HVLP or Conventional gun???? (& water in the airfeed)

[Archbish]

How do I know which I\'ve got...??

I\'ve managed to whack primer on by twiddling the knobs on the compressor and gun and practicing on the wall until I got a nice pattern laid up...

This seemed to use the full pressure of the compressor, and twisting the knobs on the back of the gun sorted out the pressures and stuff.  Apparently... *grin*

But is there a definite way of knowing whether I have an HVLP gun or conventional, as I understand the difference, but the guns all look the same to me!!

Also, I do seem to get a fair bit of water in the airline feed.  I drain it regularly, but seem to have water condensing quite a lot of the time.  Is this going to be a problem when I\'m laying on the cellulose topcoat and clear?

Cheers peeps!

OJ

[Jono FD3]

Answer to your water question.... YES BIG PROBLEM MATE!! if you get water droplets thrown out the guy you will end up with spots in the paint as they don\'t mix...... unless you use the new water based paints (then it\'s not too much of an issue!! You can get a water catch tank that sits between the compressor & the gun.... very good invertment if you are sparying!

As for the gun.... if you have a gravity feed gun (paint in a pot on top of the spray gun) then these are normaly HVLP units as they don\'t need the air pressure to draw the paint up from the bottom, this is your conventional gun.... basicaly you need to run a Higher pressure for spraying with these as you need to draw the paint up from below the spray gun!

Hope this helps,
Jono

[Archbish]

WINNER! Thanks dude.  I\'m using cellulose paints, so will look at getting one of these water catcher things...

Cheers

OJ

[Ricco_04]

Just read this - good info, I didn\'t know the difference and just started to get some water mist coming out when using the blow down gun.

Is it best to get that water seperator thing.  I seen some things which keep the guns lubed up  are these worth getting do you know (or just as effective to give the gun a good clean and lube up yourself?)

edit : I mean lube up the GUN yourself!  :spank

[Jono FD3]

Water seperator is esential if you are spraying base coat, celulose or synthetic 2 pack.... with the water base paints it\'s not so critical as they are water based and the condensed water mixes with the paints!!

To be honest with you I have never lubed up my spray gun, the reason being oil & paint don\'t mix!! you would be better off giving it a thorough clean out with thinners!! Clean the gun out, then blow through some as if you are spraying with it!!

Another thing to be very weary of is silicone! this sounds silly, but if you have silicone anywhere you will get what\'s known as fish eyes in the paint! this stuff can come from any spray can e.g polish (not only silicon sealant) I was spraying my old mini years ago, and the old man cleand the apolstry of a boat 40 foot away with pledge furniture polish..... sprayed the car the next day after a wash down & ended up with fish eyes all over the car!!! you don\'t initialy see them as the paint doesn\'t seperate imediatly.... it\'s only about 15 mins later you see them & by that time you have coverd most of one side & can\'t stop because the 2 pack & celulose would set in the gun!!! so make sure the rags you are using are clean & never been anywhere near polish!!


Jono

[Ricco_04]

Fish eyes - Never even heard of that one!  Expect to see it on a lil Saxo soon then :spank

Thats great, thanks for that, must get one of those water seperators then.  Not ever lubed up the gun either, just cleaned them (was just a lil concerned for long term use

[Archbish]

So looking on EBAY for a shiny new HVLP gun.  There seem to be loads on there for about £20 delivered - are these OK, or just a cheap way of wasting expensive paint?

Also, what\'s the best setup routine for these paint guns?  The pressure states from 7 psi to 50 psi, which is quite a range.  I have traditionally sprayed onto the garage wall twisting all the knobs til I get a pattern that looks reasonable.  I\'m sure there is a better approach to getting the pressure and paint feed sorted...  (I\'ve only put on the primer so far, and I do seem to have a habit of high pressure, thick coats so far...)

[RXphil]

Good point jono about the fisheyes, I always clean everything down with bodyclean before i paint, 5lts costs less than a tenner from your paint shop.
 
As for the gun, I use a gravity fed as seen in pic below, but the knob on the back used for flow control can never be set at one point, depends on the viscosity of what your spraying, eg, laquer is a lot thicker than the base coat.
 
Lots of fun tho and very rewarding :yes
 

[Archbish]

Actually, further to the above, using normal cellulose auto paint, what psi should I be spraying at?  From what I\'ve just been reading, I\'ve been using far too high pressure, and should be no more than 30psi at the regulator?

[Jono FD3]

Normaly I spray with about 30-35psi at the gun, but like stated by RXphil, it all depends on what you are painting as to gun set up!!

[Grizzly]

LOL......

I am a Painter and i take GREAT!!! care not too get any sort of Fluid in the lines which is why i find this funny (i get vapor coming out of my gun ), if you are using a Piston type compressor you are going to struggle from day one with Fish eyes (oil coming through the air lines) this is mailnly because the Comp is basically a Piston engine that is driven by an Electric motor, so the Bores of the chambers have to be oiled (hence the oil in the lines). The water is Mostiure from the air, this can be contorled to a fasion by picking your times and weather to paint in (oviously if its hot an Raining it will effect you more).

The main thing with water/Oil traps if size matters bigger the better and go for a good name (devilbiss or Sata etc).

The big thing is if you use this sort of Comp DO NOT!! use an air fed mask (the oil and water can make you poorly sick) plus it will eat more air than the gun, i use a 3M Fly mask when i paint out of a Booth.

[Grizzly]

Out of interest, when you say how do i know if its HVLP or Compliant? do you know what make and Model you have? Not to sound funny but usually the cheaper end of the Gun world will stamp on if its HVLP and not if its Compliant, the top end dont tend to do that because the people that buy £500 spray guns will know what there getting

If its a Good one it will be make by one of two companies Devilbiss or Sata, Devilbiss are Compliant (have smaller air ways inside them and are MUCH better for DIY jobs) i would recomend a GTI but many use the Old JGA which is a very capable gun. Sata are the top end of the Gun world, they are mostly all HVLP and have large air ways in them and take a BIG!!! compressor to get them working properly (steer clear for use at home)

[interloper393]

lol im keeping quite here :~P

[Archbish]

Hi Grizzly - thank you for the info!!  I have no idea of the make of gun - it\'s a hand me down from my dad, who got it from his mate...

I\'m happy to buy a new gun if it will help, but this is for amateur-home-one-car-every-couple-of-years-maybe use, so £500 is way in excess of what I would like to pay.  Obviously money can equal results and I\'d love to be in a position to really go to town, but given this is going to be on a budget, what tools would you recommend to get the best finish in the paint possible.  Currently I have a siphon fed gun (so not HVLP), 50L compressor that is electric and noisy as hell, a water trap at the end of the hose and am looking to get an IR lamp to mount in the garage.  

I am considering getting an HVLP gun, but given I don\'t know what I don\'t know about this, what other advice would one give about equipment or technique...

Thanks guys, this is becoming really useful and learning new stuff!!

im keeping quite here

don\'t!!!  I wanna learn about this!!!!

[interloper393]

i posted alot of info on a thread when someone else was asking about painting there car, cant find it now tho :S

Also iv found out that not adding thinners to the clear coats stops the orange peel effect so no need for loads of sanding bck and repolishing
And i always use a base coat and clear coat now, stoped using the solid colours as its a mare to use plus it scratches for a pasttime.