|
Post by mrtravelingman on Jan 16, 2014 16:28:29 GMT -8
|
|
|
Post by slimshavings on Jan 16, 2014 16:37:17 GMT -8
I'll be watching this. I live in a Tiny house and have been rattling the idea of a 20-30 gal propane tank as the barrel,4x4 sq or small burn tube and running a couple runs about 4ft long against the wall under my desk. Like you I freeze at night but I it only take about 4000 BTU to heat the place up. I have been using small propane but it just went up 25%. And since I am a cabinet make with a lot of sticks laying around ...... I was going to experiment with a design outside before I bring it in to see if one would work.
|
|
|
Post by 2tranceform on Jan 17, 2014 8:13:43 GMT -8
A metal burn tube and heat riser is not advised. Metal will fail in the oxygen rich, high heat environment. You are better off using fire brick or castable refractory (premixed or diy) to make the hot portions of the stove. Concerning the gas stove, I am not sure how well that will work. A rocket heater, J-tube or batch, creates a high amount of heat, especially the batch version. I do not know the heat output of the gas stove vs. a rocket. This info may help when guessing if the gas stove will hold up.
Have you considered using the tried and true J-tube rocket and a barrel? It is relatively simple and it is a known quantity. Just my $.02.
|
|
|
Post by satamax on Jan 17, 2014 9:27:30 GMT -8
Yep 2tranceform, i forgot to say it, and you did! Metal is doomed!
|
|
|
Post by mrtravelingman on Jan 17, 2014 12:34:50 GMT -8
Yes I agree that metal is not the best to use for this, But I need to make it as cheaply as I can. Then IF it works I will build the one for the bus with a molded burn and heat riser. But the first thing is to build it and try this idea. I did check on the metal used in the gas fired heater and it is better than a 55 gal. drum. This is more a forced air heater than a mass heater - as the bus will not carry the weight of the mass. So I am trying to find another way to heat with very little wood.
Thank-you for your responses and if you have any other thoughts on this idea please speak-up. Again thank-you
|
|
hpmer
Full Member
Posts: 240
|
Post by hpmer on Jan 17, 2014 15:24:42 GMT -8
|
|
|
Post by satamax on Jan 17, 2014 21:20:09 GMT -8
Well, you see all sorts of nasty shit on youtube, called "rocket" which are just that, nasty shit, undocumented builds etc!
|
|
hpmer
Full Member
Posts: 240
|
Post by hpmer on Jan 18, 2014 5:59:59 GMT -8
Well, it is an example of a small space heater in a similar space as Mrtravelingman's. Shows what's possible. I think the build is quite similar to a rocket but could use an insulated burn chamber.
Lots of ways to address the need.
|
|
|
Post by satamax on Jan 18, 2014 9:11:45 GMT -8
Well, it is an example of a small space heater in a similar space as Mrtravelingman's. Shows what's possible. I think the build is quite similar to a rocket but could use an insulated burn chamber. Lots of ways to address the need.Yep, but if it hasn't got an insulated feed/burn tunel and riser, it's not a rocket. If it's made of insulated metal, it's bound to fail.
|
|
|
Post by mrtravelingman on Jan 18, 2014 15:40:15 GMT -8
To start - Thank-you hpmer for the link. I have watched most of the vid's on u-tube. So far they are all radiant style which I just do not have the room for. That is why I would like to make a fan forced style with a small mass on top. Sir satamax I know that you must think there is only one way to build. This I have found to be UNTRUE. I came here seeking help and ideas. With that in mind maybe you could give me some help on my idea as I need as much as I can get. Thank-you all for your responses.
|
|
|
Post by satamax on Jan 18, 2014 19:30:38 GMT -8
Well mate, where in the world would i be bound to reply to you? To help you? even more when you despise my advice!
I know that there's many ways to skin a cat.
