I would love to get my hands on a propane torch that would use
pressurized air (reguires an air compressor) to create more heat as to
be able to bend heavier iron bars. So...

1. Is there such a "combination torch" available anywhere?
2. Could I convert a regular propane torch to use pressurized air as
well?
3. Could anyone provide me with instructions how to make such a torch?

All ideas and links appreciated

Thanks in advance

max writes:

I would love to get my hands on a propane torch that would use
pressurized air (reguires an air compressor) to create more heat as to
be able to bend heavier iron bars

Why would compressing the air increase heat? That's a property of the
fuel/oxygen/inert-gas ratio.

On 27 Jul 2005 23:42:59 -0700, max wrote:

I would love to get my hands on a propane torch that would use
pressurized air (reguires an air compressor) to create more heat as to
be able to bend heavier iron bars. So...

1. Is there such a "combination torch" available anywhere?
2. Could I convert a regular propane torch to use pressurized air as
well?
3. Could anyone provide me with instructions how to make such a torch?

All ideas and links appreciated

Thanks in advance

A good normally aspirated burner should produce all the heat you need. look
up Ron Reil's site, especailly his Mongo burners. Simple and work well.
Otherwise a fan will do for the air supply.
There is still a limit to the heat output - 80% of the combustion air is
effectively inert, sucking up heat and volume. This lowers the flame
temperature and heat output.
You need air volume, not pressure. You need 25 times as much air as LPG, so
the volumes can be a lot. With the flamespread testing machine we have just
finished building at Uni, it uses a pilot burner. This initially was set
with a pressure regulator, but this was incredibly touchy - the needle
wasn't off the stop. We ended up using a $5000 mass flow controller - dial
up the airflow to 6l/min +- 0.01%
If the air velocity is higher than the flame velocity, then it will blow
the flame off the end of the burner. It doesn't take much.
Geoff

On 28 Jul 2005 03:24:07 -0500, Geoff M
wrote:

On 27 Jul 2005 23:42:59 -0700, max wrote:

I would love to get my hands on a propane torch that would use
pressurized air (reguires an air compressor) to create more heat as to
be able to bend heavier iron bars. So...

1. Is there such a "combination torch" available anywhere?
2. Could I convert a regular propane torch to use pressurized air as
well?
3. Could anyone provide me with instructions how to make such a torch?

All ideas and links appreciated

Thanks in advance

A good normally aspirated burner should produce all the heat you need. look
up Ron Reil's site, especailly his Mongo burners. Simple and work well.
Otherwise a fan will do for the air supply.
There is still a limit to the heat output - 80% of the combustion air is
effectively inert, sucking up heat and volume. This lowers the flame
temperature and heat output.
You need air volume, not pressure. You need 25 times as much air as LPG, so
the volumes can be a lot. With the flamespread testing machine we have just
finished building at Uni, it uses a pilot burner. This initially was set
with a pressure regulator, but this was incredibly touchy - the needle
wasn't off the stop. We ended up using a $5000 mass flow controller - dial
up the airflow to 6l/min +- 0.01%
If the air velocity is higher than the flame velocity, then it will blow
the flame off the end of the burner. It doesn't take much.
Geoff


If you want lots of heat....

http://www.harborfreight.com/cpi/cta...emnumber=90621

Gunner

Liberals - Cosmopolitan critics, men who are the friends
of every country save their own. Benjamin Disraeli

Most any jewelry supply will sell you an air-propane torch head. They
aren't really designed for heating and bending big steel bars. For that
you can buy a 3,000,000 btu weedburner for about $50. It runs directly
off the tank pressure without a regulator. No air line required.
Bugs

In Glass blowing we commonly use a National 3A blow pipe. It's a hand torch.
Although they are rated for use with Oxy, they were originally a gas / air
torch. They still offer gas / air tips for them. The link below should take
you to the torch itself. The second link should take you to the gas /air
tips.

If you should get such a set up and have any grief from you local fire
marshal because you're not using welding hose, or have the crimp fitting
rated for 300 psi, or the tip & torch are not UL listed as a welding torch.
Please tell em to KISS YOUR ASS. NFPA 51 does not apply to Gas/ air torches.
Only when oxygen is used does it apply as a hazardous material.

Good luck,

Randy H.


http://www.waleapparatus.com/search_...cti on=Page+2




http://www.waleapparatus.com/search_...ir&PRODUCT_ID=

"Geoff M" wrote in message
...
A good normally aspirated burner should produce all the heat you need.
look up Ron Reil's site, especailly his Mongo burners. Simple and work
well. Otherwise a fan will do for the air supply.

Don't forget the firebricks! Heavy bar will take a few minutes to heat up,
even with a hot forge.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

On 27 Jul 2005 23:42:59 -0700, "max" wrote:

I would love to get my hands on a propane torch that would use
pressurized air (reguires an air compressor) to create more heat as to
be able to bend heavier iron bars. So...

1. Is there such a "combination torch" available anywhere?
2. Could I convert a regular propane torch to use pressurized air as
well?
3. Could anyone provide me with instructions how to make such a torch?

All ideas and links appreciated

Thanks in advance

It would help if you would define "heavy bar" in terms of size.

Meanwhile, visit
http://www.frontiernet.net/~gnreil/design.shtml