apollo hvlp gun trouble - Help!

I finally pull out the Apollo hvlp system I bought some time ago (the kitchen's been delayed time and again) to try to varnish my porch ceiling (obviously it's wood, ok). The floor pad thingie was not really amenable to being used upside down. But,an unexpected discovery - new hair style hold product - poly; so much firmer than regular old hairspray.
Anyway, fortunately I decided to follow the suggestion to practice w/water because as soon as I turned on the turbine, water started spraying out the nozzle. I turned it off, closed the material valve completely, tried again - with the same results.
I did change the conical doohickey (can't recall the terminology) inside to a larger opening one (#4).
Anyway, is this thing broken or am I messing up?
Thanx Renata
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Renata wrote:

I am not familiar with "The floor pad thingie" or a the "doohickey", but I am fairly familiar with Apollo guns, and very familiar with HVLP turbine guns.
To my knowledge, Apollo only makes and sells bleeder guns. So you will have some air pressure pushing out around the front of the gun at all times. You shouldn't think that is the same as any of the valves (pressure or material) on the gun are open.
However, it does sound like one of two things are going on. First I would check to see that the material control valve is clear of all debris and is seating properly. I mean, pull it completely out and inspect the needle and the seats completely. Regardless, flush them out with a solvent that is copatible with your last coating you sprayed. Remember that if you are switching between water based and solvent coatings you can create problems that are difficult to undo. I got the wrong solvent (thanks to the knothead coatings rep at Coronado) for their 15 minute dry industrial enamel and it turned the enamel into a cottage cheese inside my gun. 3 hours were lost taking the gun completely apart and cleaning every last speck of that crap out of it.
Second, I would make sure you are not tilting back the gun to the point where you are partially clogging or blocking one of the ports. Without seeing how much water is coming out, it is hard to say what it could be. However, I have heard that some of the older guns (from all HVLP suppliers) did not have the little backflow check valves in the line to prevent back flow. Unlike paints, enamels, or other coatings, water could rock back into the gun if held at a severe angle and go into the gun assembly.
Soo.... to diagnose this as the problem, keep your fingers off the trigger, and turn on the pressure with the material control valve closed. Does it spray water when the gun is level? Tilt it back like you do when you spray and observe where the water comes out. Does it come out of the center of the aircap? If either of these happen, it is likely that the needle valve is dirty or maybe worn (not likely). Clean completely as above to remove any foreign debris.
If it comes out of the horns on the aircap, you are getting some water into the pressure line so that means some kind of backflow. Make sure the pressure line on your gun is oriented properly for your application. Put it in front since you are tilting the gun back instead of in back as normal when you put on the cup.
Do not overfill the cup. If you are spraying at about 45 degrees to your surface over head, Don't fill the cup more than half way. Do not try to spray at 90 degrees to the overhead surface as the gun was no designed for this application. There are plenty of guns made for this type of application, but yours isn't one of them if it has a cup attached to the gun.
Hope this helps. Let us know how it works out.
Robert
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snipped-for-privacy@aol.com wrote:

My wife and I refer to this strange language as "thinglish". After 15 years of mariage, I still don't understand her half the time. I make her stop and re-ask the question in english before answering her question.
brian
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On 1 Nov 2006 10:53:37 -0800, snipped-for-privacy@aol.com wrote:
Thanx for the detailed reply!

I understand that air will be coming out at all times. This is not air, but what's in the cup (water in this case).
Which one's the pressure valve?

This gun is brand new and has never been used. I followed the instructions which suggested practicing with water in the cup before actually using a finish.

The gun was sitting flat on the concrete floor. Or, in my hand, relatively upright.

Trigger locks when the material valve is all the way closed. Yes, it sprays when gun is level. I think it came out the center, but I don't have it right now so I'll have to double check. All the stuff is new. Shouldn't have debris, but I'll take it apart and check.

Cup was half full or less. BTW, is there a trick to getting that sucker (the cup) off? The lever is real tight and very hard to move.

Thanx again for the detailed reply. But, I still need help (s'il vous plait), though I will check for debris.
BTW, is Apollo tech support crappy? The tech support # leads to an answering machine. No call back in 2 days. Maybe 'Jason' is on vacation or something. Email has yielded nada in 2 days. I've never experienced such slow response time.
Renata

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