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Technical Information
Diving Equipment Warnings and Cautionary Notes
Non safety related issues which may affect the operation or longevity of your DESCO product.
ALL SAFETY related warnings are listed on the SAFETY page
12/16/11: The Bailout Non-return Valve on the Air Hat is a modification of the standard adapter. The inlet is drilled to 3/8" to allow the nipple on a SCUBA whip fitting to enter the adapter. The Bailout Non-return Valve adapters are done in small batches.
We have been informed of a problem with fitting a SCUBA whip to the Air Hat Bailout Non-return Valve. The problem was traced to a 3/8" drill bit whose diameter had worn down a few thousandths (enough to make fitting the whip impossible). We are replacing all our used 3/8" bits and will be setting aside bits to be only used for bailout adapters. Also we are purchasing a pin gauge in order to check each bailout adapter before assembly. If you have a Bailout Non-return Valve which has this condition contact us for a free replacement part. 12/22/11: Update. We received the pin gauge and it will do what we need it to. All Bailout Non-return adapters will be checked (100% inspection) from now on, instead of checking sample parts.
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11/17/11: Nomenclature Change on the 59091 Non-Return Valve There has been a change to the part descriptions on the 59091 Non-Return Valves. The adapter and body descriptions have been reversed. We also found an error on the Air Hat exploded view dating back to the original catalog artwork which had incorrectly listed the part number for these two parts. Below is a view with the correct part names and part numbers.
The decision to change the part names was due to the inclination to call the 53079 a body since it is the major part in the assembly. Also with the introduction of the 53029B the 53029 actually adapts to the hose fitting.
Powder Coating Soldered Diving Helmets
Over the years we have had to repair more than one DESCO Air Hat that somebody attempted to powder coat. Helmets made by DESCO Corporation be it Air Hat or Classic Style are made of Copper and Brass components which are soft soldered with a 50/50 Lead Tin solder alloy. The melting temperature of 50/50 solder is in a range from 365–419 °F - 185–215 °C.
The thermoset or thermoplastic coating when sprayed onto the part adheres to it by electrostatic charge. Once the part is sprayed it must be heated to melt and cure the coating. The typical coating requires heating to 390°F - 200°C for 10 minutes in order to cure. This temperature falls right in the middle of the range to melt soft solder. Ten minutes is ample time to soften and/or melt out the largest solder joints on a helmet.
Once a helmet is desoldered in this manner it must be totally disassembled, the old solder cleaned up, and the helmet completely resoldered. No solder joint can be left "as is" since it is not possible to visually verify the integrity of an affected joint.
Powder coating miscellaneous parts of the helmet doesn't work either. The coating is by necessity fairly thick. The additional thickness of the coating will put parts outside their dimensional requirements and they will not fit or will not function as designed.
The snout, tail, and speaker ring came off the helmet. 90% of the solder was gone from the shell to neckring joint on this Air Hat.
The powder coating gets into areas where it can't be left. The clamps and bolts were both coated so now they won't fit together. Having either coated would have made assembly impossible. The valve handle will not fit onto the valve stem. The hole could be re-broached but it is likely the coating would crack and chip, defeating the purpose.
DESCO Air Hat information
Neck Ring Gasket Adhesive:
The neck ring gasket in the DESCO Air Hat is cemented in place using "disk adhesive". This adhesive is used to attach paper sanding disks to the foam pads on DA sanders. This adhesive allows for easy removal and replacement of the neck ring gasket. More aggressive adhesives will make removal of the neck ring gasket difficult and almost impossible to achieve without destroying the gasket. The most common brands are 3M™ Feathering Disc Adhesive, Norton No. 10 Disc Adhesive, and Carborundum Disc Cement. One or more of these brands are available at auto body supply stores.
Air Distributor and Lambswool:
Lambswool is a coarse fiber material that does not compress to the point where it would choke airflow. THERE IS NO SUBSTITUTE FOR LAMBSWOOL. Cotton and other similar materials will compress to a point where it can impede airflow. Never substitute another material in the air distributor. Lambs wool is available in Drug Stores, and the health products aisle in most department and grocery stores. The Lambs wool will also act as a filter in the incoming air.
WARNING: Teflon® Tape
Teflon® tape should never be used on any part of the Air Hat. The possibility exists for pieces of Teflon® tape to enter the air delivery system and cause a blockage. Use plumbers putty to seal Non-return Valves to the Air Inlet Elbows.
Air Control Valve Stem Adapters
When the valve handle on the Air Hat was changed a few years ago it was decided to do away with the extender on the adapter. The skirt on the new valve handle offers protection to the valve stem. Air hats using the old style handle will still benefit from the adapter with the extender. The parts list has been amended to list the adapter in two versions. Part number 61132 is the stock adapter, while 61132E is the adapter with the extender.
