I got two big bags at the nursery. I'm not sure how much was in each but they were huge bags. If I were to guess, it would be around 1 cubic yard (27 cubic feet) in total.
Perlite and vermiculite are NOT the same thing. You want to use Perlite. Vermiculite will absorb water, which will turn to steam and crack the concrete when you heat it.
@@webtheweb I've never used vermiculite - even though I said it in the video by mistake once or twice. I'm going to go with Perlite though because it is so easy to get and it works great in this application.
My man,for starters u took onthe diy challange so "what u did wrong" is very irrelivant,comes very second to u doing the actual job,in my eyes u cant do "anything wronmg,major anyway!!!
My next attempt will be to pulverize my failed cast and reuse the perlite and clay with 100% water glass, form bricks that will easily assemble to my specs, than fire each till they achieve maximum hardness. Then I can piece my core together and seal it with furnace cement.
I found all the perlite, vermiculite, and volcanic glass pebbles that you will ever need at hydroponic gardening stores. The volcanic glass pebbles seemed most promising.
Yes, I still have some minor stuff to do but it's done for the most part. Stay tuned, I am going to put a video together from start to finish on how I built it. It will be mostly from pictures but I will narrate and explain what I did.
Helping advice for mixing in a wheel barrow. A mortar hoe is different tool than a garden hoe. Mortar hoes are heavy and strong, resisting breaking the tool. 1.alternate layers, the portland will always be the middle layer, to reduce the portland getting into the air while mixing. 1/2 of your agregate Portland remaining 1/2 of agregate A 6 cu ft wheel barrow can mix 4.5 to 5 @ 5 gallon buckets of dry material, plus the water. Premix the dry material, blending well. Mixing method: Grab the hoe as close the head as is comfortable, this allows you to apply more force while chopping and slicing through the mix, especially once the water s added. Starting close to you, begin chopping or slicing and pulling towards you little sections of material until all is mounded on your side. Now switch to empty side, slicing and chopping, pulling little amounts, moving from left to right across the mound of material, until all of the mix is mounded near you. Adding water: With mix mounded to one end pour 1/3 of the water into empty end. Beging slicing and chopping, pulling the material into and through the water, mounding it near you. If you run out of water part way through the mound, splash a little more. The pile should be damp, and not yet contain all of your required water yet. Mix through 2 or 3 times this stiff mix. Then add small amounts of water and pull through. At this point it is easy to add too much water, which would make the mix unusable. Once the mix is the consistiency of peanut butter you can add small amounts of water until you get to the point of miracle whip consistency. IMPORTANT: Wear gloves while mixing, portland will burn and cause small wounds on fingers.
Perlite is white, vermiculite is kind of yellow, they are different materials, vermiculite is heat expanded mica a bi-product of china clay mining. Perlite is volcanic rock. They behave differently. Looks like you were using perlite, coz it's pearly white.
kool job man.refactory cement would've been better ,but this is how we learn what we can and cannot get away with.don't ever let people tell you that it can't be done because you don't quite have the write materials.I grew up in a family of masons that were like that and they never built anything for themselves."PS" the pearlite ,I would imagine helps disperse the heat more evenly than a solid crete pour ,because of the porosity of the mix.D. I. Y. it's" O KAY" man. if you were getting payed for the job however" error on the side of caution". I'LL SAY IT AGAIN EXPERIMENTATION IS HOW WE LEARN.---HUNGRY FOR PIZZA NOW>post by jd avery
Terri I'm not expert, but I believe the pearlite is used for two purposes. One it will lighten the weight of the concrete and two will reduce thermal conductivity of the cement. I have seen this done in large commercial safes for fire proofing. The concrete in its normal mix of sand and gravel ratios will thermally conduct the heat of the fire to the internal part of the safe much faster than a mix such as Lee has made im sure they have other components too but with the added benefit of some weight reduction. So the heat Lee will generate with his wood fire will go more to the heating of the food vs heating of the floor of his oven.
