first coal forge

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Phillip5505
Posts: 16
Joined: Wed Aug 24, 2016 11:20 pm

first coal forge

Unread post by Phillip5505 » Wed Aug 31, 2016 11:34 am

I'm building my first coal forge and have questions. I have looked at meny different forge designs. I cant figure out what the real difference is between a rivet forge and a shop forge. Other than portability and the size of the pan is there any difference that makes one perform better than the other?

Martin Pansch
Posts: 312
Joined: Thu Feb 14, 2013 10:44 am
Location: Young America, MN

Re: first coal forge

Unread post by Martin Pansch » Wed Aug 31, 2016 9:18 pm

Hi Phillip,

Rivet forges generally have a flat bottom with no fire pot. Back before every farm had an Oxy/Acetylene torch they had relatively cheap rivet forges to heat things up, bend them back into shape and, in a pinch, forge weld them back together (though you had to get creative with your fire building). These were also common for, you guessed it, heating big rivets for any construction projects using steel, like sky scrapers, ships, etc so these forges can be found all over the place.

Most proper blacksmith forges have a fire pot of some sort. This is the sunken area in the middle of the forge that, well, holds the fire. This lets you more easily make a deeper fire which is important for controlling the oxidation of the piece you are working on. It also helps with getting a more focused fire for forge welding.

You -can- do a lot of work with a rivet forge if that is all you got but I would suggest making a pseudo-fire pot with a couple bricks. Also, many rivet forges have rather small blowers on them too meaning you have to pump/crank the bejezus out of them to get enough air to heat anything big or hot enough for forge welding. All things considered though you would probably be more happy with a forge with a fire pot and good sized blower.

Phillip5505
Posts: 16
Joined: Wed Aug 24, 2016 11:20 pm

Re: first coal forge

Unread post by Phillip5505 » Wed Aug 31, 2016 10:56 pm

This is what i have so far with only about $50 invested in the steel and pulleys. Any suggestions would be greatly appreciated. The blower on the rivet forge in the background is shot and had to be removed. Im not above starting over if thats what would be best but i don't have much extra funds.
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Phillip5505
Posts: 16
Joined: Wed Aug 24, 2016 11:20 pm

Re: first coal forge

Unread post by Phillip5505 » Thu Sep 01, 2016 11:51 am

Would it be a good idea to taper the sides in with refractory material? I lined the bottom to hold the cast ironplate in place and to fill the bolt holes

Martin Pansch
Posts: 312
Joined: Thu Feb 14, 2013 10:44 am
Location: Young America, MN

Re: first coal forge

Unread post by Martin Pansch » Thu Sep 01, 2016 12:54 pm

Hi Phillip,

I love the Rube Goldberg-ness of your blower. What it lacks in compactness it makes up for in ingenuity. How well does it blow? Can you comfortably crank it while tending the fire?

Yes, I would think claying the sides of the fire pot so that the coal funnels down towards the tuyere will improve the performance of it. I have never clayed any of my forges or fire pots before but have made octagonal truncated funnel inserts out of steel plate for fire pots like yours to do the same thing and it improved things. Some folks have told me they experienced hot, coking coal sticking to the clay a little in use. I will be interested to hear your experience.

The other thing I would recommend, if you haven't planned for it already, is to have some sort of forge top that your fire pot is sunk into. I like having it level with the top of the firepot so it makes raking the coal into the fire pot easier. You could make a fire in it as it is but in the course of managing your fire you are going to be dropping coals, some of them hot, from the fire pot all the time. Enough to make it messy and a bit of a pain. If you don't have any material suitable let me know, I have a collection of steel plate drops that might work.

Phillip5505
Posts: 16
Joined: Wed Aug 24, 2016 11:20 pm

Re: first coal forge

Unread post by Phillip5505 » Thu Sep 01, 2016 10:35 pm

There is a pan in the works but im trying to decide what gauge and design to use. I'm going to work it as is for now until I can decide

Ashurbanapol
Posts: 4
Joined: Fri Mar 08, 2013 10:50 am

Re: first coal forge

Unread post by Ashurbanapol » Fri Sep 02, 2016 10:47 am

Phillip, a lot of experience tells me that refractory anywhere clinker will form is not a good idea. The clinker will bond to the refractory and pull it off when the clinker is removed. If you use refractory, I suggest leaving a flat area around the air inlet (tuyere) . A firepot that comes to the tuyere without a flat area will choke with ash and clinker very quickly. The good thing is you can modify refractory easily. If the refractory gets clinker stuck to it, it should not be there and you need to modify it a bit. I suggest jumping in and doing it in a reasonable way and pay attention to the above. It's how we obtain an education!

Phillip5505
Posts: 16
Joined: Wed Aug 24, 2016 11:20 pm

Re: first coal forge

Unread post by Phillip5505 » Fri Sep 02, 2016 5:02 pm

Well I've tried it out and the coal im using doesnt like the hand blower. It's almost impossible to keep it lit. Also was hard to crank fast enough. So i hooked up an exaust blower from a furnace and now it works good. I needed a more constant air flow i think.

Martin Pansch
Posts: 312
Joined: Thu Feb 14, 2013 10:44 am
Location: Young America, MN

Re: first coal forge

Unread post by Martin Pansch » Tue Sep 06, 2016 5:13 pm

Sorry to hear the blower doesn't cut it. I always root for the home built equipment. Maybe a little tinkering will get it working better. Of course, it is tough to improve on a nice Canedy Otto or Champion designed by serious engineers in a time before engineered obsolescence. That said, an electric blower is really nice too.

As for the coal not staying lit, what kind of coal are you using? If it is anthracite stoker coal versus good blacksmithing bituminous it can be really difficult to maintain a fire even if you have a good blower.

Phillip5505
Posts: 16
Joined: Wed Aug 24, 2016 11:20 pm

Re: first coal forge

Unread post by Phillip5505 » Wed Sep 07, 2016 11:31 pm

Im using anthracite rice coal i got 400lbs for $25 so ill make it work for now it a long way for me to get the good stuff

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