The Unofficial Mamod and Other Steam Forum

Bogstandard · Posted: Fri Jan 18, 2008 9:48 pm Post subject: Oil trap for small engines

This is going to be a one hit post, no sketches, due to the fact these can be made in all different sizes, it is just the method of operation is the same for all.
What we need to do is get the steam/oil mix from the engine to do some work and make it drop the oil particles plus a bit of water and then let clean steam escape to atmosphere.
So basically we use two methods, the first is to drop the pressure fairly quickly, this is done by entering the chamber and also the exit pipe is larger than the inlet. Like a low pressure weather system, this allows droplets to fall like rain does. The other bit is to make the steam travel against the cooler wall of the chamber and so condense the water and oil out, then what is left, finds its way to the larger diameter pipe and exits, hopefully as nice clean steam.

The first pic above shows the bits I have used. A piece of brass plate, 1 1/4" square with a mounting hole in each corner, two bits of pipe, a 1/8" piece (inlet pipe) that has a 45ish deg. bend on it, and a bit of 5/32" (outlet). Next is the main chamber, I used 1 1/8" diameter plumbing pipe by 1 1/2" high. This is first drilled straight across at 1/8" then one side was opened up to 5/32". The next bit is the lid, this needs to be fairly heavy, but not overly so, if you have made this right it will not lift off unless you do it, and this needs to be a snug fit in the chamber. Just a word of warning, don't drill your holes for the in/out pipes until you have made the lid, this makes sure that the lid fits all the way in.
This one I have made is about the same size as Odilons famous film canister, and should last a couple of steamings before emptying, a lot depends on the ambient outside pressure, as this will also control how much water/oil comes out of the steam.

As can be seen from the shot above, everything is CLEAN, muck and silver solder just don't get on well together.
I have done my usual trick of silver soldering from the inside, this does do a much neater job and saves hours on cleaning up. Also I have only used just enough SS wire to do the job. Why waste an expensive commodity.
Just a little note about hard soldering, it works by capilliary action, so thru holes should have a small clearance to allow it to flow, in copper I just scrape the inside of the hole with a scalpel to give about 0.002" (0.05mm) clearance.
I never let the flame from the torch come into contact with the silver solder, I started by heating under the baseplate to get the flux flowing, then the flame was played around the base of the chamber. After a few seconds I saw a shiny ring form all around the base, the solder had flowed, the heat had transfered by itself up to the top tube joints and they had perfect fillets on them, inside and out. The knob was soldered onto the cap at the same time, from underneath.

The above shot shows how the inlet pipe faces down and to the side of the chamber. It also shows the perfect fillets for the base and pipes, once the technique is mastered, you will never look back.

After a basic polish it is starting to look something like. This shot shows how the fillets come out on the outside, perfect, nothing at all to clean off.

Here is the one I have just made, sitting next to an expensive commercial one from a fairly large model boat installation. There are three pipes on that one, in/out, plus one that you have to suck the gunk out of the chamber. To me not a very good idea, the lid method allows you to give the chamber a good clean out when needed.

Just a bit of a note to the machinist amongst you. When cutting copper, it can be an absolute pig, and grab with no warning at all. The correct lubricant is tallow, but because I haven't been able to catch any tallows recently (supposedly, they shed their legs at this time of year, and can't land), I use full cream cows milk, and does a very good job as a replacement. But do clean your iron down afterwards, it tends to smell a bit after a couple of days.

This will be my last build post for a bit. The local butchers at the hospital get hold of me early next week, so I don't know how long before I can get back in my shop. But I will still be here to answer questions.

John
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IndianaRog · Posted: Fri Jan 18, 2008 9:59 pm Post subject:

John, beautiful in design and simplicity...thank you!!

Best of luck at the butcher shop, hope they do well by you.

cheers,
Roger
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Mister Occlusion · Posted: Fri Jan 18, 2008 10:23 pm Post subject:

That's a thing of beauty, John. Much more elegant than my glass jam jar with 2 or 4 pipes soldered into the lid

I was going to try building a combination separator and chimney out of bits from the plumbing aisle at some point.

I won't be silver soldering it, but I think your tips on soldering can be applied in general and should do well for me.

I just wish I could find solid solder in smaller gauge. Only fine stuff available is rosin core and the heavy plumbers stuff is pretty crude to work with.

I hope the quack does you up proper. Take care

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Gingerly prodding the envelope since 2007.

Bogstandard · Posted: Fri Jan 18, 2008 10:46 pm Post subject:

Roger,
Many thanks.

Mark,
Again many thanks, and I think I have a solution to your problem.
This is one of my pics from another site about the finger engines I built, but just look at the pic.

