spray guns - whats good and whats not!!

[Rowan]

Realise that I am probably opening up a can of worms but I need some advice about buying a good spray gun.

I currently have a $69 gun that I have used 3 times and already the O-rings are breaking and the gun only sprays flat out or not at all.

I am spraying "Mirocat" and am finding it sux when it comes out flat out as it seems to go on far to thick and un-even.

So can anyone give me some brands to look at and even advice about how to set up the system. What sort of gun is better gravity feed or not etc. Currently I am just running the gun straight from the compressor (2.5hp 40lt), no regulator or anything. Having no idea about setup I am open to all advice.

Also can anyone give me ball park prices for HVLP systems..

[DarrylF]

No expert here, but I've been doing some research for myself.

I'm told the best bang for the buck is Star - 770 for a normal gun or I think 770G for the gravity fed (overhead pot) gun. Best price I've seen so far is $155 on the gravity fed and I'm planning on picking one up.

Supercheap Auto have a kit with filter/regulator, gun (copy of the Star I think) and two different sized pots for $299.

You definitely need a filter, otherwise you're going to get moisture into the gun, which will certainly 'flatten' the finish. Almost all guns have built in regulators, so separate regulators are only really needed for air sanders, die grinders etc. A filter/regulator is anything from $50 to $200. $50-70 should take care of it for our purposes though.

I'm also told that basically all guns these days (decent ones) are essentially HVLP, whether marked as such or not. Gravity fed guns in particular require less air to move material (lower pressure). It's mostly in the setup anyway - you can adjust any decent gun to do what you need it to do.

Look for a needle size between 1.1 and 1.5mm - smaller needle for thinner materials. I think the Star 770G comes with a 1.4.

I've done a bit of spraying before, but I'm being told to go play with spraying flat surfaces (old piece of ply etc) to work out how to set it up right.

[echnidna]

I have never yet seen a spraygun with a built in pressure regulator. Buy a regulator and use it before you condemn your gun, they wont last at real high pressure so maybe all that's wrong is that excess air pressure has blown the o rings.

[rodm]

Rowan,
You will need to fit a regulator. Once you have the air pressure evened out make sure your air compressor can keep delivering the required volume of air. Many of the units selling today may be able to pump up to 100 PSI and higher but they take a long time to get there. Spray guns use a lot of air and if the compressor does not make up the air quick enough then you are in trouble. An easy test is to fit the regulator and set the spraying pressure (the regulator will have a pressure gauge on it) then run your spray gun with water in it. Watch the pressure gauge on the compressor and if this pressure falls below the set pressure on the regulator then your compressor isn't up to it. You may be able to still use the unit as a spray outfit but you will need to stop spraying longer and let the compressor catch up.
Also look at alternative spray guns such as touch up guns. I use mine a lot and it is surprising how big a job you can do with these. Being smaller they are easier to do the insides of cupboards. They have the same material, air and spray pattern adjustments of their bigger brothers.
Also your paint may require thinning as the symptoms you have given point to the material being too thick.
When I started spraying I practised with water (cheap and no permanent damage to anything) and sprayed fences, shed walls, etc to sort out the technique and feel for all the adjustments. Worth the investment in time compared to having to strip and redo an important project.
Hope this helps a bit

[bigAl]

Has anyone had any experience with the guns in the Carabatec catalogue? I was planning to get the HVLP one they've advertised.

Al.

[TOMARTOM]

The advice given to me from a year or so a go was spot on. I went and bought a CIG easy sprayer for around $150.00, and it has been terrific, I sell through a shop and have had no problems, and also it pumps up air mattresses. Fot the money it is good value. If you are familiar with a high pressure spray gun then the change over will be no probs..
Regards Tony

[silentC]

Tony,

I've got one of those but I thought it was only suitable for water-based paints. What do you spray with it?

Cheers,
Darren

[TOMARTOM]

I too have used it for waterbased polyurethane but most of all I use it for turps based stain and varnish, for the stain I allow very little fluid through and when toning even less and apply as required.

I am not a first class finisher, but in my circumstances as a general furniture maker I have to weigh the cost vs return on my work.
It beats rubbing in thinned down finishes by hand, in production numbers.
It may be that you require a superior finish to that I need, and I have no doubt that a HVLP/turbine system will offer this at a higher cost.

I have seen from time to time second hand HVLP systems for sale at reasonable prices in the trading post.

Shane Watson in the finishing section of the BB is of great assistance and I believe him to be a high class finisher, he would be able to answer all questions regarding finishing(I have not seen one he could not answer yet)..

