DSR3 afterburners in the USA: who wants one?

[iau461]

I've received a quote from Quinsis in Belgium for pallets of 10 afterburners, of the same type being used by the Loam Freemanship, referred to by peterberg. 

Sizes and prices (without shipping) were quoted as follows:

177mm ID x 305mm long, 30 mm thickness (approx. 7x12x1.2", good for a 6" system), 10 for 663 euros or about $71 each

240mm ID x 416mm long, 30 mm thickness (approx. 9.4x16.3x1.2", good for an 8" system), 10 for 838 euros or about $90 each.

I am looking into what it will take to get them delivered to my address near Reading PA. From there I could potentially ship them individually to others in the US, or hold them for pickup. I would provide them to you at my cost, I'm not looking to make a profit. Even if shipping triples the price to you, it still beats the best quote anyone has got from a US provider for vacuum-formed ceramic fiber tubes. And these tubes have a track record in Europe, with clay mixed in for added structural integrity, which AFAIK the US suppliers are not offering.

Please let me know what size and quantity you are interested in.

Also, if anyone has any pointers on arranging shipping across the pond, please let me know.

[pianomark]

lau461,

6 or 7 years ago, a member (briank) organized a group buy of vacuum-formed riser tubes. I got a pair of them, they are still functioning well after 4 (5?) heating seasons. I stacked them for a 48" vertical riser in my traditional batch box.

Brian lived somewhere in Pennsylvania, and picked up the bulk order somewhere near Pittsburg, then shipped them to me and others around the country. Not sure if Brian is still with us, he has had some health issues since then.

The tubes I got were 6" ID, 8" OD and 24" long, and fairly inexpensive as I recall. I think they came from temptek, or temtek, or something like that. Not sure if they are still in business.

I just thought this info might save you from "reinventing the wheel", and some shipping costs too. My apologies if you have already researched and eliminated this possibility.

[iau461]

Mar 14, 2023 11:21:45 GMT -8 pianomark said:

The tubes I got were 6" ID, 8" OD and 24" long, and fairly inexpensive as I recall. I think they came from temptek, or temtek, or something like that. Not sure if they are still in business.

A web search leads me to believe that Temtek disappeared somewhere around 7 years ago.

[josephcrawley]

Have you explored casting the tubes using a light weight castable refractory cement? Most pottery supply places carry it. At my local shop it is under $70 for a 55 pound bag. Which is approximately 1 and 1/3 cubic feet.

[iau461]

Mar 15, 2023 18:30:41 GMT -8 josephcrawley said:

Have you explored casting the tubes using a light weight castable refractory cement? Most pottery supply places carry it. At my local shop it is under $70 for a 55 pound bag. Which is approximately 1 and 1/3 cubic feet.

Explored it briefly and then got scared away, some say it's easy but seems like so much to go wrong. I think I saw that peterberg had cast an entire core that cracked into pieces, and that was enough to rule it out for me while I tried to read/learn so many other things. Maybe I should reconsider.

To cast the afterburner, I would want to do it in 3 pieces, in the same way peterberg cut his solid tube, to prevent thermal cracking. Right?

Then there's the shaker table... and the one-use molds... ugh. I've built a lot of stuff but seems like the risk of failure here is pretty high. I can test-fire the core before we mortar it together but after that the upper chamber will be inaccessible and will have to work for decades. I'm doing this as the primary heat source for a large house, not an experiment.

Given all that, would you try it if you were me? Or instead spend maybe $200-500 to get a tested product delivered?

[martyn]

I am not convinced any refractory materials that are super heated every day will last for decades, I would make sure all the components are accessible.
The design allows for a top and bottom doors that would give you a way inside to both monitor and replace anything that deteriorates.

[iau461]

Thanks Martyn. I had decided to close off the upper chamber due to the ceramic fiber carcinogen issue, which I believe affects even vacuum-formed material. Maybe that's another reason to reconsider castables.

So far I'm a bit surprised nobody has expressed interest in a Belgian tube, my expectations appear to have been wrong. As they often are. :-) Anyhow, I'm still working on shipping costs from Belgium, I have a preliminary quote that would add ~$100 per tube to an order of 20 tubes. Adding delivery from my house to elsewhere in the US would bring the price to around $200, lower than the best quote I've seen from a US manufacturer.

[martyn]

Well rocket mass heaters are no exactly common, in many parts of the world most designs would not be excepted by house insurance companys and there has probably only been a handful pf people who have even seen your post!
You could try facebook but even then on the english speaking threads, interest seem to be on the decline.

It could be that the majority of folk who post on here and the other forum already have their own stove so it could be a hard sell.
Having said all of that, I dont know why general interest on the forums has declined so much as if you look back 10-15 years ago there were dozens of post every day?

Is there a reason why you prefer this design over the more established original batch box?

