boiler explosion. what not to do.

[Bentwings]

see also Advice on a boiler burner

Thank you for the note. Have plan or hydrauitest. I’ve don this in industry so I’m fmilar with the process I also have a set up for ultimate test. If I get 100 psi I’d be happy I actually have two pressure relief valves as well as electrical timers to prevent un attended us. I do call local boiler inspection since I’m not usi fired boiler they are not concerned unless I was in a garage or inclosed space my boiler I really to small fr them to inspect. A pressure cooker would be more dangerous . I don have that other . I have a lot of respect for danger of steam. I’ve done home work . There will be no welding on the aluminum and it can’t get to high enough heat to weaken the material welding I would be very concerned as I’ve done lots of tech Tig welding on aluminum I don’t like even comercial luminance or tanks even my new air compressor is steel tank . They are subject to rusting if aways been fussy about wat in air Ann’s as I used to o painting so even my little thing has input Ayer filtration . And it’s only used to run my steamer and fill an occasional bike tire . It also has dual relief valves . I’m new to boilers but I’ve done a lot of research to gain knowledge needed .
Thanks gain for the input . Once this thing is completed an tested I’ll report on it.

byron

 

[Steamchick]

On Condensers...
Condenser (steam turbine) | Engineering | Fandom
This may help?
K2

 

[BillHowcroft]

JE Gordon in 'Structures' has a couple of pages on riveted joints where he quotes Rudyard Kipling's' story 'the Ship That Found Itself' which is about the movement in structures undergoing ocean wave forces.
He says that it is a shame steel riveting has gone out of fashion due to its extra cost and weight. The riveted joints act as crack-stoppers and also, because the rivets can slip slightly, they can redistribute loads and thus reduce stress concentrations ( a bit like the shakedown that occurs at pressure test in welded structures).
As well as the removal of riveting from boilers, the aero industry has tried to move towards machining from solid and adhesive construction to reduce cost and the additional weight of rivet overlaps; but rivets are still there.

The Ship That Found Herself
My father was skipper of the Rajula (sister ship of the American-losses HMT Rohna) in its final years and he complained about rivets popping out of the shell as they weathered a typhoon near Madras.

 

[Bentwings]

We still use buck rivets in trailers they rarely pop out . I’m using button head cap screws in my new boiler. I suspect there will be leakage but hopefully the high temp sealer will stop that .
Byron

 

[Bentwings]

We still use buck rivets in trailers they rarely pop out . I’m using button head cap screws in my new boiler. I suspect there will be leakage but hopefully the high temp sealer will stop that .
Byron

interesting. It looks like I’ll have a small water fill tank I’m going to try to filter the condensate before it goes into th fill tank. I’ll keep an eye on it. I haven’t come up wt a water tank yet. I have a bunch of boiler tube left over and some aluminum bar stock oni coul easily make a matching fill tank . I have some plastic gets that I’ll try to make a gear fill pump. I’ll have an abundance of motors to drive the pump. I may also just creat a pressure vessel and let it fill to a given pressure. Then I won’t need the gear pump excep as a transfer pump from the condenser . I’m not getting too excited about this at this point as I have a lot of instructing going now I’m waiting to see how much water I’ll be using.
byron

 

[Bentwings]

interesting. It looks like I’ll have a small water fill tank I’m going to try to filter the condensate before it goes into th fill tank. I’ll keep an eye on it. I haven’t come up wt a water tank yet. I have a bunch of boiler tube left over and some aluminum bar stock oni coul easily make a matching fill tank . I have some plastic gets that I’ll try to make a gear fill pump. I’ll have an abundance of motors to drive the pump. I may also just creat a pressure vessel and let it fill to a given pressure. Then I won’t need the gear pump excep as a transfer pump from the condenser . I’m not getting too excited about this at this point as I have a lot of instructing going now I’m waiting to see how much water I’ll be using.
byron

Lots o good information. I had to start with a fresh white page. Fortunately my engineering background is still functional . I now have instant library available and countless spread shears have been created so designs can be self checked. I’m not planning on high pressures and temps. Since im
Not doing fire tube boiler .

byrn

 

[BillHowcroft]

