Spraying Problems

[Kernite]

Hi

I'm new to posting on this site - hopped over from the Landy site
Currently learning to spray paint in preparation for starting on the bodywork of my Landrover. Practicing on my garage door at the moment, although have done the chassis.
Equipment I am using is an old compressor - about 120 L and up to 12 bar pressure so man enough for job. I was given the gun which is a Comaria Suction (called semi professional!)
The paint I'm currently using is cellulose based "QAD Matt Enamel" and I will be finishing with QD Polyurethane Enamel.
Im thinning with cellulose Terosyl General Thinners which I was told was cellulose. I have a couple of problems and because of all the variables find it hard to work out what I am doing wrong.

1. Occassionaly get a matt grainy finish that rubs off. Diluting paint by about 10% what happens if I dilute more?
2. The fan width is fairly narrow so I'm tending to end up with a stripey finish - how can I get a wider fan for large body panels
3. In my instructions I cant find advice on how to position the Horns should they be horizontal or vertical if I am painting horizontally. Not entirely sure what they do.
4. I seem to get through a lot of paint - just done a small area of the garage door about 2.8 m2 using about 1/4L of paint. How do I get less wastage.

Have played around with pressure - started at about 40Psi,but have dropped as low as 30psi - Im wondering whether I have too little pressure?

Will be grateful for any advice/thoughts

Many thanks


Jonathan

 

[jaykay]

celly thin 50/50. spray pressure 40-60psi. what ever suits you really.
keep distance for panels consistant,about 9-10 inches.
have the gun horns vertical.
the fan should get better with thinner paint.
never heard of that gun,so can say.

 

[the snooper]

cellulose should be thinned 50/50 and if you are spraying horizontally the horns should be horizontal, as for your stripey finish when painting a pannel you should coat horizontally then vertically to ensure even coverage.
your spray pressure should be no less then 40 psi as the gun wont atomise the paint properly at too lower a pressure.
the grainy finish is due to the paint being to think as is the amount you will use.
cellulose also has a tendancy to bloom especially when the temprature is too low but dont worry about the blooming when the paint is dry you will need to polish it anyway which will remove overspray and the bloom use something like faracla g3.
also make sure you have a water filter in line otherwise you will endup with water bubbles in the paint.

happy painting

 

[the snooper]

have the gun horns vertical.

this would give a horizontal fan no good for painting horizontally

 

[KTMMICK]

this would give a horizontal fan no good for painting horizontally

You are wrong! they work opossite.

 

[jaykay]

in laymans terms,have horns opposite to how you want the fan.

 

[Chipper]

Test the fan on a bit of card, wall, passing dog etc... OK maybe not the last.
Dry spray, perhaps the gun's too far away from the piece.
Slightly overlap passes, so the fan edges aren't sitting on top of each other, to eliminate stripes.
Is the pattern adjusted out to a 'flat', not a 'dot'.

Might be the gun is a bit cheapo and the fan is all airy at the edge and fat in the middle, making it more likely to stripe.

I guess you mean synthetic enamel. It can be thinned with celly but there is a synthetic thinners, it's less fierce and a bit slower so might help with dry spray.
Around 10-15% thinned for synth but the stuff I have varies out of the tin, some is real gloopy, so numbers are more of a guide than a rule.

 

[Kernite]

Thanks

Thanks guys this has been really helpful - as I guessed a lot of variables and if I don't know whether the gun is any good I could be wasting time, effort and paint. Clearly I need to change each variable within the guidelines and see how it changes the end result.

Now about the direction of those horns ........

 

[eil]

It is a bit confusing isn't it, you want to spray along the horizontal or left to right (right to left) then have the horns horizontal which would produce a vertical fan, if you want to spray on the vertical (up down/ down up) have the horns vertical to give a horizontal fan... simples... isn't it?

 

[jaykay]

why are you using celly thinner with enamel???
you would get on a lot better to use the right stuff.
over lap should be 50%

 

[Kernite]

why are you using celly thinner with enamel???
you would get on a lot better to use the right stuff.
over lap should be 50%

I thought I was following the advice from the guy who sold me the paint - but perhaps I have the wrong info so will check back.

Many thanks

Jonathan

 

[the snooper]

You are wrong! they work opossite.

they work as per diagram vertical horns ie 1 top 1 bottom horizontal fan

 

[the snooper]

It is a bit confusing isn't it, you want to spray along the horizontal or left to right (right to left) then have the horns horizontal which would produce a vertical fan, if you want to spray on the vertical (up down/ down up) have the horns vertical to give a horizontal fan... simples... isn't it?

i couldnt agree more

 

[the snooper]

I thought I was following the advice from the guy who sold me the paint - but perhaps I have the wrong info so will check back.

Many thanks

Jonathan

you are right for that paint you should thin 10 to 15% and the thinners should be universal so he will have sold you the right stuff have just looked at the data sheet

 

[jaykay]

that says nothing about using celly thinners.

 

[the snooper]

that says nothing about using celly thinners.

no but his first post said
Terosyl General Thinners which could just mean universal.
cheap celly usually says standard cellulose thinners on it.

we will have to wait and see if he can clarify what he has

 

[jaykay]

sorry go back, it say celly general thinners

 

[jaykay]

the thing is as a novice it will just make things hard for him.
it might get by with celly,but i would'nt use it.
it will dry fast,maybe too fast.that would give him tramlines for sure.
with a syn. thinners, you put on a dust coat let it flash for 10 mins then wet on wet and walk away,it will take longer to dry, but that lets it flow out nicely.
in 40 yrs of spraying,i've never come across a celly base syn.sounds like mis infomation,to me.

 

[the snooper]

yeah does sound a bit strange or has he mis-read or heard what he actually has hard to say without seeing it.
would rather use 2k any day synthetic has horrible and sticky overspray

 

[pedrobedro]

I've used this kind of thinner from a few manufacturers which is classed as universal and can be used in synthetic enamel or cellulose and works in Zinc 182 type paints as well.