Blown globes

[bumble]

Hey all
Just wondering if anyone can give me a insite to blown ( exploding ) globe?
The short story is had 100w exo terra globe in and I wasn't getting enough heat 29.5-30 max hot end so I decided to get a 150w exo terra globe , heated up perfect , didn't touch the globe when fitting it ( used lint free cloth ) got temp to 32.8 and tank held the temp, 2 hours later BANG! Any ideas why ? Is it common for heat globes to just explode ??
Thanks
Derek



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[Newhere]

Some light fittings have a sticker saying 100w max or whatever so your fitting might not be able to deal with the 150w bulb, or it could just be a dodgy bulb.

 

[bumble]

Fitting have printed 150w that's why I went up to 150w. Hoping it's just that and not something common as you go up in watts


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[Snowman]

They can last 2 hours, 2 months or 12 months. Just luck of the draw on how much stress has been out on the filament while being moved around. IE shaking while shipped.
A dimming thermostat will help to make them last longer. As the on off, constant expanding and contracting of the filament causes it to get thin and break in one spot eventually.
If it's just for pythons, just use the reflector globes from bunnings for $8 each. Put the thermostat on a timer for 12/12 hours.

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I use these...

 

[sd1981]

I read somewhere that the oils in a persons skin will potentially cause globes to blow after the oils heat up and create a weakness in the circuit etc.... I used to go through light globes very regularly when I'd use a bare hand to screw in a globe... After reading this, I used a gloved hand to remove the globe from package and screw in, and haven't replaced a normal heat globe for around 12 months or so.... Not sure if there's any scientific evidence to support this theory, but I've saved a putload of $$$ from not having to replace globes every week or 2....

 

[Rogue5861]

I read somewhere that the oils in a persons skin will potentially cause globes to blow after the oils heat up and create a weakness in the circuit etc.... I used to go through light globes very regularly when I'd use a bare hand to screw in a globe... After reading this, I used a gloved hand to remove the globe from package and screw in, and haven't replaced a normal heat globe for around 12 months or so.... Not sure if there's any scientific evidence to support this theory, but I've saved a putload of $$$ from not having to replace globes every week or 2....

I use some g9 halogens in my monitor enclosure and the bulbs specifically say not to touch with bare hands, same as a car headlight. This is due to the temperature at which the bulbs get.

Im sure the same applys for any other bulb that gets hot enough (say +60w), but most dont say it on the box. If for any reason you do touch the bulb its always a good idea to clean with alcohol based cleaner.


Rick

 

[Snowman]

I read somewhere that the oils in a persons skin will potentially cause globes to blow after the oils heat up and create a weakness in the circuit etc.... I used to go through light globes very regularly when I'd use a bare hand to screw in a globe... After reading this, I used a gloved hand to remove the globe from package and screw in, and haven't replaced a normal heat globe for around 12 months or so.... Not sure if there's any scientific evidence to support this theory, but I've saved a putload of $$$ from not having to replace globes every week or 2....

The glass is an insulator so has nothing to do with the circuit. The only type of globes you cant touch are halogen globes. The glass gets so hot that if there are oils left on it, it creates a hot spot that can cause the filament to get too hot and break. Glass on incandescent globes is a lot further away from the filament and has no effect on breaking it or overheating it.

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You can also get a sparky to wire the globes in series. It will make them last for ages..........

 

[sd1981]

The glass is an insulator so has nothing to do with the circuit. The only type of globes you cant touch are halogen globes. The glass gets so hot that if there are oils left on it, it creates a hot spot that can cause the filament to get too hot and break. Glass on incandescent globes is a lot further away from the filament and has no effect on breaking it or overheating it.

Cheers for the additional info Snowman, couldn't recall exactly what type of globes that were specified, or exactly how it was effected, but I now don't touch the glass and get a much longer life expectancy for it, which makes me (and the minister for finance, my wife) much happier....

 

[bumble]

Awsome thanks for all the info guys


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[andynic07]

Some light fittings have a sticker saying 100w max or whatever so your fitting might not be able to deal with the 150w bulb, or it could just be a dodgy bulb.

This would cause the fitting to burn out rather than the globe to explode.
[MENTION=39613]bumble[/MENTION] Lights can blow for a lot of reasons including high volts or poor workmanship. Like Snowman says it is luck of the draw sometimes. I am surprised that a 75watt light can not get to temperature in the middle of summer. Can you describe your setup and your location plus where a bouts your enclosure is in your house please.

 

[bumble]

[MENTION=34534]andynic07[/MENTION] , put it to you this way , in the heat Sydney had the past week or so ( high 30s ) no aircon on , 100w globe I got 30deg hot end 25 low end , so that's why I went to a 150w , I'll attach a pic of the set up , location is western Sydney. Enclosure is in lounge room in the corner , I've got tiled floors but it's on a stand , enclosure is a suburra 669 with there stand .


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[bumble]

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[Snowman]

Put the probe from the thermometer on the basking spot and see what reading you get.

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And move the thermostat probe further away.

 

[zulu]

I used to use bulbs and spotlights about ten years back ,got sick of replacing them. The price was adding up 8 each x the amount of times they kark it.
With the spots i was using them to heat little monitors ,would have been way more efficient to use ceramic heat emitters.
Ceramic heat emitters dont put out light ,they last for years,ive onley replaced one and they can be bought very cheaply online in different wattages

 

[andynic07]

Nice looking setup mate, that is very strange that in the heatwave you could only reach 30 degrees, is you house well insulated and quite a bit cooler than the high 30's outside? Maybe there is too much heat escaping through the mesh top. I have a 50 watt light in a lot of my enclosures and 75 watt in my two BHP enclosures and GTP enclosure but I am in Queensland.

 

[bumble]

@Snowman I try that when I get back from work , I moved the probe up a few days ago just to see if there was any major difference and there was about .5 deg over 30mm from basking spot but I will try it again , with the thermostat prob I'll move it more to the right and see


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@andynic07
Thanks mate , it is insulated ok but with out aircon on it still got warm high 20s low 30s inside . I was thibking heat could be escaping from the mesh top just trying to work out the best thing to put on top . Uming between mdf or sheet metal or perpex


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[andynic07]

I think perspex or mdf because they don't conduct heat away from you enclosure as much as sheet metal would. If you are happy using larger lights then stick with that but remember that winter will be harder to heat. Also was your light running full power to get your 30 degrees or was you thermostat cutting the power off at that temperature?

 

[bumble]

Right ok didn't think of sheet metal like that , think I'll go black mdf , tbh I don't really care what size lights I just want to have the right temps cause I don't want issues come winter . Thermo never cut off until I put the 150w in , I have the thermo set at 32.5


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[Snowman]

I used to use bulbs and spotlights about ten years back ,got sick of replacing them. The price was adding up 8 each x the amount of times they kark it.
With the spots i was using them to heat little monitors ,would have been way more efficient to use ceramic heat emitters.
Ceramic heat emitters dont put out light ,they last for years,ive onley replaced one and they can be bought very cheaply online in different wattages

Ceramics are good. I use them, but have started moving back to globes on account of how dry the air in Perth is. My digital hygrometers often read bellow 20% with ceramics. I get about 35% with globes which seems to be the minimum before I get shedding problems with the BHPS. I think where you live and what you are trying to achieve is an important aspect in regards to heat source choices.

 

[pinefamily]

We have successfully used silver heat insulation tape to partially cover a mesh top tank.