[TheForge] atmospheric forges getting hot

Tue May 31 02:52:33 EDT 2005

Solutions to the problem of not enough air flow are as old as the craft, 
pretty much.
Long before there were blowers and compressed fuel gasses, folks used 
thermosyphons to aspirate their forges, furnaces and kilns.
Build a stack..preferably insulated, for your exhaust...if you do it 
right , it'll really suck.
When I had a big job splitting and drifting a couple hundred 1" sucker 
rods, my little Sandia forge had trouble keeping up.
But it was possible to coax enough extra heat out of it to keep forging 
nonstop by improvising a stack using bailing wire and refractory 
half-bricks ..plus cranking up the gas pressure. PF

Chuck Robinson wrote:
> Hey Ralph, Michael,
> I've got 2 optical pyrometers that use a comparator lamp, but need to 
> jury rig some 4.5 volt batteries for them.
> The one I'm using now is pretty unusual, it contains a vacuum 
> thermocouple and is self powered by the heat source. It is also dead 
> accurate.
> Ralph you are right on about forge temps. To get
> your average design, atmospheric Burner (AB) forge much beyond 2200 F 
> requires a lot of tweaking.
> I've observed that the AB's are very sensitive to back pressure, so the 
> present forge has very little. I also experimented with various sized 
> mig tips to attempt to get the optimum burn.
> I haven't tried the IR coatings yet but intend to.
> The best explanation in my mind is that the AB is self limiting in it's 
> heating potential because the venturi effect limits the amount of O2 in 
> the burn.
> One fellow I read about, said that the  Nitrogen/O2 ratio in air about 
> 80/20 limits the amount of O2 that can be drawn thru the burner shaft.
> He experimented with a closed bell reducer with inlet tubes for 
> compressed air and an O2 generator and was quite happy with the results.
> I have an O2 generator left over from my open heart surgery so I might 
> try his technique.
> The need for the AB forge is for demonstrating Damascus forging at 
> primitive sites.
> Mardi is using Pure TI and AL4v TI in alternating layers.
> He cleans the surface oxide before assembling the billet. I think he 
> said that he uses a borax flux in open forges and blows inert gas thru 
> his forge at home.
> What does Phillip say his forges maximum temperature is?
> "K" thermocouples short out at 2450 F  and stop recording accurately at 
> about 2300 F.
> so his controller thermocouples must be some high temp beauties.
> Chuck
> 
> 
> ----- Original Message ----- From: "Ralph Sproul" <brhlbsmt at mcttelecom.com>
> To: "Sponsored by ABANA" <theforge at mailman.qth.net>
> Sent: Monday, May 30, 2005 2:12 PM
> Subject: Re: [TheForge] atmospheric forges getting hot
> 
> 
>> This castable refractory nozzle with the 40 some odd holes sounds like 
>> the
>> ones made for glass blowers heating large kilns.  If you put one of 
>> those in
>> a confined space you certainly have heat - they do require a blower.
>>
>> Chuck? - I noted mentioned NOT using compressed air - were blowers being
>> considered for getting temps above 2500?  Or was the question just 
>> naturally
>> aspirated burners?
>>
>> Ralph
>>
>> ----- Original Message -----
>> From: "Ries Niemi" <rniemi at fidalgo.net>
>> To: "Sponsored by ABANA" <theforge at mailman.qth.net>
>> Sent: Monday, May 30, 2005 1:37 PM
>> Subject: Re: [TheForge] atmospheric forges getting hot
>>
>>
>>>
>>> On Monday, May 30, 2005, at 08:17 AM, Chuck Robinson wrote:
>>>
>>> > I'd like to hear from anyone who uses an atmospheric propane burner of
>>> > any design that actually has accurately measured a forge temperature
>>> > hotter than 2500 F-
>>> > with out usig auxilliary O2,  compresser air or a blower boost.
>>> > Chuck
>>> >
>>>
>>> Chuck- I am pretty sure mine does, but I have never measured it.
>>> Mine is an atmospheric design developed by the amazing Phillip Baldwin.
>>> Starting at Carbondale in the late 70's, Phillip and a few others have
>>> been refining atmospheric forge burners.
>>> He manufactures MokeMegane, and he needs controllable high temps for
>>> his processes- he has digitally controlled propane forges and furnaces
>>> that are capable of quite high temps.
>>> The forge I am currently running, which is one of his latest designs,
>>> is a cast refractory cylinder, with cast refractory ends. 2" of kaowool
>>> is wrapped around the outside- none on the inside. The burner itself
>>> features a Baldwin forged from pipe mixing chamber, and a cast
>>> refractory burner tip that is approximately 4" in diameter, with maybe
>>> 40 small orifices, each about 1/8" in diameter. Air/gas mix is
>>> controlled by a sliding gate well before the burner.
>>> You might email Phillip at his website- www.shiningwave.com
>>> and ask him more about his designs.
>>> He forge welds in them all the time, and does a wide variety of highly
>>> controlled mokeme, as well as ferrous laminations. He also uses them
>>> for accurate heat treating of knives and swords- they are probably just
>>> what you are looking for.
>>>
>>> Me, I am just an ignorant user of them- but Phillip has evolved these
>>> designs over 20 years, and he really knows what he is doing. They are
>>> quiet, very hot, and very nice forges to use.
>>>
>>> ries
>>>
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>>
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