Thank you for the note. Have plan or hydrauitest. I’ve don this in industry so I’m fmilar with the process I also have a set up for ultimate test. If I get 100 psi I’d be happy I actually have two pressure relief valves as well as electrical timers to prevent un attended us. I do call local boiler inspection since I’m not usi fired boiler they are not concerned unless I was in a garage or inclosed space my boiler I really to small fr them to inspect. A pressure cooker would be more dangerous . I don have that other . I have a lot of respect for danger of steam. I’ve done home work . There will be no welding on the aluminum and it can’t get to high enough heat to weaken the material welding I would be very concerned as I’ve done lots of tech Tig welding on aluminum I don’t like even comercial luminance or tanks even my new air compressor is steel tank . They are subject to rusting if aways been fussy about wat in air Ann’s as I used to o painting so even my little thing has input Ayer filtration . And it’s only used to run my steamer and fill an occasional bike tire . It also has dual relief valves . I’m new to boilers but I’ve done a lot of research to gain knowledge needed .
Thanks gain for the input . Once this thing is completed an tested I’ll report on it.

byron

Small electric steamer

 

[Bentwings]

Small electric steamer

M so sorry this spell check does it’s own thing no matter how well I review . It changes thugs during te post. Even using a different device. I’m hoping he engnefms will b paint by next us day so I can get assembly started . I’ll mount the basics on a temporary board then transfer to he plastic be . I have a bunch of stepper motors to convert to generators I’ll probably get a driver so I can use couple to drive what ever I need that he tamer can not . I just don’t know how much power and rpm I’ll have to work with . It’s parry of the interest .

 

[kf2qd]

There have been numerous articles that I have read over the past 20 years on making small model boilers. They all used various forms of hard silver solder. Often solders that melt at different temperatures so inner part could be assembled with a higher temp solder and outer pieces with a lower temp solder. Those boilers were all made of copper, as it has excellent pressure characteristics and is easy to form and work, and with basic attention it does not corrode readily.
Test any pressure vessel with it totally full of water, absolutely no air inside, and make a simple one shot hand pump to bring it up to pressure with water only. If you do have a failure you are only having to relieve the energy stored in the vessel, as water does not compress, and therefore does not store much energy, and if there is a failure or a leak it will very quickly release all pressure with just a small spurt. Only pressurize it with air or steam after it has passed a static test with just water under pressure at a minimum of 2 time the working pressure. Find out what rules your local government has for small boilers, some places have very strict regulations, others have very limited regulations. Here in the states, many locals do not want to be bothered with small boilers and trust the maker to do their due diligence and produce a safe unit. This is because there is only a small amount of stored energy is the risk is regarded as minimal.
And ultimately, safety relies on you using your head and intelligence, and no amount of regulation or examination can correct for you not using safe practices. And since most of us are familiar with running various machine tools, all with their own inherent dangers, we should be familiar with the idea of thinking things out and preventing injury.

 

[Steamchick]

Hi KF. Just for peace of mind, I use ASME pressure requirements (and stress limits) for copper boilers. NOT because I have to, as I am in the UK, but simply because it is a "sensible safety level agreed by a concensus of very knowledgeable professional Engineers". I.E. Better advice than any you'll get from me! Except, maybe "Please follow ASME". EVEN IF you do not think it applies to you formally. It is (only) a Safety standard, and I guess any Engineer with any sense of responsibility, professional acumen, or any other excuse would do so. It just seems stupid not to follow Professional Safety advice.
But it is a free world, and (as a Motorcyclist that has beaten the statistics) I am always suprised by people who choose NOT to follow simple SAFETY measures. (Like riders in Florida who choose to ride without helmets!). Usually, because "they know better", or "don't need Safety advice".... etc.
Nuff said?
K2

 

[Bentwings]

Hi KF. Just for peace of mind, I use ASME pressure requirements (and stress limits) for copper boilers. NOT because I have to, as I am in the UK, but simply because it is a "sensible safety level agreed by a concensus of very knowledgeable professional Engineers". I.E. Better advice than any you'll get from me! Except, maybe "Please follow ASME". EVEN IF you do not think it applies to you formally. It is (only) a Safety standard, and I guess any Engineer with any sense of responsibility, professional acumen, or any other excuse would do so. It just seems stupid not to follow Professional Safety advice.
But it is a free world, and (as a Motorcyclist that has beaten the statistics) I am always suprised by people who choose NOT to follow simple SAFETY measures. (Like riders in Florida who choose to ride without helmets!). Usually, because "they know better", or "don't need Safety advice".... etc.
Nuff said?
K2

