The Spray Painting Thread

[DrNick]

I know how a carbie works but that doesnt explain the atomization (not to me anyway). Yes in a suction feed gun if it is relying on the bernoulli effect to lift the paint out of the pot then you would need a bigger pressure differential to do so than you would in a gravity feed gun where the paint is already moving toward the tip.
But the atomization happens at the tip, so if you had the same amount of paint at two different 1.7mm tips then you should get the same atomization for a given pressure. If its the lower tip pressure that harms the atomization(assuming HVLP), then why not just back off the paint flow a bit?
I bet theres a simple explanation for it and I'll wonder how I missed it

["Z" UTE]

DrNick, the increased airflow and how it works in the suction gun is what it is all about. You are actually getting air mixed with the paint at the top of the pot, as atmospheric air forces the paint up the spout, and straight into the airstream that has created the low pressure area.

Effectively the suction gun uses 25-30% more air to deliver the paint to the nozzle.

This additional air can result in a dry spray, so you have to slow down your delivery passes to get a wet coat.

The gravity gun delivers a stream of paint to the nozzle, it has very little air in the paint at this point, which is then atomised by the internal air passages.

cheers Chuck.

[takai]

Nah, its not a problem. I got my new yesterday and it was a 1.7mm tip. Must have misread it as a 1.4. Had a quick test spray to make sure it was all working and it is perfect. Just adjust down the plunger slightly.

P.s. there is some hillarious engrish in that manual. Things like "tighten pants before use"

[oldcorollas]

it would be terrible if your pants fell down while spraying, and you fell into the new paint...
maybe it's an american warning?

[Z2TT]

Takai did you spray some colour with it? Was it 2pak and how did you go? Might be ok for acrylic but its 2pak is what im worried about with the 1.7mm tip.

[turbocaldina]

a 1.7mm cap is going to be ok just wind the fluid in a bit if its coming out to wet, all sizes are ok you just have to set it up right. Also different fluid cap sizes are not all exactly the same for different guns eg. a devilbiss will spray different to say a sata with the same cap

[takai]

Yeah, sprayed some quickdry enamel under the guards last night, and touched up some engine bay stuff in 2pak this evening. Both were fine. Sprays almost as well as the STAR ill be using for the rest of the car.

[mr75]

I brought a star gun yesterday. I hope it works well takai or else

[Z2TT]

Guess I'll just bite the bullet and have a go.

[mr75]

let me know what the bullet tastes like when your done

[Z2TT]

Spray gun arrived today :



The information sheet said Nozzle : 1.4mm (1.7, 2.0)

And on the box says Nozzle size - 1.3-2.0mm.

Also there is precaution info on changing the nozzles.

But nowhere in the package are different nozzles included.

And the gun currently has a 1.7mm nozzle.

Ahh and here is the manufacturer website this may be of help, let's see if they reply to my email.

http://www.bssairtools.com/en/lxwm.asp

[takai]

Ill be doing some more 2pak in the next couple of days on the engine bay with my gun... will report back with pics.

[Z2TT]

What about on flat panels though, that's where the peel would be most noticeable.

["Z" UTE]

Orange peel is a natural part of painting. Check out your everydayboganmobile, it has heaps. Some cars have a little.

For the average guy who does a little painting, It truly comes down to practice. My 1st full paint job was orange peel city, next one was Niagra Falls with all the runs, I persevered, and now I can get a decent coat of paint on most anything. Gotta remember though, that my firat paint job was 30 plus years ago.

When doing repairs, you simply try to match the existing level of peel as best you can. Doing a Rolls Royce finish on an AE82 Corolla and vice versa is just not how it is done.

cheers Chuck.

[takai]

Also probably gotta remember a bit that i dont worry quite as much about peel as ive got a race car