Boiler for putting around in small dinghy.

[rolphill]

Good news and bad news.

Good news, the firebox is done, straightforward and easy.


Bad-ish news. I finally got around to taking apart the steam engine I built a couple years ago. On the outside, it was filthy from sitting in the barn for two years. On the inside, it was nice and clean, no visible wear. Except...


The X rings on the piston valves were all torn up, even though I barely used it. Mostly on the side with the big hole for steam input. The small slots that went to the cylinder weren't so bad. I thought about converting it to slide valve, but that's almost as much work as building a whole new engine. Plus the port positions aren't ideal. After thinking about it for a while, I took apart an industrial compressed air spool valve, which is basically the exact same thing. On the inside bore, there are cavities with chamfered lead ins where all the ports are, so the o-rings never actually slide across edges. I'm going to try to replicate that in my piston valve before trying anything drastic.


Also, I'm out of x rings, so I'll have to get more and probably make more valves which isn't hard.

 

[rolphill]

Good news! I got my engine working better than ever. I figured out where I went wrong with the piston valve. If you look closely at the previous post you can see it. There was WAY too much clearance between the bore and the piston, so the rings just bent and tore super easily. I made a new one that seems to be working much better, but time will tell. I also took the opportunity to correct some issues where things were rubbing against each other.

I also managed to test my new oiling system. It's similar to a hydrostatic lubricator. I have an air cylinder, with the back side hooked up to the engine steam line, so it sees the pressure going to the engine. The piston rod side of the cylinder is also connected to the steam line, but through a needle valve. This side is filled with oil through a filler cap until the piston is fully retracted.

When steam (or air!) pressure is applied, there is a small differential force between the two sides of the piston due to the different surface areas from the piston rod. This slowly pushes the piston forward, pushing oil through the needle valve into the steam line. The advancing piston rod also gives a visual indicator of the amount of oil remaining.

Unlike a displacement lubricator, this method works on compressed air too. The needle valve controls the rate of oil injection, and the engine will get a bit more oil as the steam pressure goes up. No oil is dispensed when the engine isn't running either! If you can prime the line properly, you could probably locate this cylinder remotely, away from the engine.

I do need a smaller needle valve, and I need to make some sort of background with lines so I can see the rate of oiling more easily.

 

[Steamchick]

The only problem with your lubricator that I can see, isn't really a problem for you. When this type of lubricator is used on locos and traction engines, shutting the steam valve stops the oil flow and thus lubrication of the steam cylinder and valves. In your case however, the screw will stop and the slight bit of water motion is unlikely to rotate the engine while not lubricated. (You can't bump-start a ship!). Massive trains continue to drive steam locos when the regulator is closed and they are coasting down-hills, so they cannot tolerate this type of lubricator. But I think you'll be OK?
Well done!
K2

 

[rolphill]

I hadn't thought about that scenario with locos. Won't a displacement lubricator act the same way though? Locos also had to have extra equipment like snifter valves to deal with extended coasting anyways.

If the engine is just rotating without steam, the scouring of the oil from the walls by high speed steam will also be greatly reduced. In the same way that a 2 stroke IC engine only needs ~50:1 oil mix at idle and ~20:1 at full throttle. Alternatively, you could leave the cutoff centered and apply a bit of pressure and still get some oil flow, depending on how your valves behave when centered.

 

[Steamchick]

Most locos have mechanical lubricators (I think?) so oil is applied whenever pistons are moving.
K2

 

[rolphill]

Redesigning the valves seems to have worked wonders. I only have round silicone o-rings in them at the moment, but I ran the engine on air for a few hours with no issues. I made a little background with lines on it and attached a little indicator wire to the oil cylinder. I went to go refill the cylinder after installing the indicator and got quite the surprise!


First, I shut off the air going to the engine. Then I closed the oiling needle valve. As I opened the cap to refill the oil cylinder, a bunch of oil splurted out of it as the cylinder emptied completely. Everything downstream of the main air valve was still pressurized! I ended up opening each drain valve in turn and finally got a burst of air out of one. This means that there was zero leakage across the piston valves and the pistons and all the gaskets for at least a good minute. I was impressed.

I have an extended weekend, so I'm hoping to get some work done on the boiler. From what I can tell, the clishay boiler is held in place by the piping going to it through the shell. I'm not a fan of that, so I came up with a couple mounting brackets held up with threaded rods. I will likely just let the boiler rest on these brackets by gravity, as it would be a pain to reach nuts underneath them.

