Titanium Regulators sound awesome, anything made from Titanium sounds awesome. Titanium is both a lighter and stronger metal than what we usually make regulators from. However it does have a couple flaws. Fantastic for travelling divers because of it’s reduced weight, Titanium has a relatively poor thermal coductivity so it doesn’t work so well in cold water.
Put simply Titanium doesn’t transfer heat as quickly as other metals. When scuba diving in cold waters you need your 1st stage to warm up from the surrounding water. The air rushing through the 1st and 2nd stages going from high to low pressure reduces the temperature of the metal parts and ice can form. So if you use a metal that doesn’t absorb heat quickly then you increase the chances of ice from forming. For diving in cold waters you want a traditional chrome plated brass or even steel 1st stage.
Titanium also has a flaw when it comes to Nitrox diving. Titanium regulators are not recommended by any manufacturer for Nitrox mixes over 40%. Air and normal recreational EANx mixes like 30-35% should be fine but there is a combustion risk at higher percentages and pressures.
It’s hard to believe that your regulator can catch fire but Titanium can burn at relatively low temperatures and at least one diver was hurt when diving a mix of over 70% when his regulator caught fire and burned through their wetsuit. NASA have done plenty of testing with Titanium and oxygen and found a very high sensitivity to ignition from Mechanical Impact and pressure and state that Titanium must not be used at Oxygen pressures above 207 kPa (around 2 Bar).
The general consensus it that adiabatic localised heating during the pressurisation of the system can cause ignition of high EANx mixes. By opening valves very slowly you can mitigate this risk but it isn’t worth the risk. Others consider the chance of contaminants or un-oxidised sections of titanium sparking the reaction but for me I’dd prefer to just steer clear of the potential problem all together.
No, you just need to understand that you should avoid using them with Nitrox and in cold waters. Titanium Regs are great for travelling divers becuase they can shave a surprising amount of weight off your reg set.
Many second stages contain Titanium parts but you don’t need to worry about any problem with ignition. The pressure of the gas is reduced by the time it gets to your 2nd stage.