Hey Tom, How’s the MV - UV resin curing experiment working? You said you were trying out a 175? watt flood light and had experienced less than optimum results? My memory about fixture glass finally came forward. Silicon glass filters some reasonably large percentage of UV light. Some light manufacturers even use fixture glass which filters extra UV. If you haven’t already done so, you might try removing the face plate glass from your MV flood light. Failing that, you might need to add another flood light.
Noodle: Thanks for the followup. Mine is an older fixture that has the 175 watt MV mogul base bulb, no protective cover. I tested it on a very cold morning at an approximate 18" distance from a scrap piece of foam with cloth and lam resin. I really need to test it suspended at a ceiling height that would allow a whole board to be exposed (at least a 6’6" or so) Perhaps 2 lamps would do for a 9 footer. The bulb I’m using is very old and may have lost its “juice” or maybe I didn’t let the fixture charge up fully before trying it out. They do come on slowly and take a few minutes to heat up. Let you know but I’ve not given up hope on it. Tom>>> Hey Tom,>>> How’s the MV - UV resin curing experiment working? You said you were > trying out a 175? watt flood light and had experienced less than optimum > results?>>> My memory about fixture glass finally came forward. Silicon glass filters > some reasonably large percentage of UV light. Some light manufacturers > even use fixture glass which filters extra UV.>>> If you haven’t already done so, you might try removing the face plate > glass from your MV flood light. Failing that, you might need to add > another flood light.
Noodle:>>> Thanks for the followup. Mine is an older fixture that has the 175 watt MV > mogul base bulb, no protective cover. I tested it on a very cold morning > at an approximate 18" distance from a scrap piece of foam with cloth > and lam resin. I really need to test it suspended at a ceiling height that > would allow a whole board to be exposed (at least a 6’6" or so) > Perhaps 2 lamps would do for a 9 footer. The bulb I’m using is very old > and may have lost its “juice” or maybe I didn’t let the fixture > charge up fully before trying it out. They do come on slowly and take a > few minutes to heat up. Let you know but I’ve not given up hope on it.>>> Tom Yeah, ceiling height would put the flood about 4’ from the board. I’m guessing you would need two 175 watt floods to do the job. Even then, you might want to suspend them a foot closer to the board. Most floods have a pretty wide light spread. You’re right about bulb warmup. Most bulb manufacturers quote full brilliance in 1 to 3 minutes. You’re probably aware, loss of MV brilliance over time is a factor of burning time, not of age per se. A new MV bulb can sit on the shelf for 10 years with most of its life still intact. Good luck.
I bet that bulb has a zillion hours on it. I took down a light pole that had been in place with this fixture mounted on if for many years. I saved the whole thing (including the pole)intending to remount the fixture somewhere or recycle the bulb as needed. Good info. T.>>> Yeah, ceiling height would put the flood about 4’ from the board. I’m > guessing you would need two 175 watt floods to do the job. Even then, you > might want to suspend them a foot closer to the board. Most floods have a > pretty wide light spread.>>> You’re right about bulb warmup. Most bulb manufacturers quote full > brilliance in 1 to 3 minutes. You’re probably aware, loss of MV brilliance > over time is a factor of burning time, not of age per se. A new MV bulb > can sit on the shelf for 10 years with most of its life still intact.>>> Good luck.
I bet that bulb has a zillion hours on it. I took down a light pole that > had been in place with this fixture mounted on if for many years. I saved > the whole thing (including the pole)intending to remount the fixture > somewhere or recycle the bulb as needed. Good info.>>> T. Yeah, the MV bulb manufacturers make it easy on lighting designers. They show brilliance vs time charts for dusk-to-dawn applications. They intentionally overload the arc tubes with elemental mercury, inhibiting light transmission. As the bulbs burn they oxidize mercury and deposit on the arc tube, again inhibiting light transmission. The output curve goes from initial 90% brilliance to 100% after about one year. After four years they trail off to 75%-80% brilliance. At about 50% brilliance, bulbs lack enough elemental mercury to sustain an arc. They start cycling in 2-5 minute periods.