These threaded rods will also extend down and hold the ash pan.

 

[Steamchick]

I shall be interested to know more when you fire the boiler. This Clishay design seems really simple and effective... but you will prove that I reckon. I may be moved to make one... (just slow - like a mountain - to start ...).
I think you are progressing well!
K2

 

[rolphill]

I agree, the Clishay book has been very helpful. The engine and boiler are simple, easy to build, and universally applicable to whatever you want to power. There's nothing locomotive specific about them. I've made a CAD model of the engine with almost everything converted to metric. The text is also very useful and describes many techniques for doing more without fancy tools.

Anyways, I made very good progress on the boiler. The boiler is mounted, almost completely plumbed, the inner shell is installed and finished, the ash pan is finished, and the mounting frame is installed.


The boiler is installed. Letting it sit on the brackets ended up working perfectly. Two of the flange bolts are long, and go in the holes in the mounting brackets. It's just held in with gravity, and the "stickyness" of the threads in the holes.


I made a short term grate out of some expanded steel I had laying around. It won't last long, but it'll last long enough for initial testing. There's something missing in this picture...



I piped in the water gauge. I raised it up so that the top of the visible glass is a little below the top of the vessel. I currently have a 100psi gauge and an 80psi safety valve, as that's what I had laying around. I need to get another gauge and a 100psi safety valve at some point.



This is the steam turret. The brass valve is for blower, and the big bronze valve will be the throttle. It's a REALLY nice globe valve I've had for years. I think I bought it on ebay a long time ago. The capped end will go to the whistle at some point.



The tube coming out the top goes all the way down to the bottom for blowdown. I took a compression fitting and drilled it out so the tube can go through it. The end of the tube is cut at an angle so it's not blocked by bottoming out. I don't like how far up it sticks, but I'll see how the stack fits later. This is the only time I'll use compression fittings.


I grabbed the hand pump I built for my steam kart a couple years ago and it happened to bolt right on. It's certainly on the big side, but it'll work for now.


The ash pan is just a sheet metal tray I pop riveted together. The walls are about an inch high, and it bolts on to the four threaded rods with wing nuts.


The mounting frame is angle iron. I ended up welding the angle iron to the base plate instead of bolting it because my bolt holes were too close, so bolt heads wouldn't fit. I only ran a couple beads so I could redo this later if needed. I screwed it to some 2x4s to lift and steady the boiler. Yes that is a galvanized piece welded to the angle iron. I've never had an issue doing small welds on galvanized steel as long as I do it outside and be mindful about where my nose is breathing.



It's almost ready for testing, but there's still more to go:
I need to get some steel brake line to make a superheater.
I need to put together the stack.
I forgot the fire door!
I need to add the insulation and outer shell.
There are some other small plumbing jobs to be done as well, like the water pump and blower tubing.

All in all the big work is done, and I'm very pleased with the results so far.

 

[Steamchick]

On boilers...

1. First determine the Normal working pressure you need or the engine, etc. - Add "10% for piping lost pressure" = NWP.
2. Design (calculate material strengths, thicknesses, etc. and configurations) to at least 8 x the NWP without exceeding elastic limits of materials.
3. Make using appropriate quality materials and procedures.
4. Pressure gauge normally 1 1/2 to 2 x NWP for full scale deflection - so it is working at NWP around 1/2 to 2/3rds of scale.
5. SAFETY RELIEF valve: set to fully blow at 4% USA/10% UK. over-pressure above NWP.
6. Design and manufacture safety test = 15mins at 2 x NWP without loss of pressure, leakage, any permanent distortion anywhere....
7. IF Hydraulic test is OK, a Steam test, at full fire, regulator (steam delivery valve) closed, full steam blower through fire, and no added water, for 15 minutes when safety valve operates at max pressure. The max pressure seen during the steam test shall not exceed the limit: 1.04 x NWP for USA.
8. You may need to add fuel carefully and sparingly to the fire to maintain it at full fire, but not over-fuelled such as to dampen it.
9. After the test 15 minutes at full safety-blow-off, add water if required, slowly and carefully, and reduce pressure slowly to determine safety valve closes. Then raise pressure again and confirm blow-off initial pressure and max. pressure at max blow-off again.

