Rocket mass Heaters finishing?

I'm looking through the forms and I can't find any talk of finishing the cob heater. We have ours inside and I want to be able to sweep and mop without small amounts of cob coming off, so what would you use to make the outside hard and stable to sweeping and mopping?

A good hard plaster coat is what is needed. That can be as simple as sharp sand and clay slip (try a bunch of tests and find the sweet mix that has the minimum of slip to stay tough) or you can get into other plasters (lime) or ammendments. Get ahold of the Natural Plaster book by Cedar Rose Guelberth/Dan Chiras or find someone to show you.

thank you was just what I needed to know. will do all above till it works out right.

I never tried it but don't some people linseed oil their cob/plaster after to waterproof it?

I had heard of that but wasn't sure if it made it hard enough to not flake off when sweeping and mopping.

I am not sure cured soaked in linseed oil would make the surface harder, but I would assume it would make it tougher ie more resistant to chipping.

Several coats of linseed WILL make it harder, it's what we use on earthen floors.
Seems like a bad choice for heaters. The oil is likely to do something funky in the heat.

Something I've used to lock down dusty plasters on a stove is exterior grade white glue. Thin it with water and paint on a couple-few coats. It'll golden up the color a little and give it a slightly "glazed" look. The exterior grade stuff can be wiped with a damp cloth and seems to slightly resist coffee stains..

been having a lot of trouble building it think we are at Rocket mass heater Ver 1.09 keep, so tired of brake it down and start from scratch. but if anyone is intrested I have bunch of videos of what not to do at
http://www.youtube.com/user/DavidTexen?feature=mhee

will keep putting them up and talking about our experiences as we go along.

Burns have been an epic fail, only getting 100 F on top of drum. tearing down to base. Only thing i can think of is we just built it with only cob. Going to break down the cob this time and add charcoal and actually make forms . add the charcoal to cob and make actual fire brick from the forms. hope this does it getting so tired of this, don't know where I am getting the strength to do this every day. We are up to Rocket mass heater V1.09 and am just spent. one man team with the wife as foreman now so maybe you guy's can understand where I'm coming from. She hasn't helped at all on any of it yet she want to try this and that, and I'm like I tried that back in ver 1.04. Thought for the day, is living off the grid suppose to be this hard lol

I find a good olive oil soap works pretty well. if it is a bench or bed. for the floor i treat it with paraffin wax then normal floor wax. linseed oil melts if its not yet dry and the only way around it is to use thin coats till you have the desired surface. Bee's wax melts at almost body temp while it is harder to melt paraffin or olive oil soap.