[TheForge] New forge

Sat May 5 07:40:35 EDT 2012

I had a busy two days sorry for the late response.

I did the tune up of the burner, got the flare sorted out and put some 
control on the air inlet to be able to control the flame better. I am 
very happy with the result. I took a 20mm square bar from cold with a 
cold forge to dull orange in about 3 minutes. The hard fire brick in the 
bottom of the forge was only dull red by that time.

I am a happy camper I'll keep that forge for a good while I think.

I do need to make a good stand and some peripherals to go with it now.

Thanks for all the suggestions I did use them in what I did.

Bruce I do appreciate the explanation about the pressure regulator. I'll 
keep my eyes open for one to either modify if it is a low pressure 
regulator or use if it is suitable as is.

Geoff

On 3/05/2012 10:55 PM, Bruce . wrote:
> Glad you're having better luck.  Remember that the orifice also
> matters.  As Frosty points out, a longer orifice may give a better
> laminar flow -- analogous to shooting a rifle rather than a pistol.
> However, I've got quite good behavior from holes drilled in pipe walls
> or pipe plugs.  Inspect the orifice to be sure it's clean and
> burr-free, especially on the outside (i.e., where the propane
> emerges).
>
> Yes, do look into getting a regulator.  Like I said, some gas-grill
> regulators can be modified to work.  (I've done it.) A valve alone
> does not control pressure, only restriction.
>
> If you're into electricity, it's rather like having a battery that
> will lose voltage with time (or sometimes gain voltage if warmed), and
> trying to control current with just a variable resistor.  Unless you
> have a voltage regulator (analog to a pressure regulator) in the
> circuit, the current (flow) will change as the voltage (propane
> pressure) changes.  Since small propane tanks cool significantly
> during use, this can be quite a nuisance.
>
> In the case of propane, which never produces much pressure at the
> tank, lack of a regulator is probably not a great safety concern.
> (It's a different matter with a high-pressure -- e.g., 2400 psi --
> cylinder.  Those should never be used without a regulator.)
>
> As to flux in the forge -- it will destroy  mineral wool in no time,
> and insulating firebrick only a little more slowly.  The answer is to
> put a protective layer on the bottom.  You can use kiln shelf, if you
> can get it, but the simplest is to cut a thin SS sheet to fit the
> bottom of your forge -- and maybe a little up the sides -- and use
> that whenever you use flux in the forge.
>
> On Wed, May 2, 2012 at 7:17 PM, Geoff Nelson<gjn.pub at gmail.com>  wrote:
>> Thanks for the comments Bruce.
>>
>> I did a test yesterday evening with a 3/4 inch pipe on the Side arm by
>> using a pipe nipple and reducer. Much better. I don't think I will get
>> to welding heat in the current forge set-up. Not that I want to destroy
>> the interior with flux. I don't use a regulator. I attach the burner
>> directly to the propane tank and use the valve on the propane tank for
>> controlling the flame.
>>
>> I need to work out a flare for the smaller burner tube to help with
>> flame stability.
>>
>> I'll make a smaller forge specifically for welding Damascus billets.
>> Made one once before form one hard fire brick and one insulating fire
>> brick that were suitably carved out with an angle grinder and then
>> placed together as a two brick forge. It worked very well for small
>> billets as I could easily get welding heat out of it with a smaller
>> burner. I think it could be a little more efficient than running the
>> larger forge up at welding heat.
>>
>> I'll have a look around for an old regulator to see if I can do the
>> modification and start working with a regulator.
>>
>> Geoff
>>
>> On 2/05/2012 9:35 PM, Bruce . wrote:
>>> Geoff,
>>>
>>> Have you checked the available resources about burner design?
>>> Here's one:  http://ronreil.abana.org/Forge1.shtml
>>>
>>> There's a book available (which I haven't read):
>>> http://www.amazon.com/Gas-Burners-Forges-Furnaces-Kilns/dp/1879535203/ref=sr_1_1?s=books&ie=UTF8&qid=1335958147&sr=1-1
>>>
>>> A 1" burner sounds a bit on the large size if, by that, you mean 1"
>>> schedule 40 pipe.  My burners are all 3/4" pipe.  A #70 drill orifice
>>> will give you good heat but not welding heat.  You should not need
>>> larger than a #60.  This assumes you have a propane regulator that can
>>> be cranked up to 20psi or so (though that's not always needed)
>>>
>>> A side note:
>>> I'd known for years that the range of a regulator could be changed by
>>> swapping out the adjusting spring.  I recently discovered that some
>>> regulators thrown away with gas grills have a screw-cap over the
>>> adjusting spring.  These regulators normally put out low pressure --
>>> probably less than 1 psi (I haven't measured it).  Swap out the spring
>>> and you can go much higher.  You'll need to find, modify, or make a
>>> coil spring to fit the space.  The length, OD, and flatness of the
>>> ends must match the original spring.
>>>
>>> On Wed, May 2, 2012 at 2:55 AM, Geoff Nelson<gjn.pub at gmail.com>    wrote:
>>>> Normally I lurk but it is quiet.
>>>>
>>>> I have managed to do something in-between working on my house and
>>>> working for the money to work on my house. I built a small gas forge
>>>> from an old propane tank. I lined it with wool impregnated with a
>>>> rigidiser. No idea what the product is as I bought it from a refractory
>>>> supplier as it was over runs from a commercial project. The bottom of
>>>> the forge has a hard refractory brick to rest material on. I am using a
>>>> 1 inch side arm burner. Yesterday I decided to make a stirrer for dry
>>>> wall compound and got a length of 8 mm reo to forging heat in less than
>>>> 2 minutes from cold. I am very happy with the performance.
>>>>
>>>> However I am not entirely happy with my burner so I am going to have to
>>>> do some work on that. I think I do not have the correct ratio between
>>>> gas jet size and burner open area. I don't know the size of the orifice
>>>> so I will play with open area rather than rebuild the whole burner.
>>>>
>>>> Geoff
>>>> Drouin, AU
>>>>
>>>> On 2/05/2012 1:18 PM, Mike Spencer wrote:
>>>>> Dan wrote:
>>>>>
>>>>> dk>      testing.....I haven't gotten a letter from theforge in 7 days....
>>>>>
>>>>> and Frosty replied:
>>>>>
>>>>> jf>      Been hanging around, not much to report...
>>>>>
>>>>> Same, more or less. Doing odds and ends getting ready for gardening
>>>>> time -- fix up electric deer fence, haul home some manure, compost the
>>>>> past year's kitchen garbage, intall a new pea trellis.  No excitement
>>>>> at the anvil.
>>>>>
>>>>> jf>      ...except it's been warm and I'm enjoying it.
>>>>>
>>>>> In Nova Scotia, two 80F days in mid *March* -- unheard-of.  If it hits
>>>>> 80 for a week in August, everybody complains about the heat.  Now
>>>>> three nights of hard frost at the very tail end of April.
>>>>>
>>>>>
>>>>> Just keeping Dan's mailbox warm, y'unnerstand. ;-)
>>>>>
>>>>>
>>>>> - Mike
>>>>>
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