Technical Tips

Removing Box Clips

US Divers used seven "box clips" to hold the cases together on their two hose regulators from the very beginning. These clips were clamped over the edges of the regulator boxes, and they are sometimes very difficult to remove. Some US Divers repair manuals recommend that they be cut off and replaced with new. But new factory clips are no longer available, and may never be, so it's best not to destroy them.

There are various methods for removing box clips, but what works best for me is to remove them by rounding off the tip on a standard screwdriver, and sharpening it. Next, wrap some electrical tape or shrink wrap around the screwdriver shank - this prevents the shank from scratching or damaging the top box when prying off the clip. On most two hose regulators, there is a small gap between the box clip and the case on the yoke side of the regulator. Now take your custom tool, and put the tip of the screwdriver in the small gap and gently pry off the clip. Obviously the sharper your screwdriver is, the smaller gap it will fit into. If there is no gap, make a second sharpened screwdriver tool, and gently pry underneath the clip on the edge of the box, thereby producing the gap needed to pry the clip off. This technique has been very successful for me, on hundreds of regulators, and should not damage or scratch the regulator or box clips in any way. Sometimes there are scratches where the box clip was installed. If so, re-install the box clips in the same position to hide the scratches.

Differences Between the Royal and the DA AquaMaster 

When the Royal Master came out in 1964, it was advertised with this opening line: A balanced First Stage in the famous AquaMaster gives this "King of Professional Regulators" an even smoother performance under all possible demands. After rebuilding hundreds of Royals and DA AquaMasters, I've been able to note the differences between the two and other than cosmetics, the only differences are in the nozzle and nozzle parts. Because the Royal is "balanced", it has a larger spring block with a spring on either side, and this requires a longer nozzle to hold these extra parts. A "balanced" regulator permits easy breathing and dependability to remain constant over all ranges of cylinder pressure.

The Royal was also advertised as having a larger orifice for better flow at depth. It took me a while to find this "larger orifice", but I finally discovered that the nozzle "volcano" orifice is .110 inch, while the late model DA AquaMaster is .092 inch. It's interesting to note that the older dull chrome AquaMaster nozzles are even smaller at .080 inch. The nozzles are interchangeable between the Royal and DA AquaMaster because everything else on these regulators is identical. More than once I've purchased a "Royal" AquaMaster only to find out that it was a plain AquaMaster with a Royal label. But there is an easy way to tell the difference without disassembling the nozzle. Because the Royal nozzle is taller by about 3/16 of an inch, there is more play in the yoke on the Royal and it will move up and down about an 1/8 of an inch whereas the AquaMaster yoke only has about 1/32 inch up and down travel.

You can upgrade the Royal high-pressure seat by using one from a newer Conshelf/Titan single hose regulator. The new seat is Teflon®, as opposed to the Royal's rubber seat, and it will last longer and withstand higher tank pressures. When using this new seat, you will also have to replace the original push pin (part no. 1046-18) with a longer one of the correct length. The nozzle springs should also be replaced, since the original springs tend to get weak with age and can cause a free flow with 3000 psi tank pressures.

US Divers Non-Magnetic DA AquaMaster Identification 

The US Divers non-magnetic AquaMaster regulator was used by US Navy UDT teams to disarm magnetic mines, so the regulator had to have very low magnetism. Since chromium has some magnetism, they did not use chrome plating on this regulator. But they did need corrosion protection since it was used mostly in salt water. They chose to gold plate many of the parts including the nozzle (1012-12), the HP seat (1010-65), the spring block (1000-23), the LP seat holder (1010-04). and the LP seat retainer (1010-07). These gold-plated parts are clearly marked as to distinguish them from the standard unplated brass parts. They all have a circular groove around the part to show it is non-magnetic and gold plated. I also have a filter (1000-38) that looks like it is gold plated, but it has no distinguishing marks.

Also, as many already know, all non-mag regulators had an unmachined hookah port on the regulator body and the entire regulator had a black oxide anti-glare and corrosion resistant finish. I have seen many examples of these regulators and most have had many parts switched in them over the years. Many of them that you find today will have some chrome and/or brass parts instead of the original gold plated ones.