What happens when you screw a propellant bottle into the ASA of a horizontal Max-Flo 3000? No, this is not a riddle or funny.....the pressure leaks out and scares the living daylights out of you and anyone else in the immediate proximity. Well, maybe the look on everybody's face might be just a little bit funny anyways. This simple modification will rid your marker of this reoccurring headache and render it back to the state it seemingly should have been in the first place.

What is this phenomenon?

The reason that this is happening is that for some odd reason, Smart Parts designers decided to make the raised boss that depresses the valve pin in your propellant tank, longer than any other that exists. What happens is that when you screw the bottle on, the raised boss prematurely lets the pressure from the tank flow before the o-ring on the tank has time to seal the pressure on the inner flange of the ASA. This of course makes for an impossible seal since the pressure is already leaking through past the o-ring. It can also ruin the expensive poly tank o-ring especially when using C02.

Why in the world was the ASA designed this way? Got me but I'll bet it helps stimulate sales of a certain companies aftermarket on/off tank valves and on/off tank extensions. How can we resolve this seemingly unstoppable outburst of pressure? I suppose we could just submit and purchase one of the aforementioned on/off articles or use 'the o-ring trick'. By simply placing a poly o-ring in the ASA before screwing the tank on, it will seal the face of the bottle valve before the valve pin is depressed and pressure released.......voila!!! The o-ring trick!!! Thing is, even the o-ring trick gets a little monotonous after performing it time after time. There is another relatively simple and permanent way around this though, read on..........

The ASA Modification

With a few tools, you can permanently rid the horizontal Max-Flo 3000 of this headache. You'll need a dremel, caliper measuring tool and a small flat head grinding stone attachment similar to the one shown in the above photograph. By simply grinding the ASA boss down to the height that it should be, you can now screw a propellant bottle on and off as you would normally do with any other marker. Use the flat end portion of the stone to slowly grind the end of the boss away and try to keep the top surface as parallel to the base surface of the ASA as possible.

I would suggest a little prep before using the dremel: Using the caliper, measure the normal length of the ASA boss from another marker. Duplicate that measurement to the ASA boss of your Max-Flo when dremeling it down. Just to give you a ballpark measurement, it should be somewhere between .010 - .020 inches high from the base of the ASA. I ground mine to .015 inches. Take the measurement yourself so you'll be satisfied with the results. If you grind too much off, you'll be left with something that will not open the tank valve pin enough to let the proper flow of pressure through the Max-Flo. Just be careful, take a little off at a time and measure often in between.

To be safe, use a small piece masking tape and cover the pressure inlet hole in the base of the ASA so no grit or metal shavings will get into your regulator. I would suggest covering the threads and top of the ASA with masking tape as well to protect them from any possible contact with the grinding stone. You never know when a slip of the wrist may mar these areas. When done grinding, blow out all remaining grit and metal shavings from the ASA. Use a piece of paper toweling with alcohol to wipe any dust particles from the ASA before removing the tape covering the ASA pressure inlet hole. You definitely want to prevent any of this residue from entering into the regulator.

Turning The Bottle On And Off

Turning the bottle on is pretty much straight forward. Turn the bottle clockwise and once you feel the pressure enter the marker, hold the bottle stable and turn the marker onto the bottle. It's much easier to turn the marker onto the bottle because it is less likely to slip in your hand. Using a small dab of Dow33 on the bottle o-ring and threads and the ASA flange and threads will make it much easier to screw on and off as well. For those of you that don't know the proper way to remove a bottle, unscrew the bottle 1/2 - 1  turn then shoot out any leftover pressure in your marker then unscrew it the rest of the way. I have noticed that turning my HPA bottle takes 1 1/2 turns before it will allow me to shoot the excess out of my marker. Once the pressure is relieved from within the marker, there's nothing left to restrain the two components together or swell and tear the o-rings. If you use these techniques, you'll not go through so many of those expensive white poly tank o-rings and conserve on a bit of propellant as well.

Technical Information