Outer Limits 4x4 Board

what is the key (or keys) to doing good, fast, neat oxy cuts in thick steel? I have read instructions on how to do it and had plenty of cracks at it but I can never make it cut any faster than the 9" with a quality cutting disk, and I almost always end up with a lot of hot slag blowing around especially when I try and cut anything thicker than about 8 - 10mm. I have seen it done with very neat narrow kerf and minimal slag, through inch thick plate, while using minimal gas. what's the secret?

i found that when i had hot slag blowing around and joing the cut back up, it was because i was going to slow, need to heat lots at the start, then get a good steady feed rate, having those wheel things on the tip helps, cauz then you dont need to think about keeping the right distance as well

i am a boilermaker by trade.you need to make sure you are using the correct size tip in relation to the plate thickness,tip must be really clean,correct pressure must be set at regulator,flame must be adjusted properly,and your speed must be just right,not too fast,not too slow.practice makes perfect.

You got to have the right tip size and have a very clean tip and have the regulater set proply then you should`nt have any problems.if its not set proply you will always get slag build up

dumbdunce wrote:what's the secret?

correct tip size for the material to be cut .......

correct pressures for the material to be cut .....

correct cutting speed for the material to be cut ....

and then it comes down to practice practice paractice.

I go for the oxy before I grab the grinder most of the time, its quicker, cleaner, quieter, and nice n warm in winter
Once its setup right then there's nothing you cant do with one, I regulary cut material from 1" thick down to 1.6mm thick. The largest cut I have ever done was through 6" plate !!! and it was alomst a perfect cut except for the bottom inch which wandered a little.

Like I said .....setup & practice

Kingy

V8Patrol wrote:
and then it comes down to practice practice paractice.

.....setup & practice

Kingy

wish I could practice on someone else's steel using someone else's gas

so how do I know if say the gas pressures are too high or low, or the flame is too rich or lean, or if I'm going too slow etc?

when lighting the torch and adjusting your flame press the cutting lever the flame should then be long and slightly tapered so long as you have a good clean or new tip...

another thing that helps is to set your cutting wheels so the tip is about 7-8 mm above the surface being cut ,also in winter time or colder times of the year a bit of preheat just to take the chill out of the job helps too

size of the tip is important too...

dumbdunce wrote:so how do I know if say the gas pressures are too high or low, or the flame is too rich or lean, or if I'm going too slow etc?

duck round to the local scrap metal joint and grab a few scraps.!

i'd post up some pics for you but that option is down at the moment

Kingy

and make sure you've got a nice set of wheels to go with it , keeps it at a constaint distance

have you tried those new 9" cutoff wheels for stainless. half the thickness of a normal disk. so quick and accurate, far more accurate for straight cutting than an oxy.

i use an oxy lpg setup, old boy was obsessed with the idea of cheaper gas. funny how you use more than double the o2 and lpg is like $26 a swap. . sucks cause its like 200 degrees colder and makes it so hard to cut with as you have to adjust it just right

all the cancer inhalers keep stealing my lighter too

cheers bru

when i worked with the boilermakers i used the smalest cutting tip we had
made sure the lil blue flame was right back so when u pulled the leaver
the blue flame only came out 10-15 mm
nice steady hand even flow and i was right cutting10-20mm thick steel
dont quote me on it thou its been a long time sinced i used one so yeah just my opinon

bru21 wrote:have you tried those new 9" cutoff wheels for stainless.

cheers bru

yes! they are awesome, they cut really fast, last for ages and put next to no heat into the steel - for straight cuts in plate up to 1/2" and through RHS etc they can't be beat but for curves especially convex shapes for brackets etc I want to get the oxy working good.



thanks all for the tips, I'll be giving it some more practice!

cheers

Brian

depends on what you want to cut but find someone with a plasma cutter, heaps easier.

Or learn how to use cad, draw your parts and get them cut. This is generally cheaper than you buying the steel sheet and cutting it yourself.

dumbdunce wrote:

bru21 wrote:have you tried those new 9" cutoff wheels for stainless.

cheers bru

yes! they are awesome, they cut really fast, last for ages and put next to no heat into the steel - for straight cuts in plate up to 1/2" and through RHS etc they can't be beat but for curves especially convex shapes for brackets etc I want to get the oxy working good.



thanks all for the tips, I'll be giving it some more practice!

cheers

Brian

I like these but you have to be careful to keep them straight coz they grab and break easier than a normal cutting wheel.

For Oxy cutting your presures should be about:
Oxy: 250 kpa ( 40 psi )
Act: 100 kpa ( 25 psi ? )

On light up set the Act flame so it just touches the tip and so theres no thick black soot at the end of the flame. Make sure the Oxy tap next to the Act tap on the hand peice is turned on fully, this will help prevent the flame going out with a bang. Turn the front Oxy tap on so to turn the flame to a blue colour and till you have 5 neat little blue fames exiting from the tip at approx 5 mm depending on the size of the tip. Then depressing the cutting lever fully, adjust the 5 little blue flames till they exit approx 5 mm from the tip. With it adjusted properly the flame should not change when the cutting lever is depressed. When cutting have the little blue flame approx 3 mm from the plate.
Have a look on most cutting tips and it will state the recomended plate thickness it should cut

TUFF60 wrote:For Oxy cutting your presures should be about:
Oxy: 250 kpa ( 40 psi )
Act: 100 kpa ( 25 psi ? )

On light up set the Act flame so it just touches the tip and so theres no thick black soot at the end of the flame. Make sure the Oxy tap next to the Act tap on the hand peice is turned on fully, this will help prevent the flame going out with a bang. Turn the front Oxy tap on so to turn the flame to a blue colour and till you have 5 neat little blue fames exiting from the tip at approx 5 mm depending on the size of the tip. Then depressing the cutting lever fully, adjust the 5 little blue flames till they exit approx 5 mm from the tip. With it adjusted properly the flame should not change when the cutting lever is depressed. When cutting have the little blue flame approx 3 mm from the plate.
Have a look on most cutting tips and it will state the recomended plate thickness it should cut

yeah that's the good stuff! thanks!