Help with HID Test Tube Replacement

[Rick Inman]

Well, I left my Salvo 21w HID on out of the water today and cracked the test tube. I'll call Salvo Monday and have them quick-send me another, which comes with new O-rings (just $15).

Any tips on installation (removal of old, installation of new). How do you push on the tube, since once you get past the first O-ring there will be air pressure in the tube? Should you warm the bulb and tube before install so that the heat of the bulb doesn't pop off the tube?

What else?

 

[JeffG]

Well, I left my Salvo 21w HID on out of the water today and cracked the test tube. I'll call Salvo Monday and have them quick-send me another, which comes with new O-rings (just $15).

Any tips on installation (removal of old, installation of new). How do you push on the tube, since once you get past the first O-ring there will be air pressure in the tube? Should you warm the bulb and tube before install so that the heat of the bulb doesn't pop off the tube?

What else?

Push it on slow and steady. I had one tube blow up in my hand putting it on in a rush (left a nasty gash)

Turn the tube back and forth to get over the o-rings. I didn't warm the bulb up before putting on the new one and haven't had any issues (and don't forsee any in the future). YMMV

Just make sure that its clean. No dirt, hairs, or any other junk. That is the most important thing.

 

[Sideband]

Take a strand of heavy fishing line and stick one end into the new test tube. Slide the new TT over the light then pull out the line. This will allow excess air to escape as you push the tube over the O-rings. If you don't do this you will build up pressure inside the TT as you push it on over the O-rings and then when you heat that air up the TT will shoot off and be lost forever. I have 1 tube in Haigh Quarry and one in Paradise Spring in Florida that I lost because I didn't know this trick. I did the fishing line bit and have not had any trouble since.

Joe

 

[miesemer]

I don't have a Salvo but my Dive Rite uses a test tube lens over the bulb. When I remove/replace my lens, I direct a gentle stream of compressed dry air (from a scuba cylinder) into the test tube as I fit it over the bulb. This greatly reduces the amount of condensation that forms inside the tube during a dive.

 

[undrwater]

Take a strand of heavy fishing line and stick one end into the new test tube. Slide the new TT over the light then pull out the line. This will allow excess air to escape as you push the tube over the O-rings. If you don't do this you will build up pressure inside the TT as you push it on over the O-rings and then when you heat that air up the TT will shoot off and be lost forever. I have 1 tube in Haigh Quarry and one in Paradise Spring in Florida that I lost because I didn't know this trick. I did the fishing line bit and have not had any trouble since.

Joe

This doesn't slice up the O-rings at all?

 

[Rick Inman]

Finished with the replacement.

First of all, Cory at Salvo gave the usual excellent Salvo Service. I called for the tube on Monday and had it in my hands Wednesday before noon. Cost: $15 or the tube, $15. for 2 day airborne.

After setting the light-head straight up in a vice, I replaced the O rings, blew some dry air into the tube and set it over the bulb until it rested against the first O ring. Then I turned on the light and waited about 60 seconds - just enough for the air in the tube to heat up. Then, with a dish towel so as not to get burned, I gently twisted/pushed the tube all the way on. I let it cool, and then submerged it on into a tub of really cold water.

No fogging in the tube, no popping off of the tube, which looks perfectly secure. The entire process took less than 5 mins.

Thanks all for the help.

 

[Sideband]

This doesn't slice up the O-rings at all?

No. You only do it once. I got that method from the guy at Blue Grotto in Florida. He and a partner designed and build (I think he just sells them now) the boxy style of halogen canister lights that use the test tubes. I had lost both my main and my spare tubes due to them popping off (I used the heat and push method) and I had to buy 2 more. This time I asked him how to install it. He said to either cut a strip from a business card or use a piece of monofilament line to lay across the threads when you push the tube on. I have not lost a tube since.

Joe