UK Firebricks that are not too thick? (for floor of gas forge)

[MikeTheMike]

Looking for firebricks for the floor of a gas forge. The forge doesn't have much height, and as I'm putting in blanket and refractory cement, so there'll be even less height.

Am in the UK.

So, firebricks shouldn't be too thick, maybe like 20mm? 

Any recommended ones that don't crumble after 3 or 4 heats?!

OR, if I have used blanket & refractory, do I need firebricks on the floor? - I've not used refractory cement before so need advise! (more used to coke forges, just getting in to gas forges).

Looking at the blanket & refractory cement below... Will be doing mixed forging, variety of things but to include forge welding at times.

Remove commercial links per TOS.

Thoughts on firebricks, if they are needed, and/or if the above 2 products are decent? (Do I need a rigidizer too or can I get away with the refractory straight onto the blanket?).

Edited September 19, 2021 by Mod30
Remove commercial links.

[Frosty]

Welcome aboard Mike, glad to have you. If you put your general location in the header we won't forget where you are as soon as we open a different post. Heck I had to go back half way through reading this one.

That product is refractory MORTAR it is NOT a flame face refractory suitable for lining a propane forge. It is an adhesive suitable for sticking bricks together. Mortar will degrade quickly as the inner liner.

Look for a 3,000f, water setting, high alumina, castable refractory. There are a number available but I don't know product names in the UK. I don't see one by Vitcas but I'm not digging through the site.

I like the 1430c. fibereboard better than the blanket. I've been using a 2,600f ceramic blanket for years and it's served well. I don't see a ceramic blanket with a higher rating on the Vitcas site either and I'll leave sorting through it to you. 

If you plan on using a borax based forge welding flux you MUST use a high alumina refractory flame face or molten borax will dissolve ceramic blanket, fiber board and fire brick like hot water on cotton candy. No fooling!

If you trowel in a high alumina cast refractory inner liner you don't need a fire brick floor. If you want a flat floor add a strip of refractory blanket with feathered edge down the center and use the castable refractory to smooth the edges and make the floor. Provided you're making a cylindrical forge, if you're making a cube or rectangular profile just apply a smooth refractory floor and it's good to go.

If flux or physical damage becomes a problem it's easy to patch with some of the castable refractory you have left over. Yes?

Frosty The Lucky. 

[Irondragon Forge ClayWorks]

3 hours ago, MikeTheMike said:

Am in the UK.

Like Frosty said adding that to your profile, as we won't remember it once leaving this post. If you want a removable floor, check with some pottery suppliers for high alumina kiln shelves, they are thin like about a half an inch (12.7mm) thick.

[MikeTheMike]

Hey! Frosty Cheers for the detailed reply! A huge help

Would this be better? Remove commercial link  It looks like it would?

Also, with the blanket, you mention the 2600f - this is 1430c / 2600f, think that would work okay? Remove commercial link.

Fibreboard, I'm not used to... never used it, would that be used instead of blanket? Would you still coat it with the castable refractory?

I'm thinking about the blanket and the 1700c (3092f) refractory. The forge is rectangular one, so thinking just the blanket and coating would be ok, keeping it nice and flat.

Sound okay?

IDFCW Oooooh! Removable floor!!! Hmmm, is that like a fibre board? Wondering if it'd prolong the life of the blanket that'd be coating in the cement? Would that work?

 

 

Edited September 22, 2021 by Mod30
Excessive quoting and commercial links

[Frosty]

You're welcome Mike, I like talking and you seemed like a willing audience.  It's my pleasure to help folk when I can. Yes, this is a MUCH more appropriate refractory. The details look good though I don't see if it's a high alumina refractory or not. If you apply a kiln wash it will protect the liner from hot flux erosion. 

Yes, fibreboard is a stiff version of refractory blanket, a little less insulating but it's more structurally sound for a flat roof, it doesn't sag or droop. 

Don't be afraid of using blanket for a rectangular forge it's not hard to keep everything right but it takes longer. You can plaster the floor and walls at the same time. Let it set hard, THEN turn the forge upside down to plaster the ceiling and let it set hard. Everything will come out flat without sag or droop. 

You'll only need maybe 3/8" for walls and ceiling, I LIKE my forge floors a LITTLE thicker because the floor takes the most beating. 1/2" MAX is about heavy enough to make my, "Overbuild every darned thing!" voice happy.

