Roy Honcho Gregory

Doors for a propane forge. Please

18 posts in this topic

I working on a gas forge out of propane tanks. Things are real close.
I am wondering about Doors.

1, If I use metal for doors I'll have to cover them with that Unifrax blanket, RIGHT

2, If I use fire brick how would I do the doors ? I have seen pix around here,
but can't seem to find them. Any ideas


Thank All of You for your help

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You can make a metal frame to hold firebrick.

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Doors can be a pain, the fire has to exhaust somewhere and out the door is the usual. This means metal is going to warp unless you put enough refractory on and around it to shield it from the fire. I've made doors but haven't liked them much. The forge I use now I stack firebrick to restrict the openings.

I'm not familiar with "Unifrax." What's it's working temp range, failure temp, availability, etc.?

Frosty The Lucky.

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I weld C-channel (3-inch standard) on the ends of my forges and use soft fire brick for the doors. I also cut a slot in the side and weld a little table on the bottom.... and use soft fire brick for a door there when I don't want it open... Soft fire brick can be cut with any hand saw (yes, it is hard on the saws) and/or course file. I cut the brick so it can easily be slid back and forth.

Works well for me.

I do this with both round and box forges.

post-585-0-62023300-1332811473_thumb.jpg

post-585-0-56367000-1332811492_thumb.jpg

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Roy: 2,600f is plenty, I'll be checking these guys out. I may be able to get it here, we have to ship everything in so there's no telling what you may find.

Dave's set up looks good, just don't make the tracks fit too closely, they will warp from heat and if they're tight it won't be long before the bricks won't slide.

I just stack bricks in the opening to block as much or little as necessary. The attached pic is my forge in action, you can see some of the bricks I use to restrict the openings. Only one quarter is running and you can see some of the bricks I use to block the chambers internally.

Frosty The Lucky.

post-975-0-15031100-1332829186_thumb.jpg

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Dave we should have our own forum LOL. I'm lookin to you for help at both threads.

When you say your using SOFT bricks I see frie bricks in your pix

I understand soft bricks to bee kinda like Styrofoam and easy as butter to cut. Do I have them mixed up ?
I did start door like yours. but I still may use 1 20# tank instead of 2, 20# tanks

Thanks for all you help Gents.. Someday when I get this done and banging some metal.
I'll beable to help the next batch of new "Iron Heads"

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Roy...

Soft fire bricks are almost as easy to cut as styrofoam. I use an old carpenter saw and/or a farrier's rasp to shape mine. If you put your 3" channel about nine and a quarter inches apart (inside measurement, and parallel), you should only need to shave a taper off both sides on the top and bottom. Be sure they slide easy, or you will be breaking them. Also, they do degrade because of the heat (over time), so you have to replace them occasionally.

Best of luck....

Dave

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Dave I have read several threads you have had valuable input on. I am new to the idea of building a gas forge, but your pictures and insights I believe are helping me along quite well. I Have a question though, is there a reason you chose to go with the soft bricks for making your doors over the hard bricks?

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my thought is the simplest way to say it is the hard brick are meant to withstand the heat but not retain it where the soft brick will retain the heat but breakdown more quickly

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Hard fire bricks take a lot of heat from the forge, but they last longer than a soft brick does. Both bricks can be helped by coating them with a bit of ITC100 or the like so that the IR from the forge is reflected back in.

Saw one guy actually wrapped his bricks in chickenwire and then coated them with a refractory....

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Plane-crazzy.....

Sorry I didn't see your question before now... I use soft bricks for two reasons. First of all, they are easy to cut to allow them to slide in the C-channel. Secondly, as stated by others here, they allow the forge to heat up quickly. I had used soft brick for doors for years without any reflective coating. I started using coatings on them last year with even better results. I'm confident that ITC-100 would work well as a reflective coating on them (increasing effiency)... just be sure that, when you cut the bricks to size and shape, there will be enough room to put on the coating without affecting your ability to slide them easily (if you use C-channel). Also, be sure you have removed all dust from cutting before you put on the coating (I blow it off, but be careful not to breathe the dust). You can also just stack bricks in front of the ends of a forge. I use the C-channel because I want the foot print of the forge to be small... and I want to be able to move the forge easily.

I know smiths that use hard brick for doors, but it takes significantly longer to get to forging heat. Also, cutting the hard brick to fit the C-channel I use would be difficult. It could be done though, using masonary blades in a saw...(like for ceramic tile cutting). A wet saw would be best, but I have cut hard bricks with a dry masonary blade (wear a mask while cutting).

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I have been watching Hoenirson's forge build with great interest, as I am about to embark down this same path.  His very well made forge is at the point of tweaking the door design.  Doors on gas forges bring up so many questions in my mind, I have noted that designing a forge is a little like designing an airplane everything you do is a compromise, you can make the airplane very fast, or you can make it capable of lifting heavy weights, but you cannot make one that does both.   Same with forges, you have to sometimes give up something if you want something else. 

I am thinking that my new forge is just going to have sliding fire bricks for doors.   Here are the problems I see with metal doors:  Besides structural design complications,

When shut.

You cannot see the work piece to determine its temperature.
The back pressure on the burners changes considerably, possibly effecting combustion?
Many work pieces are longer than the forge which restricts closing of the door/s anyway.

It seems to me that the only time I would want to shut the doors is when bring metal up to forge welding temperatures, and then I would be reluctant to do it because I was taught to watch for sparklers before the metal starts to burn,  I need to see the metal to do that!  And this thought assumes my new forge will get that hot, and I don't know that it will. 

I hope to hear from those of you who deal with gas forges everyday and who have opinions about doors.  Why would I need a good closing door on my gas forge?  Thank you.

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10 hours ago, stockmaker said:

 

I hope to hear from those of you who deal with gas forges everyday and who have opinions about doors.  Why would I need a good closing door on my gas forge?  Thank you.

Subscribing because I was wondering the same thing. I am planning loose fitting fire brick doors with channel tracks but I don't forsee them ever being closed all the way.

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My Kast-O-Lite is presently curing and I will be starting my doors soon. I am going with 2 soft fire bricks that will slide on angle iron rails. One thing I am considering is to cut a notch into each fire brick so when the doors are closed I will still have an opening for exhaust and a viewing hole. Not sure if this would make the bricks break though. I could accomplish the same thing by just not closing them all the way and having a vertical slot instead.

forge sun.jpg

firebrick doors.PNG

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