Smith Oxy Acetylene Torch - OX Torch Pressure?

[Beltzington]

I have a Smith W200 blow torch setup I have not used for years until recently I used it to heat some metal for bending. I adjusted the mixture until I got a nice even 1/4" blue flame from the tip and was able to quickly heat 3/4" metal to cherry red and bend it. Before I shut the gas off I hit the oxy blow lever and was surprised I could barely notice a change in the oxygen flow or the flame.

Troubleshooting I have verified the tip is clean, changed the tip, removed the tip and just adjusted the valve without any acetylene. Still getting very little increase in oxygen flow when I hit the lever. As I recall it seemed to be much more of an increase when I was using it several years ago.

According to Smith Instructions the lower inlet OX valve should be full open and flame is adjusted with the upper ox valve. Using an SC 12-1 tip and 10/40 gas to oxy pressure off the regulators.

I accosted a man driving a welding service truck in the Home Depot parking lot and he said it sounded like maybe the torch was clogged which would make sense had been used or exposed to dirt or bugs but it has not.

So how much additional oxy should one expect when hitting the lever?

 

[BHD]

what was the oxygen pressure on the gauge?
and how did you set the torch,

open up the oxygen valve on the torch body, and then adjust the flame on the vale under the torch,

The oxygen gauge set about 15 to 20, there are charts for the tip size, to correctly set the pressure,

 

[Beltzington]

1600psi tank

set 40 psi ox 10 acetylene per smith tip chart unless I read it wrong

 

[RNeumann]

It’s fairly common to keep a little set of tip cleaning rods with the torch. They are cheap and about the size of a match box. You know when you hit the oxy lever- the sound changes significantly. It’s a louder hiss/shhhhh

 

[BHD]

the only thing I can think of the rear valve was not opened up enough,
and or you set the flame by the rear valve on the torch body,

 

[tjkubota93]

Like they said, the bottom 02 valve should be wide open. The one by the lever is used to set the flame.

You might know that already?

 

[Arc weld]

10 psi acetylene is overkill for cutting. 5 psi would be sufficient but it sounds like something is blocked not letting the cutting oxygen through. First thing to do is check the O-rings on the cutting attachment. They could be cracked, damaged or got brittle over time. Without even lighting the torch and the handle valve fully opened you should hear the oxygen coming out the cutting hole. With the torch lit, you should see a long straight (white) line 6-12" long right through the middle of the flames. It should make a noise as well. Also look at the regulator gauge when you hit the cutting oxygen. It should move a little but stabilize. If it's set at say 40 and goes down a few psi when the lever is pushed is OK but if it goes down anymore your regulator may need servicing. Were the adjustment screws on the regulator backed off when they were stored? It saves the diaphragm in the regulators. I loosen them off every time I'm finished with the torch.

 

[Beltzington]

10 psi acetylene is overkill for cutting. 5 psi would be sufficient but it sounds like something is blocked not letting the cutting oxygen through. First thing to do is check the O-rings on the cutting attachment. They could be cracked, damaged or got brittle over time. Without even lighting the torch and the handle valve fully opened you should hear the oxygen coming out the cutting hole. With the torch lit, you should see a long straight (white) line 6-12" long right through the middle of the flames. It should make a noise as well. Also look at the regulator gauge when you hit the cutting oxygen. It should move a little but stabilize. If it's set at say 40 and goes down a few psi when the lever is pushed is OK but if it goes down anymore your regulator may need servicing. Were the adjustment screws on the regulator backed off when they were stored? It saves the diaphragm in the regulators. I loosen them off every time I'm finished with the torch.

I just rechecked everything you mentioned and did not find any problems except noted the following:
With just the oxygen connected, regulator set at 30psi, handle valve full open, upper valve closed when I depress the cutting lever I get very little air flow out of the tip, not much more than blowing hard through a straw. When I open the upper valve all the way, don't depress the cutting lever, I get significantly more airflow which I would estimate to be close to the 30psi on the regulator. I am sure it is not the tip as I have tried this with 4 different tips and I also get similar results with the tip removed although it is not as pronounced because the airflow is less focused. Based on this I feel there must be a problem with the torch but certainly would like to hear from the better qualified on this deduction. TIA

 

[Industrial Toys]

You should get a real blast when you pull the trigger. The center hole is the only one that does the cutting. The outer holes preheat the metal prior to hitting it with the OX. When I learned this, my cutting technique improved. It also allowed me to better recognize if the torch was working properly.

It does sound like something is plugged up. I have ten or so torches in varying states of mis-operation. They also suffer from seal deterioration.

 

[Beltzington]

Thanks to all - found the problem, the silicon compression ring had softened and was blocking the air flow when the oxygen lever was depressed. Trimmed and reseated the gasket and everything working correctly.