Building a 4' Tower Lamp - advice welcome

[Todd]

Greetings!   I've made some progress on my 4' tall tower lava lamp project.  The base is done, glass vase obtained (nice thick walls), and coupling is done - very secure.   I'm getting ready to mount the 200W spot light (on a dimmer - we will be going at this slowly) in the base and am looking for advice on space between the top of the bulb and the bottom of the glass floor.  In my Magma 3' tower the space is less than 1/2", but that's a pro built lamp with the special low expansion glass, and mine is just normal blown glass.    So, I was thinking an inch, or even two, to lessen the thermal gradients, but wonder if I'll end up struggling to get enough heat to warm up the whole column (5 gallons).

Advice and suggestions welcome!

Todd

[tim]

That's a very cool and ambitious project and it looks like you are making good progress on it! The quality and condition of the glass are going to make all the difference in terms of how well it will respond to the change in temperature.

Personally I would put quite a lot of space between the bulb and the glass (at least at first) and then just move the bulb closer if it doesn't get hot enough. Or you could mount the bulb very close to the glass and then use the dimmer to keep it from heating up too quickly. That's what makes the most sense to me but I've never made (or even owned) a lava lamp of that size so I don't have any experience to back my ideas up.

Good luck!

[Marcel Goolamp]

I can tell you, from my own experience, that you need a heat resistant glass. A tube like this will definitely crack, expecially with a 200w bulb. You can try to start it extremly slow, but I am very sure, that it will break ;-)
Because of this, I/we only use only Heat resistant borosilicate Glass Tubes, like we sell in our shop:
https://goolamp.com/en/bottles/176-9005-xxl-bottle-gl200-200mm-empt...

[Marcel Goolamp]

If you want to stay with the blown glass, you could fill it with glitter instead of lava.
You can use a 35w LED bulb and the glass would be save.
The same is possible with our GL200 Lamp, which use a 20L bottle.

Marcel Goolamp said:

I can tell you, from my own experience, that you need a heat resistant glass. A tube like this will definitely crack, expecially with a 200w bulb. You can try to start it extremly slow, but I am very sure, that it will break ;-)
Because of this, I/we only use only Heat resistant borosilicate Glass Tubes, like we sell in our shop:
https://goolamp.com/en/bottles/176-9005-xxl-bottle-gl200-200mm-empt...

[Todd]

Yep, I was thinking that might be the result, and so starting out I'll keep the lamp in a big bucket. 
I certainly gotta try before even thinking about shelling out so much $$$ for a globe.  Thanks! 

Todd

[Claude J]

Great Advice
tim said:

That's a very cool and ambitious project and it looks like you are making good progress on it! The quality and condition of the glass are going to make all the difference in terms of how well it will respond to the change in temperature.

Personally I would put quite a lot of space between the bulb and the glass (at least at first) and then just move the bulb closer if it doesn't get hot enough. Or you could mount the bulb very close to the glass and then use the dimmer to keep it from heating up too quickly. That's what makes the most sense to me but I've never made (or even owned) a lava lamp of that size so I don't have any experience to back my ideas up.

Good luck!

[Todd]

Well, things are proceeding well so far (fingers crossed).  I set up the lamp with the 250W bulb 1/2" beneath the floor of the globe and ran it full blast with the cylinder full of water.   The water temp reached 117 degrees after about 6 hours.
I was stunned to see that the temp is the SAME at the top and bottom!  I can see circulation flow within and so maybe I shouldn't be surprised, but folks have been quoting numbers like 125-140 at the bottom and 115-125 at the top.  
I'm now thinking that's with wax and fluid in the globe?

Todd

 

[Todd]

Put the surface thermometers (which seem to read about 5 degrees low) on my running 7" x 28" tower lamp and got 104 at the bottom and 106 at the top!  Says to me the 250W light is more than enough heat to get this 7" x 48" tower running in the zone and will allow me to use a dimmer. 

Per Mercel's advice, I'm doing all testing in a moving bin!

.

[Marcel Goolamp]

Well, it is just a question of time when it will crack or explode.

I hat a equal Lamp build around 15 years ago and it was a mess when it exploded. 30L Water were gone and I still does not know where it went :-)
Here an other example with an exploded colossus. You just dont want that to happen, because you wanted to save a money on the globe:

[Todd]

Holy moley Marcel, that's looks like a horrible crime scene!

This thing, for as long as it lives, is never leaving the basement shop floor. And I'll have a small vent hole so if/when it does bust I'll get a wet mess in the tub or on floor instead of a wax geyser! If that happens, an order for a GL200 XXL will probably soon follow! Again Marcel thanks for the caution warnings. Claude and others speak highly of you so I know I'm asking for it trying this route first.

Todd

[Claude J]

That was Kelly Flaskerud's house

They ended up having to remodel the whole room, 
Out went the carpeting, drywall, etc
I helped her with insurance claims.

Marcel Goolamp said:

Well, it is just a question of time when it will crack or explode.

I hat a equal Lamp build around 15 years ago and it was a mess when it exploded. 30L Water were gone and I still does not know where it went :-)
Here an other example with an exploded colossus. You just dont want that to happen, because you wanted to save a money on the globe:

[andy ross]

I've been wondering what is likely to happen if the glass cylinder cracks and splits at the bottom? (leaking onto the electrics)

I suppose that could happen with any lamp though...

Claude - please may I ask if you happen to know - did the insurance pay out on the Colossus debacle?

[Claude J]

Hey Andy, WHAASSUUUP
Yes, Insurance covered it along with Shilling kicking in as well.
(yeah I was shocked too)
She remodeled the entire living room with new drywall in affected areas and installed new flooring
andy ross said:

I've been wondering what is likely to happen if the glass cylinder cracks and splits at the bottom? (leaking onto the electrics)

I suppose that could happen with any lamp though...

Claude - please may I ask if you happen to know - did the insurance pay out on the Colossus debacle?