Generally if there are dates on your tanks, then the various places that refill them may not be willing to do so after the dates expire. One might need to have the tanks re-certified. (I think). Are you talking about your smaller boat bottles, or a fill station sized tank? Mikey
Tanks cannot be legally refilled if the test or retest date is not valid, however, many paintball locations may not pay any attention to the date code whatsoever. Keep in mind that the tanks are required to be tested every so often to protect everyones saftey. Here is a decent explination: http://www.hydrotester.com/information.htm Note that if the tank is smaller than 2 in dia. and less than 2 feet long it does not require periodic retesting, so since you say yours are "smaller" bottles, they may be exempt. If the tanks do require testing, it should be done in the name of saftey, but it's usally only slightly more expensive to replace the tank as it is to pay for the testing.
I just recently had this happen at a Paint ball store. I brought in my Co2 tanks and one of them could not be filled because the tank had expired. I had a choice. Pay 20 bucks to retest it then pay additional to get it filled if it is safe, Or purchase a new bottle with a new on/off valve and free fill. I opted for new bottle, new push button valve to turn the gas on and off and a free fill. 44.oo total.
From the chart I have, the 3.5 oz tank is listed as 2" dia. and 5-3/8 long. The 7 oz = 2" dia. x 9-3/8" long so they should both be exempt. From my understanding, and I'M NOT AN EXPERT, when a tank is filled it expands a certain amount. Over time, the material fatiuges, or streches, or relaxes or whatever, and the tank may begin to expand more than allowed. Once it gets to this point, it is no longer safe, because the bottle expands too much under pressure and could be a burst candidate. Yeah, I know there is a burst disc that "should" blow first, but the testing requirement is another layer of saftey. The smaller tanks have a much smaller surface area for the internal pressure to exert force on, so there is much less of an expansion issue. So as long as there is no type of external damage to the "exempt" tanks (deep scrathces, deep dents or anything that might compromise the intergrity of the bottle) you should be able to continue to use them. I don't have any data on the 9 oz. tank, but the info I have on the 12 oz. is that it is 2-1/2" dia. So the 12 oz. would require testing, and the 9 oz. may or may not, since it falls somewhere in between the 7 and 12 oz. tanks. And keep in mind that if the tank should fail inspection, you still have to pay the inspection fee at most places. Definitly better to go for the shiny new tank and vavle in my opinion!!
One thing to keep in mind is that a few rulesets require the inspection to be current So, it's probably best to replace the tank when it gets old... Mike
