Curing times for refractory mortar

[david s]

As lime acts as an accelerant with CAC and citric acid acts as a retarder. It could be that the brickies sand you have is alkaline. Because the sand is the greatest proportion of the mix its affect will be more powerful. The washed sand is likely to have eliminated any alkalinity so would explain its better performance. If you have access to ph testing, or know anyone crazy enough to own a pool in Melbourne, it would be interesting to find out if this is the cause.

[Simonl]

I've got a simple pH test kit for soil. I'll give that a go if I can find it.

Also I've tried to attach some pics of my build but I always get an error. I'll keep trying..

[david s]

Your pics may be too large for the forum and need resizing. I find the easiest way to do this is to email the pics to myself which automatically resizes them. Then you can select the pics off your email to post on the forum. Also the forum only allows 5 pics per post.

[UtahBeehiver]

Pic size limit is about 1.25 mg which is small by today's phone standard and like David said, you can load about 5 per post.