Making a piston valve engine from mainly junk materials

[bogstandard]

I had forgotten that I had a few pics left in my camera, so I have decided to make a post out of these.
The blocks need to be made and all completed before I could carry on anyway, because the bits that fit to it have to be lapped into the main bore and the soldering has to be done first just in case we get a little bit of distortion in the main bore. I suppose you could bore it after soldering but it might be a bit difficult to hold well enough.
The sketch shows all the positions and sizes, thru a key. They are drilled in a specific order, and that is shown in pic 2.
Pic 1 shows the size of blocks required. I have stated that these can be made out of brass or steel, preferably brass (a lot less hassle to drill and tap).
Just a quick warning when you come to bore the main hole, when you are putting the larger drills thru to get to size (over 9mm) you will start to hit the bottom of the four holes drilled on the centre of each side, take it very steady. Also I would recommend drilling the 4mm tube holes from each side rather than deep drilling all the way thru. Another thing to point out is that the 3mm holes that these pass thru, have to be sealed on the outside of the block, this will be shown how to be done later.
I also have some pics left of silver soldering the control block to the pipes, so I might make a post out of that, just to pass the time until I can get active again.
By the way, this engine is starting to look a bit battered, maybe caused by being the prototype and has been taken apart more times than I care to remember, hopefully the other will look a lot better.

John

[Eddy Matthews]

Going back to silver soldering for a minute.... You mentioned using citric acid as a pickling solution John. I assume anything that is acidic will work, so what about something easier to get hold of such as acetic acid (vinegar)??

[bogstandard]

Eddy,
Never tried it, except on my chips.
What I do know is that when I used to visit a plating shop, they had pallets of rotting oranges and lemons hanging about the place, these were being used for the same process as we are doing, cleaning.
All I really know is that I have only ever used citric acid, and it works, and works well.
Sorry I couldn't answer your question any better Eddy, all I would suggest is try it, and see what happens. It might even get the steel to come out clean, as with citric acid, coupled with the heat process I think, or maybe a chemical process with the flux and copper, steel comes out with a lovely chemi black finish, seems a shame to clean it off back to polished steel.
BTW, citric acid is not difficult to get hold of at all, just tell them what you want it for, and you shouldn't have a problem. Just buy a couple of boxes of it and it should last a few years, as I do.

John

[derekwarner_decoy]

Hi PD's ....in OZ, my local Pharmacy...they said no worries Derek.....we know you won't use it for DRUG related work   just AUD$27.00 for 500 gms of Citric Acid ... :rant & :sob .......then I presented the  Citric Acid  photograph from John with the container....50 gms for UK 60 P........smart ar#e Pharmasist suggested I could purchase a lot  of Citric Acid  for the air fare to UK.............so   ....I drove to the local Home Brew shop    & :news .... a new unopened 1000 gm bag of Citric Acid  white powder

I purchased 100 gm of Citric Acid  for AUD $3.40  

[bogstandard]

Good on you Derek, that showed 'em. Mix it with a lot of water, add a bit of sugar and we're all coming round to your gaff for a barby and nearly lemonade.

[bogstandard]

Here are the last pics I have got, it shows how I soldered up the steam control block.
First off is sealing up the bit of the transfer holes that aren't required. I tapped the the outside bit of the hole 4mm and screwed in a bit of brass threaded rod, you can just use a bit of rod if you want, or even make a feature of it by turning up a little cap with a spigot on it, your choice. I use screwed rod to stop it falling out in subsequent reheating. Don't block the steam transfer holes with the plugs.
Picture 2 has the block, mounted to the assembled bits of the engine so it acts like a jig to hold everything in place, without it you would end up with a real mess with nothing lining up, the bits of the engine will get very little heat onto it. Don't forget to centralise the block on the pipes so it looks nice and neat.
As I assembled it I put a bit of flux onto the pipe ends, also notice that I have used about 1 1/2 turns of wire, this is because the pipes penetrate a fair way into the block, really it needed two turns as the fillets are fairly small on the finished block, but they were fully sealed, which is what we are after.
Now the heating up bit. Because it is a fairly large block, I used my plumbers type torch, the one with the screw on can. All I did was to play the torch onto the area between the big hole in the middle and the outer edge of the block in a rotary motion until I just started to see a faint tinge of red then just play the flame onto the block at each corner until you see the solder run. All done in 20 to 30 seconds. There is no easier way to describe it, just don't play the main part of the flame onto the pipes as you will cook the joint. Then put the whole lot into quench water.
This now brings us to piccy 3. The block has been taken off the 'jig', you can see that the flux has done its job keeping the soldered area clean, and because the heat was kept directly off the pipes the joints on the flanges are totally untouched. The solder around the plugs has remelted but they still have a good seal.
You will notice that the 'jig' has what looks like a burn mark on it, in fact all it is is a waxy like substance that just wipes off with a cloth, I think it is just a bloom caused by flux vapours. Notice all the good joints. I remeasured the main hole and there was no detectable deformation, so looks like we are in with a chance of making a good valve, Just got to wait until I can get the bits made.
The last pic is the assemblies after an hour in the pickle, looks really bad, but a wipe over with steel wool brings it up just like new.
By the way, both these assemblies fit both of my engines perfectly, they are even interchangeable, so the 'jig' worked.