I am trying to follow safe guide lines

 

[GrahamJTaylor49]

Hi KF. Just for peace of mind, I use ASME pressure requirements (and stress limits) for copper boilers. NOT because I have to, as I am in the UK, but simply because it is a "sensible safety level agreed by a concensus of very knowledgeable professional Engineers". I.E. Better advice than any you'll get from me! Except, maybe "Please follow ASME". EVEN IF you do not think it applies to you formally. It is (only) a Safety standard, and I guess any Engineer with any sense of responsibility, professional acumen, or any other excuse would do so. It just seems stupid not to follow Professional Safety advice.
But it is a free world, and (as a Motorcyclist that has beaten the statistics) I am always suprised by people who choose NOT to follow simple SAFETY measures. (Like riders in Florida who choose to ride without helmets!). Usually, because "they know better", or "don't need Safety advice".... etc.
Nuff said?
K2

Hi Steamchick, What Bike have you got?
Graham (Grum)T.

 

[Steamchick]

Hi Grum. Moto Guzzi V50 II. 1979 model (the slowest of the variants?). I have had it since 1998. Too many tales for this thread. I used it mostly for fair weather commuting. Since retirement it gathers dust except for odd trips - when the roads are salt-free! Current "entertainment with it is trying to tune it for congested city traffic. Guzzi didn't do that. They tuned it for city squirt and stop per Italy in the 1970s! - and using 99 octane leaded fuel. Modern fuel just doesn't have the combustion characterising of leaded, which tells at the top end! But the carbs were tuned with very rich pick-up, which doesn't suit crawling, at just off idle. Way too rich! So I have been milling the slides to change the air mixture just above idle (first 1/8th of slide motion).
Keep the wheels turning!
K2

 

[Bentwings]

Hi Steamchick, What Bike have you got?
Graham (Grum)T.

iv been a support f safety fr a long tim I still have all fingers and only a fe tensing scars from sports . I plays sots longbfoethe pore I equip nt of today. Playing hockey unilateralism. Was 26 my defensive partner and I had probablyamong the first chest prtectown we wore our baseball catchers vests . I don’t remember where we got the hard elbow pad but thy aced he Elvis mouth protection and the masks o today had not been invented yet so a few teeth were lost the same with baseball the regular hat gave yvt early hard hats but didn’t protect face I broke two hi tech hard cheek helmets my last year in senior ball at 72. Of course heav K9 dog training had good safety equipment but we still had trips to the ER as in football leg and knee injuries happen no matter how much padding you haveAuto racing developed extensive fire protection but ther were still a few injured . Now with stem engines a new to me area has developed I simply can’t have n open flame or Buber in my home so I into electric boiler. I’ve gone through the engineering analysis and contacted local inspection. It turns ou that my system is just too small for them to come out I got som hide lines to follow and I’ve incorporated them int my unit . Iv do industrial very high pressure vessel testing and done tank truck welding repair. So I have a god feel for what is required. I had many Tig welding certifications and even taught briefly my vision is not good so I leve the welding to my son and grand son they both are doing very well Being a senior I have to be careful every step. Say off ladders be careful walking on slippery streets etc. even sharp kitchen stuf has to be given thought many seniors get injured because of old practices . In sorts we were taught and practiced rolling when going down . Anyway I’m trying to have interesting times in steamers

byron

 

[Bentwings]

Hey guys, thought I would share a bad experience with you.
I was making a boiler for use with some small steam engines I had. I used an old propane bottle and some copper tube. I had a pressure guage and steam dome on top with two water tubes made out of copper on the bottom. With a homemade burner I was making steam in no time. NOW, here is the bad part, I used electric solder to peice everything together. I pressure tested it to 140 psi, and held it for a half hour. So I though I was good to steam it to 60 psi. Well I was wrong, It pressured up and with out any warning BOOOOOOM there goes the steam dome and pressure gauge accross the shop and boiliing hot steam went shooting out the top, and there I am standin not but two feet from the thing and did not even get a drop of water. needless to say I have not pressured the boiler up again and am verry apprehensive to ever do it again. I was lucky but i might not be next time.

