[TheForge] Sidearm burners, Murphy burners & blown burners

[Jerry Frost]

The best way to prevent scaling is to tune the burner a 
little rich, more fuel than air. The neutral air fuel 
ratio for propane is nominally 17.5:1 and you can 
certainly hit this mark. The problem though is propane 
and air don't mix easily so even if you have a 17:1 
ratio you'll have both unburned fuel AND unconsumed 
oxygen being introduced in your forge. A 16.5:1 ratio 
will give you a reducing fire and unfortunately quite a 
bit of CO with the dragon's breath.

My burner runs so rich it reduces scale but it'll have 
your head spinning in a closed space in NO time. I 
don't use it in a closed space if you're wondering. 
I'll build new burners when I get the shop enclosed and 
start equipping it.

Another way to prevent scaling is with an oxygen 
scrubber. This is anything that absorbs free oxygen. My 
favorite is a small piece of charcoal though wood would 
work as well. The possible problem using something 
other than pure carbon is potential contaminents. Wood 
gives off a lot of byproducts when it burns, wood 
alcohol and creosote being the two that I know of off 
hand. Charcoal has already had all the impurities 
driven off.

A gun burner on the other hand doesn't lose to back 
pressure like a naturally aspirated burner does. This 
means you can use a long tube with bends, swirl plates, 
cavitation, introduce the propane ahead of the blower 
vanes and other strategies to mix the air and propane 
thoroughly.

Pros and cons to everything. <grin>

Frosty
-------------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.

http://www.artmetalradio.com/

-- 
From: "Ron Childers" <munlaw2 at hcsmail.com>


> Murphy's atmospheric forge w, double burners doesn't 
> seem to scale the work
> like my blown forge. Maybe a small piece of oak in 
> the forge would reduce
> the oxidation?
>
> Ron C
>