And yes, coat fibreboard with the same refractory though you can use a thinner coat. 

An alumina kiln shelf makes an ideal forge floor, it's very hard and impervious to borax based flux. 

It might cost a bit much but the Zircon Paint coating looks promising as a kiln wash. The final coat of armor between your forge and the flame. Maybe Mike will read the product description and let us know what he thinks. Zircon kiln washes are more his baliwick than mine. 

Frosty The Lucky.

[Irondragon Forge ClayWorks]

I see the links you posted have been removed. It is OK to put in the name of a product, so folks can look it up but links to sites selling stuff are not allowed. Like Frosty said kiln shelves are hard ceramic (but fragile if dropped or hit hard). They can be cut to fit but take special blades used to cut tile to cut them.

[MikeTheMike]

Ah fair enough about links! Tho if I owned Vitcas... hahaha, I'd be quite happy

Anyway - Product for the refactory 'Refractory Castable Grade 1700'

Zircon Paint... that has me confused, so would that go on TOP of the refractory? There's quite a few types... Can't ask you to link to the most appropriate one, hmmm the castable one? (Zircon Coil Plaster Castable) or (VITCAS Zircon Paint Coating) or (Zircon Rapid (5kg+Liquid) ? Sorry to be a pain! Just don't want to buy the wrong thing lol.

Yer... The refractory isn't alumina tho - or it doesn't say so. Is that an issue? 

Edited September 23, 2021 by Mod30
Remove excessive quote.

[Irondragon Forge ClayWorks]

If you owned Vitcas and put in links, you would have to pay Glenn for advertising.

[Frosty]

The Zircon Paint that drew my eye would be a kiln wash applied as I was suggesting. Starting with the forge shell, outside skin. First is the insulation, I like ceramic blanket, 2 layers of 1" 2,600f refractory blanket. The next is a layer of hard water setting, 3,000f preferably high alumina castable refractory. Last is the flame face or contact layer and this is typically a painted on high alumina product that seals the interior against penetration by the highly reactive propane flame and combustion products. It is also more chemically inert against welding fluxes and other . . . stuff. 

Yes, the liquid, paint it on after the hard refractory is set up. 

Were I in the market for Vitcas refractory I'd ask them, there is a question section. Of course it's another big company "ignore the small sales," linking you to a blog hoping someone else will say something helpful. Just eyeball it, don't get your hopes up. Of course I'm used to being wrong they might answer simple questions.

Instead I'd call the company direct and NOT tell them how much I was interested in buying. If they THINK you're going to buy in quantity, say by the RR car they'll talk to you. All you really need to know is if it's a high alumina refractory and the %. It wouldn't hurt to ask if they have a bubble refractory as well.

Frosty The Lucky.

[MikeTheMike]

Thanks! Sorry to ask... What is a bubble refractory?

Edited September 23, 2021 by Mod30
Remove excessive quote.

[Frosty]

Don't be sorry. If someone says something you don't understand ask for clarification, not asking is the mistake.

Bubble refractory is maybe a trade name. What it is is a refractory containing very small evacuated silica spheres (spherules). They replace a portion of the sand in the aggregate serving two functions, first it lightens it physically and is often used in "Light Concrete", the second is it increases the insulating characteristics. When refractory reaches about 1800f or maybe hotter the silica melts and disperses leaving spherical voids sort of sealed with the remains of the silica. 

I can buy it at a local masonry supply or a concrete mix plant, it's a common additive to concrete and in many instances to thicken plaster or polyester and epoxy resins so they stay where placed. 

It was just a thought, I don't think I'd mess with commercial refractory recipes were I you. Maybe later when you have more experience with them. No good reason to make things more complicated.

Frosty The Lucky.

[Irondragon Forge ClayWorks]

I believe it's trade name is Bubble Alumina. This gives the properties of it from alchemy mineral.

Quote

Bubble Alumina is produced from high-purity alumina in an electric arc furnace. Once melted, the alumina is atomized with compressed air, which produces hollow spheres. The melting point of Bubble Alumina is approximately 2100ºC. The hollow spheres are chemically inert and have very low bulk density, extremely low thermal conductivity, high hardness, high wear-resistance, and superior insulating properties.

That is what we used to coat the layer of Satanite refractory in our forge.

 

[Frosty]

Bubble alumina isn't what I was referring to but if you can, it IS the stuff to use.

Frosty The Lucky.

[MikeTheMike]

Thanks guys