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Kyle Wheeler
Posted: Nov 29, 2010 08:12 PM
Fusion AP Stroke
I know that I am going to take some heat for asking this question because I should know the answer but I never really paid attention to how far the mixing chamber strike when the trigger is pulled. It says in the manual that the air cap should be flush with the retaining cap. So obviously my question is....should the air cap be flush with the retaining cap? The reason I am asking is that I have lots of air coming out of the mixing chamber when I pull the trigger with the fluids off and the cleanout air valve turned off. I believe they call this the air test? The gun seems to be spraying fine but I believe if I can resolve the continuous air flow out the mixing chamber it might help the tip build up problem I have been experiencing?

I apologize in advance to the more advanced sprayers. I know someone is going to say "call your supplier" but I obviously have asked the question and get very little help. Thanks for the help.
Posted: Nov 29, 2010 08:37 PM
Hey Rookie

With the trigger not pulled, your aircap will stick out about 3/8" to 1/2" at the most. When you pull the trigger, it will be pretty well flush, but not indented. If it is beyond the cap, then the teflon washer needs to be changed.

On another note, if your fluid manifolds are shut off and when you pull your trigger, air comes out of the mixing chamber, the o-rings are bad on the trigger itself.

If you remove the aircap off of the back of the gun, take out the spring and from the front trigger side, pop the trigger stem out, it will come out of the back of the gun. There are 3 small o-rings on there and if you have never changed them out before, one of them may be split.

If you tend to use carb cleaner when you clean your gun, it will eat up non graco o-rings up in one or two cleans. If you are using Graco O-rings and use carb cleaner you may get 8-10 cleans out of it.

Check those small three orings on the trigger stem and if you replace them and pull the trigger with the fluid manifolds off, no air will come out of the mixing chamber or very little when you pull the trigger.

Hope that helps!

Posted: Nov 29, 2010 08:45 PM
Hey Rook

Another thing, I clean my cap and mixing chamber on every pass on a roof while I am spraying (5' x 50' passes). One little piece of foam remnant gives my spray pattern fingers making it impossible to spray completely flat.

Are you getting such a build up that you cant see your mixing chamber any more. I don't spray houses all that often anymore, but even now, I clean my cap and chamber out every few studs. It just makes a prettier pass.

Go behind some of these other yahoo's out there that do a sloppy job and you can see all of their mistakes. Material to cold, fingers in their spray patterns leaving one area higher on a pass than the others.

Don't be worried about being to careful cleaning you air cap and chamber unless you are constantly crossing over, then you have other problems to worry about.
Kyle Wheeler
Posted: Nov 29, 2010 08:58 PM
The strange thing is that both of my guns are doing the same thing. The one gun is my spare which has only been used once since I got it. I took it apart and let it soak and then reassembled it and put it back in the box. Once I noticed that the other gun was not stroking all the way I pulled my spare out of the box and like I said, it was stroking the same.

How often should I be replacing the teflon o-ring? I had thought of the o-rings on the valve stem but I thought it was strange that the new gun would have same issue. I am wondering if it is in the way I reassemble the gun? I will definitely check the stem o-rings tomorrow. I do not have any fluid leakage when I am spraying through out the day so I never considered the side seals.
Posted: Nov 29, 2010 09:57 PM
I only change the large teflon o-ring once or twice a year. Usually because I skin it up with a razor knife cleaning it every now and then.

You will notice it if you can push your aircap back through it. Once that happens, then it is time to change out that large teflon o-ring.

You may want to make sure when you soak your gun that you remove the o-rings if you want to use them again. Dynasolve is notorious for swelling those o-rings up and making them unusable.

I haven't soaked a gun in a couple of years. When it is still wet with fluids, I will hit it with carb cleaning fluid and it cleans it up quickly. It takes me less than a couple of minutes to break down the entire gun spraying with carb cleaner fluid. When I am finished, all I have to do is replace my o-rings and the gun is as good as new.

Get the Carb Cleaner from Walmart in the White Can with orange writing. This is one of the only ones that doesn't burn your hands while cleaning. They have one in a blue can, pass on that one if you can.

Another thing to think about. Very rarely does my gun ever have a hard time triggering back and forth. The only time that I ever had this problem is before I went to a 15 cfm air compressor. Smaller compressors have a hard time keeping up with two stick pumps and a gun at the same time.

Lack of air will definately keep you from fully triggering. Make sure all of you air holes are clear on your gun handle itself. You can take a long 1/16" or 1/32" drill bit that is about 8 inches long and go from the bottom of the gun into the trigger area on both holes at the bottom of the gun. Take your pin wheel on the other two holes in the inside of the gun and make sure you can go through to the trigger area from there. The front air port is a little tricky. It will go in about an inch before taking a 45 degree angle down towards the trigger area. You will need something flexible to make it all of the way to the trigger area.

