What's gone wrong now?

[Gern]

Used my new (used) H&S Infinity yesterday. I sprayed Tamiya XF1 flat white thinned with about 40% MLT as a primer. Today I sprayed a top coat of Tamiya X7 gloss red thinned once more with about 40% MLT.

Looks nice and shiny but how come the surface looks like it's been pebble dashed?

[Ian M]

Sounds like it could be either tip spatter; paint is a little thick or the pressure to low so it's being forced through the nozzle in pulses, or conversely its to thin and drying in the air ... is it like pebble dash or sandpaper? A picture could help.

It could be you mixed them the same 40% but not all paint is created equal.

[Ian M]

Can you post a photo of it.
If its like sandpaper, its drying befor landing. = to thin + to much air. if its like pebble dash with larger bit in, most likely to thick and or not enough air.
You might have thinned them the same, but not all paints (even if the same brand) are created equally.

Side note best undercoat/primer for red finish is yellow

[Waspie]

Side note best undercoat/primer for red finish is yellow

That's useful to know, thanks Ian.


I had the pebbledash effect a few times with primer until I turned the pressure down. (Never knew why then).

[Mr Bowcat]

I'd consider thinning more. As a general rule 50/50 is a good starting point, I tend to thin 60/40 (60 thinner/40 paint)

[Gern]

I'm spraying at about 27psi according to the gauge. I'll try dropping it - any recommendations?

I guess I'd best remove the paint and start again?

I'd love to be able to show a picture but my camera skills are non-existent. I'm 90% sure it's not tip splatter though. I've seen that before and it appears very random whereas the pebbledash effect I have is very consistent over the whole surface.

Thanks for the tip about the primer colour Ian.

[Tim Marlow]

27psi seems quite high. I usually airbrush at about 15psi, but I have a side feed brush so it might not be completely transferable.

Sounds like you need a little more thinners as well. From your description I’d say you’ve got orange peeling. I believe this is caused because the paint has been too thick to flow out properly on the surface, drying too fast.

I’d go for a little more thinner, spray a little closer, and use a slightly lower pressure and see if that cures it. You should see a wet paint film on the surface for a little while after application.

[Waspie]

I'm usually in the 15 to 20 psi range. Only time I have anything higher pressure wise is when I use the AB as a duster to blow away dust of such. Then it's wound back down to my usual 15-20 psi.

The method I use for mixture has been honed after listening to the likes of Tim etc on here.

I start with a 50/50 mix, give it a good stir, then keep adding thinning agent until it drips on its own accord from a brush or the mixer I use. (That works for me). Together with the psi. Took me ages to get it right but once I found what worked I've stuck with it.

[JR]

Perhaps setting the AB on fire might help .

TAXI

[Tim Marlow]

Perhaps setting the AB on fire might help .

TAXI

In the old days, before I developed common sense, I used to use Ronsol lighter fluid as a dilutent when spraying humbrols. It was a common idea, widely promoted in magazines. They sprayed superbly, but I thought about it one day and realised I was creating a fuel air bomb. I bet it would have been easy to set fire to the airbrush then LOL….

[Jim R]

I use lighter fluid to degrease a model prior to painting but never heard of it as a thinner.
The things we did when we were young and knew no better.

[Flip]

Dave,
I use an H&S Evolution CR Plus. I was getting a similar thing to you and it was driving me insane. I, at the time, was working in the same pressure range as you with a 0.2mm needle as standard (to force the paint through the small gap). Nowadays my standard setup is 0.4mm at 15psi max, sometimes only 10 psi.

The reduced pressure and increased nozzle size aid in:

• reducing tip drying
• reducing resultant clogging of the nozzle
• reducing overspray
• reducing air drying
• reducing "spider" formation

You will have to have your AB closer to the model, though.

I must confess that I am unfamiliar with the abbreviation "MLT" but if it includes the words Levelling Thinners then that's spot on :thumb2:. I would echo the sentiments above that the thinner ratio should be upped to at least 50%.

As an addition, I am really against hype and the latest fashions but I have found a marked improvement by migrating to MRP. The Tamiya paints are really good (I have plenty of them :smiling3 but the MRP paints perform markedly better and the issue you report, coupled with the amended AB settings, has been eliminated. The AB settings and thinner ratio should be more than enough as a minimum though!

Happy spraying.

John

[Tim Marlow]

MLT is a common abbreviation for Mr Levelling Thinners John :thumb2:

[Gern]

Perhaps setting the AB on fire might help .

TAXI

I've heard that warming primers can improve the finish but I suspect setting fire to them may be just a tad extreme. Still, if all else fails ....

[Gern]

Dave,
I use an H&S Evolution CR Plus. I was getting a similar thing to you and it was driving me insane. I, at the time, was working in the same pressure range as you with a 0.2mm needle as standard (to force the paint through the small gap). Nowadays my standard setup is 0.4mm at 15psi max, sometimes only 10 psi.

The reduced pressure and increased nozzle size aid in:

• reducing tip drying
• reducing resultant clogging of the nozzle
• reducing overspray
• reducing air drying
• reducing "spider" formation

You will have to have your AB closer to the model, though.

I must confess that I am unfamiliar with the abbreviation "MLT" but if it includes the words Levelling Thinners then that's spot on :thumb2:. I would echo the sentiments above that the thinner ratio should be upped to at least 50%.

As an addition, I am really against hype and the latest fashions but I have found a marked improvement by migrating to MRP. The Tamiya paints are really good (I have plenty of them :smiling3 but the MRP paints perform markedly better and the issue you report, coupled with the amended AB settings, has been eliminated. The AB settings and thinner ratio should be more than enough as a minimum though!

Happy spraying.

John

I asked about MRP a while ago. Everyone says they are excellent when sprayed but, like Tamiya, very difficult to brush paint. My budget won't allow me to swap all my paints just to improve my spraying so for now I'll persevere with Tamiya. I'll be trying the suggestions offered and I'll let you know how I get on.