Terri - I didn't use refractory cement to make the perlite concrete because it was going to have a full fire brick between it and the actual fire. So it really doesn't get severe heat - at least not more than regular cement can tolerate. And mrelectronic62 is correct, I am installing this solely to insulate the bottom of the oven to retain heat longer.
The words are a little similar. I made this video so long before the RU-vids were a thing, and I'd love to add a some subtitles to clarify things, but it's currently not possible.
would it work better if you mixed all the dry ingredients first making sure it is very well incorporated then add water to get the proper consistency just wondering
It's a good thought, but the difference in coarseness in the perlite and Portland cement makes it so that the fine cement quickly settles through the coarse perlite. The cement won't act like the binder until it is wetted. If mixing with a trowel or hoe isn't your thing, use a cement mixer.
There's a lot of videos on YT for making Water Glass (Sodium Silicate), but I mixed roughly 4-5 cubic feet of perlite, 20 lbs of fire clay, 1 gallon of furnace cement and roughly 4 liters of water glass to 4 liters of plain water to make my rocket stove. Gave it all 3 days to dry, did a 2 hour burn on the 4rth day and left to dry more till the 6th day. Well that still wasn't enough b/c when I tried to lift it all, it kind of exploded under it's own weight. Water glass, though relatively easy to make, can get pretty expensive to make. The Lye is $9.00 for 2 lbs and Silica $15.00 for 5 lbs.
+Michael J 2lbs LYE $4 or I bought mine 32lbs for $50 at essentialdepot.com Not sure about shipping charges as I bought allot of other stuff also when I bought my 32lbs Lye. I also make soap so use allot of lye! Also several brands of CAT LITTER is just silica beads! I forget brand or cost right now, but it is FAR LESS than $3lb and can be bought local near anywhere !
Thanks for posting. I can see from the video that you are working very hard and it should serve to alert the faint of heart how much work it entails to take something like this on. By the way, just as an aside comment, perlite and vermiculite are two different materials and, though they may be used in gardening in similar ways, they have different properties from each other and are mined from different rock formations, and should not be confused when making ovens or furnaces. Cheers!
Yes I said vermiculite a few times in the video by mistake (I had my hands full of tools and camera so lost my concentration a little). I was using perlite not vermiculite for this application. Thanks for watching. I'll be posting a video of the whole oven build soon I hope.
i'm big on calculating volume: basic math would get you their. I think you used a bit too much water. i made rocket stove (alot smaller project and much more ghetto than your fire pit) and my mixes appeared a lot more dry to the touch. i put the 5 gallon cans into a trash bag for amonth to let it cure. sadly, one 5 gallon rocket stove is still standing tall, the other one has crumbled from the inside out. i think i might have not mixed it good enough. good job though. your pit should be fine, make sure to next time let it cure longer and cover with plastic so it cures slowely
I don't know if I used too much water but I'm pretty sure I use the minimum amount I could to just get the mix wet. This was for the floor of a pizza oven so it got covered up by fire brick within a day or two. I don't think curing it properly would have made any improvement in this application. It might in a rocket stove set up.
You did two things wrong: 1 Extremely important to mix dry parts THOROUGHLY before adding any water. 2 Your mix looked just right to me but you stopped working it too soon. Use a wood float or a darby (easy to make) and worked the surface it would have smoothed right out after a few minutes. Then, using a mason's steel finishing trowel, you can finish the surface to make it uniformly smooth and hard-wearing.This floating and finish troweling brings a mix of cement and fine suspended particles to the surface. (Masons call this "raising the fat"). I suggest viewing a "hand-finishing concrete" video on RU-vid. It could have saved you a lot of time and effort. It's easy to master.
Yes I agree, definitely mix it before adding the water. I am pretty familiar with concrete finishing and I think you would have a very difficult time finishing this perlite concrete mix to a smooth surface like normal concrete. It's a very lean mix (lower cement to aggregate ratio). There wasn't any reason to finish it smooth anyway because I was going to top it with a layer of fire clay and then fire brick for the bottom of my pizza oven.
