaper guns, but this will be reflected in their performance.
My BIL bought a SATA last year it was £400 + and it performs like a dream, good balance, excellent atomization, easy to use, fan width and fluid control both excellent. A perfect example of you get what you pay for.
 
Sorry for the late reply - neck deep in a build.....

Anyway - The DeVilbiss are considered among the best made - and not quite as costly as you might first think - here's an example of one that would be a good "starter" for someone looking to do regular spraying (regular as in at least every week):

http://www.ebay.co.uk/itm/Devilbiss...787?pt=LH_DefaultDomain_3&hash=item43d59ca173

This one requires just 5cfm's at lowest demand.

You might be wondering why I would recommend a solvent ONLY based spray gun - and the reason is that spraying water based paint, for a novice is actually pretty tricky - many factors have to be taken into consideration:

- paint viscosity is far more critical to get good atomization; too thick = spatter, too thin = massive overspray (misted paint like fog that gets EVERYWHERE)
- ambient temperature - a warmer day will affect both how the paint acts at the gun and flows out over the surface
- getting the air pressure feeding the gun right is also trickier - too much and you'll have horrible (paint) runs, too little and the paint will spatter and dry in the nozzle before even getting to the surface - or worse, flow AND spatter (think pebbledash).
- paint application technique also takes more time to master, because of the faster drying time.

There are additives like floetrol that will help, but only marginally and most of the above will still need to be considered.

I know that solvent based paints (oil mainly) take longer to dry, and require a bit more care in where you spray, but spraying solvent based is far more forgiving; ambient temps don't really affect it until you get to about 5deg, air feed pressure is also simpler because the paint is much less likely to clog the needle leading to spatter, application is simpler because of the enhanced flowout (self levelling) characteristics requiring a less practised hand.

There are ways to be able to cover both sides of an item using slower drying oil based paints - like hanging them vertically - or stacking them with painters pyramids.

If you really have no choice than to spray water based paints, then I would do several practise runs first, preferably in the area you'll be doing all your spraying (if in a semi stable workshop environment) on a similar surface to see how the paint acts - if you are going to be painting objects that require several passes per side then practise by buying a roll of fairly heavy lining wallpaper and making a frame of some kind to make a test surface, and make test passes with the normal overlap trying to get even coverage on a single pass, but be warned if you are doing it in open air outside, the weather WILL complicate matters so that a setup today won't work tomorrow if the weather is warmer by more than 5deg (and sometimes less).

A cheaper gun just to do testing and see if spraying is something you wish to pursue:

http://www.ebay.co.uk/itm/PRO-HVLP-...258?pt=LH_DefaultDomain_3&hash=item3f34337d2a

This is about as entry level as I would go price wise.

This will take water and solvent paints, the regulator will help with setting up, and not too expensive that you could buy 2 - one for oil and one just for water - I do not recommend just 1 gun for both unless you are EXTREMELY fastidious in your cleanup after (you have been warned). If you buy more expensive later this basic model can be used for priming.

Lastly - prep the paint to be used properly, mix it up well, add appropriate thinner as required, FILTER IT!!!!!! before it goes anywhere near the gun (tights are good) - even twice won't hurt.

Oh and only mix up what you need - thinned prepped paint if left for long periods can go weird when stored - never tested this, but I've read such advice on many spray webpages.

Spraying is something that does take a fair bit of practise to get consistent results, but once you know how, painting doors, furniture etc will give you excellent results time after time; and far quicker than rollers or brushing.
 
Rafe, you do realise the DeVilbiss you link to is not a true HVLP gun. It is a compliant/conventional gun, hence it's lower air demand.
A conventional gun will create clouds of overspray and have a bigger appetite for the material.

Another point I think needs raising is recommending spraying solvent based paint.
Solvent based paint should only be used in a spray booth with the correct filtration and the correct PPE. Spraying this at home could get you in serious trouble.
I doubt very much household insurance will cover you in the event of a problem (fire, overspray issues, poisoning of water courses, etc).
I expect neighbours will also be unhappy, some even moan about a 'rattle can' let alone a full spray set up.

Water based paint is something we will all have to get used to and to be honest it isn't difficult to spray.
The drying of water based paint is where the problems lie. Not so much if you're not in a rush, just let it air dry.
Water based paint really needs a warm air flow across the surface to dry off, pro painters use dedicated blowers to flash off between coats.
A hot air gun works fine and so does the wife's hairdryer.
Flash off times need to be adhered too, these will be provided by the manufacturer.
It's easier to clean up. It's safer to use and store.
 
Ive used both and id reccomend both tbh,

You cant get the gloss with a waterbased, and its very slow, with added grain raising, but its alot safer.

Solvents are very quick (2k) very accomodating with contaminants, easy to apply and work with and cheaper....

Interesting people say water based is easier to clean. I find it a pain compared to solvent. Water doesnt cut into the paint like solvent does, and where are you putting the washings if thats what you mean by easier? Thats the biggest floor i think with waterbased. Everyone tips the used paint down the sink.

There isnt alot of difference in guns in the early stages, weve had results from a £5 multipack gun lol. But started off with a devilbiss flg5, and you shouldnt need anything else.
 
Bradshaw Joinery":1auv4c6n said:
Interesting people say water based is easier to clean. I find it a pain compared to solvent. Water doesnt cut into the paint like solvent does, and where are you putting the washings if thats what you mean by easier? Thats the biggest floor i think with waterbased. Everyone tips the used paint down the sink.

Just as an info - I use pound store orange essence based general purpose cleaner - it cuts into the water based paint / varnish brilliantly - I use it before a water rinse, so I empty the paint cup as much as I can then spray it directly into it, let it sit then pull the trigger so it bleeds to the needle and nozzle, then out. A few applications will get rid of most of the residue then a bit of water to finish off - a few minutes and it's good to go.

If I've been lazy and it's dried up a bit, oven cleaner, but not harmful spray can stuff - the trigger spray version - sit to loosen then clean as normal.

As I don't do that much spraying - for water based washings I leave in a bucket to evaporate off. For mineral spirits I keep a separate container and put them in there - a week or two and all the paint varnish etc has settled to the bottom and I can reuse it! - I've got white spirits that have been through dozens of cleaning cycles and still works just fine for cleaning (not as its not "virgin" I never use it for anything else.)

Edit: when I was talking about solvent based I meant oil based, which is fine to spray in the back garden - not nitro / 2 pack etc - for overspray you could hang an old bedsheet etc in a simple U framework, that'll catch most of it.
 
rafezetter":3ucu60n4 said:
Edit: when I was talking about solvent based I meant oil based, which is fine to spray in the back garden .

Poor advice IMHO.

Then surely you would be thinning the paint with white spirit?
Maybe consultation of a white spirit COSHH sheet would be in order:-
http://www.crowndecoratorcentre.co.uk/P ... 112012.pdf

On page 2 you will find S61 "Avoid release to environment".
Please explain how this could be avoided when spraying in the back garden.
 

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