Seph

First Gas Forge

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Good evening ladies and gentlemen!

Having read though a few of the previous threads in the gasser subsection I couldn't find information which would improve my understanding of the intricacies of constructing a forge.

Ignoring which burner I would construct to heat my forge I was hoping I could list out the materials I would use to construct the forge and learn whether or not the items I intend to buy would work or be a waste of time and money?

I aim to build my forge inside of an empty gas canister 500mm in diameter and about 700mm in height. For lining the forge I was going to use a two layer system of ceramic fibre blanket underneath castable refractory cement in order to speed up the heating of the forge and save fuel. I've read in other threads that where people had only used castable refractory it lead to increased heating times and fuel inefficiency while fibre only builds introduced the risks of breathing hazards and damage to the wool from the flame exposure.

My only concern is that the fibre that I have singled out (being available by the metre as opposed to buying a whole whopping big roll of the stuff!) has a lower melting temp than my refractory.

The temperature limits are 1260degC for the fibre and 1600degC for the cement. Would 25mm of cement be enough to protect the fibre from temperatures in excess of its melting point or would I need to go thicker, increasing heating time but not liquefying my fibre?


I'll post links to the products I intended to use before happening upon iforgeiron and prepare myself to be schooled :)

 

Ceramic: http://shop.vitcas.com/vitcas-refractory-castable-grade-1600-refractory-concrete-505-p.asp

Fibre: http://shop.vitcas.com/ceramic-fibre-blanket-25mm-vitcas-ceramic-insulation-197-p.asp

Rigidiser: http://shop.vitcas.com/vitcas-ceramic-fibre-rigidiser-1035-p.asp

Many thanks in advance!

Seph

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First thoughts throw up 2 questions:

Why so big?

Where in the UK are you?

I'd really suggest you sit down with a pencil and paper and make a couple of lists. One with the "must haves" and the other with the "would likes". Aim to keep the must-haves to the stuff you realistically expect to be doing within 3 months. Be realistic and include the sizes in the lists. Also be honest about welding; if it can go in the "would likes", it makes building for the "must haves" a whole lot easier (and cheaper).

Come back with the must-have list.

Forget any ideas you might have about building the ultimate forge first-time. Whatever you might know about forges now, you'll know a lot more with 3 or 6 months experience under your belt and will be in a much better position to decide what you need to build in order to do the job(s) you want your forge to do (be aware that the jobs you want it to do may well have changed by then, too).

Castable within fibre is certainly a good way to go for some things. Be aware that the drying schedule for castable can be pretty difficult to accommodate in many places over here if you work in an unheated shed, particularly coming into winter. Not all burners are able to provide the turndown for low-firing the castable either.

As you are in the UK, I'd urge you to at least consider a burner based on an Amal Atmospheric Injector if you have not already decided.

 

 

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Looking at my unit converter the ceramic refractory blanket should do fine under 12-13 mm of hard refractory inner liner or flame face. You can check with companies who service boilers. I don't know about your side of the pond but here they can't use left overs servicing a furnace so any that's been cut from the roll but not used gets thrown out. They give it to me when I ask. I haven't purchased Kaowool (the ceramic refractory blanket they carry) in many years now. They also give our blacksmith club a commercial discount. Good guys and they LIKE to talk about fire especially HOT fire.

I have to agree with Tim, you really need to learn more about the craft before you start building equipment we ALL build too big especially when we're starting out. My newest gas forge is less than 1/2 the size of my old shop forge and guys are asking me why I built this one so big.

There is a LOT of  good solid information in the sections here on Iforge there is also a couple threads going about building burners and forges a couple seminars hosted by Mike Porter, well known for designing high performance home build propane burners. His book can be found online if you look. I build a different burner of the same basic type. MIkes run like Ferraris ad mine run like a trusty old pickup truck. We've also been talking about building forges the hows and whys of different designs.

You'll be much farther ahead if you set your current plans aside till you've spent some time reading and hopefully taken a couple classes in blacksmithing so you'll have some idea of what you need and how to build it.

