Home Foundry

[GreenTwin]

I ran across another individual who had a broken bearing cap, and so I decide to practice my pattern and mold making skills on that, and see if I could cast it without defects.

I had to build up the original cap a bit using wood tongue depressors.
The owner wanted the numbers retained, otherwise I would have just made a new pattern from wood.

 

[GreenTwin]

I was running out of time and used some tape on the top of the bearing to fill in a few low spots.
Normally I would continue filling the pattern and sanding it, and would only use the blue painter's tape on surfaces such as the round bore, to prevent the pattern from sticking to the sand.

 

[GreenTwin]

I did not need a core for this pattern, but rather just used the bottom of the pattern itself for the round interior.
I used the ceramic mold coat again, and burned it off.
Don't burn your shop down with the alcohol-based ceramic mold coat if you happen to use it.

You can use rotary rasps and such to machine the sand after it sets, to add runners, etc.
You can cut gates into the sand using a small knife with a straight end.

 

[GreenTwin]

The pour went flawlessly, and this is the result.
Iron castings must be left overnight in the mold, so that they cool very slowly, else you will have hard spots (chills) in the castings.
The best way to ruin a good iron casting is to pull it out of the sand mold as soon as the metal solidifies, but when the metal is still very hot (ask me how I know this).

I was very pleased with the surface finish and how I was able to retain the original letters/numbers.

You can see the mold was poured with no flask around it, but with some heavy weights on top the mold, to prevent the cope and drag from separating due to hydraulic forces.

 

[GreenTwin]

Here is the casting with the gates/runner/sprue cut off.

I sent this part to the owner, and he machined it, poured new babbitt, and installed it on his machine.
He was a happy camper to get a new bearing cap.

I was glad to use this as a verification that I had finally got the new furnace and iron process to a point were it could make consistent defect-free and easily machinable parts.

Edit:
You can see how the bound sand mimics the blue tape exactly.
I normally fill and sand the pattern, and don't use tape, but was running out of time.
I was going to buff out the tape lines, but did not have time for that either, so I just mailed the casting as-is.

 

[GreenTwin]

Large gray iron electric motor end bells make very good scrap iron material.
The paint and rust does not need to be removed prior to melting the scrap; it all comes out in slag.
The difference in the amount of slag between melting a perfectly clean piece of iron and a rusty piece of iron with paint on it is very little.

I was initially told that the scrap iron had to be very clean, but I found out that is a myth.
As long as the metal inside is a good grade of gray iron, it will make a good casting, regardless of what is on the surface.

The furnace interior was clean since I had just coated it with a reflective ceramic coating (ITC100).
The coating is not necessary, and since ITC prices have skyrocketed in the last few years, I don't use it anymore, and I can't tell any difference in melt times.

 

[GreenTwin]

These are the typical Morgan clay-graphite "Salamander-Super" crucibles that I use.
They are ferrous-metal rated, and work well with iron.
Other crucibles that I have seen others use that are probably not ferrous-metal-rated, and perhaps not rated for 2,900 F, often appear to fail quickly, and at the worst possible time.

I use Morgan clay-graphite crucibles for all metals, but do not mix metals and crucibles (one crucible for each metal type).
These crucibles can be purchased in a range from very small to extremely large.
I use a #10 a lot, but have also used a #30.
I have seen several backyard casters using a #70.

For capacity, these crucibles will generally pour about 2.5 times the crucible number, ie: a #10 will pour about 25 lbs. of iron.
You need some space at the top of the crucible to be able to pour the iron without spilling, so you don't fill them brim-full.

 

[GreenTwin]

My workload has been extremely heavy for the last year, and will continue to be that way for a while, but when I get caught up, I plan on casting a 60% scale model of this engine, which I found in Oregon.
These engines seem to be rather difficult to find, and this was one of those miracle finds that I stumbled across by chance.

Edit:
That is the seller' Ford, not mine.
People look at that photo and say "Great auto. Is there a steam engine in the photo with that great auto?". LOL

 

[GreenTwin]

And after the O-S engine build, I am going to cast a 60% scale Frisco Standard marine engine.
JasonB and friends made the helical gear patterns for this engine (many thanks Jason and friends; could not have done this gear without you folks from across the pond).
Jason nailed the 3D model for these gears to give an exact 2:1 speed ratio with a perfect mesh, and I must say this is not an easy design, at least not for me.

The 3D model for this engine was developed from photos that were found online of a 4hp engine.

Being able to create a 3D model from photos, 3D print the patterns, and then cast the parts in gray iron is I must say a fabulous experience, and I really never dreamed I would get this far with the process, but here we are, with help from JasonB.

