Bobcat torch - Hotter than usual??

MelissaQ · #1 08-09-2005, 05:39 PM

I noticed today that my Bobcat, which usually only has heat from the tip to an inch down, is hotter than usual. Maybe twice as far down the torch than usual. My husband

is arguing with me - he says there is no way that the torch is supposed to stay cool because the longer you use the torch the hotter it's going to get!! So I'm glad I have all of you very smart people here on WC. I haven't even used the torch for more than 30 minutes today and I know it's not normal for it to be this hot. The center tube did seem a bit clogged with carbon. Could this be the cause? I'm a little scared now.

What do you think??

CarlisleGuy · #2 08-09-2005, 06:13 PM

Melissa, I would like to help out, but I have to say that I am not as familiar with the Bobcat as I am with the Carlisle line of torches, so definitely double check on the statements below in case anything I have said is not applicable to a Bobcat.

- Your husband is wrong. The torch will not keep getting hotter as you continue to use it. Most torches will build up some amount of heat, but there is a point where the heat just can't conduct back any farther (assuming everything is in proper working order of course). On some torches, this point might be 1" down the barrel and on others it might be just before the valves. Unfortunately, I am not sure where this point is on a Bobcat, so I can't address your measurements (1" and 2") directly.
- Carbon build-up can and will definitely cause the torch to overheat more. Carbon is an excellent conductor of heat. So, once the carbon forms on the face of the torch, it will conduct heat from the flame into the torch body. Always remove the carbon as it forms to keep this from happening.
- Also, if the Carbon build-up is blocking any of the ports, especially the oxygen ports, this will cause heat build-up. The flow of the gasses out of the torch is one of the natural coolants built into every torch design. Oxygen is a larger contributor to cooling than the fuel gas, but both help tremendously to soak up the heat from the torch.
- The more oxygen you use in the flame the cooler the torch will run, as pushing the flame off of the face helps to keep it from building up in the torch in the first place.

These comments should be universal for any torch, but as I said, I am not an expert on the Bobcat.

P.S. keep in mind that the torch heating up is actually the cause of carbon build-up in the first place. Since carbon build-up actually contributes to the torch heating up, you end up with a vicious cycle.

Foofaraw · #3 08-09-2005, 06:27 PM

Melissa, I have a bobcat and it does usually only get hot about 1 inch down. Try giving it a good cleaner with the wire that should have been sent with it and see if that helps any. Carlilse Guy did an excellent job of explaining the whole carbon issue.

baroness · #4 08-09-2005, 06:29 PM

Melissa,

Turn on your oxy, leave it on, and clean your torch well.
Carbon build-up, as stated above, is NOT your friend!
Maybe your fuel is dirtier than usual?

MelissaQ · #5 08-09-2005, 07:10 PM

Thank you CarlisleGuy for clearing that up for me! (I knew my husband was wrong!

) I did notice the center port was clogged a bit because I cleaned it after I noticed that all was not normal - and it was a little difficult to get the cleaning wire in the center port. So I will try again and see if maybe that was just the case. Also, I'm towards the end of my propane tank so maybe the fuel is a bit dirty. But I do thank you for your replies, your information makes me feel ALOT better! I've cleaned my torch and ready to try again. Thanks so much again CarlisleGuy, Jenn, & Baroness

kbinkster · #6 08-09-2005, 11:21 PM

A clogged port on a Bobcat, especially on a center tube, could indicate that you are running too short a flame. Running a short flame can cause it to overheat and the center tube to get hot enough for carbon to start sticking to it. After you give it a good cleaning, try to run your flame a little further out than what you've been running. That should help.

MelissaQ · #7 08-09-2005, 11:43 PM

Thanks Kimberly, I'll try that - although the instructions said try to run it at about 9 inches and I think it's maybe longer than that at times. But it was the center tube that seemed to be the most clogged. I did give it a good cleaning and that did help but I still kind of felt that it was warmer a little further down the barrel than usual. But it could just me being paranoid now! If it was the case that my flame hasn't been quite long enough, could the torch be damaged now? How do you know when it needs repair??

CarlisleGuy · #8 08-10-2005, 08:23 AM

Quote:

Originally Posted by MelissaQ

Also, I'm towards the end of my propane tank so maybe the fuel is a bit dirty.

