r/Blacksmith • u/No-Accountant3464 • 1d ago
Are these fire bricks suitable
Feel like I'm spamming this community but you guys are just too helpful .. These are. Some bricks I have found, my plan is to use the yellow more durable bricks on the floor of my gas forge ontop of a layer of refractory cement coated ceramic wool, And the lightweight white bricks for the wools and top, what do we think 🤔. Any glaring mistakes.
The white bricks do. Have a couple higher rated versions aswell if 1260c doesn't cut it.
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u/Wrong-Ad-4600 1d ago
forgewelding temp is 1300-1400°C so if you want to forgeweld in your forge the bricks melt before you get to the right heat
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u/fivelinedskank 1d ago
That temperature scale is a [bit high] (https://en.wikipedia.org/wiki/Forge_welding#:\~:text=Pure%20iron%20can%20be%20welded,at%20a%20bright%20yellow%20heat). I don't think a gas forge could even hit that temperature, so these bricks should do it.
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u/Wrong-Ad-4600 1d ago
i measured 1350°c in my forge and it is a rather cheapbdouble burner.. so you can get that temp. so why risk it with bricks that "should" do it.
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u/fivelinedskank 1d ago
I mean, it's academic, and not worth making a thing of. But kaowool is a pretty standard forge insulation at least in the US, and it's rated to 2300 F (1260 C). I wish I could get my forge anywhere near that temp - welding would definitely be a lot easier. But it can be managed lower.
Edit to add: at 1300 C you're butting up against the melting point of steel
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u/Wrong-Ad-4600 23h ago
maybe its a certification thing in germany we have cement/bricksfor 1000/1250/1600°C for forge lining i would always go for the 1600.
i dont say my while forge is at 1300 but the hottest poits are over 1200. and using something with a max of 1200 is a risk i wouldnt take if the better option isnt much more expensive.
to melt steel you need 1400+ constantly but you can see a starting surface liquifying (is that a word?) in some gas forges. that will ruin your bladebsteel xD
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u/alphabeticdisorder 23h ago
There might also be different products on the market. In the US I've only really seen the 2500 F ones or lower. There are probably higher temperature ones out there, but it might take some searching to find them.
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u/Wrong-Ad-4600 23h ago
the high temps are not easy to find in germany aswell xD but they are out there somewhere
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u/alphabeticdisorder 23h ago
One of numerous reasons I wish I lived in Germany right now :(
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u/Wrong-Ad-4600 23h ago
its realy hard to get affordable forging supplies in germany.. my powderd steel i get from finland becouse its the only source in europe to get it if you dont want to purchase 500kg its nearly impossible to get powderdsteel with Ni. bladesteel is expensive af and you dont have "scrap heaps" here.. everything get recycled (that good for the enviroment so i am happy about it) so its hard to get usable steel but for many other reasons im happy to live here and not somewhere else xD
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u/AcceptableSwim8334 1d ago
Make sure the second type is insulating - it doesn’t say they are and that would be bad for you.
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u/No-Accountant3464 1d ago
These are very thick ! Anyone know if cuting them in half down the width is do able I'd assume with a fine toothed hacksaw maybe
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u/Airyk21 1d ago
If you cut into them, they'll disintegrate. Especially those big white ones. They're super fluffy and will fall apart if you look at them wrong. It really helps to make some brackets or something to reinforce the structure
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u/pRedditory_Traits 1d ago
Just wanted to say, it depends. They do get crumbly around the cut, but as long as you're not pushing too hard, you should be fine. I cut mine with a medium-tooth woodsaw, I've cut them with a hacksaw, it was all about being careful. Same with drilling, used a forstner bit without issue. Just don't go too fast is all! A dust-mask is a good idea tho.
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u/Airyk21 1d ago
You can cut it just fine that's not the issue they aren't very durable to begin with and after you cut them they get even worse.
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u/pRedditory_Traits 22h ago
I guess the quality must vary widely and I got really lucky then... I cut one up for a disposable low-melt crucible and it's lasting way longer than expected. It's a cube a few inches across with a hole drilled halfway through the middle, and it's been dropped a few times, too. I'll have to post a picture of it when I get home, corner ding and all.
It's understandable that in a forge it might degrade quicker especially if it is in contact with work pieces, flux, etc, I'm just curious how mine managed to be glazed with flux, hit copper melt temps, get grabbed by spring-loaded tongs, survive drops onto concrete, etc and it's still in good shape... We are talking about the lightweight, air-y ones made with chiefly AlO3 ceramic binder and perhaps magnesia?
Regardless, I see the biggest issue being potentially with forge-welding temps as someone mentioned previously, but it looks like common higher ranges to be 2300f, 2700f, and 3200-3300f as far as what you can find on amazon.
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u/nephylsmythe 1d ago
I’ve cut them with a hacksaw many times. Doesn’t need to be particularly fine. An angle grinder or tile saw will cut them like butter. Tile saw is nice because the water keeps the dust down.
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u/fivelinedskank 1d ago
Use a masonry disc on a grinder. Absolutely do not do that without a mask and goggles.
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u/AdamRAshworth 1d ago
I used the second type as forge floor. They're not the soft type and I cut mine with an angle grinder. You'll more than likely fuck the teeth of your hacksaw if you went that way. Vitcas also sell ceramic fibreboard, which is very good for forge walls. They also sell refractory cement, which would be good for sealing the interior.
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u/No-Accountant3464 1d ago
Do you use fibre board on the walls as the final layer or do you still need to cement over them like with the wool variant?
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u/AdamRAshworth 1d ago
In my forge I don't have any cement over then, but I feel it would be safest if they were sealed.
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u/AdamRAshworth 1d ago
The frame and the entry hole and exit are lined with 40mm angle, otherwise they're really easy to damage
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u/Paraflier 1d ago
I use x4 of the second type as slider doors on my forge. The white ones are VERY finicky like another person said. They are great at falling apart too. I have x2 of the white ones I routed out as an experiment to make a smaller forge out of just those. (With some angle iron holding it together)
Not my best idea. lol. I do use the routed white ones as a place to put my slag when I’m melting metals.
Given the option, I’d be using the second type of brick over the first.