Gold Coast supplies?

[david s]

I get mine from Bradfast Townsville who are our local Sika supplier. Try online perhaps, through EBay. These pp fibres are normally used in concrete to reduce early shrinkage cracking, but have the quality of melting at a low temp (160C). I have tested this in a conventional oven to confirm the result. Other fibres like sisal probably won’t work at such a low temp, but you could test them. Also maybe test human hair, easily obtainable from a barber, or dog hair from a pet groomer. CAUTION, make sure your wife is not around when you test them in your kitchen oven, hair really stinks when it burns. Use a proper oven thermometer rather than the oven thermostat. You can get them for less than $10 at kitchen shops, accurate and measure the actual oven air temp.
Also remember that the smaller the fibre, the greater the difficulty in dispersion evenly in the mix.

[Nicholasd]

The Sika ppm 48/19 are in short supply still (17/03/2023) and one shop can get the product for $50 + $50 small order fee from Sika and $20 postage! $120!

Is there an alternative? Can I use hemp or sisal natural rope fibers?

[david s]

Phone Sika Australia or go online to ask where to obtain the product. There are 3 Sika distributors on the GC, Pickenba, Nerang and Brendale.
Basalt fibres are pretty new, I had to purchase mine online from domeshells. Do an online search.

[Nicholasd]

Hi Everyone,
Trying to keep the Gold Coast thread up to date as of feb 2023.

I'm having great trouble getting burnout fibers. Sika ppm 48/19 for my cast dome. I called Sika sales rep who sells wholesale to the big concrete companies who won't/can't sell it on to me. Only if I buy concrete with the fibers in it! The sale rep also said it is in short supply at the moment.

Some companies I called either don't stock it and won't order it in for me. Lyndons won't order it in for me.

The concrete warehouse (Yatala) may be able to help, they will call me back. They also said that at least three other people making pizza ovens had come in the last couple of weeks... So if you are lurking in the background drop a comment please as it may help others (ME!).

I got my bricks, Ceramic insulation from Jim at JB Refractory Temantin/pick up Caboolture.

The Field Furnace Refractory website only lists NSW.

Carbonparts don't seem to have Basalt fibers listed anymore.

[david s]

I'm severely constrained by freight charges, particularly for bulky or heavy materials, being so far north.
As you're in the GC you might be able to save heaps by picking up yourself from Field Furnace Refractories in Brisbane.

[david s]

To me this is a crazy rule. Not only does it go against the spirit of this forum (to share info) but it is the antithesis of the purpose of the internet. Yeah, I have read the reasons for doing it, but a couple of moderators should be able to handle the handful of posts that have direct links and weed out any that are spammy.



I sure have. Taking your advice ;o) Plus you might recall the exchange about flywire on the underside instead of the top to keep those potter wasps out.



It has steel mesh plus multiple 25mm steel bars running the full width. I am pretty confident it will hold, but thanks for the advice.

Thanks for the reminder re the mesh on the bottom, I now put it on both sides of the slab.

25mm of steel bar is huge and should be more than enough. There is a problem with thin slabs and steel reo in that there may not be enough embedment to prevent moisture entry to the steel, (Google correct position for slab rebar). I'm sure you'll be ok so long as the steel was placed in the middle and not sticking out the sides or close to the top or bottom surfaces. Driving on extensive overhead roads in Sicily is a nerve- wracking experience with LOTS of exposed rusty reo, bound for structural failure pretty soon. The whole island is riddled with it.

Apologies re the posting of supplier details. Utah has advised me it only applies to links. I had thought that it must be a directive from our generous hosts FB because they thought it might impact their sales, I was wrong.

[Gulf]

................To me this is a crazy rule. Not only does it go against the spirit of this forum (to share info) but it is the antithesis of the purpose of the internet. Yeah, I have read the reasons for doing it, but a couple of moderators should be able to handle the handful of posts that have direct links and weed out any that are spammy.................

I think that David gave you the name of the company in the very next post. That is acceptable by our forum rules. Just no direct hyperlinks to commercial sites. It's not very difficult for someone to cut and paste the key words into a browser IMO.

[microbe]

I get mine from Sydney, but as it’s against the forum rules to provide supplier details, I can’t help you. Just search for “refractory materials”

To me this is a crazy rule. Not only does it go against the spirit of this forum (to share info) but it is the antithesis of the purpose of the internet. Yeah, I have read the reasons for doing it, but a couple of moderators should be able to handle the handful of posts that have direct links and weed out any that are spammy.

The larger the piece, the more susceptible it is to cracking, because of uneven heating and the resulting thermal expansion difference. That is also why the floor bricks are best left un-mortared so they can expand and float freely. It also makes replacement easier. If a brick cracks in half it is simply reducing its size by itself and will not effect its performance.

Have you made some drain holes through the supporting slab so the moisture can escape?

I sure have. Taking your advice ;o) Plus you might recall the exchange about flywire on the underside instead of the top to keep those potter wasps out.

That looks like a pretty thin supporting slab. Not sure of the weight it will have to support, but are you sure it's strong enough. The strength of a concrete slab is proportional to the square of its thickness. So for example a 4" thick slab is 4x as strong as a 2" thick one. You have a fairly wide span there as the slab does not cantilever over the supporting piers. Perhaps another supporting pier in the middle would be prudent if you think the slab is not thick enough.

It has steel mesh plus multiple 25mm steel bars running the full width. I am pretty confident it will hold, but thanks for the advice.

[david s]

Try the Sydney firebrick company.

[david s]

I get mine from Sydney, but as it’s against the forum rules to provide supplier details, I can’t help you. Just search for “refractory materials”
The larger the piece, the more susceptible it is to cracking, because of uneven heating and the resulting thermal expansion difference. That is also why the floor bricks are best left un-mortared so they can expand and float freely. It also makes replacement easier. If a brick cracks in half it is simply reducing its size by itself and will not effect its performance.

Have you made some drain holes through the supporting slab so the moisture can escape?

That looks like a pretty thin supporting slab. Not sure of the weight it will have to support, but are you sure it's strong enough. The strength of a concrete slab is proportional to the square of its thickness. So for example a 4" thick slab is 4x as strong as a 2" thick one. You have a fairly wide span there as the slab does not cantilever over the supporting piers. Perhaps another supporting pier in the middle would be prudent if you think the slab is not thick enough.

[Pizzarotic]

but use firebricks for the floor.

.

Hi David,
Do you know of a supplier for the larger size floor bricks?
Maybe, 300*300*50 would be good to minimise floor joints,
Brad

[microbe]

Here is what I ended up doing under the insulation layer on the hearth - the tiles (including lots more) cost me $2 at the local tip recycling shop.





I hope this helps others

[Gulf]

Here is an example of elevating board insulation with ceramic tiles. A poured insulation would a require a fine mesh like window screen material or landscape fabric to prevent the spaces from being filled with insulation.

[Gulf]

That depends on what you can source. Some have used 2" concrete pavers. Some have used glass foam block. Some have used mosaic ceramic bathroom tiles that come already spaced on a sheet. The theory is to get the insulation above the structural hearth level where it can stay high and dry. You may be able to find some examples by using the key words "elevating insulation" in a search of the forum. You may have to change the key words get different examples.

[microbe]

+ elevate the insulation off of the structural hearth.

What is a good way to do that?

Gotta say, so far this thread has been almost as helpful as all my other research combined. Thanks!