Oxy Propane Hose Diameter?

[AdventuresInMetal]

I've been thinking about purchasing an oxy propane setup exclusively for heating and cutting, i have no intention of gas welding so avoiding acetylene for availability and cost reasons.

Looking at purchasing a Harris 142F cutting torch however I'm having a hard time finding any information on which hose bore to go with, common bores seem to be 6, 8, 10 and 13mm, I'm looking at getting a 10m set for around the workshop but may occasionally add on a 20m extension for a total of 30m when needed. I'm "probably" never going to cut anything over 50mm thick so which hose diameter should I go with? I'd like to avoid a larger hose than necessary but have absolutely no idea on the requirements so any advice on this would be greatly appreciated.

 

[Erie Fred]

I think the tip charts have CFM needed, you might be able to use that
to get a flow rate for each hose size with length factored in.

 

[Jack Ryan]

I don't use long hoses and I don't use propane, but..

If it were O/A, I'd use the common 5mm hose.

As you are using propane, the required oxygen flow increases by over 3 times. This will cause a pressure drop causing the flow to drop. If the use of a long hose cutting 50mm will be an infrequent thing, I would be tempted to just increase the oxygen pressure, if needed, to regain the flow. I haven't done any calculations to determine if there would be a noticeable problem.

If you want to do some calculations, use the tip flow requirements and a pressure drop table.

In a nutshell, I'd use standard 5mm hoses and adjust the O2 pressure.

Jack

 

[Bornfree]

Go 8mm for your 10m main set and 10mm for the extension.

 

[Barking Mat]

I don't even know if it comes in different diameters ?

 

[brightspark]

i have light duty hoses and lightweight torch and you can get the heavier larger bore stuff and torch for cutting and welding they do it in 6.0mm 8.0mm and ten mm bore hoses

 

[Erie Fred]

So the worst case scenario as I see it is:
1. longest hose
2. thickest cutting

Do you foresee a case where you want to cut 50mm (roughly 2" thick)
at 30 meters away from the tanks ?
Or can you get by when doing the 50mm using the shorter 10 meter hoses ?

 

[Turbo]

I had a set of 6mm hoses, they perished & were replaced by 10mm hoses. They are ok for heating & cutting but are horrible for bench work like brazing because they are too bulky & stiff.

Plan is to get a pair of 6mm hoses, fit y-pieces at the regulators & have both sets of hoses connected up.

 

[AdventuresInMetal]

Do you foresee a case where you want to cut 50mm (roughly 2" thick)
at 30 meters away from the tanks ?
Or can you get by when doing the 50mm using the shorter 10 meter hoses ?

Yes, the shorter hose will mostly be for small shop work and the longer on the heavier stuff.

 

[Erie Fred]

Yes, the shorter hose will mostly be for small shop work and the longer on the heavier stuff.

I would buy the long hoses with the larger bore, the short hose as the smaller bore.
When you need the long, unhook the short from the regulators, leave the torch on them,
add in the larger & longer at the tanks.

Are hi-speed tips avail for the torch you want ?
These work good on thick material, use less oxygen.

 

[metalmagpie]

I would try 6mm until it gives you a problem. I use that size for a very wide range of heating, brazing, soldering and cutting needs.

Thinner hose is more flexible and thus easier to store. Not trivial with the cost of shop space today.

metalmagpie