I’ve been trying to bend 5" wide piece of 2.5mm steel 90 degrees and I’m struggling, so I need to heat it up. Used to have oxy acetylene, but not anymore.
Does anyone have experiences of what the best gas and torch to use for the highest heat. I think it will be a jet nozzle for the heat, but this is new to me, so to speed up research, maybe someone can help? I don’t want a huge piece of professional kit, just something about the £75-£100 all-in mark.
For highest temperature from a normal non-acetylene gas/air torch, you need to use MAP gas.
I’m not sure if that gives the highest calorific density though (I suspect that it doesn’t).
Yes, I’ve narrowed it down to map gas with a Rothenberger SuperFire 2 torch. Looks about right. Not sure if this gives enough heat for 2.5mm steel. Probably will.
It’s the calorific density (“enough heat”) that I’m questioning as well.
Would it be cheaper/better to get it done by someone with the relevant kit if it’s not going to be a regular job.
Got a resonsbly good blowtorch maybe a decade ago but it’s not been used for years.
in my experience the effect can be considerably enhanced by working in/on a forge style space. A couple of fire bricks (like those in a wood burner) will help in concentrating the heat. I get by with a regular propane torch by Bullfinch.
Standard use for these things nowadays seems to be melting PVC doors to gain entry to people’s homes more or less silently…
Assuming you have a large vice and lump hammer?
I have a vice and lump hammers, but the problem is that a vice can only accept a few inches of the metal.
2.5mm is a lot harder to bend than I thought.
I have bought a Rothenberger SuperFire 2 with map gas. It works very nicely and the torch is very well made. It started raining, so didn’t get a chance to try on the 2.5mm steel.
I’ll come back to you on that, when I have a minute. It might be a long paragraph though😅
Yes, what you need to do is the mark the fold line and bend a section at a time by say 20 degrees until the whole length has a 20 degree bend, then move to 40 degrees and so on. The MAP torch should help.
This was only 1mm but I used my little vice to make it.
Well the answer is that even with the map gas and a professional blow torch, it’s not enough for 2.5mm steel. I only needed to bend 4 corners of 4” wide steel to 90 degrees and although I eventually managed it, it took ages and was a ridiculous pain.
The important thing is you didn’t have to pay anybody to do it 
Yes. However it wasn’t for the payment reason, it’s just I want to do all jobs myself if possible. I always want to learn things and have found by doing jobs myself, not only does it make life far more interesting, it opens up other avenues. I now have a proper blowtorch and gas for loads of other things. I was doing a small area of cladding a couple of months ago and was going to char (Yakisugi) wood. The blow torch I had was rubbish, I had no gas and when the Siberian larch arrived, it looked beautiful, so I didn’t bother. I will now char something. Probably my hand.
It’s too easy to pay someone else to do jobs. I don’t want to be the 80 year old looking out the window with a mug of tea, I want to be like Fred Dibnah (even though he died too young).
I’m with you 100%
As I have found on my car restoration paying just lost me money and not the results I wanted. It was sort of my retirement present but the workmanship simply isn’t good enough.
I’ve always been able to do small paint jobs but I’m now doing the entire car 
I agree with that approach generally, although in this case if you could have found a sheet metal workshop they would have been able to put a proper, tight 90° bend in your steel sheet in a few seconds. With the right tools for the job it’s so quick and easy I doubt they would have had the nerve to charge you anything, and it would have been far neater than anything you could achieve with a vice and a blowtorch. But perhaps that doesn’t matter!
“If” The two small sheet metal places in my home town are gone now.
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