Heatstop 50 offers no strength?

[Kemo]

I just got off the phone with a representative of a local masonry supply store. I was trying to source some Heatstop 50 drymix. The guy mentioned that he had refractory mortar but only in the bucket already mixed up. I asked him if that stuff was waterproof after drying and he said he wasnt sure. I told him I was building a pizza oven and that the dry mix of Heatstop 50 was what I was looking for. He then went on to tell me that refractory mortar offers no strength at all and I should be using regular concrete.

does this sound right? There are plenty of people here on the site using only refmix or heatstop 50 without any issues.

It always strikes me as odd when people that you would view as local experts give conflicting advice with what Ive read on the board.

Any thoughts here?

[james]

Hi Steve,

Can't we just get you Refmix? It says made for "forno a legna" right on the bag. :-)
James

[Kemo]

well...Chris from the board was nice enought to pass along a full bag of heatstop 50. Just to stay consistent, I contacted a local vendor just to see how much they sell it for to save a few $$$ on shipping. After talking with them, I think I need to go ahead and order some Refmix and be done with it.

[Gentcpa]

Might depend on definition on strength. No issues using heat-stop here. Sourced here for $25 for a 50lb bag, sorry James. I actually get along better with it than regular mortar (can't explain that one but there you have it).

Did he know that you are building using bricks and not just mortar or concrete. I have also ran into the same issue with brick yard folk not knowing about product. One place wanted to sell me regular bricks as firebricks. At my source for heat-stop 50 and firebricks the women during the week (who don't look like they belong in a brickyard) know exactly what everything is while the guys on the weekend have no idea.

Fun trying to find this stuff locally isn't it?

[dmun]

Heat stop is plenty strong for what we are doing here. Here's a picture of a shard cut off one of my heat-stop glued triangles:



You'll note that it's in two pieces and they stayed mortared together despite the vibration and frictional heat and water of cutting. That was no fluke. They stayed together triangle after triangle.

[Ken524]

Originally Posted by Kemo

He then went on to tell me that refractory mortar offers no strength at all and I should be using regular concrete.

does this sound right? There are plenty of people here on the site using only refmix or heatstop 50 without any issues.

No, it doesn't sound right at all. Regular "concrete" (he must have meant "mortar"... so he really doesn't know what he's talking about!) won't hold up to the temps that your oven will go to.

I'm using HeatStop50. The stuff is easy to use and solid as a rock. Even if strength was an issue, the oven dome is mostly self supporting anyway by virtue of the geometry.

Go with RefMix if the economics are close or better. As James says, it's designed specifically for what we are doing.

If you need to use HeatStop, insist on "HeatStop 50 -the dry mix in a 50lb bag". Disregard whatever your dealer says. Tell him that's what you need and to please order it .

[Acoma]

I sense adrenaline here. Heat Stop 50 in 50lb bag, or Refmix. Nothing else, no way, no trying

[Hendo]

Originally Posted by Ken524

Even if strength was an issue, the oven dome is mostly self supporting anyway by virtue of the geometry.

My brickie echoed these sentiments when I commenced the dome – he maintained that the strength of the dome was down to the design of the dome, rather than the strength of the refractory mortar.

But like David, I’ve stuck bits of brick together and then cut them in a wet saw, and the shards remained intact. One cut of this 4" shard was done in a wet saw, the other using a diamond blade in a 5” angle grinder:



Minimal mortar thickness too – like David’s – so it can’t be too weak!

Paul.

[Ken524]

Originally Posted by Acoma

I sense adrenaline here. Heat Stop 50 in 50lb bag, or Refmix. Nothing else, no way, no trying

No adrenaline. The problem is that so-called "dealers" will try to sell you whatever is in the back of their store. I've had dealers insist I needed a 50# bag of "fireclay". If you want HeatStop50, you simply have to put your foot down and make sure they understand that's what you want.

Or just call FB and get exactly what you need.

[Acoma]

100% agree with you Ken. The adrenaline mentioned was towards the ignorant sales people not listening to the needs of us consumers, and just selling product without knowledge.