Then you are safer when you go near "joe public"... Or a certified boiler test inspector!
I realise this is your project and it may have skimped on some of the initial stuff, but PLEASE do proper testing before you risk anyone else near the boiler. The steam test is really the first time when you see what the boiler needs to run it properly. DO NOT steam at more than 15% over NWP! Dampen the fire and add cold water to reduce pressure when the pressure gets to 10% over NWP and is not held from exceeding that by the safety relief valve.
Examine every joint and component for signs of permanent distortion/damage/leaks after the test and when everything is cold.
TAKE CARE. High pressure steam in invisible (white clouds are NOT steam!). High pressure steam leaks can cut flesh, or cook it instantly, and it doesn't grow back. (And hurts like HELL!). My mate has only half the muscles on his arm from a burst gasket at a joint. He didn't see the steam jet! - 6 months of hospital for that one. Fortunately your boiler is contained in the firebox, but pipes etc. outside can instantly leak at a joint, etc. and blast a jet of steam you cannot see, where you do not want it. Wear leather welders gloves and apron, eye protection, etc. (It is what I do). A jet of steam is like an invisible oxy-acetylene flame.
So please take care.
Hope this helps? (Sorry if I bang-on a bit about safety).
K2

 

[Steamchick]

re: "I've made a CAD model of the engine with almost everything converted to metric."
I should enjoy seeing a non-CAD drawing - if a scan/photo and PDF or something can be posted?
Just General Arrangement, and Boiler? + Boiler details?
What track gauge is it?
I have a Sun engine that could make a 3 1/2" gauge "narrow gauge" loco. (like the Shay?). And my existing 3" vertical boiler could be re-made...? - I sense a possible project here...
Thanks,
K2

 

[ajoeiam]

On boilers...

1. First determine the Normal working pressure you need or the engine, etc. - Add "10% for piping lost pressure" = NWP.
2. Design (calculate material strengths, thicknesses, etc. and configurations) to at least 8 x the NWP without exceeding elastic limits of materials.
3. Make using appropriate quality materials and procedures.
4. Pressure gauge normally 1 1/2 to 2 x NWP for full scale deflection - so it is working at NWP around 1/2 to 2/3rds of scale.
5. SAFETY RELIEF valve: set to fully blow at 4% USA/10% UK. over-pressure above NWP.
6. Design and manufacture safety test = 15mins at 2 x NWP without loss of pressure, leakage, any permanent distortion anywhere....
7. IF Hydraulic test is OK, a Steam test, at full fire, regulator (steam delivery valve) closed, full steam blower through fire, and no added water, for 15 minutes when safety valve operates at max pressure. The max pressure seen during the steam test shall not exceed the limit: 1.04 x NWP for USA.
8. You may need to add fuel carefully and sparingly to the fire to maintain it at full fire, but not over-fuelled such as to dampen it.
9. After the test 15 minutes at full safety-blow-off, add water if required, slowly and carefully, and reduce pressure slowly to determine safety valve closes. Then raise pressure again and confirm blow-off initial pressure and max. pressure at max blow-off again.

Then you are safer when you go near "joe public"... Or a certified boiler test inspector!
I realise this is your project and it may have skimped on some of the initial stuff, but PLEASE do proper testing before you risk anyone else near the boiler. The steam test is really the first time when you see what the boiler needs to run it properly. DO NOT steam at more than 15% over NWP! Dampen the fire and add cold water to reduce pressure when the pressure gets to 10% over NWP and is not held from exceeding that by the safety relief valve.
Examine every joint and component for signs of permanent distortion/damage/leaks after the test and when everything is cold.
TAKE CARE. High pressure steam in invisible (white clouds are NOT steam!). High pressure steam leaks can cut flesh, or cook it instantly, and it doesn't grow back. (And hurts like HELL!). My mate has only half the muscles on his arm from a burst gasket at a joint. He didn't see the steam jet! - 6 months of hospital for that one. Fortunately your boiler is contained in the firebox, but pipes etc. outside can instantly leak at a joint, etc. and blast a jet of steam you cannot see, where you do not want it. Wear leather welders gloves and apron, eye protection, etc. (It is what I do). A jet of steam is like an invisible oxy-acetylene flame.
So please take care.
Hope this helps? (Sorry if I bang-on a bit about safety).
K2

You might want to indicate that these recommendations are made for COPPER boilers rather than for any other material.