[josephcrawley]

Mar 15, 2023 21:00:16 GMT -8 iau461 said:

Mar 15, 2023 18:30:41 GMT -8 josephcrawley said:

Have you explored casting the tubes using a light weight castable refractory cement? Most pottery supply places carry it. At my local shop it is under $70 for a 55 pound bag. Which is approximately 1 and 1/3 cubic feet.

Explored it briefly and then got scared away, some say it's easy but seems like so much to go wrong. I think I saw that peterberg had cast an entire core that cracked into pieces, and that was enough to rule it out for me while I tried to read/learn so many other things. Maybe I should reconsider.

To cast the afterburner, I would want to do it in 3 pieces, in the same way peterberg cut his solid tube, to prevent thermal cracking. Right?

Then there's the shaker table... and the one-use molds... ugh. I've built a lot of stuff but seems like the risk of failure here is pretty high. I can test-fire the core before we mortar it together but after that the upper chamber will be inaccessible and will have to work for decades. I'm doing this as the primary heat source for a large house, not an experiment.

Given all that, would you try it if you were me? Or instead spend maybe $200-500 to get a tested product delivered?

I think you are over thinking it. It is not a complex shape so the mold could be as simple as a wooden box with the appropriate sized duct pipe in the middle. A block of wood the size of the port on one side in the middle. You won't need a shaker table since you could use a stick to ram the material into the mold. Just follow the instructions and don't add to much water!

I plan on doing this for my next stove job.

Oh and I would make it in two pieces. Might as well plan for the crack and put it where you want it.

[iau461]

Mar 16, 2023 11:25:30 GMT -8 martyn said:

Is there a reason why you prefer this design over the more established original batch box?

1) the original batch box has a slightly smaller firebox width x height, so would need to be fed a bit more often, and I prefer the wider DSR fireboxaesthetically

2) the original batch box takes up more space

3) the original batch box seems more prone to overfueling/runaway.

[iau461]

Mar 16, 2023 15:57:14 GMT -8 josephcrawley said:

I think you are over thinking it. It is not a complex shape so the mold could be as simple as a wooden box with the appropriate sized duct pipe in the middle. A block of wood the size of the port on one side in the middle. You won't need a shaker table since you could use a stick to ram the material into the mold. Just follow the instructions and don't add to much water!

I plan on doing this for my next stove job.

Oh and I would make it in two pieces. Might as well plan for the crack and put it where you want it.

OK, no shaker table. The rest of that also sounds good but I can't quite transform your words into a 3D model of the molds in my head.

Are you imagining your two pieces as each with a semi-circular cross-section? In other words, like a single pipe cut in half lengthwise? (one of which has the port molded in)

Or are you imagining your two molds as each creating a round pipe, roughly half the length of the whole afterburner?

Either way, are you imagining your molds as being horizontal, or vertical?

Either way, I can't figure out how it can be done with "a wooden box with the appropriate sized duct pipe in the middle". Maybe with 2 duct pipes, one with an ID of 1-2" greater than the other, nested. Sorry for my stupidity, but can you elaborate?

Seems mysterious why nobody else, apparently not even peterberg or the Loam Freemanship, has tried this for a DSR3. Makes me wonder whether you and Martyn are just subjecting me to some kind of initiation hazing ritual. :-)

[martyn]

Ha Ha yes you are under interrogation …
Well I am a vortex man myself but I were to build a DS3 I would cast an afterburner or build one from vermiculite and replace when necessary.
Two pieces of plastic pipe would make ideal molds, some refractory mixes will benefit hugely from a high frequency vibrating but some insulating mixes might be ok with just careful loading of the mold.
I think in both Peters case and the builder you mention, the stoves are being built for other people so a more guaranteed component is required.
I did not realise that the batch box was prone to over fuelling! 

[masonryrocketstove]

Don't forget the heat treatment schedule that most castable requires. Potters using castable can do the slow temp rise between heat treat stages as they slowly warm up their kiln. Casting and then putting the green mold directly into service as an afterburner in a batch box won't be able to follow the heat treatment instructions that come with most castable. That can have a negative impact on cracking or spalling and overall durability of the cast.

[josephcrawley]

Mar 17, 2023 10:24:34 GMT -8 iau461 said:

OK, no shaker table. The rest of that also sounds good but I can't quite transform your words into a 3D model of the molds in my head.

Are you imagining your two pieces as each with a semi-circular cross-section? In other words, like a single pipe cut in half lengthwise? (one of which has the port molded in)

Or are you imagining your two molds as each creating a round pipe, roughly half the length of the whole afterburner?

Either way, are you imagining your molds as being horizontal, or vertical?

Either way, I can't figure out how it can be done with "a wooden box with the appropriate sized duct pipe in the middle". Maybe with 2 duct pipes, one with an ID of 1-2" greater than the other, nested. Sorry for my stupidity, but can you elaborate?

A tube shape in a rectangle will work. Just honor the cross sectional area in the after burner. I built a dsr3 using soft fire brick in this manner and it works well.

I would spilt it length ways as I imagine this is how it will want to crack.