John

[derekwarner_decoy]

Morning PD's.....John....when we look at 'sketch for steam control main block.jpg'.... in the listing Faces C & D.....

the drillings C2 for the 4 mm tube... are these not shown in the following 'all holes drilled ready for joining .jpg' as being pre drilled with a healthy chamfer :?:

[bogstandard]

Hi Derek,
You will notice that I always give all my drilled holes a good chamfer, usually because there is something bolted to the face and if not well chamfered it tends to hold off whatever is fixed to the face, and usually causes problems. But well spotted about the larger chamfers for the holes that are to be silver soldered, I forgot to mention about them, they are there to promote good penetration and a stronger joint. With you eagle eyed lot, I can't get away with anything.

To all following this lengthy build.
I know that this large assembly does look a bit daunting, but if you follow a few basic rules and a bit of practice I am sure everyone will be able to assemble it. If you really don't think you are up to it, if you can get all the bits to me by whatever means possible, with your 'jig' I will gladly build it up for you. So remember, cleanliness of the parts and a good flux plus don't overcook it are the keys to good SS.

Hopefully by the weekend I should be active enough to carry on with the build. There are only about 7 or 8 more bits to make and it is all finished. I have got to get mobile again, I have been asked today to display my engines in conjunction with the model boat club I belong to, at a steam rally in a couple of months, so I have to get going to get them all finished and prepared.

John

[derekwarner_decoy]

Hi PD’s & sorry to post outside the forum…. but couldn’t get this attachment to link up……John …this is the 0.5mm diameter SS wire offered in OZ & that we have spoken about……66% Ag? sounds very high… I have yet to get confirmation of my order now for six pieces ….& the Easyflo flux – Derek
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<  


Silver solder wire easy .5mm per Mtr
- lowest temperature silver solder
Price per pack is $AUD6.60 or $US5.3
(other currencies click here)



 Post generated using Mail2Forum

[derekwarner_decoy]

deleted ...Derek

[bogstandard]

Hi Derek,
The stuff you have got there is absolutely perfect for general purpose silver soldering, like we are doing here, but definitely a little on the expensive side. I would mail you some by airmail and it would be a lot cheaper, but I don't know if it would be picked up by customs or anti terrorist agencies as being a suspect envelope.
I have just found this web site and although it reiterates most of what I have already said, does contain a bit more about the use of silver solder for larger fabrications like boilers.
http://www.pollymodelengineering.co.uk/global/technical-notes/basic-silver-soldering.asp
I think you are worrying a little bit over this, I always thought you lads were ready for anything, or is it the thought of opening your wallet that makes you sweat.
I know it does me, I did a few weight calculations yesterday about this engine, like on average two thirds of the material is taken off due to machining etc. and the cost of this engine will come to well below the ten pounds I originally said, that is of course because I use recycled bits from the scrappy. The fixings and bits of rod will most probably end up at around ten pounds. If you had to buy all the materials from retail sources, maybe the whole lot would come to less than £50, but you would also end up with most probably enough left over materials to build something else.
But you can't include your time, that is as I see it, many hours of pure bliss, enjoyment and sometimes frustration. But isn't that what doing your own thing is all about.
So don't worry about your SS, all of a sudden everything will click into place and you will be running round SS everything you can get your hands on.

John

[sandy_ACS]

edited

[sandy_ACS]

 

Hi PD's,

Ok so I have taken a few hours off rebuilding the domestic galley...... what a diabolical job, it has fought back at every opportunity....  :rant  

SS....... Derek...... If the wire you have has 66% Ag then it most certainly is not easyflo and will/may have a much higher melting point.... possibly in the region of 720 deg - 780 deg C which would also need the higher temperature type flux.... Tenacity No. 5 or similar.
A further problem with the HIGH Ag content types is their reluctance to flow around the joint, especially if the flux gets exhausted.

If you are SS brass tube with this stuff, then take extreme care as it will be very easy to melt the tube whilst trying to coax it to flow properly.
 

Easyflo has 42% Ag + 25% Cd + 17% Cu + 16% Zn and has a melting range of 610 deg - 620 deg C

The Cd content in this material makes for very quick and easy flow of the material, however, be very sure to keep the area well ventilated..... Cd is dangeroooossee.

Normal easyflo flux will be Ok for this, but not for the higher temperature stuff.

A good supplier for all SS products are to be found at http://www.cupalloys.com

They do a complete range of SS and allied products and offer a good mail order service.
A lot of useful info can also be found on their web site.

Alloy type 842 is the equiv. of easyflo.

Alloy type 456 is the Cadmium free equiv.   with a melting range of 620 deg - 655 deg C.

John...... Engine progress looks great, with only the regulator block to go.

I trust the final episode will include your method for setting the PISTON VALVE timing?..... I know how to do it, and I am sure you do, but I am sure others would need some help on this...... NO PD's you don't adjust the eccentric position... this must remain at 90 deg. to the crank.

Best regards to all.... congrats to the DOG  :no1 ..... ***** to the CAT  :nah ,

Sandy.  :computer  :vacat  

[bogstandard]

Hi Sandy,
I am leaving the timing of the engine to the very end.
Control valve is done and tested, not as great as I expected but it is a lot better than the disc type with two crescent slots.
I am at this moment making the lubricator.
Having a bit of trouble drawing at the moment but hopefully will be able to get everything together by tomorrow.
Here are a couple of pics of control valve.

John

[crash93]

Have you got a picture of the innards of the steam valve please.Peter

  ps

Great build