I need to seal the bottom a barrel

I need to seal the bottom of the barrel.

I don't want to screw this up so I thought I'd ask first.

My design has an open barrel resting on a bed of fire brick, except that in the front there is a rectangular opening starting at the bottom of the barrel for the fire tunnel to go through. There is very little gap except where the fire tunnel made of fire bricks goes through, and there it is about 1/8" to about 3/8 ". If I had access to clay in bulk I would just mound it all around the barrel to seal it. I do have access to type s mortar mix, portland, lime, masonry sand, gravel and portland and perlite. I also have 2 bags of bentonite clay and a 50 lb bag of ground fire clay which I had to pay over 30 bucks for (ouch). I also have access to metal to masonry furnace cement for about $12 per quart

What should I mix to together that is going to do a good job sealing the bottom of the barrel, as well as mechanically holding it in place but at the same time not concreting it in place for all time?

PS One more thing - I see some articles about building pizza ovens that talk about using portand where you have to wait about 3 weeks before first heat. As it is now past mid-November in Vermont, this just isn't an option. I need something that will be ready in 2 or three days if possible, if just to get me through winter, and then in spring I can do something better.

Thanks.

Hello David,

I hope others will have a chance to share with you their thoughts, but as I gave a quick scan of your design, I had more questions than good advice. I don't translate "words" well into three dimensional shapes so I will admit to not really understanding the actual design of your stove, as it does not seem to me to be of the standard RMH format.

What I can share, and many of us here are writing all too often... Just because it is on the web in words, or video, does not make it a good idea, concept or design...

Portland (OPC) has no place in stove, kiln or masonry heater design. It doesn't even need to be in the foundational elements, but definitely does not belong in any of the interstitial or dermal component matrix.

Bentonite clays are too expansive to use in the design matrix of combustion chambers.

I am not clear on, "If I had access to clay in bulk I would just mound it all around the barrel to seal it..."
If you have access to a type s mortar, thens I don't really know of any area that doesn't also supply clay...even really inexpensive clay just out of the ground. Almost all over North America there clay, often good clays just found in roadside ditches, either naturally harvested or bag as simple processed fire clays. If you can get 50 lb bag of ground fire clay then that is all you really need unless I am missing something that others will catch about your design.

PS One more thing - I see some articles about building pizza ovens that talk about using portand where you have to wait about 3 weeks before first heat. As it is now past mid-November in Vermont, this just isn't an option. I need something that will be ready in 2 or three days if possible, if just to get me through winter, and then in spring I can do something better.

Please share the link for, "pizza ovens that talk about using portland cement," for my own understanding, I would like to see what someone may be trying to suggest.

I will share again, just because someone is doing something and making a video about it, does not make it a good idea. OPC is not a material (nor industry behind it) to support or use for such an application. I too live in Vermont, and it can be frustrating to have seasons sometimes, but just like I can't expect to plant a garden now, neither can I do certain other activities...like building an outdoor clay oven...or at least...not with more effort than it is worth.

If you can provide photo or drawings of your design I know that wil help everyone in giving their opinions and assistance.

Hope that helps some,

Oh I am sure there is tons of clay around. Where I do not know. Anyway I have come up with a better solution by cementing a few pieces of fire brick inside the barrel to keep it from shifting, and I will then just use a bead of high temp cauk to seal it. I ground down rthe edge odf the vbarrel to eliminate practically all the gaps, and stuffed the larger gap where the fire tnunnel goes through the side of the barrel with stove door gasket impregnated with furnace cement. Just waiting for it to cure now. Thanks again.

Hi David,

I loved the video on the way you cut firebrick. Have been meaning to tell you that for a while. If you are just wanting to experiment with things...go for it...and let us know how thing turn out...

Most of the Permie builds for such things as RMH try to keep the design as "natural" and low tech industry (independant) as possible. I am not sure if a cements and high temp caulks are the solution in the realm of natural and low impact building materials. I can promise that most cements and caulks, unless designed for ceramic kilns, and crucible use do not have the endurance to last long under the heat of a RMH.

As for clay, you can by it cheaply at most masonry supply stores...

Good Luck, and let us know how things go...

I used the lid off a barrel and set it in the cob around the core and exhaust area. A little clay slip seals the barrel to the lid.

12 oz tube of high temp caulk as opposed to heavy machinery digging up clay from open pit mines that take centuries to revert back to their original look. I think I'll go with the 12 oz tube of caulk. Thanks anyway : - )

12 oz tube of high temp caulk as opposed to heavy machinery digging up clay from open pit mines that take centuries to revert back to their original look. I think I'll go with the 12 oz tube of caulk.

Hmmm...apples and turnips...as a 12 oz tube of industrial high temp caulk did not come from an industry that just made 12 ounces of the material...and it will most assuredly have a similar (if not much larger) carbon footprint than a bag of clay from the way I have learned to look at this subject.

Dave, not for nothing, I support experimenting, but when it comes to understanding "carbon footprinting" I try really hard to stay on top of that subject and always keep an eye out for new info.

Most of this planet is made of clay...it is one of (some consider it the "one") most dominate. Many of the clay pits have been (and will continue to be) worked for centuries. I agree, there is a "carbon footprint" with anything we do...project life span being another contributing factor...(i.e. how many time does something have to built to get it working the way it should.)

I support experimenting but can not agree, having studied this subject for over 30 years that cement, and related products (and the industries that manufacture them) have any where near a lower "carbon footprint" than the many well built and working wonderfully natural cobb RMH.

Again, I am all for experimenting if one is curious, however if the goal is a functioning RMH, there are plenty, even here in New England, that are built with more natural materials than what concrete is going to offer. This being a permaculture site, I am always going to lean toward, and suggest natural and/or recycled materials over anything that is industry based...and/or...as little industrial footprint as possible and still achieve a well functioning design...be that architecture, or a RMH.

I don't want to screw this up so I thought I'd ask first.

Please by all means use whatever is planned for to experiment with...I don't mean to dissuade anyone from experimenting (if its safe) and all the luck in the world with it... Nevertheless, when someone asks a question here they are always going to get pretty good advice and a spectrum of it from some pretty knowledgeable and experienced folks...It get frustrating sometimes when folks want to debate the advice given over the choice it would seem already made...

If there was already a plan, then go for it and share the results...we would love to see it...

You will see that after first askinjg for advice that I stated that I found a solution for sealing the bottom of the barrel. At that point you chose to suggest that I should have used clay My response to your suggestion was that in any event that I found using a 10 oz tube of high temp caulk as opposed to using clay (which I just previously had stated that I didn't have access to anyway) was more environmentally responsible. You then chose to label my statement as "debating" advice which I had asked for. #1 I did not ask for advice as to whether to use high temp calk after I had already used it; and #2 it seems that debate (or as we sometimes describe it here in Vermont: discussion) as to materials would always be appropriate. Thanks anyway.

What should I mix to together that is going to do a good job sealing the bottom of the barrel, as well as mechanically holding it in place but at the same time not concreting it in place for all time?

David I am sorry if I offended you in some way. That was not my goal at all...apologies.

The above would seem to be counter to your last post...it is...indeed...a question about sealing. If I missed some other points, or read into this "discussion" too much, for that I am also sorry. It does get draining for those here in the forum that volunteer a great deal of time trying to help...only to find themselves in a "discussion" about explaining the advice they give to "asker" who doesn't seem to care for the advice... Perhaps that wasn't the case...but either way, I will leave it to other from now on to address your query, as the results I hope will be more positive than anything I could offer.

Good luck and I do hope you continue to share results of your project...