the morel,
DONT USE ELECTRICLE SOLDER TO MAKE BOILERS

kel

I guess I thought I had commend negatively but not viscerally . Inotherwords not trying to be. Nasty or a. Dork.LO

quite a long time ago I began monitoring mode airplane gas engine heat areas. Ylhea temps spark plug temps and exhaust temps. I mistakenly thought could be the hi Gas temps with copper tubing pip soldere together. I had an entire system literally fall apart befor I was able to taxi the plane to the runway. Probably fortunately. Almost all of the solder joints just fell apart. Since I can see very well now I’ve limited my welding to instruction of my soon and grand son. Both are tracking me like a search and rescue dogs. LOL. I did a lot of ver precision tig welding Abel as taught in the company I work at. As I go into model steam engines it didn’t take long to look at making boilers. I’ve seen some truly scary videos of soldered boilers. Silver brazing and just plaibrazing of copper is really easy I think and very capable. Of course there is poor edutainment too. The exact thing you experienced was noted s possible in several videos.just the visual appearance before functional was bad enough. Some I would not have gon as far as filling with water let alone heatin. Almost any hand hld Roman orbttled fuel gas torch can get to 1000 deg F well past the elating temp of any soft solder So it follows that if it gets near a soldered joint it could melt the. Solder even if it’s cooled by internal water. It’s not real hard to braze with these units but silver solder is quite eepensive but standard brazing rod wiiyhout flux works too, if the copper is well cleaned. I did make at least half a dozen scale functioning rc airplane exhaust with copper fittings and just brazing rod. None melted in operation. Almost immediately this brings up soldering aluminum with some of the new aluminum stuff. I’m definitely opted to this have tig welded many very complex thing from aluminum. Some alloys I’d aluminum are not weld able and I would not even think of trying any kind of soldering. Remember you SAR trying to join metal that sbsorbs a radiates heat better than most common materials. It’s not even easy to tig weld in aluminum . It takes a very steady gavdan lots of patience.
Anyway as usual I’ve drifted off topic.
bottom line useelectrical solder for wires not boilers. I’m very glad you were not injured in your nasty experience. Steam is very dangerous.

 

[Bentwings]

I guess I thought I had commend negatively but not viscerally . Inotherwords not trying to be. Nasty or a. Dork.LO

quite a long time ago I began monitoring mode airplane gas engine heat areas. Ylhea temps spark plug temps and exhaust temps. I mistakenly thought could be the hi Gas temps with copper tubing pip soldere together. I had an entire system literally fall apart befor I was able to taxi the plane to the runway. Probably fortunately. Almost all of the solder joints just fell apart. Since I can see very well now I’ve limited my welding to instruction of my soon and grand son. Both are tracking me like a search and rescue dogs. LOL. I did a lot of ver precision tig welding Abel as taught in the company I work at. As I go into model steam engines it didn’t take long to look at making boilers. I’ve seen some truly scary videos of soldered boilers. Silver brazing and just plaibrazing of copper is really easy I think and very capable. Of course there is poor edutainment too. The exact thing you experienced was noted s possible in several videos.just the visual appearance before functional was bad enough. Some I would not have gon as far as filling with water let alone heatin. Almost any hand hld Roman orbttled fuel gas torch can get to 1000 deg F well past the elating temp of any soft solder So it follows that if it gets near a soldered joint it could melt the. Solder even if it’s cooled by internal water. It’s not real hard to braze with these units but silver solder is quite eepensive but standard brazing rod wiiyhout flux works too, if the copper is well cleaned. I did make at least half a dozen scale functioning rc airplane exhaust with copper fittings and just brazing rod. None melted in operation. Almost immediately this brings up soldering aluminum with some of the new aluminum stuff. I’m definitely opted to this have tig welded many very complex thing from aluminum. Some alloys I’d aluminum are not weld able and I would not even think of trying any kind of soldering. Remember you SAR trying to join metal that sbsorbs a radiates heat better than most common materials. It’s not even easy to tig weld in aluminum . It takes a very steady gavdan lots of patience.
Anyway as usual I’ve drifted off topic.
bottom line useelectrical solder for wires not boilers. I’m very glad you were not injured in your nasty experience. Steam is very dangerous.

