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I Forge Iron

clinker HELP!!


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Hi Alec,

I have a theory. Myself and a mate both have identical forges. The forges are bottom air fed via 70mm square hollow tube up through 10mm plate steel, with 9 x 3/8" holes drilled in a square pattern.
The mates forge fires directly off the plate and he boxes his fire in with house brick size firebricks. He has the same problem of the coke turning to a sticky, fluffy consistency after a half hour of lighting up.
My forge has a 1 1/2" thick firecrete pad fitted around the 9 hole air inlet thus raising my fire up off the plate steel, and I don't get the toffee mass. In fact, my fire generates clinker the size of a large marble, that are very easy to remove. I don't get the sticky mass that he does.
I reckon that if you could lift the height of your fire, it may solve or reduce your problem.

I hope you find a solution. It's not much fun forging with toffee-like coke.

Cheers,

Rob K
Secretary
Artist Blacksmiths Association South Australia

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I used a side blast coke forge for a week at a class a while back. I found the hot spot was above the blast a couple inches. The sand and clinker reflected the heat upward so I ended up placing the work directly above the end of the air nozzle. The other trick that helped was to give the clinker a bit of a lift at the start of each heat with a straight poker. I could hear the blast improve with just a slight nudge. The advantage of the side blast is it allows the clinker to settle below the air blast. I think you may be burying the work a little too deep.

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After spending the weekend at Moonies watching blokes using forge fires, one thing I have noticed is a lot of nubies need to focus on fire control a lot more. With regards to removal of clinker, keeping a decent depth of fire under their jobs, keeping on putting fuel on the fire (remember the saying little light and often), rather then letting the fire almost go out then swamping it with fuel, crush and SCREEN the coke if you are using it, keep lifting the fire up with the poker to keep air going through it, keep raking the fuel back onto the fire, after it gets pushed out the back as you push your jobs into it. Running a fire is a full time housekeeping job. The fire needs constant maintainance.
Too little fire and too much air is a sure fire way to produce clinker.

Phil

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I'm no expert on coke fires but I have learned a few things. Fire management is huge!
If your getting the muck, your fire is to small (pushing your material in to far) or your clinker is to big. Build the right fire size for the job and add little bits of coke at a time as needed. I like to keep my fire high in the pot (not high on it) so I can lay my work flat on the forge table for support. Then I cover the area I want heated with about 1-1.5" of coke.

I shared a forge with a guy I nick named "the excavator" every time he put a piece in the fire, he would drive it into the bottom of the fire pot and then push up on it. Ruins a perfectly good fire every time.

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Hi Alec, welcome to the site, whereabouts in the UK are you?

If you can, go along and see a local smith or smithing event and see and ask how they control the fire. Our website gives details of where we can be found, any of our members will be pleased to help Blacksmiths Guild Home or can you get along to the St Clem,s day event at Finch Foundry at Sticklepath later this month where you will see many smiths working in both side blast and bottom blast forges and have a go yourself with a bit of guidance if you want

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After spending the weekend at Moonies watching blokes using forge fires, one thing I have noticed is a lot of nubies need to focus on fire control a lot more. .... Running a fire is a full time housekeeping job. The fire needs constant maintenance......Phil


Unfortunately, the local guild's management has decided that because beginners tend to throw water on the fire-pots, no-one will be allowed to use water in the guild's forges to teach proper management of forge fires or to properly manage forge fires. The end result is that practically very few people in the area know how to manage coal fires any more. :(

The result is that more and more "knowledgeable" smiths are convinced that coal forges are too smoky to work with. :(
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I'm in north norfolk and i use exactly the same coke as our local blacksmith!


What is the fuel Monkton forge coke ? or other?

Do you use it how he does, and if so does he have clinker problems too?

I would suspect you are using excess air and a lot of new fuel for starters
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Hi Dphigh
I am near Lincoln, there is a chap near Bourne heading down towards Stamford who stocks smithy breeze but you have to get in at the start of the year as it goes fast.
For some time I have been using coke from cpl, its not cheap but it does the job.
I probably have to clear the clinker out of my forge about 4 or 5 times a day on a days burn - I just knock off the blower make myself a coffee then lift out the clinker and restart the blower......

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The forging coke from CPL is usually Monkton coke, it comes in two grades, I prefer the smaller grade.

It may help to let it dry out and sieve out some of the dust to minimise clinker, as well as keeping the draught down to the minimum you need to do the task you are working on.

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While I was forging yesterday i realised that the goo that sticking to my metal was actually from the bricks that surround my fire.

thanks for the comments!
p.s i probably should have said that i had a brick forge at first because i don't have the resources to weld or grind.

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