Scott Weinberg

I will reiterate my experince on IFB's.  I have  completely removed all, and not one was worth using again (anywhere) They were all used in the riser of a 7" sized batch rocket. I have to admit, I run it hard, but that is not the concern. Until someone we can trust, says- these (brand name and type of IFB's) have held up for 5 years running with narry a problem.  I will not use.

Likewise, on formed fireclay only, or even thin cast refactory. There are folks here with experince that caution the use.  While I no longer have photos, I can show where rather thick ceramic was heated far to quickly and locally on a large piece area, and then shattered. (costly to)

AS was stated, if you don't build your stove to easily get to it inside the bell, the work following that probably will be required is high. This can be delt with ( showed in my build) and yes it worked. As I am rebuilding without touching the bell.

A little for-planning like your doing will pay great dividends I believe.

Best of success.
Scott

Eric Rothoff wrote:Three things have held me back. The first is just making the time because of the other problems.

Yes, they do take commitment to get 'er done.
 

Eric Rothoff wrote:
The second is Insurance.  Even if I was to get the Rocket mass heater certified as a wood stove, it would cost at least an extra $150 dollars a year, and severely limit  insurance companies that I could use.

While this has been discussed in the past, this is something to be considered, but I presume you have a house with NO pre exhisting chimney? NO one has said this is for everyone, I think of this forum (and subject matter) as more of a "if you want to build, this is how it has worked, and please toss out your planned ideas" to others that have successfully made it work.

Eric Rothoff wrote: The third is the main reason. I have a split level home with water heat.  The normal air heating, pebble or cob stoves that just radiate heat would not work well. I might even be able to remodel my fireplace  into a rocket stove, but it would only heat one of the four floors.

Yep, sometimes the  layout is simply not right for the stove. Again it may not be for everyone.

Eric Rothoff wrote: What I need is a plan Rocket mass heater that heats water, (yea, probably pressurized as we don't want to to "Boom Squish" I would probably do a batch rocket heater ask I would not want to constantly feel the heater as I believe you have to do with the J tube heaters.  What I would want to do is heat the water for the day or two usage  when the weather is mild and more often when it gets colder.

I read this to mean you think a pressurised system is safer and more likely to NOT have "boom squish" effects?  Please explain?  As far as heating water and making use of that warm water as a mass storage. It would seem that on this forum, if there is a will, there is a way.  It works both ways. to be sure.

Scott Weinberg wrote:

Robert Ray wrote:The final heating elements (PTC) were delivered today. So I will begin this weekend on the assembly.

 Maybe not cut and dried, but it seems like there should be a "yes it worked" or
" no, it didn't work"  or a comment on where it is going from here.

Am interested.

Robert, with this fairly new thread started  " Good physical "solar sinks" for excess PV power?"  I thought by now, you may have come up with a conclusion for your experiment and it may go with the new forum thread just listed., Please comment here or both.

thank you
Scott

Mike Oswaldrosnick wrote:I had similar questions about durability, but running a cleaner fuel helped a lot. I use kiln-dried wood from https://onestopfuel.ie/ and haven’t had cracking issues since switching. Consistent moisture content seems to make the burn easier on the bricks and metal parts.

Mike, I was wondering how you determined this boughten fuel has worked better for you.   What were you burning before? And if you had cracking issues, did you replace those particular bricks?

In general, wetter wood, would have a cooler burn with the moisture converted to steam. Or were you thinking this "steam" was the problem?

Just curious.

Scott

The Purpose of a Rocket Mass Stove in my opinion.

A simple review:

Just like everything in life, it (A Rocket Mass Stove)   is not and cannot be everything to everyone.  What it is, when built to the numbers, a extremely viaable wood burning-enviromentaly sound-and quite simply a very stable and consistent heat source.

If you want to go out and look for all the reasons that it won't work you will find them. If you convince yourself you do not have the ability to build it, you will not beable to.  Such is life for some.  Mr. Can't, never did anything, and speaking to your self, "I can't do this, and I can't do that, will simply enforce your ability to not get it done, you won't"   The desire to build is something you either have or don't have.  It can be developed and nurtured with sound advice. Much of that advice is here on the forum.

Can a person develop the skills, learn a trade good enough, find new friends along the way, and end up with a soul warming, house warming endevor?  Absolutely I have friends on this forum site, I will probably never meet, but enjoy them imensely.  .

Can you drop everything, and build over the next 30 days, sure, but you don't have to. There have been many winter projects, started at the beginning of fall and finnished before spring. Nothing wrong with that.

I am off my stump, carry on good folks!

Scott

As this is rather old ( 3 years) Please don't be shy, how has this worked out for you.  

So many threads start out  " this is what I am going to do and it is going to save this X amount"  and then we never hear from again.  So, where does this "great idea" fall into?

cheers
Scott

ps  I am a equal progress comment oriented Person!  Simply meaning, if it is a great idea and has worked out well, then all want to know, and if it didn't work out, that should be stated as well. Learning from dreams of others good or bad, is the basis of true learning.

Well done... gives a warm fuzzy feeling at your progress over the last few years.

