Lesleigh McGann

Ok So I contacted Lime Works in Telford PA and they told me that NHL 5 mixed with sand will make a mortar good up to 650 degrees celsius (1200 F).  So this should be good for a permanent bell mortar.  Natural Hydraulic Lime grade 5  

Thanks for all the input Gerry

Hi Gerry

I got a thermo-couple and I got consistent temps of 1450 F on my last burn all through the middle phase.  I closed a leak that was hurting my draft and the new thermometer goes up to 2400 F so I can get better ideas of whats going on.  No smell to speak of once it got going.  Still using the black walnut as that's what I've got seasoned right now.  I cast the bell lid yesterday and will install it once the it fully sets.  Will post again after testing to see how it affects exhaust quality.

I will look into the floor channel.  Ease of replacement is a good thing.  

thanks again, sorry about divulging your code name. Lesleigh

I have seen a lot about using clay slip for the mortar in a rocket stove and the brick bell.  What I don't understand is weather its supposed to bake hard from the heat of the stove or if its always gonna be a soft mixture that can be broken apart, remixed with water and reused.  If it never gets hard then the core witch is protected from shock, wrapped in ceramic wool and wire should be okay, but the bell is subject to abuse from the people in the room and movement of wood.  Right? I read that clay is fired at 1000F to 1400F degrees so the clay slip of the rocket core could get baked hard.  But the temperatures of the bell won't ever reach that high, so another mortar can be used right? I haven't found any information on the heat tolerance of lime mortar but i know it was used in fire places and brick ovens for hundreds of years.  What temperatures can I expect inside the batch rocket bell? thanks Lesleigh

Hi Gary, thanks for responding to my post.  
1: The entire core is made from hard fire brick recycled from an incinerator.  4.5" by 9" I have noticed it takes 30 minutes for the fire brick to get warm on the out side.  I will measure
   the temp on my next burn. I have also noticed that the burns are getting more rocketty with each burn.  Maybe the result of the core drying out.  
2: I did wonder if some of the smell is coming from the Rockwool.  I know lots of products off gas and it does have some small odor when being installed in a house.  According to their
   website it is good to temps of 1000 c and I didn't think the outside of the core would ever get that hot. Inside yes hopefully.  
3: I have been burning Black walnut.  Several years old and seasoned in a completely dry wood shed.  I did notice that my last burn where I used split wood instead of 2-3" diameter
   sticks burned hotter and faster.  I have read that tree bark is fire resistant compared to the interior wood.  No painted, preserved or wet wood.  
4: I am using a primary air opening of 2" by 4".  Slightly bigger than the recommended 2 6/16 by 2 6/16, but it seems to run better that way.  I haven't made a door yet so I am
   blocking the rest of the opening with bricks.  I have noticed that chemically smell when using my vertical coal/wood stove in the past.  Getting rid of that smell is part of my interest in
   the rocket.
5: I made the P channel 2 1/4 wide by 5/8 high.  I always run with both wide open.
6: I am building it in a garage with a 6" stove pipe collecting the exhaust and running it into the chimney.  The chimney is only 8' high and made of brick so long term I intend to build it
   higher and line it with more 6" stove pipe then insulate it with a clay perlite mixture to maintain exit temperature. Since the heat riser is the "engine" of a rocket I'm not sure that's
   necessary but it can only help right? I am still in the process of building the bell.
Questions:
1:  I need to a better way to measure temperatures and exhaust quality.  Any recommendations? Where in the rocket are you measuring temp for the 1200-1800 F goals? Interior fire
   box walls?  
2:  Advice on raising the temperature in the rocket for complete combustion?
Thanks again for your time and help, Lesleigh

I built a 6" batch rocket based on Peter"s designs on batchrocket.eu  The fire box and heat riser are insulated with 3" of rockwool.   I have an infrared temperature gauge that goes up to 960 degrees F.  Sometimes parts of the inside of the fire box and heat riser will max out the reader so I might be hitting 1000 degrees occasionally but not the target temperatures of 1200-1800 degrees. The exhaust is clear with no wood smoke smell.  But the exhaust does smell dirty, sort of like a diesel engine.

Can I clean the exhaust up more?  

How do I raise the temperature inside my stove?

With this smell what chemicals are likely to be still un-burnt? ( I see that odorless Carbon Monoxide burns at 1128 degrees)

What is a good temperature tester i can get?