I have always used masonry cement--has a F temp rating of 2100 degrees so adding perlite raises the temp rating--I have no idea to how high the temp rating is but I have never to date--5 years of cracking in my rocket stove/oven making jobs.
jill still Hi Jill yes I add perlite to the cement mix, I have also added saw dust, so the mix is lighter than plain cement but takes higher temps. I just broke down a rodket I was using for garage heat after 3 years and the fire tube inside metal was GONE! The cement mix still looked almost new. Very little cresote or burned blackish powders. Not much ash for 4 months since cleaning of very hard firing it was COLD here last winter. What I need is a reliable self feed hopper. Let me know what you are building. Best wishes
Lucky B Oven project is up on the RU-vids now. It was a little more laborious putting the video together than I figured it would. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Y2vuY2kL5bw.html
Joep Stuyfzand It might be OK but I think it would be better to add some fire clay to the cement kind of like when you are making refractory mortar. I would also parge any surfaces that will get direct heat with a mixture of fire clay, cement and sand or a store bought refractory mortar mix. This application has fire brick between it and the fire.
I built my oven out of brick and I used a sand dome, not a beach ball. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Y2vuY2kL5bw.htmlsi=B_5DTRo4FRrUmnQM
Hi Lee! Greetings from Germany! Watched your great videos many dozens of times, beautiful work at all, learned a lot! Could you please tell me how the percentual mixture between perlite/fire cement/ Portland cement is and - did it got some cracks meanwhile? I´m building an oven based on a 16cm concrete plate, insulation with 6cm foam glas plates, 6cm refractory stones for the oven baking level and a dome made of fire concrete, instead like yours brick-by-brick (I´m a fool to make a dome with bricks :-) ). The upper part with the chimney I intend to surround with perlitecement like you, so I wonder how is the mixture for this? thenks & regards, Harry, Karlsruhe in W-Germany
+Baker Man I used a 5 to 1 mix 5 parts perlite and 1 part portland cement. That was probably a little cement heavy. I think I have read that you can go up to 10 to 1 ratio. I figured at the bottom of the oven it could use the extra strength. I didn't use fire clay or refractory mix in the perlite because it doesn't get that hot on the other side of the bricks where I used it. I only used that inside the oven for the mortar on the fire bricks. I would use a leaner mixture (less cement) for around the chimney unless you need the insulation for some kind of structural reason. Good luck with your oven!
That's a good question. I haven't had any failures in the bottom of the oven yet and it's been about 6 years. Regular concrete is probably good up to around 750 degree's F and I don't think it gets quite that hot on the opposite side of the fire bricks. It definitely does on the inside of the oven. Keep in mind that this is a home oven and when I cook pizzas, it runs at it's hottest temperatures maybe two or three hours max. If I were using this in a restaurant where the oven might be running at max temperature six or eight hours a day, on a daily basis, I would add some fire clay to the Portland cement. If you are an egghead and want to read it, here is a link to a good article on the subject www.hindawi.com/journals/isrn/2014/468510/ and here is the chart from that article which shows regular strength concrete's stress strain response at elevated temperatures www.hindawi.com/journals/isrn/2014/468510/fig8/. This was a test of regular concrete so I don't know what affect using perlite as an aggregate instead of regular rock and sand would have on the fire resistance of the cement.
Hi Lee, Congrats on your oven and videos..They are EXCELLENT !!! I'm also in the process of building a pizza oven. Would you be kind to let me know what you use to attach the firebricks together ?? Are you using Portland and Perlite ?? Thanks so much. Chris from Orlando.
+1972arg I just mixed sand , masonry cement and fire clay together and haven't had any problems with it. I forget what my ratios were but you can find that on the web. You can buy refractory mortar which is a little better withstanding the heat. You do want to make sure you have minimal direct exposure of the mortar to the fire so make your fire brick joints tight as possible
The less cement you use, the better it will insulate. This is not exposed so I just needed enough to keep it stable. I actually used a 10-1 ratio for some of the other perlite concrete that I used in the oven build.