Cristobal Cristo wrote:I already commented on this issue stating that there exist quality differences between various IFBs, but now I'm thinking that they should not be used in the wood flame path.
Two vendors/manufactures that I inquired about IFB use in flame path said it was OK, but at the same time it's rather obvious that they are not intended for wood flame path:

1. IFBs are rather new invention, established in industry in the 50s.

2. Industry uses natural gas, propane or electricity to melt, crack, kiln fire.

3. If wood is burnt in biomass power stations or incinerators - high alumina hard bricks are used (I read some paper), because amount of fluxes and detrimental substances is high.

I remember and fully agree now.  This is one of the reasons for my posting of the final results as they have often been recommended to use in locations just like I did.  I am not blaming a soul, just reporting the end results after 3 years of hard burning.

Cristobal Cristo wrote:
My electric ceramic kiln is lined with IFB26, but it's electric and only I converted it to propane and propane exhaust is super clean compared to wood and I use it maybe 10 times per year only, so I may not be able to notice any deterioration.
I just read that IFB/propane kilns may have longevity of 1-5 years in high use environment. High use for ceramics firing would be once per 3 days, because cooling to less than 50 C (safe for glazes) takes me around 40 hours. For quick raku firing (objects are removed hot from the kiln) firings could be more frequent with much more thermal strees.
Masonry heater will be probably fired for let's say 4 months, so with one fire par day it's 120 firings - eauivalent to once per 3 days kiln use schedule. However the fuel is wood with chlorine (bricks don't like it) and various fluxes. Also the temperature in properly built riser is equal and turbulence much higher than in a kiln.

So it looks like IFBs in wood flame path are really being tested by us. I'm really curious about performance of IFB risers built by others.

Excellent deduction for the cause of the problem and end results. While no one has asked, this was not a expansion limiting layup of bricks. Unless they could have walked, I will never know now. But I am doubting it, as the perfectly undamaged bricks were just below and besides the IFB's

Thank you Cristobal Cristo for possible root of the cause.   I would like to add one thing concerning propane heat, and cinder block only flues using standard mortar,  this has been known to cause problems. Though I am not sure the root of the cause. Some flues, as in my case, had cast high clay liners that are working just fine after 67 years,  (no propane every used, simply wood stoves all these years)

regards
Scott

Hello all Rocket Stove builders!

I am going to share an experince basically for one reason and that is simply to tell the good and bad of my past few seasons of the 7"  batch box build.

The good: It worked right out of the gate on the first burn and nearly every burn after,  easy to light, easy to clean and it simply worked.
As most of you that may have followed my various suggestions on stove building, I was and still am pretty insistent on building to the KNOWN working numbers.  (for both the stove and bell)   I don't have any experince with ducted benches thus I never comment on them.

Make no doubt about it, I have relied heavly on the advice of Tom of Dragon Fame. Fox James and his great experiments and of course Peter van den Berg  who without him I might be still rubbing two sticks together.

The bad:  Late last season during my monthly inspection I noticed a piece of IFB laying on the inside floor of my bell, but all was working well so didn't think much of it, later I found another  and this kept going... but all was working so I was only puzzled.

So finally on 9/25/2026 I took off the face plate of my bell, (very easy to make, worth every bit of time to construct, as with it off I can crawl right in if need be)
and what I found was very simple, anything I built with good hard fire brick was perfect, anything I built with IFB (Simon Brand) which was all of the riser and some re-enforcement pieces was simply junk, (cracked, broke, or completely out of place)  I doubt I will ever use those again. If I feel something needs extra insulating power, I can always add some of the Mineral wool, or many other product out there that seem to hold up well if this don't have to touch the wood.

I am sure other bricks might stand up better, but I am never going to take the risk again.

So now the really good.  Everything is repairable, (replaceable) the bell is in great shape, and the mineral wool inside was good too. Without the large face plate this would require reworking the bell to some extent, (never fun) This is not bad.

Final explanation of the breakdown of the IFB's--- This stove is run hard, I can often heat a 1/2" dia  (12-14mm) metal rod to a glowing red in less than 5 minutes and just guessing, the IFB's even though they were rated for extreme temps, simply did not hold up. Perhaps even shifting slightly during heating phases. Again, I don't know for sure, and I don't really care now, as the riser is completely out of the bell in 30 minutes of time, and the rebuild will take place.

WARM regards to all.

This can be as complicated or as simple as you want it to be.

in the very simpliest terms --- Burning wood that is 10% moisture vs 25%  produces about 83% as much heat.  Again this is a very simple calculation of just calculating how many pounds of wood your actualy burning.  90# vs 75#  if your starting with 100#   If your calculating in metric, the same 83% comes forth.  

Ironically this 83% figure remains about the same with good oak vs poor cotton wood. If you start with the same wood and maintain the same spread in moisture, the figure does not change much.
Likewise the effcieny of the stove does not effect the number much.

WE can wish for better, and precieve it to be better, but in this case, just not to be.

Now for a bit more complicated, for every pound of water your converting to steam, cost you 992 BTU's.   So above this is 15 lbs of water for every 100 pounds.
So  an additional 14, 000 btu's out the flue.  No getting around it.  If it is there (the moisture)  and your wood burned, then it consumed the BTU's to turn to vapor.  

Stay warm folks, and let the suns drying power in the summer give your stove heating power in the winter.

Scott