Firebricks - clay or vermiculite?

[aesmith]

Hi,

Reading the other thread reminded me that at some point I'll need to replace at least the side bricks in our Morso Squirrel.  The existing bricks are clay, no idea if they are the originals or not.   Replacements are available either as vermiculite board, or for about 50% more in fireclay.   What do people reckon, is there any advantage to the clay bricks?

Thanks, Tony S

[Stubby]

My stove had board as standard . When it needs replacing I by some on line and cut it on my band saw to size .

[aesmith]

Good idea if I can find a source of board at a decent price.  A set of vermiculite bricks is around £30,  I'd need a board 300 x 700 to make a single set (or one 260 x 260 and one 300 x 420).  Not sure it's worth us getting in a bulk board for several sets, unless vermiculite has a lot shorter life than fire clay.   

[neiln]

vermiculite is lighter and better insulating so better for those two aspects.  afaik its just as durable to heat but it may be more fragile to being hit by logs/poker etc.  i replaced knackered refrwctory bricks in a franco belge with vermiculite and all seems good, oh and it was cheaper.

[scraggs]

I replaced my Villager Chelsea firebricks with the Vermiculite bricks, the original clay bricks lasted 14 years the Vermiculite ones lasted just under 2 years.

[Woodworks]

10 minutes ago, scraggs said:

I replaced my Villager Chelsea firebricks with the Vermiculite bricks, the original clay bricks lasted 14 years the Vermiculite ones lasted just under 2 years.

Yes have used vermiculate board and it's easy to shape but does crack quite quickly. On the other hand if they dont fall apart can keep doing their job. The board in our stove is cracked but been like that for two or three years without falling apart.

[woodrascal]

All of our stoves work better with vermiculite bricks. I've replaced 'hard' clay bricks and steel plates with vermiculite board, easily cut to size with a hand saw. The insulation factor raises firebox temperature and so promotes a cleaner, more efficient burn. The downside is they are more fragile. When loading the firebox you have to be careful not to jam in logs against the vermiculite board or it will crack.

 

Here's a link to large sheets of the stuff -  Vermiculite Board

In fairness some 'hard' clay firebricks will also crack or crumble if not treated carefully. Clay bricks can be good when they are heated up to a high temperature as they will hold a certain amount of heat for quite a while, which can help to quickly re-establish a fire when re-loading the firebox. Vermiculite bricks will quickly loose heat when the fire dies down.

Edited October 29, 2018 by woodrascal

[BowlandStoves]

In our experience vermiculite has been the go to material to use. The benefits are well documented in this thread.

[Steven P]

My issue with the board is its life.I have a multifuel stove so will burn logs and coal.. and the vermicullite crumbles (3rd set of bricks in 5 1/2 years now). They re a consumable but original manufacturer costs quite a lot.

 

This year I was going to buy a full vermicullite board and cut it to size (get 2 or 3 sets from that for the same price as the manufacturer sells), but a chat with the girl at Victas she recommended a castable screed for a more durable option - so thats what I am trying this year - I'll let you know in 18 months how it goes. Making the molds was easy - I had measuerd the last lot of manufacturers bricks to get the sizes right last time round, 1/2 hour in the garage and I was ready to cast them.

 

I have also patched vermicullite bricks with clay.. to find the bricks kept crumbling behind the clay and it fell off, but the clay lasted quite well.

 

 

 

Note as for fire temperature, I tend to run the stove on full power.. if its cold enough to have the fire on then it needs to be getting hot.

[Steven P]

On 15/11/2018 at 13:04, BowlandStoves said:

In our experience vermiculite has been the go to material to use. The benefits are well documented in this thread.

I'd also (maybe wrongly) assumed that stove manufacturers used this because, it is easier for them to produce (just cut them to size with a band saw) and cheaper.. and we, the consumer just replace like for like