Propane has a high carbon content and will build carbon more readily than say natural gas would. But I wanted to address the word "dirty".

Carbon is always going to be in propane, regardless of the condition of the tank, your lines, or anything else. However, there is also particles of unidentified junk (this is what I consider "dirty") that can come in along with the carbon, and is usually from an older tank, older hoses, improper hoses (not "T" grade welding hose), older regulator, etc. In order to eliminate as much of the "particles of unidentified junk" as you can, I highly recommend getting filters for your supply lines.

There are fuel gas rated filters that will filter both the fuel gas and/or oxygen down to 1 micron. These filters usually cost about $35 each, last for approximately 1 year or so (under 40 hour per week use), and then you dispose of them and replace with new. These filters are great for cleaning up the flame and also extending the life of your torch, since the "particles of unidentified junk" will promote things that are bad for the torch, such as carbon build-up.

Hope that helps, and best of luck with your Bobcat. I am sure that all of the people here on WetCanvas can and will help you work through this. They are a great group of people to work with.

MelissaQ · #9 08-10-2005, 09:34 AM

Thanks Carlisle Guy. I hadn't ever heard of filters but that sounds like something that will definately worth purchasing. I'm going to check into that this morning. I really appreciate you sharing your knowledge with me! And you are right - the people on WC are great! I'd be pretty isolated lampworking-wise if it weren't for WC!!

Jakomcbean · #10 08-10-2005, 04:59 PM

I never have a problem with carbon buildup on my bobcat but I use Natural gas at home. I did notice some buildup when I recently took it to a workshop where I used propane. A quick cleaning with the old wire made it like new. I suspect different suppliers and canisters can make a difference along with how you adjust your flame. I must say dealing with it even for a few days made me feel better about spending the money to tap into my natural gas line. Although I am lucky my pressure here averages at 3 to 5 lbs so my flame is very hot. My neutral flame with one oxycon ends up being well over 7" if I turn the gas up but I am not complaining. Now all I need is a second oxy at some point so I don't have to turn the gas down to get an oxygen rich flame but for now I can do everything I need to. Keeping the ports clean on your bobcat should keep its cooling properties working as they should. I can't imagine how many burns I would get on another torch now. I routinely rest a thumb or finger on the body. Hope you figure it out.

Jako

kbinkster · #11 08-10-2005, 06:19 PM

The Bobcat (like all GTT torches) already has filters built in, they're in the end of the hose studs - already attached to the torch. GTT recognised the need for them a very long time ago. I believe that GTT offers some for retrofitting other existing torches, I'll have to check with Wally.

Bethlehem is now following GTTs lead and is offering filters for their torches. So, if you have a Bethlehem torch and would like to add an in-line filter, they are available. You might ask if they will work with other torches, as well. I don't see why they wouldn't.

MelissaQ · #12 08-10-2005, 08:34 PM

Well, I didn't know that about the filters already being in there - that's great! I guess I won't worry about that part of it. I seem to have a lot of problem with carbon build up which is probably what caused the problem last night. I started running the oxygen a lot higher than ususal and then I was going through the O2 faster than I wanted to but actually, it didn't help with the carbon problem anyway. I do clean my torch after every use but a lot of times I find I have to turn off the torch and clean the carbon out after every few beads. Maybe it's just my propane tank? I am going to change it soon as I know I'm running really low anyway. Maybe I'll notice a difference after that.

kbinkster · #13 08-10-2005, 09:07 PM

It could possibly be the tank. Has the tank ever been tipped over? The oily odorant stuff in there can go past the filters and start gumming up your jets. Some artists have also noticed this problem when they get to the bottom of a tank. If you're still having this problem after you get a fresh tank, call Wally (610-838-2446).

MelissaQ · #14 08-10-2005, 10:19 PM

Thanks Kimberly, I think I will call him tomorrow. The tank hasn't been tipped over that I know of but I think I possibly just have an icky tank or something. And it's getting low so I need to change it anyway. I did try to torch a little bit tonight but it's still acting up and I don't want to damage my torch so I will just wait untill I talk to Wally. Thank you all so much for your help!

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