 

[Steamchick]

Thanks. - Yes.... but I think the principles are the same for other materials?
So just looking at my ASME explanation book - covering "Boilers" (based on steel but not exclusive) it says:

• safety valves "full flow shall be at a pressure not exceeding 3% of the set pressure" - But I have related this to NWP - and my 4% - I think - still holds true? - or should it be 6% (I get a but fuzzy in my head remembering some of these values). - But I'm not sure where this is written? - Is the "set pressure" the same as NWP?

I'm not sure what else could be specific to Copper Boilers, but
What else would you suggest? - I.E. what bit of my ideas is simply wrong - so we can all learn and get better at this?

And I am not sure how to call a boiler Steel or copper when it may be part steel and part copper? Surely the lower pressure of these - if different - should be selected, so your advice wil be appreciated.
K2

 

[rolphill]

Thanks. - Yes.... but I think the principles are the same for other materials?
So just looking at my ASME explanation book - covering "Boilers" (based on steel but not exclusive) it says:

• safety valves "full flow shall be at a pressure not exceeding 3% of the set pressure" - But I have related this to NWP - and my 4% - I think - still holds true? - or should it be 6% (I get a but fuzzy in my head remembering some of these values). - But I'm not sure where this is written? - Is the "set pressure" the same as NWP?

I'm not sure what else could be specific to Copper Boilers, but
What else would you suggest? - I.E. what bit of my ideas is simply wrong - so we can all learn and get better at this?

And I am not sure how to call a boiler Steel or copper when it may be part steel and part copper? Surely the lower pressure of these - if different - should be selected, so your advice wil be appreciated.
K2

I vaguely remember that popular opinion on copper boilers was shifting to a lower pressure for the annual hydro versus steel boilers, to reduce the work hardening(embrittlement) of the copper.

I would say the main barrel determines what a boiler would be "classified" as. There are plenty of steel firetube boilers with copper flues. I would also consider an ofeldt with a steel center vessel and copper water tubes as a steel boiler. I've seen three drum boilers with steel drums and copper water tubes.

These all have in common the concept that the copper parts are somewhat considered consumables.

 

[Steamchick]

First ever hydraulic test is 2 x design NWP. But ASME does an adjustment for stress limit reduction which varies from copper to steel. Copper requires a higher test value, to simulate the stressed percentage of yield at elevated temp of the steam. UK just says "2 x " without considering temp stress changes, as it is not a proof test, just really checking for significant material, joint and manufacturing faults. (such as cracks formed during bending of tubes, flaws or dents in flue tubes that experience compressive forces from boiler steam, poorly made joints, etc.). So I think 2 x NWP is an appropriate test for initial hydraulic test of home use boilers?
Any boiler "in the public domain" - or to be covered by any insurance (e.g. house insurance, health insurance in case of injury, etc.) - should of course be tested by a suitable certification authority, to certify boiler safety in that country. E.g. A local Model Engineering club in my case.
Later annual hydraulic checks are at 1.5 x NWP for UK. Unless significant changes, or repairs, have been conducted, when to Design proof test must be re-applied.
That's all I know.
K2

 

[HMEL]

You might want to indicate that these recommendations are made for COPPER boilers rather than for any other material.

It makes no difference on copper or any material. The design equations incorporate the values for whatever material you are using. The material will either meet the strength requirements at temperature and pressure or it will not.

 

[Steamchick]

Thanks HMEL. I agree regarding the calculations.
But I accept the feedback from all that there is a difference when testing a steel boiler or copper boiler, in that ASME dictate that a copper boiler is tested to a higher pressure than 2x NWP, according to Kozo Hiraoka.
In fact he quotes ASME UG99 as saying the copper boiler shall be tested to 1.3 x NWP x a factor relating to the permissible stress value of the material at steam temperature of NWP versus the stress value at 20deg.C. (hydraulic test water temperature).
I.E. for a 100psi Copper boiler a test at about 280 psi.
My postulation was based on UK boiler regs. as I understand them for testing the initial manufactured boiler at 2 x NWP - which is only 200psi for a 100psi boiler. So I was not considering the material of the boiler correctly, against USA regs. (without knowing what rules really apply to Rolphil's boiler application, size, operating location, West Michigan, etc.).
As I do not know the permitted stress values for Rolphil's vessel I cannot postulate an ASME test pressure. - But 200psi should be adequate to ensure he has tightened the bolts on the gaskets, etc., suitably?
An Hydraulic pressure vessel - such as Rolphil's unknown oil reservoir? - may or may not be suitable for steam at the same pressure. If the history of the pressure vessel is unknown, some reverse engineering calculations can help confirm it is OK, but a "design" test at 2 x NWP gives one more confidence, before steaming to confirm the safety relief valve is adequately sized and set to a suitable pressure.
Also, I wanted to stress that a gauge with Full scale deflection equal to NWP is not good practice, the gauge should be capable of between 30% and 50% overpressure in normal steam boiler practice.
Thanks for your confirmation that the maths is common to all materials, it is just the permitted stress levels that change.
K2

