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"Grate" for brake drum forge


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So I scrounged up a brake drum and built a forge with it, but had a few questions/concerns about the grate. It obviously needs to be small enough such that bits of coal/charcoal don't fall into my pipes, but I also want to ensure that I get proper airflow. It's the second of these that concern me the most. I felt like I was really burning through fuel fast with my current setup, and though my fire was hot enough to forge with, it seemed like for the amount of fuel that was being consumed that it should have been much hotter. I constructed a temporary grate from a sink plug (the metal kind).

Does anybody have any suggestions when it comes to the grate? I found this picture:


Most videos/how-to's are vague, just kind of "get some steel and drill holes in it". Any recommended spacings, pattern, or shapes? Pictures would be great too if you've got them. And in general, would you recommend a greater volume of air, or greater air pressure to achieve high heat?



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might try something like this with larger holes as small lumps of coal will clog up the small holes http://www.centaurforge.com/Cast-Iron-Tuyere/productinfo/TUYERE/ or here from ebay

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It obviously needs to be small enough such that bits of coal/charcoal don't fall into my pipes, but I also want to ensure that I get proper airflow.

One mistake that is made is estimating just how much air flow was needed for a forge. More is better, and the grate should not be a restriction to good air flow. It should however not allow the fuel to fall into the air tube.

The brake drum shown in the attached photo has a 3 inch diameter opening. I welded 2 each 3/8 diameter bolts (cut to length) into the hole to act as a grate. It works very well as it allows maximum air flow and I can burn fines (coal dust), as well as other size pieces of coal. It is also used when I forge with wood (such as pallets) etc. For smaller diameter openings I use only one bolt as a grate.

You WANT maximum air flow through the grate. You can control the air flow at the blower or with a air valve if you want less air.

A side blast forge will save you a lot of time and money for pipe and fittings. Simply cover all the holes in the brake drum, and place a pipe horizontally and about 1/4 of the way across the drum. Add air and be happy. I am still experimenting with the "best" size opening on the pipe but 1 inch pipe seems to work. The end will burn away in time so just advance the pipe as it is consumed. Burned away is a little misleading as I have used mine a year with little or no length being burned off the end. Adjust the pipe as needed to get the fire you want. The clinker is formed at the bottom of the fire and does not block the air flow.

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Uh-I don't see anything on the bottom of your tee to keep air from going DOWN? You need a piece of plate on bottom that you can swing open to clean out the ash. ...Or did I miss your mention of that?

First off the link provided IS NOT to an IForgeIron Blueprint, but is a copy of the IForgeIron format. There are several places in that link that I would change, one being incomplete as to the ash dump, or plugging the bottom of the pipe in some manner to stop all you air seeking the path of least resistance and simply blowing out onto the ground below the forge. Another is using a shop vac (on what looks to be the intake, it should be the exhaust side) to supply air to the forge. This is way too much air, but that is another discussion.

The down tube on the bottom blast forge should be as large in diameter as practical, larger the better, and of sufficient volume to hold an amount of ash. With the fire pot shown in the above post I have a 3 inch down tube that is maybe 20 inches long and works well for me. It is emptied it as needed or when it is about half full.

The concept behind the down tube size is it will collect ash and when the ash fills to the T for the incoming air it chokes, or starves the forge from getting air. The only solution to the problem is to dump the ash. With a small diameter tube, the ash can stick in the tube and clog it up, and sometimes the clog will not break up even if you rap on the down tube when the bottom of the tube is open. You then have to find some way of breaking up that clog. Larger diameter down tubes do not seem to have that problem.
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I would post some pics for you to see what I did but I'm computer challenged. Look down the list of topics and look for 55 forge build. I posted some pics and one is of the grate I used.

If you have facebook then you can come visit me and look at all the pics of how we built my 55 forge. Let me know.

For the grate I used a piece of 2" blackiron pipe with two pieces of round stock welded across it. Kind of like the pic that Glenn posted for you. I don't think that the pic you linked to will let you have the necessary air flow. I have no problem with large pieces of coal falling through.

My pipes off the bottom of the brake drum are all threaded pipe which allows me to put a pipe cap on the bottom. I just empty it at the end of the day or prior to the next firing. The pipe below the "t" is 4" long which holds a lot of ash.

Glenn suggested to me that you can have the bottom of the pipe stick into a bucket filled with water under the forge. This will allow the ash to fall into the water of the bucket and the water will keep the airflow from escaping downward. Sounds good to me especially if your pipe is not threaded. Plus with water, no fires under the forge from ash falling on the ground.

I am very pleased with my 55 forge and have no regrets. The brake drum is great.


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