I acquired another Primus 1020 and also my first Radius 119 and found myself in need of two more shortened Coleman large straight sided globes. This time I decided to try my hand at cutting them myself. I used a diamond coated titanium disk in my trusty Dremel tool. I secured the Dremel in my bench vise, clamped an old block battery to the workbench as a guide, and marked the globe in the burner cage of the lamp. Then I turned on the Dremel at fairly low speed and while turning the globe with one hand, fed a dribble of water from a squeeze bottle onto the cut with the other hand. The disc cut the glass like the proverbial hot knife through butter. It is a rather messy process with the water spraying everywhere and it seems that a lower speed and shallower cut would give a better result.
Great work, must remember that one. I wonder if it would be possible to flame polish the edge? I must try that sometime.
So... now I know it's possible this is definitely going to happen! I've found out that 34oz/8 cup cafetière has the same diameter as Vapalux/Bialaddin globes so that will be my first attempt.
Update: I have changed my setup. Having the Dremel in a vertical position and the globe to be cut standing on end next to it seems to work much better. It prevents scoring marks from splinters scratching the sides of the globe as you rotate it. Using the laboratory glass stand to hold the dremel also makes it easier to adjust the height. Remember to wear eye protection and to continuously feed a dribble of water into the cut.
Wow, Wim, you've really got me scratching my head now, trying to figure out why I did it that way. No, I'm generally right handed but I can now see why you would think otherwise, looking at the photos. I gave it no thought at the time, but it seemed natural to me to rotate the glass with my left hand while feeding water with my right. Maybe I was subconsciously looking at it as if it were a metal working lathe, where one would control the left-right motion of the toolpost with the left hand and the in-out motion with the right.
Maybe save your money. The slop in my Dremel bearings is quite abysmal... I hate to say the 4 letter word that starts with J and ends with K
I'm sure a dremel copy will work just fine as long as the cutting disc does not wobble. High speed and torque not needed; just take it slow and easy.
I've ordered a diamond cutting disc and plan to use it in my pillar drill and off-set the base plate to one side to support the jug when I do the cutting. I think that should do the trick.
How about if you cut from the inside of the globe? Will this limit the spatter? Also, it seems easy enough to rig a continuous water drip from an elevated reservoir.
i have a 200a infrared that i need the outer glass for and found a straight side vase that is the right size. wondering if this method would work or if it is only good for the heat treated type of glass
I guess you can use this technique on any glass, but if it's not borosilicate glass like Pyrex it'll most likely crack or shatter. I've found that cafetière inserts made of Pyrex are the perfect diameter for Bialaddin lanterns and others. I've cut down quite a few and the pouring spout is actually quite useful for lighting the pre-heater.
You can certainly cut it using this tehnique; just slow and easy with plenty of water on the cut. But whether it will withstand the heat on the lantern is another question.
If I had an oxy-acetalene torch and an old turntable I would attempt melting the top and bottom edges so they look professionally finished but I can't justify the cost!