Regards

Tony

[soundman]

The porter cable HVLP gun from carbatec is great baught one about 6 months ago, impresive.
its a copy of something else, almost identical to the star.
yess there is a regulator that you mount directly on the gun as with most conversion type HVLP guns.
good spraying efeciency, handles well, conspicuous reduction in the amount of overspray.

cost about $200.
the big saving is in the amount of paint you don't blow away in a cloud
if spraying viscous fluids like thinned house enamel removing the product strainer is necessary.

*** must dismantle to clean properly, acumulates gunk behind the seat assembly.

you do need to run a good filter regulator with any spray gun and preferably some sort of cooling/ precipitation chamber before the filter reg.

*** moisture traps will only remove droplets not vapour, so if you can cool & slow the air stream before the filter reg you get cleaner air.

the star s770 is a good value suction gun have had one for several years no problems.
I have a mate with half a dozen of the s770's, never a problem.

the s770 has a simple "air regulator" on the handle adjacent to the air inlet but its only a needle valve.
usefull for fine adjustments fo the spraying air but needs to run after a proper filter reg for consistent results.

I have a couple cheap gunns bassed on the old arnold, one has a serious problem Ive never chased the other still sprays contact cement fine.
otherwise wouldn't spray anything more important than a picket fence with it.

Have a couple of little touch up guns,
they are great for small jobs and confined spaces.
will run down to about 20 psi on thin stuff.

[rodm]

Soundman

Are you running the Carbatec HVLP gun from the same compressor you are running the Star 770 and does it keep up with the volume of air?

[soundman]

yep same compressor but I find that I cant work effectively with a spray gun in each hand.

13cfm compressor.

[Mark Haywood]

I guess the first question that should have been asked was how much money do you want to spend, remebering that we always get what we pay for.
Your commpressor will limit what gun you could run effectively. HVLP stands for High Volume (of AIR) Low pressure (of AIR). to effectively attomise paint at low pressure (normally 10psi at the air cap) a high volume of air is reqired. HVLP guns will often consume 15 - 18 CFM. The commpressor would need to deliver at least 25 CFM to run this type of gun continuously.
Not all guns sold are HVLP however. Conventional guns or high pressure guns consume the least air but also the most material. RP or compliant guns are probably the best at present and do come with inbuilt digital pressure gauges. They consume the least air and have transfer efficiancy plus 65%, but are expensive, at around $700 dollars. They are however superb Guns!
If your budget would stretch to the $280 mark I would reccomend a SATA KLC-B 1.3 Gravity. This would last you a lifetime providing it is well looked after.
Gun set up involves balancing air pressure at the tip centre, with air pressure at the tip horns, with fluid delivery. If you were to point the gun at a piece of card, with the gun arround 20cmm from it and pull the trigger briefly, with paint in the gun, you should see the paint form a fat cigar shape. This indicates that the gun is set up correctly. If the shape is an oval this would indicate that there is not enough air pressure at the horns. if the pattern is split or narrow in the middle, this indicates that the air pressure at the horns is too high.
A good start point for set up would be Fluid 2 turns out from fully closed, Fan control (Horn Pressure) half open from fully closed. Air pressure really depends on the type of gun you are using, HVLP 30 psi inlet, RP 30-40 psi inlet, Conventional (high Pressure) 40- 65 psi inlet.
Hope this helps rather than confuses, if you like contact me at this address with your phone number and I can clarify thing further. [email protected]
Mark

[soundman]

unless you are realy serious hobiest a 25 cfm compressor is out of the question.

Unless you are in a commercial situation you wont be spraying continuously.

The porter cable gravity HVLP gun (and similar) will run happily from a 12 to 15 cfm compressor for low duty applications.

aplications like spraying 2litres of product in a session and filling from a pre mixed container.
by the time youve refilled thru a strainer the compressor has caught up.

If you were spraying cars of multiple items forget it. But then you'd have a spray booth and a 30 cfm compressor and $700 for a spray gun???

cheers

[DarrylF]

Anyone used/own the Star mini HVLP gun?

Saw this the other day and it looks perfect for furniture work - 200ml gravity fed pot (doubt I'd spray that much in a session), small conventional layout guy and it had nice balance. Seems like it would give a lot of the benefits of a touch up gun (small size, easier cleanup etc) and the better (to me anyway) layout/feel of a conventional gun.

[Rowan]

Thanks to all who posted advice for me. I have gone out and purchased the Star 710 which is the gravity fed model with a 400ml pot. Went with it as I didnt think I needed the full size pots with what I will do and it had an adjustable pot location which may be helpful with spraying inside bowls. On the advice of the very friendly and helpful staff member (a rarity in itself these days) I went with a disposable filter.

Have already tested out the gun got the feel of it and have sprayed a small coffee table top and am very satisfied with the finish considering my limited use of spray equipment.

Once again thanks to those that posted replies.