 

[HMEL]

Thanks HMEL. I agree regarding the calculations.
But I accept the feedback from all that there is a difference when testing a steel boiler or copper boiler, in that ASME dictate that a copper boiler is tested to a higher pressure than 2x NWP, according to Kozo Hiraoka.
In fact he quotes ASME UG99 as saying the copper boiler shall be tested to 1.3 x NWP x a factor relating to the permissible stress value of the material at steam temperature of NWP versus the stress value at 20deg.C. (hydraulic test water temperature).
I.E. for a 100psi Copper boiler a test at about 280 psi.
My postulation was based on UK boiler regs. as I understand them for testing the initial manufactured boiler at 2 x NWP - which is only 200psi for a 100psi boiler. So I was not considering the material of the boiler correctly, against USA regs. (without knowing what rules really apply to Rolphil's boiler application, size, operating location, West Michigan, etc.).
As I do not know the permitted stress values for Rolphil's vessel I cannot postulate an ASME test pressure. - But 200psi should be adequate to ensure he has tightened the bolts on the gaskets, etc., suitably?
An Hydraulic pressure vessel - such as Rolphil's unknown oil reservoir? - may or may not be suitable for steam at the same pressure. If the history of the pressure vessel is unknown, some reverse engineering calculations can help confirm it is OK, but a "design" test at 2 x NWP gives one more confidence, before steaming to confirm the safety relief valve is adequately sized and set to a suitable pressure.
Also, I wanted to stress that a gauge with Full scale deflection equal to NWP is not good practice, the gauge should be capable of between 30% and 50% overpressure in normal steam boiler practice.
Thanks for your confirmation that the maths is common to all materials, it is just the permitted stress levels that change.
K2

Well let me see if I can clarify that issue. The calculations are all the same based on the material specifications available. We then put a safety factor on those calculations based on the material and construction methods used. To account for the degree of unknowns we make a judgement call of how much of a safety factor we need to apply. For instance a steel product likely will have good specifications from the foundry with consistent construction techniques where as copper can very significantly and is highly dependent on the skill as well as the technique. But the process is the same both materials have a safety factor based on what we dont know. The codes will tell us the minimum safety factor that can be used.

And yes the selection of the pressure gage is based on the understanding of how they work and what part of the scale reads more accurately. And in fact these gages are or should be calibrated on a testing bench before use. This is a detail not often discussed. The same goes for temperature and pressure instrumentation.

 

[Steamchick]

Thanks HMEL:
Reading ASME (because I am a Nerd) it simply gives "permissible stress limits" for various materials, so the factors of safety have been incorporated into the development of the stress limits by the clever Engineers setting the standards.
E.g. the maximum allowable stress values for steel are given in Table 1A, of Section II, part D of ASME, and for Copper are given at various temperatures in Table 1B, of Section II, part D of ASME.
Discussing gauge calibration, the max safe working pressure shall be marked indelibly so a quick glance can identify if the needle is above or below the line.
e.g.

My glass has a red zone marked as well, but this disappeared on the photo!

