Salty sand in rocket mass heater

Hey all,

I'm preparing for my RMH build in a couple weeks.  The easiest, cheapest local source for sand is the town sand pile  It's slightly salted - just enough so it doesn't freeze in the winter and become impossible to for the town use on the roads.

Is this an acceptable sand to use to mix up the cob for an RMH?

What about for brushing between the first course of firebricks that the firebox sits on?

And for any other general mortaring (for leveling and chinking) throughout the build?

Thanks,
Jean-Paul

Hi Jean Paul;
I think the salty sand will be fine for most of your build.   However for when you are mixing your fireclay up for building the core unit. I would purchase a sack of builders sand and use it.
Just to be sure that the salt won't react to the high heat at the core unit.

May also be a good idea to keep direct contact of the salty sand away from the metal barrel and exhaust duct which could oxidize/rust them faster too.