Hey, I am about 1/4 through my pizza oven build and have totally lost all sources for refractory mortar. You are using Portland cement with your Perlite....correct? I am a total nubie in this arena but read that Portland starts to break down at about 450 F. Have you experienced any degradation or crack since you did this?
I only used the perlite concrete on the back side of the fire brick at the floor of the oven and at the very top, so I'm not sure if it ever gets that hot on the outside of the dome. Also, since the cement is on the back side of the brick, it isn't being subjected to abrupt temperature changes. That can really cause spalling and cracking. I have not had any problems with it so far. I would not use Portland cement anywhere inside the oven though without mixing in fire clay first.
I made this video in 2008 and I think those shirts were fairly new and expensive at the time. Plus in the humidity and heat down here you will still sweat plenty, even in a dry-fit shirt.
When working with cement you should first completely mix thy dry stuff - cement + perlite. Then start adding water and mix completely. The mix Should be as possible.
do you have a video showing this mix with the liquid soap. would like to see it. in theory it sounds like a good idea. how much soap to other ingredients would you suggest.
How is you 5 to 1 mix holding up? I'm working on my oven now..but not sure if the 5 to 1 is structurally strong enough. Any input or suggestion from you or anyone is welcomed.
Yes it has held up just fine. This website says a 5 to 1 mix would be a 230 - 300 psi mix. That isn't super strong, but strong enough for what I needed. www.perlite.org/overview-of-perlite-concrete-2/
I am trying to build a DIY Konro grill (Japanese table grill) similar to this one korin.com/Charcoal-Barbecue-Konro-Lg?sc=29&category=17859353 I was thinking of making a mold and using a perlite/cement mixture or maybe furnace cement to the mold and cast a grill. Do you think that would work or do you have any other suggestions?
+dave speer I don't know. I think there are people who have built what they call rocket stoves out of perlite concrete. You might want to mix some fire clay in the mix and/or line the inside where the fire is going to be with some clay flue material.
Perlite breaks down when you mix. ALWAYS use 25% to 30% more perlite than your volume calculations and TUMBLE mix don't mechanical mix or it will break down into powder...
January 2018, I bought a large bag at HD for about $17 (if I remember right). I was surprised at the price. Usually the smaller hardware stores have small bags for about $8 - the big bag was a big bargain (say that 3x really fast ;-)
what is the purpose of perlite concrete and where can I buy it? I am building my own pizza oven and will follow all your instructions and videos as they are excellent. Thanks for uploading it. I hope mine comes as nice as yours... :-)
tostafamily The perlite acts as insulation and adding cement turns it into an insulating concrete. While not as strong as regular concrete made with sand, aggregate and cement, it is much more rigid than loose perlite. You can get large bags of perlite at most big nurseries. It's used in potting soil a lot.
You would be correct if this were exposed directly to heat or flame. This is behind the fire brick so isn't going to get as hot. Plus the fact that it is totally encapsulated, even if it did get damaged by the heat it wouldn't be a problem.
I think the the perlite is too delicate to use a cement mixer. A mixer would probably break up the pertlite into smaller pieces, which will reduce the insulative (I think that's a word) properties of the mix. I mean it might work, but the mix is so lightweight that it's really easy to mix by hand.
You can use refractory mortar, but that is pretty expensive and is kind of overkill. A cheaper way, which of course is the way I did it, is to mix fire clay with regular portland cement and sand. You will probably have to go to a specialty masonry supply house to find it. I don't remember my recipe but I found one online. 1 part Portland cement 4 1/2 parts sand 1/2 part fireclay
This was one the first videos I put on RU-vid, so I didn't put much thought into it and I mistakenly said vermiculite a few time by mistake. It was perlite though.
5 to 10 parts of perlite to one part of Portland cement, depending on how strong you need it. No sand. You could put some fire clay in it if the concrete is going to be exposed directly to the flames but you don't need that if you are putting it behind the fire brick like I am.