I have calibrated water gauges against the water level in the boiler! (Involves taking a boiler at suspected minimum point of water, removing the heat, dropping pressure by cooling naturally, then removing a top fitting and using a dip-stick
to identify the actual water level. Correct the gauge system as required!).
I have experienced many water gauges that bounce around intolerably due to steam bubbles affecting the pressure in the water column. But at least a "noisy" water gauge shows it has some water at the lower end! (not blocked). As soon as the water disappears you know there is none left!
I have also experienced gauges that find a level and never move - due to near complete blockage by furring , or other defect. Shows that maintenance is required!
But water gauges can be subject to false (high) readings caused by surface tension (where a very small glass and interconnection is used) and "air-locks" - which need the glass to be blown-down before reading. - These are the most worrying, as, if interconnecting pipework (e.g. bringing the gauge from the boiler tank to the outside world) has some possibility of holding an air lock then the water gauge can show water levels higher than true level in the boiler. Directly connected gauges (into bushes on the body of the boiler are usually more accurate, but subject to steam bubbles created adjacent to the bottom steam connection, these also can be troublesome.
And the water gauge needs to be trusted... and accurate for operator safety. Large pipework to water gauges helps resolve most issues, and a parallel pipe of large bore adjacent to the water glass is sometime necessary to stabilise the readings. (See mine in the photo). Steam and air bubbles from the bottom boiler connection can vent up the larger parallel pipe without affecting the gauge level so significantly.
Curiosities: I favour a card with diagonal lines behind the glass as - at the correct distance - this reverses the direction of lines making reading a gauge very easy. Attached picture shows a completely full glass (Hydraulic test in progress). Without such lines, or other indication, you cannot see the difference between a completely full glass (Overfilled - as shown) to an empty glass (Boiler desperately in need of water!).

When the glass is half full, you can usually see the meniscus, but when steaming a small model loco it can be very hard to see the level in a boiler somewhere between your knees!
This also shows how I added a parallel pipe (lagged) - larger diameter then the water gauge itself - to stabilise readings., as this gauge is connected to a low point on the boiler via a long pipe (lagged, bottom right of photo). Perhaps RolPhil will need to do the similar mod when he steams his boiler, but he probably has larger bore pipework and gauge than my 3mm bore... so will not have air-locks, or other issues.
K2

 

[Steamchick]

To correct a previous error.
The ASME regs (PG70) require the safety relief valve to "have sufficient capacity to relieve all the steam a boiler can generate" - "without allowing the pressure to rise more than 6% over the Max. rated pressure of the boiler/system".
Also: "Small boilers shall have the safety valve SET to initiate/blow at the NORMAL Working Pressure or below". (ASME PG67-1).
So Rayphil's 100psi rated boiler shall have the Safety relief valve set to operate at 100psi or below such that at full fire and full blower the pressure cannot exceed 106psi. "Full blow" shall be held for 15 minutes on test, without addition of water, unless the minimum water level is reached, when the time is recorded and test ended as water is added...
I hope this clarifies my previous errors?
Incidentally, a recent boiler steam test identified that on full Blower, a 5" gauge loco could generate more steam than the 2 safety valves could release, and pressure rose more than 10% over NWP. No amount of adjustment could make the safety valves release more steam, so the test was failed until different safety valves were fitted that could release all the steam and keep the boiler pressure within the required limits, with no demand for steam, a fully fuelled fire and full fire-draught blower.
The cause appeared to be a larger than designed hole in the steam blower, thus firing the loco better.
K2
K2

 

[rolphill]

In any case, 160psi hydro went well. A few fittings weeped until tightened. The brass blower valve weeps a bit above 100psi or so, so I had to give it a little bit of pump during the test. Before the test I left it pressurized to 100psi and went shopping and came back to around 40 psi a couple hours later.

The flange had no issues. In my first post I did all the calculations for the flange and the hoop stress and everything checked out, so I'm not surprised. My only concern was the spot in the copper tube I had a tiny blowthrough with the torch that I filled with bronze brazing rod, but that held up fine.

I believe the hand pump has a 1 inch bore, so even with the long lever it took some force to reach 160psi. The water gauge seemed to work fine while filling it. It's all 1/2in pipe going to the bottom of the water gauge, and it's a rather overscale commercial gauge, so I'm not surprised.

I installed the fire door. I realized a little too late that I used a hinge that had a plastic bushing, and it got melty during the welding. I just held the door in place and sprinkled water on the hinge until the plastic cooled and set. If this is an issue during firing later I'll replace it. I added a "temporary" handle, and it doesn't look half bad.


Only a few things left before steam test:
Install superheater coil
add blower pipe
redo blowdown piping so it doesn't stick out so far
make the stack adapter
add insulation and the outer shell
install whistle
clean and paint?