Brick wet or Dry?

[phippsj]

I have red what seems to be contradictory information on this forum and in the downloaded guide. I will be using Heat Stop mortar to build the dome, and am wondering if the bricks are supposed to be soaked, slightly wet, or dry.

Right now I am leaning towards cleaning them the night before, and then working with them dry the next day. If anyone has used this particular mortar could help me out with this questions I would appreciate it!

Thanks,
-jared

[Tscarborough]

Re: Brick wet or Dry?

They definitely need to be cleaned; the dust, cut wet or dry, is a bond breaker.

They should be saturated surface dry when you lay them, meaning that they should be damp, but not wet. If liquid water is visible on the surface, they are too wet; if water sprinkled on the surface disappears immediately, they are too dry.

Most masons I know dip the firebrick in a bucket of water and shake it off just prior to buttering and laying them. If it is hot and windy, you may need more of a soak.

If there is a question in your mind, stick a couple of firebricks together using your planned technique and mix and see how it works.

[oventhusiast]

Re: Brick wet or Dry?

I used Heatstop for my dome and it was great! In my opinion, you MUST soak the firebrick. I found it best when I put them in a bucket until they stopped 'singing' (air bubbles sizzle to the surface) and take them out and let them sit out to dry off a bit on the surface so they are not dripping wet when you butter them up. My dome still had some cracks when I cured it but all in all, it's just fine! If you'd like, you can check out my pics at Picasa Web Albums - Rick M. some may think its ok to mortar them dry, but I think the dry brick will suck all of the water out of the Heatstop, causing it to fail to adhere like it should. Mortar should cure not dry out.
Best of luck,
Rick

[azpizzanut]

Re: Brick wet or Dry?

Hello,

Did you download the free Pompeii oven instructions? Pages 36 and 38 reference soaking the bricks before cutting or mortaring them in place. If you refer to the many posts about joint cracking and mortar failure they will often reference improper wetting of bricks or too dry bricks taking moisture from the mortar.

You need a balance with moisture from the mortar and moisture in the brick to make a good joint. Be one with the process. A sticky joint is a good joint.


Best of luck,

[RTflorida]

Re: Brick wet or Dry?

All of the above suggestions are spot on. You will also find out very quickly if you are doing it right. Properly mixed Heatstop (peanut butter consistancy) will actually slide right off a drippy wet brick (obvious no adhesion), if the brick is too dry it will suck the moisture out of the Heatstop so quickly that you won't have enough time to place the brick and position it before the Heaststop gets crumbly......trust me, you will probably experience both ends of the spectrum several times during your build.
Heatstop 50 is good stuff but takes a couple of batches to get just right....remember to mix it in small batches and DON'T try to "save" a batch that is hardening by adding more water.

RT

[SteveP]

Re: Brick wet or Dry?

Concrete needs to cure in the presense of moisture. Without water, the cement cannot build a crystaline structure to adequately bind wth the aggregates. This is why concrete companies constantly watch their w/c ratio (water/concrete). If your brick are too dry, the water will be drawn form the mortar to the brick thus reducing the amount of water available for the cement to produce their crystaline structure. It is important to ensure that you add the correct amount of water to your mortar as well as having your brick somewhat wet. And, like RT said, don't add water to your Heatstop once it becomes too dry; throw it out and make smaller batches.