cutting torch question

[tpolley]

i was cutting a truck frame the other day for a friend using his equipment. real light steel. probably 3/16 thick. the torch would cut about 2 or 3 inches and stop cutting every time. part of the time it wouldn't cut all the way thru. part of the time the molten steel would melt back together after i cut it and i'd have to cut it about 3 or 4 more times. i tried different travel speeds. i tried angling the torch forward. i tried holding the torch different distances from the cut. i was cutting in all positions.

we were outside and the temp was about 70 degrees. very little wind
oxy was set at 30psi acet was about 5psi.

this may have been most of the problem but what does it mean when the little blue flames are raised up off of the torch tip. i know it's not supposed to do that but nothing i did remedied it. i tried afjusting the gas and the oxygen.

 

[Swampy]

knock the rust off with a needle gun or chipping hammer where you want to make your cut. Sounds like rust to me. Sometimes blistered over and painted frames are a bear to cut until you clean up just a bit.

 

[Dan1955]

Rust most likely the culprit. I'd turn up the oxy pressure a bit.

 

[krusty the clown]

i normally go to 40psi on the oxygen and 7psi on the acetylene for cutting.

 

[pirana]

What size tip are you using? I'd set the gas pressure to around 7 or 8 psi & oxy to around 40 psi & use a 0 or 00 size tip & be sure the orifice is clean. Make sure you remove as much rust, paint or grease etc. as possible.