Soft firebrick vs. Hard firebrick !??

[Shonski]

Was looking to build my own kiln soon, nothing to massive, bout. 2' x 1' 6". When I went shopping online for brick, I quickly realized there's 2 different types of bricks!? I do want to do some fusing in this kiln as well as annealing. What is the difference in these bricks? Is one just more durable and longer lasting? Please help? For some reason, not easy finding this info online...

[smolder holder]

I'm curious about this too. Someone chime in

[l33t:weasel]

i think the deal is u want the soft stuff for a kiln and the hard hard brick for a pizza oven.
hard fire brick is basically regular brick from what i've heard. its too hard to work without serious tools and i would expect it sucks up a ton of heat getting warm and stays warm for a long time, not what you want.

soft brick is a little more expensive and a whole light lighter. it is also very easy to work as the name implies... like u can work it with silverware. always wear a p90 or above respirator and use mechanical ventilation when working kiln brick. drop cloths over anything in the area is a good idea too, a layer of the dust will get on everything even with the best ventilation.

[Icarus]

Soft brick is what you want for the firing chamber. You could do a hard brick outside, but it's not really needed. The soft will get up to temp faster, but will also lose it's temp faster.

[Shonski]

That's what I was kind of figuring.... Thanks a lot everybody! You have helped big time! Thanks again! A lot!

[Greymatter Glass]

actually soft brick is more insulating. more air in it. It will cool off very fast also.

hard brick is more refractory. It will heat up and hold the heat, but it takes longer as it also reflects heat away from it.

For electric kilns you only need 2300º IFB / soft brick. You can also use rigid fiber board or kaowool/ceramic fiber.

For furnaces or appliances that need to hold a lot of heat in the structure you use a mixture of hard brick and soft brick and other refractories....basically the hard bricks can be used as a "hot face" where the flame hits them directly and they don't melt down as quick... or you can cast a monolithic slab for it...

A hard brick oven/furnace/chamber will resist sudden changes in temperature better than soft brick, but at the cost of more power input to get it to temp. Also, they conduct heat more, so if you use them alone you will burn yourself on the outside of the kiln. With soft bricks, across the 2" thickness you can have 1100º on the inside and maybe 250º on the outside.

[Shonski]

@ Grey Matter, Thanks a ton, that sums up everything I need to make a final decision. I really, reaaly do appreciate you taking the time to educate me like this! Thanks again!!! Shon!

[ReLo442]

yes what he said. soft brick is also A LOT lighter, easier to work with if you need to put grooves. On another note. the fiberboard stuff is AWESOME for putting on the floor and roof of the kiln (if using side elements <------suggested). Just putting a piece on the floor of my kiln makes it heat up about 10 mins faster then before when going from 0 to 980. After putting that piece on my kiln floor im redoing another kiln just to be able to use more of this board stuff.

Ive always wanted a big kiln with soft brick on the inside, and hard on the outside. That way it would heat up quickly cuz of the soft on the inside, but then hopefully cool slowly because the hard outside holds the heat more. Dont know if that would really work tho. Just a thought. Digi controller is a much better idea

[DieselPower]

^^^ wat they all said. I'd like to add just one thing, from my experience with soft brick, it breaks up very easily.

That being said, if you use soft brick line it with the fiber board. It will add a lot of life, before you have to replace the bricks. That soft shit just crumbles up and you can break them in half without much effort. I bought a bunch of them to mod a kiln and kept dropping em, broke probably half of em within a few hours of getting em hooray for saftey break moments!! :D:D :clap:

[barefoot stash]

I'm getting one of our big annealers retooled now. The walls a floor are soft brick and we are changing the roof and door to fiber board. Hopfully no more sagging roof bricks. I post picks when it's done.

[aglassworkorange]

where are you located? i have soft and hard bricks. fiber blanket and fiber board.

[OracleGlassArts]

first hand experience with hard brick.....it dont work....got to 700 F after 4 hours, skin temp near 300 F

[somewhere]

where are you located? i have soft and hard bricks. fiber blanket and fiber board.

I agree why doesn't everyone take a min and update your profile to list your location. It kills me when people come on the board and offer goods or services and neglect to add there location.

[RamblezMarblez]

"...I would expect it sucks up a ton of heat getting warm and stays warm for a long time, not what you want." Exactly

I have tons of Fire Hard Brick....Rockspar I believe....It's very chemical resistence and can absorbs too much heat for making a kiln....Now if your just using hard brick in conjunction with a soft brick kiln, that would be ok....Like if you want to lift a mold off the floor of the kiln, that would probably work without exploding....I made a fire pit out of Fire brick (expensive brick but I got them for free) I could cook a hot dog or probably boil water just with the heat the brick absorbed....Don't let the Hard Fire Brick touch your glass if you do use it b/c they will cool down at different rates and possibly check your glass....I never tried it for real though....If ya want me to mail ya a brick or two for free just send me the shipping $$$....and some tiger stripes...Slick420

[Greymatter Glass]

I agree why doesn't everyone take a min and update your profile to list your location. It kills me when people come on the board and offer goods or services and neglect to add there location.


indeed:

http://www.talkglass.com/forum/showthread.php?p=570245#post570245

[RamblezMarblez]

....what they don't know, can't hurt me....Mwhahaha

[BigTeasel]

as a rule, the higher the temp rating, the softer the brick will be. i've seen many annealers that are soft-brick inside with board walls wrapped in sheet metal. they will get hot enough on the outside to burn your skin when they've been on for a few hours, but they cool fairly quickly which means that your annealing cycle will take exactly the time you estimate and you won't have to wait for hours for it to cool off so you can unload. if you are doing casting you'll want to further insulate the box to slow the natural cooling rate.

[Greymatter Glass]

if you are doing casting you'll want to further insulate the box to slow the natural cooling rate.

Or use a digital controller, and program your ramps. Doesn't matter what you have then.

[somewhere]

as a rule, the higher the temp rating, the softer the brick will be. i've seen many annealers that are soft-brick inside with board walls wrapped in sheet metal. they will get hot enough on the outside to burn your skin when they've been on for a few hours, but they cool fairly quickly which means that your annealing cycle will take exactly the time you estimate and you won't have to wait for hours for it to cool off so you can unload. if you are doing casting you'll want to further insulate the box to slow the natural cooling rate.

Not to get to picky because it just may be the way it's written.
I have 1900 IFB and 2800 IFB the 1900 is definitely softer then the 2800. The higher the temp rating the less insulating value it will have and the higher the temp rating the more mass (harder) it will be.

If you think of the thermal fly wheel effect the more mass the longer it will take to cool down.

Sorry not trying to tear your post apart but considering the higher insulating value the lower temp IFB has the outside of the kiln will be cooler to the touch with 1900IFB then 2100IFB.

[stellali121]

Soft firebricks are soft and light in weight. They have high porosity and excellent insulating property. Soft firebricks absorb about half the energy as hard firebricks during firing. soft fire brick insulation is mainly used in industrial and hobby kilns heated up with either electric spiral elements or gas burners, furnaces, both for hot face lining or outer back-up heat insulation.

Hard firebricks are very dense, hard and durable but not great for insulating. They are used for their structural qualities. They can be often used as the main building component of large kilns, chimneys, fireboxes and burner ports—anywhere around direct flame.