I sometimes use lead free soft solder to join mutiple parts together so I can machine them all at the same time.
If you look to the right of the pic, you will see my reel of solder with the flux underneath. If you look at the end of the solder it looks like a flag.
What you do is clean the face of a hammer, and a nice clean bit of metal to bang against (if it is not clean you will embed dirt into the solder), then just keep belting the solder until it is paper thin. Then just cut strips of it off with a pair of scissors, problem solved.
I use exactly the same method with soft solder, flux it, and put bits of solder on the joint, bit of heat, et voila!.
Goodness me, I have just found out I can speak French as well.

John
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If it looks right and feels right, then it is right.

Sandman · Posted: Fri Jan 18, 2008 10:48 pm Post subject:

Excellent tip John.

That's noted for the future.

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Reid · Posted: Fri Jan 18, 2008 11:12 pm Post subject:

Absolutely elegant, John. Applause and also the very best of wishes
that you get out with a clean bill of health again.

All thoughts with you--when I'm not breaking things here or cutting silly capers.

Your work and your postings show us the best of the best thinking and doing.

Be well,

R.

MooseMan · Posted: Fri Jan 18, 2008 11:42 pm Post subject:

Fantastic John - more inspiration! After the rough effort I posted, I've now made my first properly silver soldered displacement lubricator and fitted it to my midwest boat - works a treat!

Best of luck with the medicos!
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Stands the glass half empty,
Or stands the glass half full?
Blast your Buddhist mantra, man,
I'll take another pull.

tmuir · Posted: Sat Jan 19, 2008 12:09 am Post subject:

Nicely done and shows me I still have a lot of room for improvement in my silver soldering.

Thanks
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A nice example of an Australian made Scorpion Donkey Engine

Les · Posted: Sat Jan 19, 2008 12:15 am Post subject:

It's more like a piece of art than an oiltrap. Well done.

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Bogstandard · Posted: Sat Jan 19, 2008 12:17 am Post subject:

Thanks for the best wishes everyone.

Odilon,
It gets easier the more you do it.
I was shown this technique many moons ago by a chap who has now gone to a better place.
Jewellers use the same sort of technique, they call their bits of precious solder, pallions.
Reading thru this site will give you a lot of tips that can be transferred over to what you are doing.

http://www.lapidaryjournal.com/tech/1299tech.cfm

And always remember what it says on the site, solder always flows toward the heat.

But I still have a bit of a problem with fabrication, after the third or fourth reheat I tend to lose it a bit, maybe I should get a lot more different temp. ranges of silver solder.
BTW I will get this posted to you later next week.

John
_________________
If it looks right and feels right, then it is right.

MooseMan · Posted: Sat Jan 19, 2008 10:27 am Post subject:

Wow John - next boat I make I'll name in your honour!
_________________
Stands the glass half empty,
Or stands the glass half full?
Blast your Buddhist mantra, man,
I'll take another pull.

Steve_S · Posted: Sat Jan 19, 2008 12:58 pm Post subject:

Fantastic work John... an inspiration! And thanks for the very useful tips.

tmuir · Posted: Sat Jan 19, 2008 1:31 pm Post subject:

John what diameter silver solder do you use?

The stuff I have at the moment is huge, about 2.5mm to 3mm in diameter.
I also have my easy, medium and hard silver solder for my silver smithing that is great at 0.6mm diameter but I'm unsure whether I could use that on anything that will take a load or stress as its much higher silver content than what would normally be used for model engineering.

Thanks
Tony
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A nice example of an Australian made Scorpion Donkey Engine

toxx · Posted: Sat Jan 19, 2008 1:39 pm Post subject:

... John, what a talented craftsman you are!

That looks great! I shall shamelessly try to copy ...

Thanks for posting, mate!

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... keine Wunder sind vollbracht.
No miracles ... yet.

Bogstandard · Posted: Sat Jan 19, 2008 4:04 pm Post subject:

Thanks for all the comments.

I would just like to add.
You see all the fancy lathework, but in fact it only takes minutes to do, no special talents at all. So why not put it on, it does make bits look a bit special. I do nothing special at all, actually most of the machine work was done in about 45 minutes.

Tony,
The silver solder you use for jewellery has in fact got too much silver in it.
The pic below shows exactly what I use for 99% of my silver solder work. The little packet would most probably solder up about 10 of these oil catchers.
The Tenacity flux is a bit more aggressive than standard Silverflo, but it does allow a bit more tolerance on heat before it breaks down, plus I can do stainless steel with it.
I have a customer in Oz who has to have these bits shipped from the UK because it isn't generally available there.
For the pressures and temps that you lads use, soft solder will do just as good a job.

Toxx,
You can shamelessly copy anything I put on here, that is why I do it.
I am just trying to make things that look difficult to make within the reach of people like yourselves, by showing how easy it can be done.

My very first lathe when I was a lad, was an old knife sharpener clamp on type bench grinder (with a turny handle on the side). I took the stone off and put a drill chuck on it. I made my first steam engine with it. I am sure you lads could do the same sort of thing with a clamped down electric drill and a file.

Now what do you want to see next.

John
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If it looks right and feels right, then it is right.