Frosty The Lucky.

 

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Many thanks for all of the replies here! I didn't run off to compete for the Darwin awards ;)

Lurking in the forums here for a while now and I can see why you would be anxious about people who are just wanting to jump into this.

Upon more reading I have posted this in the wrong section of the forum as what I am intending to make is a melting foundry as opposed to a forge (although that may end up being a later project). I also understand that each come with their own risks, this particular PDF was highly useful! http://prometheus-foundry.com/The Hobbyist's Guide to Casting Metal--2nd Edition (web).pdf

This might be the reason why you thought the dimensions seemed on the large size; I am looking to hold a 0.75L A4 graphite clay crucible in it with the possible option to increase the size of crucible when I am confident at working with smaller volumes of liquid metal. As it turns out the canister is smaller that I had initially thought as well.

Attached are some quick digital model images with dimensions of the materials I am working with and what I intend to make them into.

Many thanks, Frosty, for your advice about boiler service companies! As it turns out a friend's father works as a boiler-man for a an industrial unit and procured me some ceramic fibre wool which he uses for insulating their industrial boilers. After checking the packaging it seems it's rated to the same 1260 Deg C as the wool I was looking to buy so that saved me some pennies.

As I stated in my initial post, the inner hot face will be refractory cement followed by ceramic wool. My process will be to clean the inside of the canister with a wire wheel before using a ceramic wool adhesive to attach the ceramic wool. Once glued in place I'll use a rigidiser solution to stiffen it up before mounting a form on the inside so that I can pour my cement in between the two. The final layer will be one of a zircon paint to help reduce corrosion from any eventual crucible failures.

If you have any constructive criticisms about the design they would be most appreciated.

 

(I also bought a tonne of PPE. Looking back it is absolutely ridiculous that the inspiration for this, the kingofrandom, uses none whatsoever...)

Once again, many thanks!

Seph

Gas Foundry Dim 1.png

Gas Foundry Dim 2.png

Gas Foundry Dim 3.png

Gas Foundry Dim 4.png

Gas Foundry 1.png

Gas Foundry 2.png

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Have you visited over at the alloyavenue.com ? Its a series of forums dedicated to casting---used to be backyardmetalcasting.com IIRC

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29 minutes ago, ThomasPowers said:

Have you visited over at the alloyavenue.com ? Its a series of forums dedicated to casting---used to be backyardmetalcasting.com IIRC

I have not, I'll give them a look in.

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For a typical casting furnace, you are best off to heed the advice of Wayne about choices of refractory materials; most of the guys here are not use to considering what crucibles and steel tongs can do thin hard-face layers. Also, I see no mention in your plans for an emergency drain hole for liquid metals after crucible failure during a heating cycle. You also need to provide a sand bucket for the the casting furnace to set over, so that drained liquid metals from crucible failures have a safe place to cool down; this, and a contained layer of sand for spelt metals to cool down in, along the crucible's path between furnace and mold are needed if you want to avoid a Darwin award:o

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15 hours ago, Mikey98118 said:

Also, I see no mention in your plans for an emergency drain hole for liquid metals after crucible failure during a heating cycle. You also need to provide a sand bucket for the the casting furnace to set over, so that drained liquid metals from crucible failures have a safe place to cool down; this, and a contained layer of sand for spelt metals to cool down in, along the crucible's path between furnace and mold are needed if you want to avoid a Darwin award:o

No mentioning but it is there I promise :) (bottom of the last picture)

I also have made up a small sand box which I have been doing all of my pouring over to keep things dry and safe (no pouring over concrete here!)

I have been doing small melts using a bucket forge with the same refractory and a garden weed burner as my heat input however I'll be moving towards constructing a gas blower which will be more suited to the job.

 

Many thanks for all the responses so far!

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At least you're not incorrectly calling it "smelting" like some who've been here...

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On 11/03/2017 at 1:34 AM, Mikey98118 said:

What metal did you set it up to cast?

Aluminium, Copper, brass and Bronze.

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