best way to handle cracks?

[salilah]

We're just at the beginning of the build of the oven - last weekend created the sand form, and added first layer of clay and sand, and cut door on day 2.

Returning to the oven today to start removing the sand form, there is quite a big crack right across the top to the doorway arch!

What is the best way to fill this? Clay and sand mix as original, or wetter (it's quite a narrow crack)?

Any suggestions much appreciated!
thanks
S

[turkey]

welcome to the forum, we have quite a few clay builders so hopefully someone has first hand experience.

based on knowledge of car repairs (random I know) I would enlarge the crack enough so you can be sure the filler will reach all the way in, also at the point end of the crack make this into a circular gouge the reason being that cracks act as an easy week path to follow and extend in the future, making the end a hole not a crack tip will stop it spreading easily. Make sure you thoughts edges of all this to give the new clay something to grip to.

[cannyfradock]

Hello Salilah.......welcome to the forum.

You could also try to get some heat in the oven as soon as poss. It may be easier to plug that gap when the clay starts to harden. Making the claY a little more moist sounds like a good idea.

If you are using a tarp to temp. cover it at the moment, try to keep an air gap between clay and cover.

You may get a better response from our clay oven builders if you start another thread here.. ukwoodfiredovenforum.proboards.com/index.cgi?board=ceovens

Terry

[salilah]

Thank you both for ideas!
We decided - as it was first layer - to remove it and redo...
Which meant we could go for a slightly bigger inside which I was pleased about (don't want to slice my loaves in half to get them out!!)

I'll start a thread on the build as suggested - we have the new form, first layer, brick arch and second layer now on, and a small fire done inside the first layer, so it is fun! (and a very nice tiled roof <grin>)

[cannyfradock]

Salilah

I commend your patience....a lot of people give up too early by taking on a that'll do attitude (I was guilty of this on my first Pompeii oven build).

looking forward to seeing any pics you have taken along the way.....we love pics.

Terry

[dougclay]

Sloppy version of the clay mix you used to build is best to fill cracks, but let them settle first... when the outside of you dome dries faster than the inside, you will get cracks, then once the inside catches up many of these cracks will close again, others will go through...

When u r ready to fill, take a hand full of the sloppy stuff and rub it back and forth across the width of the crack and each pass pushes the clay deeper and deeper. the water seeps into the surrounding clay and it makes a seamless fill., once dry, you will have trouble spotting where the cracks were...

btw, if you have delicate hands, you might want to wear rubber gloves as this technique will quickly "exfoliate" your fingertips...

[salilah]

Thanks all for suggestions!
Yes we are seeing a few very small cracks in layer 2 - I'll see what happens as it dries more (next weekend)...
If we do have cracks in layer 2, should we fill these BEFORE putting in the insulation layer?
The inside is probably not drying very fast, as we have only done one very small fire inside, and currently the entrance is part-blocked with sand to support the join between main and arch - which reminds me, I should go get the sand out today I think!
Will post photos soon (when I can get them sized etc...)
Sali