Some where in this boiler thread someone asked how I was going to make a. Steam dome . since my aluminum tube boiler rests on stands I thought I’d just tilt isome amount and let the steam bubble form on one end. I was just going to tap a 1/2” NPT thread hke a plumb from that t my distribution center. , well after giving more ought i m now going to still use the same tapped feature but I’ll add a brass bushing to osibily a 3/4” piece of pipe capped an ported to my distribution center. Th additional pipe will serve as a steam dome. This may or may not be big enough volune so comments appreciated.
I also ad middle of the night wake up idea. Being a car hotrodder. Ts bar o eat mor displacement for more power. Soooooo.
hatf I bore the steam cylinders for say a twice diameter piston. 4 as I have 4 cylinders. I could order 44 new cylind the make 4 larger bore pistons ? I have tone the calculations yet. Stock pistons ar only 14 mm . There is easily enough material to double the bore size. Considering that it won’t be hard to run arounf
d 100 psi in aiompressor configuration the force the pistons put on the crankshaft would increase dramativClly. The stroke is 19 mm. So it’s not har to figur it total displacment and theoretical torque amounts.I thihe crankshafts can handle it. It follows that a stroke increase would be cool too. Now this becomes mor challenging as making two “ trojer crank” could take some tight. I have ideas floating around. Imjjust starting assembly of the machine now. I got a pair of risers for the two engines so the will be more flywheel clearance.. I’ll measure up the cylinders after today. My honeyeaters gave out yesterday. Of course it well below deg F. Inside tem was down to 49 deg F when I got up in the morning. My kitty wa puffed u like a fur ball onyelectric blanket. Have Somme heaters and I’m. Nrsingbe furnaceuntill repair service gets here. I’ve managed to get indoor temp to an even 70 deg F so I’m comfortable.

 

[Steamchick]

So you think the crank - and bearings - can take double the diameter of cylinder and bore? Yes, probably for a short time. Good idea if you drop pressure, otherwise with 4 times the forces applied the durability may be only 1/16 th of the manufacturer's design. In fact it isn't 1/16, it's probably even less as it is a logarithmic function, not a square function.
Depends what you want from the engine. 1 x 1/4 mile blast? Or 24 hours racing Le Mans, or 10 years of trucking in Alaska. Or even just a few runs in your living room.
You'll probably find the ports are too small to appreciate the extra power. Steam is not like air into an ICE. As the steam expands from valve chest into the cylinder, the pressure naturally drops and the steam starts to cool. Big ports reduce this adiabatic expansion, but small ports mean too much cooling, so you are short of steam power in the cylinder. A self-defeating "improvement". If I was you I would not bother. I naturally assume the manufacturer has tuned the displacement, port sizing, bearing sizes, etc. To be a matched set, balanced for optimum running, and customer satisfaction. I am sure you know all this, so try sleeping at night.
Enjoy!
K2

 

[Bentwings]

So you think the crank - and bearings - can take double the diameter of cylinder and bore? Yes, probably for a short time. Good idea if you drop pressure, otherwise with 4 times the forces applied the durability may be only 1/16 th of the manufacturer's design. In fact it isn't 1/16, it's probably even less as it is a logarithmic function, not a square function.
Depends what you want from the engine. 1 x 1/4 mile blast? Or 24 hours racing Le Mans, or 10 years of trucking in Alaska. Or even just a few runs in your living room.
You'll probably find the ports are too small to appreciate the extra power. Steam is not like air into an ICE. As the steam expands from valve chest into the cylinder, the pressure naturally drops and the steam starts to cool. Big ports reduce this adiabatic expansion, but small ports mean too much cooling, so you are short of steam power in the cylinder. A self-defeating "improvement". If I was you I would not bother. I naturally assume the manufacturer has tuned the displacement, port sizing, bearing sizes, etc. To be a matched set, balanced for optimum running, and customer satisfaction. I am sure you know all this, so try sleeping at night.
Enjoy!
K2