But if i say metal is doomed, i realy mean it. I have made a "rocket" out of metal, proper metal. Which worked well realy well; soo well that in 14 burns, it was dead. I have melted a gas bottle, nearly 1/4 inch thick, the feed tube and burn tunnel spalled soo much that the nearly 1/2 inch metal expanded to a good inch in thickness. It was like puff pastry. And there's plenty of others here who have done the same.
I quite like your heat exchanger. But i can tell you one thing, with a metal core, you're wasting your time. Why should i waste my time alongside? I think it was courteous enough to tell you
Metal is doomed
It's soo simple to make things right. Now, there's people watching youtube shit, and think, "ohhh, they must be right, they have built one"
Yeah, isn't there videos of idiots shoving vodka inpregnated tampons up their arses? If there's enough of them doing it, will you do the same.
Here, it's a tech oriented forum.
Not a hippy'ish land of dreamers with no technical background. And i am here to kill the myth that metal rockets are possible. Untill you can find metal which can whistand 1200C° for an extended period of time, i think a little research is in order.
Build yourself a pocket rocket for the outsides, and see how long that lasts. Then switch to a J tube made out of cob, firebricks, or some refractory of some kind. See what this thing is capable off. Then, come back with metal, and explain us how you do it.
Do i sound harsh? Yes, and it's on purpose. Am i an arogant prat, yes, most certainly. But it's for the good of the craft.
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 18, 2014 21:10:45 GMT -8
Mrtraveilingman, the one thing you don't see on youtube is the failures of metal "rockets" that many people have made. People, as a rule do not post their failures. Max is only trying to save you the heartache of putting in valuable time building something that will most assuredly fail. You may think him a bit harsh in the way he says it but that does not discount the truth in his words. If you want to build it with full knowledge that it is expendable and for test purposes (I did one with materials I knew would fail after a few burns so I am the voice of experience here, as is Max) then please do. When you learn what works and what does not then build your more permanent version with the full knowledge that the materials WILL last. I like the idea of the heat exchanger and if you find a way to make it work that would be great. But when you insulate the burn tunnel and the heat riser and you do have a rocket, the metal will without doubt fail.
|
|
|
Post by mrtravelingman on Jan 19, 2014 6:03:57 GMT -8
Hi everyone - Thank-you for your responses. As I said before, I agree that metal is not the best for this build. But I have to use what I have in order to see if it will work. Today I plan on starting the build. Has anyone ever made a "J" tube that was outside the heat chamber (barrel)? The top of mine will have a 90* bend which will travel for about 6 to 8 inches. Does anyone know how this will effect the burn? Question - Does the "J" tube need the heat that collects in the barrel? If possible I will take pictures as I build it.
Right now it is 14*f outside and 25*f inside. So I am moving real slow until the sun comes up.
"Here, it's a tech oriented forum. Not a hippy'ish land of dreamers with no technical background." Yes I am dreamer with an idea I believe will work. And yes I grew up during the Hippy generation, but I was in Vietnam. Schooling quit when I was in junior high so I have no technical training in this area.
satamax will you agree that this build using metal will fail in the "J" tube. But this build is to see if a "J" tube can have a 90* bend at the top running to a heat ex-changer. If it works then this build did what it needed to. I really want your ideas on this and I am sure that you may show me many ways to improve it. I have looked into fire bricks at ACE hardware. Also I am looking into ways to cast this item. But before I spend a lot of money lets see if it will work.
|
|
hpmer
Full Member
Posts: 240
|
Post by hpmer on Jan 19, 2014 6:38:42 GMT -8
Matthew Walker has a version he detailed in a thread called donkey32.proboards.com/thread/1023/accidental-discovery . His conclusion was that as long as the burn chamber and heat riser were well insulated, the riser itself could be at a 45* angle and be outside the heat exchanger and work fine. His application was to lower the height of the barrel heat exchanger which makes it a more convenient height for cooking, but seems easily adaptable to your application as well.
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 19, 2014 7:24:19 GMT -8
|
|