|
Post by davisdesigns on Jan 29, 2016 23:40:04 GMT -8
Davisdesigns, i'm not being unpleasant. I'm just being myself, arogant and know it all The thing is, you were questioning my build. One of my first. Yep the welds are uggly, butt uggly. But it worked, nicely for a 4 incher. Untill it failed. Failure is explained at permies. You said you ignored my description of the failure. Well, fair play. But i'm not a liar, what gain would i have in steering people off metal builds, if they worked? When i say the elbow was like puff pastry on the inside, that's true. I had may be 2.5 inches of passage left. And having seen a fair bit of metal in my life, it shocked me that it could fail to that point. I knew that metal creep in building RSJ's can occur around 600C° But never thought metal could degrade that much that fast. If metal builds worked, i would be hohning my welding skills. Not steering people away from metal. Now, if you realy think you can do better. Make a real all metal rocket. Show us. I'm always willing to learn. Tho, don't brag before you've reached may be the 200 hours of burning. Don't say it's working wonderfully, if it's not insulated. I would even say; don't say it's working wonderfully, before you have tried a refractory and lots of insulation rocket. Please point out where i was critiquing your welds in hell i didn't even know it was your build. I just joined this forum to asks some honest questions that would be backed by some sort of evidence, the internet is full of hearsay. If you are referring to my mention of seeing the scallops in the weld as proof that the metal was not scaling as bad as you or whomever wrote the post on the other website as poor welding skills that's on you and i'm not in control of your emotions only you are. Only one post on this forum and you have about driven me away, weather that make you happy or not I could careless but their may be others that may gain from my skills and i from theirs.
|
|
|
Post by davisdesigns on Jan 30, 2016 0:00:47 GMT -8
Putting comments about noobs, unpleasantness and bad welding to one side... You asked the question; "Is there a(n) issue with steel when used in thicknesses as mentioned?". The answer is; "The consensus on this forum is that there is an issue with steel no matter how thick it is. A metal burn chamber/riser will fail sooner rather than later." Some hairline cracking in a castable or firebrick stove is acceptable. These usually disappear when the stove heats up. They can be repaired by smearing a refractory or clay slip over the cracks. If the cracks are major this could be down to numerous things - incorrect castable/water ratio, too much air in the castable, stove fired before the castable was completely dry, no room for expansion etc. I would advise using firebricks to start with! Everything will fail sooner or later... Rock turns to sand steel turns to rust. What i'm not getting is the people comparing 1-1/2-2" thick casting gauge size sheetmetal. How long will refractor mix last if it is say 12ga. (.109") compared to steel ? If one uses 1-/12 -2" thick steel will it out last refractory cement? I just haven't seen any 'honest' or scientific evidence that one is better than the other. Unless the conciseness is by weight and not thickness? The failure i saw was by a copant person that spent weeks researching forums (most likely this one) to get the proper mixture and materials. I build the vibatroy platform that to degass the casting's. The failure was catastrophic i.e. chunks even after heat treating in the oven for a day.
|
|
|
Post by paramick on Jan 30, 2016 2:42:58 GMT -8
I made an all steel RMH 3 years ago. The riser (4mm mild steel) fell apart after 1 1/2 season,while the rest is intact. By the time it was fine tuned to work properly (600 Celsius top of the barel),the riser became thin as tisue in just 30 or so burns. You can experiment as much as you like whith metal,but if you plan to make a serious construction,you bet on the wrong horse...
cheers
|
|
morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
|
Post by morticcio on Jan 30, 2016 4:05:39 GMT -8
The evidence you have been presented with is from member's personal experience. If you were expecting a formula or scientific paper then I am afraid you are going to be disappointed. 99% of those members haven't pursued metal any further because they wanted a stove that lasted more than one or two heating seasons. If you are happy to replace those parts as and when they fail then go ahead and use metal. Refractory casting has to be a minimum thickness (30mm?). In answer to your question, a correctly spec'd refractory mix will outlast steel. I suggest we leave it as we agree to disagree!
|
|
|
Post by satamax on Jan 30, 2016 4:59:27 GMT -8
You don't want to listen what is said to you.
That's wasting our time arguing with whatever advice is given to you. You don't believe the guys who have replied! It's no bother.
Go on, do your best on a metal build, even ask for dimensions and the rest. And come back to prove us wrong. In life, you are either a watcher or a doer. I watch a lot, and when my decision is made, i get my hands dirty. So go on, get yours dirty.