I don’t have super heat tubes in my boiler. I did see that these would be under compression as pressure rises. Frankly since it did not apply to my new boiler I didn’t worry about it . Digging through Roarks eng book I ran across hoop stress this application is a reverse ofvthe burst pressure greatly simplified there is a section on how to calculate this I also found on line calculator but again I dismissed it as it does not apply to my unit . My local rulers don’t even want to come out and look at my small boiler as long as it’s not fuel fired they don’t care now if it was a loco and pulling people it would be a different story I don’t know about boats . I’d guess call and find out. The boat club might be helpful too. Boilers are new to me so I’m no expert. I’ve only dealt with internal pressure vessels. Some extremely high and exotic materials far beyond model stuff. I recall procedures and things done but even so it’s way beyond our stuff . I know enough to be carefull and maybe over build . And don’t use soft solder on fuel fired boilers . I would not use it on any pressurized container . I have done some exotic Tig and laser welding on pressure vessels so I’m aware of procedures and equipment . I considered stainless steel and welding it as I have welder material and correct filler rod but elected not to do this due to cost and my poor eyesight that limits welding skill now. Also considered plain alloy steel as that was available too it’s much easier to properly TIG weld it. 4” diameter tubing has suddenly become very hard to get. Seamless tubing is around but about parallel to aluminum in cost so I chose fabricated aluminum as it’s much easier to work with . I could TIG weld it but I think I’ll be inside the unit as much as I’ll be servicing the steam engines.
I just ran into an issue I didn’t know about I’m not very metric so I didn’t realize there are other than standard m3 thread pitches I should know this but I seldom make things with metric threads. I can pick up Mose USA threaded objects and tell whether it’s fine or coats thread or pipe thread or even AN. Thread an note what pitch it is. But m3 is pretty small for my eyes I carefully measured the screws then drilled what I though was the correct tap hole size. Wel surprise surprise the tap ain’t going t thread that undersized hole. I had to get out the known screw and lay it along side the tap to see there was different pitch I’m not sure where I screwed up but what ever I got is wrong . Surprising the local hobby shop has exactly the tap set I wanted . I’m sure it’s not cobalt exotic material but it will tap aluminum . It was 15 min befor closing and he said he would drop it off at the post office on the way home how’s that for service? I may even get it today . Then the tap handle I ordered came without the cross handle rod so I have to use a drill for now untill I get out to the shop again.
Byron

 

[Steamchick]

Hi Byron, Superheated tubes do not go inside the hoiler. The only way to superheat steam above boiler temperature is to run them through a fire box or smoke box with higher temperatures than the boiler. You electric heaters inside the boiler cannot do that. But if the heater elements are inside tubes, they must be sized for compressive hoop stress, and stress concentration factors for ovality... etc...
K2

 

[Bentwings]

Hi Byron, Superheated tubes do not go inside the hoiler. The only way to superheat steam above boiler temperature is to run them through a fire box or smoke box with higher temperatures than the boiler. You electric heaters inside the boiler cannot do that. But if the heater elements are inside tubes, they must be sized for compressive hoop stress, and stress concentration factors for ovality... etc...
K2

I’m sorry I was confused thanks for the clarification . Since the electric heaters are essentially heating elements inclosed in stainless steel tubes I did consider boiler pressures on them still safe. I doubt if I’d ever see even 100 psi in my boiler . I have an adjustable relief valve and facility to set it. I’m also planing a solenoid valve for rapid or emergency relief . I’m considering making this automatic by connecting an electrical switch operated by pressure . I’ll have a dump bucket and venting capability . Maybe even a buzzer or alarm. I don’t intend to leave this unit unattended for more than a couple minutes. I just got my 1/4 40 TPI me tap and die. PMresearch sent a very nice catalog too they have a series of 1/12 scale pipe fittings that I’ve seen others use. I’m not sure what my piping will look like yet. I got stalled by having the wrong pitch m3 tap I expected new ones today but hopefully tomorrow I got a neat “ helping hands” soldering tool to help hold wires for soldering . That should make life easier .
Byron