Chemical Compatibility with materials used on the DESCO Air Hat
If the DESCO Air Hat is to be used in any fluid other than water the user must determine the suitability of the Air hats seals in relation the fluid. Compatibility charts are available online from several sources. Type "material compatibility" into your search engine.
Exhaust Valve Flapper Disk is Natural Rubber
Neck Seal O-Ring is Polyisoprene (Natural Rubber)
Window Gasket is Neoprene.
Double Exhaust Valve O-Ring is Buna 70
Clamp & Lock Washers are Nylon 101
Video Block Washer is SBR Rubber
Question about alignment of the Air Control Valve in the Air Hat snout
Several people over the last few years have called or e-mailed with concerns about the angle of the Air Control Valve in relation to the face of the snout. The angle is caused by the draft in the casting which is necessary to remove the pattern from the mold. (see http://en.wikipedia.org/wiki/Draft_(engineering)). When they are received from the foundry the raw casting is sanded inside and out. The front face is milled to provide a clean level surface for the window gasket. The snout is machined so its axis are all parallel and perpendicular with the rest of the helmet components. There is a small degree of draft on the inner and outer surfaces of the casting and the result is an accumulation of the draft from both sides which is visible under the valve handle. The draft angle has to be accounted for when the exhaust port hole is drilled as the exhaust base must rest flat on the face for soldering. This is done during the threading of the exhaust hole.
Angle of the Air Control Valve on the Air Hat.
Draft in the snout casting.
Aligning the snout in the fixture.
Drilling the mounting hole and relief.
The fixture holds the snout front and side perpendicular to the drill.
To date this angle has not been a safety or functionality issue. It is a aesthetic issue only. It would be possible to make the snout straight but at significant additional cost.
- The casting could be machined to be straight but that would entail changing the pattern to add material which would later be machined off.
- The casting process could be changed to investment casting but the per part price would jump significantly.
DESCO's philosophy has always been safety first (IF YOU DIE OR ARE INJURED IN OUR HELMET IT'S BAD FOR BOTH OF US), function second (BALANCE FUNCTION WITH SAFETY), cost/value third (A SAFE AND FUNCTIONAL HELMET IS WORTH MORE THAN A DEATH TRAP), then aesthetics a distant fourth (COMMERCIAL DIVING ISN'T A BEAUTY CONTEST). The ACV angle has always been there but it became noticeable with the introduction of the skirted valve handle. The skirt is there to reduce the snagging hazard posed by the valve handle sticking out. A safety consideration accentuated a aesthetic consideration, safety won.
Suspicious marks on Air Hat
Back in 2009 we received an e-mail from a customer who had just received a new Air Hat. He included photos of what appeared to be a large crack in the neck ring under the tail. Here is an excerpt from that e-mail;
ATTN. MR RIC KOELLNER
Dear Ric,
this morning from the work shop I have received information about a break in the structure of the helmet we have not yet used. Have a look to the photos and let me know how to come out of this problem because we think the helmet can not be used in this conditions. I will call you later by phone.
Greeting.
From the photos at first glance it sure does look like a crack running up the neck ring right into the tail. The problem is the neck ring and tail are two distinct pieces and the odds of them both cracking simultaneously, and the cracks aligning perfectly, are so astronomical as to be impossible for all practical matters. Our best estimate was something either marked the helmet during packaging for shipment, or during unpacking since this was a new helmet. The other option was the plating became discolored through some contamination at this point.
From the text of the e-mail you may have gathered this was an international shipment. The customer could have saved himself some worry and a long distance phone call if the helmet would have been looked at just a bit more closely. We do want any questions about our products brought to our attention whenever necessary. Ric responded by e-mailing back;
Dear XXXX
You can "come out of this problem" by using soap & water. It is "dirt".
Sincerely
Ric Koellner
DESCO Corporation
Nomenclature Change on the 59091 Non-Return Valve
There has been a change to the part descriptions on the 59091 Non-Return Valves. The adapter and body descriptions have been reversed. We also found an error on the Air Hat exploded view dating back to the original catalog artwork which had incorrectly listed the part number for these two parts. Below is a view with the correct part names and part numbers.
The decision to change the part names was due to the inclination to call the 53079 a body since it is the major part in the assembly. Also with the introduction of the 53029B the 53029 actually adapts to the hose fitting.
DeepSea DSL B-2 Helmet Wiring Diagram
When DESCO receives a B-2 Helmet from CBE it is wired according to common usage in Europe. DESCO rewires the helmet to suit our customer base. Below is a diagram of the wiring configuration of DSL B-2 helmets delivered by DESCO to customers in the Americas since March 2007. If your umbilical does not match this configuration simply move the helmet pigtail connections (Red, White, Green, Black) to the correct terminals on the block. The binding posts should always have a direct route to the earphones. The microphone should be routed to two of the pigtail wires by themselves.
A printable copy of this diagram is available on our Downloads Page.