 

[stragenmitsuko]

casting grey iron , now that is impressive .
thx for sharing

 

[MRA]

The O&S engine looks like the one Dave Richards used to use in his 'Old steam Powered Shop' youtube series. There are about 60 videos, and he moves to a larger engine about half way through. Thanks for posting your pictures here - I have got as 'hot' as brass and bronze, but not iron yet (I can see diesel working better than old engine oil there). I especially enjoyed seeing you build-up that bearing cap for shrinkage - I replicated my home setup at a small museum where I volunteer, and it looks likely we'll need to replicate parts for machines there (mostly pre-war diesel and gas engines) in the not-too distant future. I had been thinking about shrinkage and I'm glad to see your approach is practical.

When you use an oil pump, do you plan to use a smaller jet in the end of your fuel tube in the burner - and is this expected to give a 'better' flame? I'd not thought of this - my burner is like a very, very simple carb - the air tube is reduced in diameter a little for more velocity, and the gravity-fed fuel tube (1/4" or so copper pipe) just terminates somewhere near the end, in the middle of the air tube, and the air flow drags oil out in blobs and strings! Well, it burns, but I could imagine screw-in jets perhaps, especially with pressurised, clean (!) fuel.
cheers
Mark

 

[GreenTwin]

casting grey iron , now that is impressive .
thx for sharing

Thanks.
I noticed today that the member here "sawyer Massey" is also pouring iron, and making steam engine parts.
He appears to be making some nice castings, and so I have to guess he has been at it a while, or is a quick learner.

I know a handful of people who melt gray iron in a backyard setting, but there are not too many who make parts regularly that I am aware of.

Casting aluminum is very easy.
I have done it (as shown above) with a stainless sauce pot, a propane burner, and some sodium-silicate-bound sand (it could be greensand also).
Aluminum melts in the 1200 (+) F range, and as long as you don't have any dampness, moisture, water, etc. in the mold, or in the ingot mold, then it is easy to melt and pour.
Any water anywhere, and you can have a face full of molten aluminum, since the even a tiny drop of water will flash to many times it size, and blow the aluminum right back out of the mold and onto the person pouring (another one of those don't ask me how I know this).
Full face shield and eye protection are critical, as well as some leather all over for personal protection.

It took me on and off about 7 years to learn how to get consistent gray iron castings.
Work kept interrupting me for long periods of time, and so the real amount of time from first iron pour to consistent iron pour was probably 4 or 5 years.

Without understanding the entire process, ie: the burner operation, the furnace operation, how and when to handle the slag, the ferrosilicon additive for machinability, and getting set up to safely handle the every intense radiant heat, then one can have on and off successes, which is what I did for about 5 years.
One casting would turn out well, and the next one would not be usable, but I can finally consistently make a good machinable casting basically first time, every time.

Pattern making, shrinkage, draft angle, etc. are things that have to be understood.
Pour basins, sprues, runners, gates, risers, etc. are sort of an art to lay out so that they work every time.
Nobody agrees on how to do pour basins, sprues, runners, gates, risers, but I have a method that works well for a variety of pattern shapes and sizes.

I got a little help from some folks online who do iron castings, but sometimes people will not share all of their iron secrets, and sometimes people are simply not good as describing in fine detail exactly what the iron process is.

I finally did a lot of experimentation on my own, and established what the fuel and combustion airflow should be to get a fast iron melt (fast being about 1 hour).
I build a somewhat lightweight iron furnace, with about 120 lbs of refractory, and it heats up relatively quickly using an oil burner.

I also experimented with many burner types, fuel types, sand types, etc.
I am not really aware of a good book for backyard folks about how exactly to consistently melt and pour quality gray iron castings; at least I could never find such a book. The Navy Foundry Manual was somewhat helpful, but so dated that it was not very much help.

.

 

[GreenTwin]

The O&S engine looks like the one Dave Richards used to use in his 'Old steam Powered Shop' youtube series.

It is the same engine that Dave Richards uses, and as I recall he said his flywheel was fabricated, and he noted that my engine has an original flywheel.
Its a very nice engine to say the least; classic styling, and simple.

If you can melt brass and bronze, then with a little more learning, you can also pour gray iron (*assuming you get set up correctly to melt iron).
I know of one individual who went from brass/bronze to iron this year, without too much trouble.
Don't expect your first iron pour to be perfect.

.

 

[dazz]

Hi
What ceramic coating do you use for the moulds?
Is it available in powder form to avoid the cost of shipping it as dangerous goods (adding alcohol before use)?


Dazz

 

[GreenTwin]

When you use an oil pump, do you plan to use a smaller jet in the end of your fuel tube in the burner - and is this expected to give a 'better' flame? I'd not thought of this - my burner is like a very, very simple carb - the air tube is reduced in diameter a little for more velocity, and the gravity-fed fuel tube (1/4" or so copper pipe) just terminates somewhere near the end, in the middle of the air tube, and the air flow drags oil out in blobs and strings! Well, it burns, but I could imagine screw-in jets perhaps, especially with pressurised, clean (!) fuel.

