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-   -   GTT Bobcat review (http://www.lampworketc.com/forums/showthread.php?t=317554)

rcktscientist 2021-09-14 1:17pm

GTT Bobcat review
 
3 Attachment(s)
Hello LE community!
I just bought a GTT Bobcat and I wanted to share some feedback since I found it difficult to get info when making my torch purchase decision. Chose this over an Alpha, the Minor(s), and National torches.

Cost: $270 shipped to Los Angeles (included tiny L-marver)
Wait time: Quoted 2 weeks, turned out to be 2 months. Classic GTT
Condition: Perfect, no damage
Performance: Good valves and candles are all very even

I'm running an M10 oxycon dialed down to 8 lpm for purity's sake. I control my flame with propane knob only and can dial down the flame to a 1.5" long pin point. I can also turn it up to a 5/8" wide, 1ft long neutral flame and a slightly bigger reducing flame. Gets dragon breath flame as well for flame annealing.

So far the biggest item made was a 1" soft glass marble. No issues at all and I'm guessing I could have gone to 1.5" without too much trouble.

vetropod 2021-09-14 3:35pm

Just out of curiosity, why is the torch base covered in tin foil? Trying to keep the bad vibes out, or what?

kansassky 2021-09-15 7:33am

I too, keep my torch base covered in foil. It keeps the base pristine for resale.

Makes a huge difference in appearance when you are ready to sell.

rcktscientist 2021-09-15 2:14pm

Yes, basically to keep the base clean and to ensure that the sticker doesn't catch fire since adhesives are flammable.

I plan to upgrade to a Sidewinder/Lynx or Phantom so I'll be re-selling in less than a year.

...plus it keeps the bad vibes out :)

vetropod 2021-09-15 2:53pm

I think if you're ever in danger of catching the sticker on fire you've got bigger problems. I've had my torch for maybe 16 years, the base doesn't look bad at all (except the silicon feet have been missing for many years.) I don't know how/when the sticker disappeared, but good riddance. You're not really using the tool properly if you're primarily looking out for the resale value. http://vetropod.com/images/icons/ghost.gif

I'm glad you're happy with your new torch though, now go melt some glass!

rcktscientist 2021-09-15 3:33pm

I burned the sticker on my Mirage when I owned it due to a gob of molten glass landing on the base and when I pushed it away the sticker flared up. Looked and smelled like crap. Don't want a repeat plus it looks so clean for re-sale.

Not sure that I agree with the idea that properly used tools will suffer damage. I'm not really wired that way so all my tools (auto/home repair, 3d printing, lampworking, etc) generally look new and last forever. I have a few 'beat up' tools but they still look pretty good in comparison to many others. Different strokes I guess...

Thanks for the encouragement! I work 40 hrs but still been melting almost every night. Still developing my product line but happy to be making glass again after a loooong break.

rcktscientist 2021-10-15 12:16pm

UPDATE -
I managed to adjust my M10 oxycon to 6 psi to match my Airsep Elite. (I was assuming the pressures but checked them and was surprised to find the M10 at 4.5 psi) It required disassembly and regulator adjustment but it worked. While, I had the cabinet open, I also removed the "bio-filter" and replaced with tubing.
So, my M10 is pushing 8lpm at 6psi and my Elite is pushing 4lpm at 6psi. These settings theoretically give high O2 purity and it sure seems like it. The torch hisses if pushed and generates a big, hot flame. 12lpm seems to be a bit overkill for this torch but I just dial back the O2 using the knob, something I wasn't doing before. I even managed to incorporate a foot switch and check valve for the Elite so it can be 4lpm 'on-demand' with 8lpm constant. I love it!

Been working 26mm solid boro to make 1.5" marbles with no trouble at all. Also been making tons of tube prep. This little torch is awesome considering the price. Yeah, a Lynx would be better but also would have cost me easily $250 more (for new).

My next set-up will likely be a GTT Sidewinder w/Lynx center paired with a homemade HVLP 12-gal system. My calcs say I can run it with my current oxycons at a 20/10 duty cycle; 20 min filling to 120psi while still torching, then 10 min to drain tank to 90psi. This set-up provides an average of 9lpm at 15 psi which is basically using centerfire constantly with occasional outer-fire for melt-ins.

Hope this info help somebody

Utopia 2021-10-16 12:52pm

Thanks for sharing your experience with the new torch and all this info. Super generous and helpful of you!

rcktscientist 2021-11-09 1:55pm

ANOTHER UPDATE -
I installed a compressed air system on my torch.
I used a medical nebulizer (makes about 9lpm at 30psi, way overkill so I used a relief valve), a needle valve, a check valve, a relief valve, and some brass fittings. The nebulizer flows into a brass tee that has the 15psi relief valve installed (keeps the nebulizer from burning out when maximum air is not being used). From there through the inline needle valve, through the inline check valve, and into a tee at the fuel line. The air comes out a little 'pulsed' due to the way the nebulizer works but I really like the control it gives me. It provides a cool, bushy flame on a Bobcat that could not be achievable otherwise and allows me to work more thin, hollow stuff. I wired it with a foot switch for convenience.

Got the idea here on LE so I'm paying it forward.
The next experiment is to see if I can use the nebulizer to boost my 10lpm oxycon pressure while still running 9lpm out of it.
Imagine, an oxycon flowing 9lpm at 30psi for the price of a nebulizer (about $50)....

LarryC 2021-11-09 2:22pm

Quote:

Originally Posted by rcktscientist (Post 5117584)
ANOTHER UPDATE -
I installed a compressed air system on my torch.
I used a medical nebulizer (makes about 9lpm at 30psi, way overkill so I used a relief valve), a needle valve, a check valve, a relief valve, and some brass fittings. The nebulizer flows into a brass tee that has the 15psi relief valve installed (keeps the nebulizer from burning out when maximum air is not being used). From there through the inline needle valve, through the inline check valve, and into a tee at the fuel line. The air comes out a little 'pulsed' due to the way the nebulizer works but I really like the control it gives me. It provides a cool, bushy flame on a Bobcat that could not be achievable otherwise and allows me to work more thin, hollow stuff. I wired it with a foot switch for convenience.

Got the idea here on LE so I'm paying it forward.
The next experiment is to see if I can use the nebulizer to boost my 10lpm oxycon pressure while still running 9lpm out of it.
Imagine, an oxycon flowing 9lpm at 30psi for the price of a nebulizer (about $50)....

GTT makes compressed air manifolds for a lot their torches. My mirage has one

rcktscientist 2021-11-09 2:57pm

Quote:

Originally Posted by LarryC (Post 5117586)
GTT makes compressed air manifolds for a lot their torches. My mirage has one

They don't make them for any standard torch or lower-end triple-mixes. Only Phantoms and up.

rcktscientist 2021-12-07 4:30pm

LAST UPDATE (probably) -
Torch is running great.
I found an air pressure snubber that removes the pulsing of the nebulizer so no more pulsing flame when using air.
Also, I purchased a cheap Smith Little Torch clone and drilled out tips #1 - 3. I made them .041, .051, and .063. I left 4 and 5 at .020 and .029.
I know its a cheap piece of equipment and can be low quality so I leak check often and treat it with care. So far I am very happy with the performance. I used the Griffin valves to 'T' off my main lines for gas supply.
My seals are already looking better. I also use it to polish punty marks while my glass is sitting in a marble mold.

Plus, I built some very basic rollers using conveyor rollers, bolts, and a drilled/tapped aluminum plate. It has been very helpful in keeping all my work truly on-center. Since I don't have a big torch I didn't need the wheel rollers for big work.


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