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You could try Thompson Building Materials, there's one up by you. I called them at one point and they were not carrying HeatStop products, so may the force be with you.
Truthfully, the feeling here is that HeatStop is grossly over-priced and places a limit on the amount of mortar you can mix up in a batch since you don't want to throw any excess away. Of course, YMMV.
There is a growing legion of builders who swear by homebrew mortar, myself included. If (when) I build a second oven dedicated solely to bread, I will go with the homebrew again. Honestly, I wouldn't use anything else.
I was thinking about the homebrew and am happy to hear you say that. What ratio of cement sand clay did you use?
I bought a couple of sacks of premixed mortar from thompsons last time I was there. Assuming the mortar is premixed, how much clay would you add?
I have two sacks of the premix mortar and two sacks of clay...maybe I'll just go to it and get started on the walls later today.
I'm also looking into Harbison Walker's products. They have a number of mortars....Refrac Air Dry, Recrac Wet Dry, etc. I'm waiting for a call back from their salesman to see what cost and shipping is likely to be.
I would and did use a premixed thin airset mortar for a barrel, it sticks real good and will have less of a tendency to crack and fail.
You will need 2x20 litre buckets and costs about A$30 per bucket.
Its the joints that fail in an oven, my joints are about 1 to 2mm thick.
The English language was invented by people who couldnt spell.
What do you guys thinkl og using this stuff fopr a thermal break at the entryway? It's an HW product and sounds very durable and easy to mold/work with.. Comes in a one gallon tub or in caulk tubes.
"Moldable
INSWOOL MOLDABLE is a 2300?F ceramic fiber, putty-like consistency material, used for linings up to three inches thick, to pack large voids, or even fill thin cracks. It can be troweled or hand packed into place.
INSWOOL MOLDABLE is light weight, with very low thermal conductivity, and therefore a good insulator, yet it develops a strong hot face surface to withstand physical abuse and high air velocities as compared to conventional ceramic fiber products. It is also used as a high temperature gasket material, and as a general purpose patching product. Its ability to compress makes INSWOOL MOLDABLE an excellent material for expansion joints and for filling contraction cracks. It is also an ideal material to fill ceramic cuplock anchors for ceramic fiber blanket linings, and can be used in contact with molten aluminum.
The classic homebrew ratio is 1-3-1-1: portland cement, fine sand, hydrated lime and fireclay. Check your premix mortar bag for content and adjust with fireclay and lime accordingly.
I would not buy any kind of mortar and perhaps anything else from Frank Dicken, the Sales Manager at HW. He sold me a bag of refractory mortar that he claimed was suitable for a WFO. I used a little bit of it on my firepit and found out after a rain (it was even covered up) that was water soluable because it crumbled into dust. When I called to discuss with him he would not return my message. I found out on this site he sold the same bag to someone else for a bit less than what he charged me. Further, he gave my name and number out to a guy who solicited me for some kind of networking thing. Totally unprofessional and I have since taken my business to a competitor down the street.
John
Wow...Frank is the guy who I'm waiting for a call from. I left him a message telling him that I'm building an outdoor pizza oven and want to talk to him about a proper mortar choice....ought to be very interesting to hear what he says if he calls me back.
Wet mix mortars are considered a problem in oven building. For one thing, they are heat setting, and they aren't waterproof in our application. Also, they are designed for thin joints: they are not so good at filling the wide gaps on the outside of the dome. If you're getting the stuff cheap, it may be out of date, and wet mortars don't store well. It might also have been damaged from too hot or too cold storage.
I'd steer clear if you have another option.
Just read dnum's post.
The premixed I use is an air setting type, takes about 10 minutes.
For a barrel all you will have is thin joints.
Wet mortars have to be used or they will go off.
The English language was invented by people who couldnt spell.
Search on Premix..
Dmun has a horror story about premix and if I remember correctly Splatgirl used premix and was happy with it.
I used premix, Sairset, and didn't, haven't had problems, but my oven is enclosed in a house and water isn't / wasn't an issue.
What I liked was;
Open the bucket remove what you expect to use, add a bit of water and mix to the consistency of smooth Peanut butter and go.. Whatever is left, goes back in the bucket to be used later.. Clean up is easy, wipe down with a wet sponge, this is the up side of John's down side.
The home brew is cheap and easy to make up, I used it on the chimney and liked it. As long as you clean up right away it's not a problem.
Many people "dis" the premix and it's really meant for kiln building, but it bonds, and as far as I can tell works well and doesn't let go with use. I would warn anyone not to use it where it would get wet or might become wet. But then.. I'll state that re-curing these ovens is not something you really want to do and if it gets wet, well, that's what has to be done..
I am not versed in the rehydration limits of wet premixed mortars. I understand some mortars can handle a rehydration step or two, others none. I do know that if I had used the stuff Frank Dicken sold me on my oven and the bricks started to fall out I would have been really pissed. It was called Sairbond, because it was dry.
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