Ok im at the stage of practicing my spraying technique but, no matter what, i cant seem to get my spray gun working right. On just about every setting, it leaves a very lumpy surface and sprays little blobls of paint. I was just using etch primer with the right amount of thinners and it was on a perfectly smooth VB commy bootllid. How do you guys go about setting up your spray guns before doing a job?
Setting up a spray gun
Started by
_202LX_
, Dec 02 2008 10:53 AM
6 replies to this topic
#2
TerrA LX
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Posted 02 December 2008 - 11:09 AM
Sounds like orange peel.
Several things can affect this including the tip/needle/cap set up not big enough for the media you are spraying, air pressure, cup not vented (blocked), spraying too close to the job and too much paint flow.
Try backing off (turning in) the paint flow till you have just a little less than you need coming out than will give you even coverage and work from there.
Once you have enough paint flow, start with high pressure and back the pressure off till you remove dry spray.
Always keep the gun a full hand span (with fingers stretched out) away from the surface.
Several things can affect this including the tip/needle/cap set up not big enough for the media you are spraying, air pressure, cup not vented (blocked), spraying too close to the job and too much paint flow.
Try backing off (turning in) the paint flow till you have just a little less than you need coming out than will give you even coverage and work from there.
Once you have enough paint flow, start with high pressure and back the pressure off till you remove dry spray.
Always keep the gun a full hand span (with fingers stretched out) away from the surface.
#3
MRLXSS
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Posted 02 December 2008 - 11:16 AM
Have you got the right mixture of Paint to thinners? And is the gun nice and clean to allow a really nice flow (ie no clogged filters etc)
#4
_202LX_
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Posted 02 December 2008 - 11:25 AM
Yeah, its just really bad orange peel. I have a 1.4mm tip and im only doing etch and that would be ok wouldnt it? i know i need a 2mm for my HB primer tho.
#5
_Bomber Watson_
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Posted 02 December 2008 - 09:02 PM
How i set a spray gun up for myself is probably a bit different to how you would use it.
When painting a car or large area, i wind the fluid all the way out, get the fan as big as possible and start with max air pressure. I then wind down the air pressure till the fan is a nice big perfect oval. If its a bit shaky i cut the fan down a tiny bit. I spray with the fluid controll all the way out and just vary how much i pull the trigger in, but this takes practice.
For you, do exactly that but start with the fluid two turns out from all the way in. For the second coat go 2.5 turns, if its a bit dry try 3. Thats assuming your using Acrylic (think you were?). If 2k then reduce those settings by half a turn. You will have to readjust the fan and air each time you change the fluid mixture. Usually less fluid can handle less fan, the air you wont have to change much but perhaps a tiny bit less for less fluid. You are using a Grav feed if i remember correctly so will need a little more air most of the time.
Now for your current problem, what type of filter are you using when you put the paint into the gun? do not rely on the little filter in the pot, always filter the paint going in. Nylon cone filters are the best, available from paint stores, but a stocking will do. Plus side of that one is you get to feel like a deviate standing in the line of Big W buying ladies hosiery
Etch primer i usually spray around 1 part primer to 1 part thinners. Remember with etch if you are simply putting it on to promote adhesion you do not need it thick. In fact barely visible is perfect. If you are putting it on for some form of rust protection you will need it on reasonably thick, but remember it is definitely not made for this and bare metal in etch primer will only last a day or two before starting to surface rust if exposed to the elements. The acrylic primer filler i told you about is best sprayed somewhere between 1:1-1:1.5. Ie somewhere between 100 and 150% thinners, depending on the condition of the vehicle. Acrylic top coats are usually thinned about the same, depending on brand and the colour, some colours can be thinned more than others. And with any paint thinning the last couple of coats out a bit more usually is a fairly good idea, but there is a bit of an art form to it so perhaps just practice at one ratio.
Lastly always put heaps on. With the primer filler put on 4-6 reasonable coats, never put acrylic on to thick or it will solvent boil and you will have shrinking problems later. With acrylic top coats you are going to be buffing for the rest of your life, so put on at least eight coats of whatever s going on top, whether it be a solid colour or a clear. Again remember not to put it on to thick or you will have shrinkage problems and solvent boil.
Hope this helps a little bit, i know i went a bit beyond your first question but one tip kinda lead to the other.
Cheers.
When painting a car or large area, i wind the fluid all the way out, get the fan as big as possible and start with max air pressure. I then wind down the air pressure till the fan is a nice big perfect oval. If its a bit shaky i cut the fan down a tiny bit. I spray with the fluid controll all the way out and just vary how much i pull the trigger in, but this takes practice.
For you, do exactly that but start with the fluid two turns out from all the way in. For the second coat go 2.5 turns, if its a bit dry try 3. Thats assuming your using Acrylic (think you were?). If 2k then reduce those settings by half a turn. You will have to readjust the fan and air each time you change the fluid mixture. Usually less fluid can handle less fan, the air you wont have to change much but perhaps a tiny bit less for less fluid. You are using a Grav feed if i remember correctly so will need a little more air most of the time.
Now for your current problem, what type of filter are you using when you put the paint into the gun? do not rely on the little filter in the pot, always filter the paint going in. Nylon cone filters are the best, available from paint stores, but a stocking will do. Plus side of that one is you get to feel like a deviate standing in the line of Big W buying ladies hosiery
Etch primer i usually spray around 1 part primer to 1 part thinners. Remember with etch if you are simply putting it on to promote adhesion you do not need it thick. In fact barely visible is perfect. If you are putting it on for some form of rust protection you will need it on reasonably thick, but remember it is definitely not made for this and bare metal in etch primer will only last a day or two before starting to surface rust if exposed to the elements. The acrylic primer filler i told you about is best sprayed somewhere between 1:1-1:1.5. Ie somewhere between 100 and 150% thinners, depending on the condition of the vehicle. Acrylic top coats are usually thinned about the same, depending on brand and the colour, some colours can be thinned more than others. And with any paint thinning the last couple of coats out a bit more usually is a fairly good idea, but there is a bit of an art form to it so perhaps just practice at one ratio.
Lastly always put heaps on. With the primer filler put on 4-6 reasonable coats, never put acrylic on to thick or it will solvent boil and you will have shrinking problems later. With acrylic top coats you are going to be buffing for the rest of your life, so put on at least eight coats of whatever s going on top, whether it be a solid colour or a clear. Again remember not to put it on to thick or you will have shrinkage problems and solvent boil.
Hope this helps a little bit, i know i went a bit beyond your first question but one tip kinda lead to the other.
Cheers.
#7
_Yella SLuR_
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Posted 21 December 2008 - 03:33 PM
What sort of paint, 2k or Acrylic? 1.4mm is too small a tip for acrylic.
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