Could I have a problem?

[tompyro]

Hi Group,
I have started building my oven and decided to poke around the forum. I have used mostly bagged mortar from Home Depot. All of the bricks have been miter cut at least on one direction. My question for all is what will be the problem with using basic mortar and not fire resistive mortar in the joints? Should I tear it down and start over using a mortar with fire clay? I am at the point of building out the hearth entry and chimney so now is the time for the decision. Thanks in advance.

[almondsurf]

Re: Could I have a problem?

I am in the process of starting my oven and have read to "only" use refractory mortar. From what I gather, regular mortar will defiantly deteriorate over time.

[david s]

Re: Could I have a problem?

Hi Group,
I have started building my oven and decided to poke around the forum. I have used mostly bagged mortar from Home Depot. All of the bricks have been miter cut at least on one direction. My question for all is what will be the problem with using basic mortar and not fire resistive mortar in the joints? Should I tear it down and start over using a mortar with fire clay? I am at the point of building out the hearth entry and chimney so now is the time for the decision. Thanks in advance.

Having got this far it will be extremely difficult to tear it down and clean off all the mortar. Perhaps you could finish it, fire it and see how it goes. If the mortar does break down to the extent that the oven becomes unusable then it will simplify the deconstruction and brick cleaning. I would expect you'll have some cracks appearing, but still have a good working oven.

[jeeppiper]

Re: Could I have a problem?

Just a guess, but the breakdown of "regular mortar" will occur over time due to thermal cycling, not just after one firing. The constant expansion and contraction of firing and cooling creates stresses in the firebrick and mortar joints.

I may be wrong, (so please over-ride me if anyone has any experience), but I am thinking that it might be wise to bite the bullet and rebuild using refractory mortar.

think of it as an investment in Piece-of-mind rather than worrying about it.

[stonecutter]

Re: Could I have a problem?

You have to make that call. Do you want to invest more time,effort and money into an oven that WILL eventually have mortar issues?

How much time?

Who knows, but relative to (an occasional use) ovens lifespan, it will be relatively short. How short, depends how the mortar cured, how you dried out your oven, how you use the oven, environment, etc,etc,etc.

If it was me, it would be torn down now and refractory or fire resistant mortar would be used to lay the brick. Better to rip the band-aid off fast than to slowly pull it off.