Please could we clear up this issue because I'm confused after reading recent comments.
1. Someone said that soup ladel reflectors can cause MH lamps to overheat and explode, they also said that a soup ladel reflector just scatters the light and recommended that people use spherical reflectors with optical coating etc.
Now I can understand any of these things on their own but won't a proper spherical reflector cause a MH bulb to overheat even more than a soup ladel since the soup ladel is scattering the light more due to uneven surface etc., while the proper spherical reflector is focussing more accurately light (and radiated heat) towards the centre of the lamp?
2. Is a soup ladel reflector a sperical reflector? Assuming its is spherical and not one thats been flattened out at the bottom then I would assume that it was (albeit with less optimised surface). The theory thread uses the terms interchangeably but some people seem to be saying it isn't one. So what exactly is one?
Finally I guess what I'm really after is what is the best type of relector to use with a double ended HQI lamp? I was about to fit a soup ladel but I'm not sure what the score is.
1. Someone said that soup ladel reflectors can cause MH lamps to overheat and explode, they also said that a soup ladel reflector just scatters the light and recommended that people use spherical reflectors with optical coating etc.
Now I can understand any of these things on their own but won't a proper spherical reflector cause a MH bulb to overheat even more than a soup ladel since the soup ladel is scattering the light more due to uneven surface etc., while the proper spherical reflector is focussing more accurately light (and radiated heat) towards the centre of the lamp?
2. Is a soup ladel reflector a sperical reflector? Assuming its is spherical and not one thats been flattened out at the bottom then I would assume that it was (albeit with less optimised surface). The theory thread uses the terms interchangeably but some people seem to be saying it isn't one. So what exactly is one?
Finally I guess what I'm really after is what is the best type of relector to use with a double ended HQI lamp? I was about to fit a soup ladel but I'm not sure what the score is.
I dont see why a ladle is not a spherical reflector, The right ones are half a sphere.
The problem with a soup ladle is two fold. It relflects around half the light back at the arc (If placed in the center of the sphere). It also keeps some of the bulb from getting direct cooling from a fan. The oneida ladle, I bought from target, is a half sphere and has a mirror finish to it. I dont see why it would scatter the light if properly installed. The best part is they are cheap. Keep good airflow on and around the bulb to cool the heat.
The problem with a soup ladle is two fold. It relflects around half the light back at the arc (If placed in the center of the sphere). It also keeps some of the bulb from getting direct cooling from a fan. The oneida ladle, I bought from target, is a half sphere and has a mirror finish to it. I dont see why it would scatter the light if properly installed. The best part is they are cheap. Keep good airflow on and around the bulb to cool the heat.
doughboy said:
Presumably a proper spherical reflector made for the the purpose to be used in an optical setup would have the same problem though and direct even more light back at the bulb?
Hmm, I always thought that blowing air direct on the bulb was a bad idea.. Well I read that on here somewhere too.
Most here have their bulb in an enclosed area in some form. Reflectors and condensers only add to the heat problem. You would have to have a fan cooling the light engine or it will overheat. The fan may be around a corner, but the air is still flowing around the bulb. Im sure you could cool a bulb too much, but thats one reason why theres the outer glass shell. It helps keep the arc in a more stable enviroment.
An optical setup could use a cold reflector, link. Ladles will absorb IR and reflect it back at the bulb.
An optical setup could use a cold reflector, link. Ladles will absorb IR and reflect it back at the bulb.
Looks nice. Well I think Ill just give it a go with a soup ladel reflector and a condensor lens from a 400W halogen OHP. The bulb will be a bit enclosed by these items but the main encloser is quite big (OHP size)and Im hoping the fan will keep it quite cool tho its not blowing air directly on the lamp, its just sucking out the back of the case. Its 150cfm so should shift alot of hot air I hope 🙂
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