If you don't feel at home here, you're not bound to us. There's plenty of other rocket sites. Go to the facebook rocket page. That's where you will find the most metal likers. But please, don't waste our time arguing about metal. I have no better proof to offer you. And as far as i know, nobody else has so far. You will get the same reply from everybody. Properly made Rockets, made out of metal will fail.
And that is from people who have actualy built rockets.
But please, don't come back with an uninsualted thing, because it's no rocket then. Don't come back with youtube videos, with no follow ups. You can even come back with non steel metals. Like tungsten carbide, or iconel. We're willing to learn.
|
|
|
Post by satamax on Jan 30, 2016 5:10:00 GMT -8
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 30, 2016 7:23:09 GMT -8
|
|
|
Post by Dan (Upstate NY, USA) on Jan 30, 2016 11:26:57 GMT -8
Good read karl, thanks.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 31, 2016 8:40:42 GMT -8
The flame temperature of a properly build rocket stove may exceed 1200°C, but this does not mean that any material touched by the flames could actually reach the flame temperature.
The industry uses stainles steel for similar conditions since quite some time. Some stainles steel is rated for up to 1150°C under corrosive conditions, but this kind of steel is very expensive.
If one is willing to spend quite some money and lots of time for careful selection of material and design, one may be able to build a durable and high performing metall rocket stove.
|
|
|
Post by davisdesigns on Feb 7, 2016 23:08:47 GMT -8
Thanks for that DATA, Most is structural though and doesn't really apply, mostly degradation.
|
|
|
Post by davisdesigns on Feb 7, 2016 23:15:44 GMT -8
The flame temperature of a properly build rocket stove may exceed 1200°C, but this does not mean that any material touched by the flames could actually reach the flame temperature. The industry uses stainles steel for similar conditions since quite some time. Some stainles steel is rated for up to 1150°C under corrosive conditions, but this kind of steel is very expensive. If one is willing to spend quite some money and lots of time for careful selection of material and design, one may be able to build a durable and high performing metall rocket stove. That is the same conclusion i came to after questing people that build metal rocket stoves. Stainless in the thickness required to last say 15-20 years is not feasible, we are talking thousands $$$$ just for the SS pipe. I have decided to do a hybrid burn chamber and riser will be cast refractory, Feed chamber, 1st-2nd air, 'capacitor' chamber and all exterior will be steel. Thanks for your input.
|
|
|
Post by peterberg on Feb 8, 2016 2:09:38 GMT -8
I just haven't seen any 'honest' or scientific evidence that one is better than the other. From what you mention, you now are convinced heavy gauge steel won't do the job. You appear to have found new "evidence", could you elaborate about that? You seem to plan a J-tube version, where is the so-called capacitor coming into that?
|
|
|
Post by plcnut on Feb 8, 2016 4:04:03 GMT -8
I used a piece of 2" schedule 40 pipe for my Walker port, and after 3 months in the firebox it is about half as thick as it was. I had to take it out and beat it back toget her with a hammer because the sides had bent apart and started to fall over where I had cut the slit in the pipe. I took a picture of the pipe when the stove is burning, but you can't tell the difference between the coals and the pipe in the picture... I have done a bit of fabrication, and really like to work with metal, but I would replace the only metal piece in my stove with something else if I could...
|
|
|
Post by peterberg on Feb 8, 2016 4:38:32 GMT -8
plcnut, That piece of pipe is being cooled by the incoming air. When you leave that out the steel would be gone by now, I'd think. I a situation where's a cooling factor in play, the size and weight of the steel need to be reduced. So the cooling would be much more effective, all according to my own opinion.
|
|
|
Post by davisdesigns on Feb 8, 2016 9:51:15 GMT -8
I just haven't seen any 'honest' or scientific evidence that one is better than the other. From what you mention, you now are convinced heavy gauge steel won't do the job. You appear to have found new "evidence", could you elaborate about that? You seem to plan a J-tube version, where is the so-called capacitor coming into that? Contacted people on youtube that have videos of all steel construction, the consensus was they dont last long and the ones that do, are not real 'rocket stoves' reaching 'incinerator' temperatures. This stove is for my Mom so i dont care to risk burning her house down, if it were for me i could properly evaluate degradation. The only part that scares me is i have almost no experience w/ refractory casting but it will be encapsulated in steel just in case of failure. The 'capacitor' will be a #100 propane tank which is a bit small but i'm not going to put a 55gal drum in her small living room.. I'd like 24" diameter but not finding tanks available in that size and i do not have a sheet metal roller.
|
|