Samson S-90 spray gun question

[LenS]

I have a shed full of tools and I don't know how to use some of them. One is a spray gun. It has 4 adjustable knobs and I was going to just connect it up to the compressor and run some paint through it and test what each knob does.

A better way might be for me to post a photo of it and get some basic instruction from you guys.

It may not be obvious to you, but I hav e never used a spray gun before

Also, hello and it great to find an active looking forum

[falcon]

Triangle

sry i cant help with your problem, but i will be watching the thread with eager anticipation

[durwood]

Triange,

The gun you have is most probably a suction feed spray gun, which means it sucks paint up from the pot underneath when you pull the trigger. If it is one and you have the pot, the pot will have a hole in the top of the lid. The same body is also used for a pressure feed gun which has a hose connected to the thread where the pot connects to. You say you are going to try it so I assume it is a complete gun. If it is apressure feed one the controls are the same.
the gun has three main controls

The one at the top on the back of the gun is for the fan width. If you turn it in you shut off the air supply to the two holes in the air cap in the projections on the side. This makes all the air come out around the tip which the paint comes from and you get a round spot pattern.

If you open the fan control you let air out of the side holes (the projections are called horns) and the air flattens the spot making it long and narrow or a fan shape. Usually you spray with the fan open so you can paint a wide area. If you narrow it down all the paint is concentrated in a smaller area suitable for narrow area.

The control underneath the fan control is the material contral which determines how much paint comes out of the gun all it does is stop the needle which seals the hole the paint from coming out further . Screwed right in No paint ( the needle can't move its stuck between the tip and the knob end - the further out you turn the knob the more the needle can open the hole for the paint and the more paint you get out. The gun is set up so the amount of paint is enough for the fan width you have set. Depending on how fast you move the gun depends on how you set these two. The more paint you have coming out the faster you have to move the gun.

Most guns are made so you can set the material about the middle of its travel and get a good result.

The third controll on the underside of the handle controls the amount of air you get out of the gun, it only closes off the hole the air passes through and is used as an adjustment while spraying if you need to change, normally the air pressure is adjusted from a proper regulator this adjustment is not a proper constant pressure one and the air will go up and down as all you are doing is blocking its path. A lot of guns don't have this knob only the fan and material ones.

You say there is a 4th adjustment What is it ? as far as I can tell they are the only ones on the gun.

Hope that helps let us know if you need more info.

[LenS]

Here's the offending item. The fourth adjustment thing I was talking about was the nozzle.

Thanks heaps Durwood. I'm going to spend the afternoon spraying stuff.

Falcon, may your eager anticipation be satisfied!

[MurrayD99]

Durwood has it right. The nozzle is just adjustable for a vertical or horizontal pattern - but you can also put in a different nozzle with a different aperture. I'd assume you have standard aperture unlessa it behaves strangely. Probably test it with clean water. On my gun, the book says open the material control till the first thread appears - then adjust more or less from that point. Beats a brush!

[falcon]

Durwood...thx for the info, was very useful. A furher question if i may. I have seen some suction feed guns that have a small bit of clear tubing coming from the pot to the gun. What are these ?? Are they what is referred to as HVLP guns ??

[woodcutta]

Durwood

Do you know where I could get spare parts for this gun. I broke the nozzle several years ago and couldnt find a replacement.

woodcutta

[durwood]

You should be able to buy parts still they are Australian made ( used to be in Marrickville Sydney) but its been years since I have been there but try the phone numbers here and quote the part you need.

http://www.itwfinishing.com.au/profile.php?product=100


You may have to buy a complete set up. which is needle, nozzle and air cap. If so ask for the one most suitable for the material you are spraying ( lacquer, enamel 2 pack etc)

[Harry72]

Looks just like mine, its a good gun for polyU and enamel(1.8mm tip) the only problem with this gun is the cfm required for large jobs... its 20cfm+!
But as I found you can cut this gun right back to successfully use with a 12~17cfm compressor(25~35psi), it has very fine atomisation, cutting the air down does lower it somewhat but with the nature of poly and enamel its no real concern unless your painting with top quality car enamel on a prestige car.

What ever you do dont use it with waterborn paints... they corrode real fast, its why mine is cactus.
I took it to work and painted a whole heap of gear(we got well over 100cfm@90psi!)using water based acrylic, its amazing the size of the fan spread these guns have with the correct air supply... its near 18"@18"from the surface.(paint a car in seconds)

Another place that sells them(some parts too) is www.justtools.com.au

[durwood]

Harry, you obviously have the top end "set up," you may have noticed from the thread I posted that it comes in versions that start at 8 cfm up to 21cfm. What you get are "set ups" that have larger holes for the extra capacity.

The more consumption (cmf) the wider the fan the more paint you use per second. If you are painting something large the compressor must be able to keep up with the gun so usually you pick a "set up" that is a bit less than the compressor rating. In a workshop with more than one person operating air tools you need to add the capacity of all of them together to work out your compressor size ( and add a bit for later expansion if needed)

Your right about the water based paints things can go rusty but most top quality guns use stainless steel for the needle & nozzle and air caps are usually brass. if you use water based paint always wash the gun out with metho after water and oil the moving parts before you store them away.

[Harry72]

Yep, go's by the colours red is the largest flowing gun, this helps it atomise so fine.
The extra capacity can be fun... like running while spraying the gun actualy keeps up... do a 1ltr pot in 1min flat!