These are important. When you pull the trigger, air flows through the back of the gun through the portals pushing the mixing chamber back. When you release the trigger, the air comes through a different port pushing the chamber forward. If for some reason one of these is clogged up with iso or foam, the gun won't work properly.

If you need me to, I will break down one of my fusion ap's down and get one of the guys to shoot video for you that I can email or send mms showing the ports at the bottom of the gun.

If you have ever completely crossed over your gun before chances are you clogged one of these up.

Hope I didn't confuse you to much.

Check your o-rings on your trigger stem and work from there. Hopefully that is the culprit!
Posted: Nov 29, 2010 10:49 PM
Hi Rookie,

Let's think about this for a second. If you have the fusion gun in the spray position, then the two side holes in the mix chamber are aligned with the holes in the side seals. If the metal to metal seal is good, and the side seal orings are good, then the holes in the side of the mix chamber are closed off from the air that is in the cavity around the mix chamber. The only way for air to be coming out of the mix chamber would be if the side seal oring or the metal to metal seal was compromised. If this were the case, you would have a mist of material coming out of the mix chamber when the gun was not spraying and the fluid valves were on. I would guess that you have air coming out around the mix chamber when the mix chamber is in the spray position (the cleanoff air). You can check this; with the fluid valves off, put air on to the gun and squeeze the trigger. With the mix chamber in the spray position, turn off the air to the gun, making sure the mix chamber stays back. Pack some white lithium grease into the front of the mix chamber and the small ring around the mix chamber where the cleanoff air comes out. Hold the trigger of the gun and turn the air back on. See if the grease only comes out of the cleanoff air passageway or if it indeed comes out of the mix chamber. If it is cleanoff air that you just can't turn off, then oring # 23 needs to be changed, or your cleanoff air valve is worn out. If the #23 oring was damaged, or the wrong size oring was used, then you would not get as much purge air as you should be getting which would cause excessive tip buildup.

I wouldn't tell you to ask your supplier, but I might suggest that you find a new supplier! LOL! We get more and more calls from guys who are out there on their own with little or no help from their suppliers. Very sad. As a supplier, I can tell you that selling foam is easy. Actually supporting your customers so that they can spray is what takes time and lots of effort. Please do not ever apologize for asking a question here! Your supplier should be the one apologizing!

Sorry for the little rant,

George Spanos
Daniel X
Posted: Nov 29, 2010 11:01 PM
Do you already have a manual?

If not you can download one from Graco's site.

It might help to see the exploded views of the internals...
clint moore
Posted: Nov 30, 2010 10:05 AM
There are two O-rings that keep the clean off air going where it is supposed to. 1). The white o-ring inside the retaining ring, this seals the outside of the air cap. Easy test is if you can push the air cap through the retaining ring it needs to be replaced. 2). Where the chamber comes through the housing there is a o-ring that seals the back stem of the air cap, if worn air will escape around the cap. Also check the air needle valve to see if air is leaking out of it, if so replace. Remember if the air needle valve is closed you are getting minimal clean off air. From closed position, one full turn to set. Guys that do walls because of blow back you can try one and a quarter turns to get a little extra clean off air. One more note: I have had this happen before, when you release the safety remember to push in then turn. Some guys get in a hurry and try to turn the knob without pushing it in and unscrew the bar on the back of the cap,so even when released cuts the travel of the air piston. Thus they get a low output of material. I actually think this is how they came up with the adjustable flow rate for the CS gun...LOL.
Daniel X
Posted: Nov 30, 2010 11:10 PM
This might sound weird too, but make sure the exhaust port at the bottom of the gun handle is clear... Just as a general maintenance thing more than pertaining to this exact problem.
Yvan Richard
Posted: Dec 01, 2010 01:15 AM
When you are experiencing slow triggering, there is not enough air getting through the trigger. By yourself a pipe cleaner brush and run it through where the trigger goes, numerous times. I had a small build up of ISO and so I boiled the gun in Dynasolve CU6 and then scrubbed the trigger area and the problem was solved. Definetly get yourself some Dynasolve CU6 and a crockpot, your gun will have a showroom shine to it.
Gianni Latona
Posted: Dec 26, 2010 08:10 PM
Boiling a gun bod in cu-6 every so often is a good idea? Does it give off alot of negative vapor? How long do you leave it in for? I am interested in these ideas, thanks.
Posted: Jan 11, 2011 10:16 PM
verdino - depends on the amount of build up, you dont have to cook the dynasolve cu-6, but its faster. Always wear nitrile or chemical gloves, even if you decide on the carb cleaner - then your hands wont burn - you dont want chemicals seeping into your body or passing onto children/food in your mouth.

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