I think I did a 5 to 1 perlite cement and you put just enough water to wet the cement. The more water you add, the less strong the mix will be. I think you could actually use a 10 to 1 mix - although it would be less strong, it would insulate better at that ratio.
A garden shop will likely carry it. That's where I got mine in a 4 cubic foot bag. In the US, big box stores like Walmart and Menards carry it as well, in smaller quantities.
Portland cement is best. I used Portland for most of it but ran out at the end and used mortar mix to finish the pour. Mortar mix is just Portland cement with lime added. It will be OK in this application.
I got mine from a nursery here in Orlando that is closed now. But most big nurserys should have it. You can get it at the big box places like Home Depot and Lowes, but they only have really small bags of it. Most serious nurserys will have huge bags of it.
I used regular Portland on this, mainly because it was all on the opposite side of the brick from the flames. If you're planning to use the perlite in a situation where it would be subject to intense heat - I'd say over 600F-700F degrees, like if you wanted to build one of those beach ball pizza ovens - you should use the refractory cement.
It's not really durable for foot traffic nor is it smooth. If you topped it with a regular slab it might work but there are better and cheaper ways to insulate a basement floor. The perlite concrete is good for very high temperatures which is why I used it on the pizza oven.
How did yours come out? I made a rocket stove without about this much water and it mostly stays together, but crumbles off all the time. I felt like I should have added more water...
Its falling apart because of two things. Portland is notable to take as much heat as in you application. That is the primary reason to the crumbling. If you used a different mix with equal parts fire clay and portland and lime AND mixed it just to the point of holding together in your hand this would be good for your application.
Well, I'm assuming you've seen the video of my build ( watch it here if you haven't ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Y2vuY2kL5bw.html), but the decorative concrete top didn't hold up worth a crap and I will be tearing it out and replacing with granite as soon as I get finished with some other projects around the house. Other than that I had a little bit of cracking right at the flue transition back to the center mount chimney, which I re-sealed with some masonry caulk. Every oven is going to crack a little bit somewhere. Everything else has held up great and it's been 10 years now since I built this oven.
I have never heard that before. The problem with getting regular concrete too hot is that it will cause it to spall. I don't think the perlite concrete ever gets that hot in a brick oven because of the brick between it and the fire. It might cause a spalling problem in an application where fire will directly be hitting it.
Try mixing up all the dry consistant and then the water - that is how they do it when baking a cake. and it is the way I was taught when helping my dad build a fireplace.
Lee McNeil 'WR Grace', look em up. They poisoned the water up in Boston killing a bunch of children. There's a movie about it called, 'A Civil Action', starring Robert Duvall and John Travolta (probably John Travolta's best performance).
@@geodes4762 Try calling Oldcastle Coastal (239) 334-8022. I am pretty sure they will have them or can get them. I got mine at a masonry supply yard owned by a ready mix concrete company called Rinker, that has been bought by a company called Cemex, so you could also look those guys up and give them a call. I got my Old Chicago brick from Oldcastle.
+Soren Ingram I think the perlite is a little better resistant to water damage if it gets wet. I don't know though really - I haven't worked with vermiculite before.
Oh yeah. That oven isn't going anywhere unless someone buys my house and wants to tear it down, And if they do they better pack a lunch. The perlite concrete works great though. I haven't used the oven to cook anything with residual heat - like baking bread in it - so I haven't really tested out how long the oven stays warm after a fire. But I will say when I cook something in it like pizza at night and just let the fire go out with the door off, it's still pretty warm in the morning.
That's great very good to know I will build it on a stand with wheels and when I move it can come with me lol also I live where we get gruesome winters lots of snow so I would have to move it indoors this was very helpful thank you I am building the oven today with my kids ahh wish me luck ...thanks again
S & N are mortar types and the difference between them is the Portland cement/lime/sand ratio. I was probably using type S which is the high strength mortar mix. It has a higher cement to lime ratio than type N.