At the moment, I am using a Delavan siphon nozzle, which is a spray nozzle very similar to a paint sprayer in that it uses compressed air to atomize the liquid (diesel in my case) and spray it in a fine mist.
The problem with a siphon nozzle burner is that it requires a somewhat decent air compressor, and over time, the air compressor tends to wear out.
If the air compressor fails in mid-melt, then you have a problem if you don't have a backup.

The latest burner I am using looks identical to a siphon-nozzle burner, except that it uses a gear pump to pump diesel to the nozzle at 100 psi, and no air compressor is required, since the 100 psi does the atomization work.
The gear pumps are readily available from the commercial heating-oil furnace market, as are the siphon and pressure nozzles.
The siphon and pressure nozzles can be used with the same brass adapter, but they operate differently, and are not interchangeable.

Gear pumps can be driven by a fractional horsepower motor, and are quite efficient.
It is much easier to carry a small gear pump/motor combination around, than an air compressor, and a gear pump motor may draw 3 amps or less at 120 volts, whereas some air compressors can draw 12 amps or more at 120 volts.

.

 

[GreenTwin]

What ceramic coating do you use for the moulds?
Is it available in powder form to avoid the cost of shipping it as dangerous goods (adding alcohol before use)?

I think the product that I found is called "VelaCoat", and it is alcohol-based.
I am not aware of a dry product, but I have never asked anyone if they sold that either, and that would be a good idea, and cheaper to ship.
I am not sure if ceramic mold coat would work on green sand (greensand being clay and sand mixture).
I use resin-bound sand, and so the mold sets and becomes hard, thus making it impervious to spraying on the ceramic mold coat and burner off the alcohol.

I tried alcohol and graphite many years ago with petrobond (tm) sand, and that was an absolute disaster.
I have not tried ceramic mold coat with greensand, and I don't use greensand.

.

 

[GreenTwin]

When you use an oil pump, do you plan to use a smaller jet in the end of your fuel tube in the burner - and is this expected to give a 'better' flame? I'd not thought of this - my burner is like a very, very simple carb - the air tube is reduced in diameter a little for more velocity, and the gravity-fed fuel tube (1/4" or so copper pipe) just terminates somewhere near the end, in the middle of the air tube, and the air flow drags oil

I will have to detail how I set up my siphon nozzle burner and pressure nozzle burner.
Below are the internals of a Delavan siphon nozzle tip.

Basically, with a siphon-nozzle burner, you feed compressed air in the center pipe, and fuel in the side of the adapter via an elbow fitting.
There are two parts to a nozzle, which is the adapter body, and the actual burner tip.

 

[GreenTwin]

A few more siphon-nozzle photos.
You can see there are small spin vanes built into the burner tip that spin the fuel, and the compressed air comes out the hole in the center of the tip.

 

[GreenTwin]

This is the schematic for a Delavan siphon nozzle burner.

I use 10 psi compressed air pressure on the fuel tank with a 30 psi safety valve, in order to get a consistent diesel fuel flow at all times.
I use an automotive inline fuel filter in the fuel line just before the burner.

I use about 30 psi compressed air to the siphon nozzle.
Some folks use slightly less compressed air.

I use a #30609-11 nozzle, and a #17147 adapter with the siphon nozzle burner.
The chart below lists the #30609-11 at a nominal 1 gal/hr fuel flow rate, but it actually operates over a wide range of fuel flows, depending on your compressed air pressure, and fuel tank pressure if you are using a pressurized fuel tank.

People that use waste oil for fuel often use a drip-style oil burner, since waste oil is often not clean, and can be prone to clogging.
There are no fine passages in a drip-style burner to clog.
I don't use a drip-style burner because they don't have the fine control I want in a burner.

Generally people who use waste oil thin it perhaps 15-20% with diesel to make it flow better.
Handling waste oil and trying to filter it is not worth my time and effort, so I use diesel only.
Diesel burns cleanly with no concerns about the heavy metals that are in waste oil.

I have seen folks melt iron with diesel, kerosene, cooking oil, waste oil, etc., and they all seem to work well.

Some hydraulic oils are reported to be toxic when burned, so don't just use any waste oil; use caution.
Waste oil is notorious for being contaminated with sludge, water, antifreeze, etc., which is another reason I avoid using it.

 

[GreenTwin]

Here is the pressure nozzle arrangement.

I think the connect can be simplified.

I plan on using a needle valve in the return line, instead of the pressure-regulating-valve PRV.
Closing the needle valve forces 100% of the fuel flow out the nozzle tip, and no fuel flows in the bypass.

Opening the needle valve allows fuel flow in the bypass line, back to the fuel tank, and so the fuel output of the nozzle can be varied from very little up to its maximum rated amount.

Note that siphon and pressure nozzles both use the same adapter, but the nozzle types are not interchangeable due to the differences in how they operate.