O2 setting for National 8m

willieswonder · #1 2012-04-02, 7:47am

Hey all, I am a noob. I have been running a National 8m for about 8 hours or so. I seem to be blowing through o2. Just yesterday I went and got a K tank, and I am already at 1000lbs with only about 3 hours on it. I have tested all my connections and nothing seems to be leaking. I have my pressure set about 15psi, and I am running the SM21 tip.
I am using an older regulator that is a little noisy (hissy).
Could it be a leaky regulator diaphragm? or am I setting it wrong? or could it be the SM21 tip? should I grab something like the HTC2?
Any and all tips welcome. Thanx!

LarryC · #2 2012-04-02, 7:58am

Depends on the tip, I am not familiar with that torch, and the flame settings. On my Lynx center if I am working color in an oxidizing flame I get 8-9 hours on a K tank.

willieswonder · #3 2012-04-02, 8:21am

Thanx. I guess I need to consider that I may ust neto consume a lot of O2. I will say the, chart that came with it list psi settings for a lot of tips, but not the SM21.

LarryC · #4 2012-04-02, 9:43am

I am not familiar with the national but your Oxy consumption does not seem excessive compared to mine. Maybe someone else familiar with that torch can make comments or suggestions. One way to be sure that there are no gross leaks is to open up the tank valve and dial in the regulator with everything else closed tight. Is there a drop in the regulator dials? Everything should hold as you set it. Also spray some soapy water onto all of the hose terminations and fittings and look for bubbles with the pressure up.

deb tarry · #5 2012-04-02, 8:26pm

You could post in the torch room you might get more response.

Role · #6 2012-04-02, 8:46pm

The SM21 is a BIG flame:

You are not leaking, you are just using a lot of O2.

On your HTC-3 question National says:

"The HTC-2 and HTC-3 are the most sensitive tips to burning out and these
are not recommended for beginners who are learning how to adjust their
torches properly"

Your mileage may vary

Onekura · #7 2012-04-02, 10:26pm

I have the 8M and the SM21 - your oxy consumption is about right. Get used to using Oxy big time with this tip. I had the same problems - saving oxy - and my work/colors never turned out the way it should have. Mate, crank it up and enjoy the glass work - don't save oxy - turns out better in the end if you just go for it and don't cut costs . . . . this is not a cheep hobby . . . but, use a smaller tip that might do the job just as well and you save a lot . . . I use the SM 7 most times - much cheeper. And I found that running the SM21 the torch gets so hot after a while, it scared me . . . Then I changed to a Bethlehem Barracuda and never looked back.

willieswonder · #8 2012-04-03, 12:04pm

Thanx. I did give it another leak test, none. I guess I wll be spending 20$ on gas a little more often than I thought.
I appreciate the help.

Icarus · #9 2012-04-12, 9:14am

Do you make sure to open your oxygen cylinder valve all the way? The type of valve in there seals at fully closed and fully open. If you just open it halfway, you will experience leakage from the tank. Granted, you could just be raging that hard, as that is as burly as the surface mix tips come. What capacity tank are you using? Might be worth it to upgrade to a larger tank.

But make sure you're opening your cylinder valve (the valve handle on the top of your tank) all the way when you turn it on to flood your regulator and lines.) That would be the first place I would start. If you aren't doing that, you might notice your oxygen consumption go down a bit, but like Onekura said, you may just need to get used to using a lot of oxy with this tip. If you can swing it, it might not hurt to try to find a lynx. I can get about 18-20 hours on my lynx with a fully charged (2200 PSI) 250 cu ft tank.

willieswonder · #10 2012-04-12, 10:11am

Quote:

Originally Posted by Icarus

Do you make sure to open your oxygen cylinder valve all the way? The type of valve in there seals at fully closed and fully open. If you just open it halfway, you will experience leakage from the tank. Granted, you could just be raging that hard, as that is as burly as the surface mix tips come. What capacity tank are you using? Might be worth it to upgrade to a larger tank.

But make sure you're opening your cylinder valve (the valve handle on the top of your tank) all the way when you turn it on to flood your regulator and lines.) That would be the first place I would start. If you aren't doing that, you might notice your oxygen consumption go down a bit, but like Onekura said, you may just need to get used to using a lot of oxy with this tip. If you can swing it, it might not hurt to try to find a lynx. I can get about 18-20 hours on my lynx with a fully charged (2200 PSI) 250 cu ft tank.

Thanx, that is a good tip. I believe I am opening the valves all the way, and I am using a K tank.
I ordered an SM7 tip today to see if I can dial this flame back a bit. I wanted the versatility of the interchangeable tips, but maybe I should have gotten the SM7 originally and upgraded to the SM21 when it was time.
I haven't had much time to do any glass this past week (Easter traveling), so I will get a new tank of gas Saturday morning, and go through that this weekend! Tankfully I get tanks for 21$ That's less than I spend in gas money to get to work in a week.

cheng076 · #11 2012-04-12, 10:31am

Shudda got a GTT!!
Long live the Mirage and Kabuki...yeaaaaah!

LarryC · #12 2012-04-12, 12:30pm

Quote:

Originally Posted by cheng076

Shudda got a GTT!!
Long live the Mirage and Kabuki...yeaaaaah!

GTT? thought this was about the national?