FB Brand Insulation

[FrankHawkins]

Re: FB Brand Insulation

Hi there. I am from the UK. Just joined this forum and think it's great! Finding it very helpful!
The problem I have is that it seems the products you are talking about have different names over here.
I am looking to find an insulating blanket to wrap around the dome.
Could I use rockwool? Which is the Same as the insulation I use in my loft. Or is it not heat resistant?
Would a fiberglass blanket or ceramic fibre blanket be something I should use?
Cheers.

[vtsteve]

Re: FB Brand Insulation

Rockwool is fine temperature-wise, but thick or high-density versions are pretty stiff (harder to wrap around the dome). There may be a smell for the first few firings, while the resin binders cook out. Ceramic blanket is the "best" -- easy to drape, good R-value per inch, and you'll never overheat it. Fiberglass has the lowest temperature rating, so I'd avoid laying it against the dome.

[FrankHawkins]

Re: FB Brand Insulation

How do I work out how much vermiculite I need for the insulating base. I will be pouring it into a space of 140cm x 140 cm by 10 cm deep. I've found bags of 100 litres. How many of these do you think I will need?

[vtsteve]

Re: FB Brand Insulation

10cm x 10cm x10cm = 1 liter
14dm x 14dm x 1dm = 196 liters = 2 bags

If you're doing vermicrete at 5:1, it will probably compact somewhat while mixing, but 3 should be more than enough.

[FrankHawkins]

Re: FB Brand Insulation

Thankyou. That's really helpful!
Also what is fireclay?
I saw people talking about the mortor mix for the dome. And I havnt a clue what fireclay is!

[Greenman]

Re: FB Brand Insulation

Fireclay is powdered firebrick clay that has been fired or powdered fire brick, or the 'dust' from cutting firebricks.

You can usually buy it from the usual suspects that supply the firebricks and the like or save the material that is produced from cutting your bricks.

[FrankHawkins]

Re: FB Brand Insulation

Oh ok.
I will buy some from a company that I have found.
I am using some old red bricks to build the dome. My dad has pallets and pallets of old reclaimed bricks. And I have been told that the old reds are ok to use instead of fire bricks.
There's quite a variety, so some are hard bricks, and some are soft bricks. Which would be better for using to construct the dome. I Wasn't sure which would handle the heat better?
Thankyou so much for all your feedback Steve. You've been so helpful.
What is it you do? Is this your profession?

[vtsteve]

Re: FB Brand Insulation

I was going to suggest entering "fire clay UK" in the search box - lots of hits.

Storage heater bricks also seem to be a popular UK option. If I were using the reclaimed bricks, I would use the harder ones, since they've already seen temperatures higher than you're likely to achieve in your oven. Fire bricks are nice for the floor, because they're sized to fit with a very thin (or absent) mortar joint, and they're generally smoother.

[FrankHawkins]

Re: FB Brand Insulation

Oh ok.
for the base of the oven I was going to use a material from work, as I am a stone mason and we have just had a new material come in that is a man made ceramic type slab. It's 12 mm thick and is rated up to 1250 degrees. I was going to do the floor in one piece so no joins at all. And as the material has such a high tempreture rating I'm hoping there should be no problem with it cracking.

[Greenman]

Re: FB Brand Insulation

Oh ok.

Thankyou so much for all your feedback Steve. You've been so helpful.
What is it you do? Is this your profession?

I am retired and built my oven because I always wanted to build one but had no time for it. My previous profession had nothing to do with bricks and stone other than some of the institutions being built of them.

[Al's oven]

I'm new to this forum. I am in the beginning stages of planning an oven build in the spring of 2018. I am stuck trying to decide on FB brand insulation or vermiculite/Portland cement mix. I am leaning toward the FB brand insulation but am worried about it getting wet. I understand that a tarp is an option but it appears that people are still having trouble with condensation when the board is covered with a tarp. If it does get wet – will it dry out if exposed to the sun? Also, won't it dry out during the curing process?

[Gulf]

Hi Al,

Welcome to the forum. Damp from humidity/condensation is one thing. Water logged from being exposed to a deluge is another. Yes, condensation can accumulate under a tarp. But, I feel that most "real" problems are caused by the insulation actually getting wet. There have been some good improvements on the forum to the original FB plans. Some of the later ones are: elevating the insulation above the concrete hearth, placing a moisture resistant barrier between the insulation and the concrete hearth, and drain holes through the concrete hearth underneath the insulation. Those are all good practices for any oven. They will help during construction, drying, and any future problems with the intrusion of moisture or water. No matter the the style of oven, Igloo or enclosure, those tips will help.

Keeping the insulation as dry as possible during the construction phase is crucial. A well placed tarp (that sheds water off off the oven and the oven stand) will help a bunch. It must be tied down and anchored or it may be all for naught. An "easy up" tent above that will help shield the builder and the oven from the elements during construction.

[francisb]

My FB Casa Oven came with the FB insulating board. It has 2 sides white and tan. Does it matter which way up it should be installed? It's not mentioned in the instructions or insulation packaging. Thanks.