Jake's In Mass (Started July 3, 2011)

[jatsrt]

OK, I'm back, new phone and recovered lost pictures. At the end of this build I'll post a full gallery of all the pictures I have taken.

Here are two pictures of the hearth and insulating layer. Like I said above the vermiculite compacted way more than I expected.

So, what did I do? Well the first two bags of vermiculite I got from my Dad. He ordered "super coarse" from the supplier he orders from. This was a very coarse vermiculite, pieces 1/4" or larger. While it was nice and very "airy" it compacted quite a bit. With this I was able to get about 2" of the 5" I hoped to get. A 60% loss was definitely more than I expected. Given, I was never exact on what I should expect in the first place.

So, my dad had surgery and I decided to hunt down vermiculite on my own. Agway was selling 20lb(4cuft) bags of "coarse". I decided I'd go for it and I grabbed three more bags. I did not look inside when I picked it up, but it felt "chunky".

When I got home and looked at it, it was significantly less coarse than my first two bags. However it was less consistent with fine material and larger material. I decided to mix it up and live with what I got. Overall it mixed much better and compacted significantly less.

So, what I ended up with when it all settled is about a 4" layer of the "chunky" stuff. Which is the right size insulating. Then about 1" of the smaller stuff, when I mixed it I mixed it wet and it naturally settled this way.

So chat away, let me know your thoughts. It looks good to me and I don't feel like I need to also include any type of fiber board too.

[jatsrt]

Oh, and that was all mixed about 5:1 vermiculite to portland.

[jatsrt]

Next, to nerd it up. This is a picture of my lates thermocouple reader. This uses an analog/digital MUX in order to cut down on the number of very expensive MAX6675 ICs for temperature sensing.

I also dropped from an Arduino Pro to a PICAXE 14M2. This wend from about a $20 part to about a $4 part. There are definitely cheaper ways to go, but I am not an "embedded" programmer so I need at least a little hand holding and both Arduino and PICAXE are very hobbyist friendly.

I am working on redoing my schematic and board layout and will post those if anyone is interested.

What you don't see in the picture is the Bluetooth modem and the LiPo battery supply, but they are both part of the design.

[jatsrt]

One last note for tonight:

I ended up using 4 1/2 bags of vermiculite for the hearth That's about 18 cuft of material and my form was about 11 cuft. That is about a 60% yield/40% compaction. Not too bad I guess. I hand mixed some and machine mixed some, compaction was the same.

[PizzaIdiot]

Glad you got the new phone. Keep the pictures coming!

So you used 18 cf of vermiculite and at 5:1 that means you used 3.6 cf of portland cement. By my calculations that's about 7 94# bags.
Is that right?

I'm not trying to challenging you on this, it's just that this is my next step and I have 12 cf of perlite ready to go (hopefully this weekend) with 1.5 cf of cement (3 94# bags) to fill 9 cf. Sounds like I need to plan to mix it all together and use as much as I can - and hope I have enough. Worst case is I'll leave a 'hole' in the middle and fill it in when I get more perlite and cement.

Thanks,
-jeff

[rodeair]

Jeff - Be careful of the portland, 1 94# bag is 1 cubic foot the way I understand it.

Leigh

[PizzaIdiot]

When I checked the density, it's about 198#/cubic foot.
The bags are also about the same size the 80# concrete mix, which is about 0.59 cubic feet.

So how many bags of cement did you wind up using?
In any case, it looks great.

I hope a few other people will weigh in on this.

-jeff

[rodeair]

I did an insulation layer of vermicrete 4.5 inches thick. The calculations showed I would need 8.5 cuft. I ended up needing 10 cuft of vermiculite and (2) 94# bags of portland which gave me a 5:1 mix.

Leigh

[PizzaIdiot]

Leigh
Thanks for the timely input. Maybe I'm being too technical in my thinking, but I would have thought yours was a 10:1 (assuming 1 94# bag is 0.5 cubic feet).
-jeff

[jatsrt]

So, I also took a 94# bag of portland to be 1 cuft. A 80lb bag of ready mix is .66cuft, the 94 lb bag is slightly larger.

So, for each 20# bag of vermiculite, about 4.4 CUFT each, I use a little less than 1 bag of portland cement. That gave me somewhere between 4:1 and 5:1 at 5" thick.

Overall the mix looked just about right, it is strong, but airy.