My Casting Blunders and Successes

I will split my casting blunders and successes out into a separate thread, since this may take a while.

I am going to post my blunders because sometimes it is as important to understand what does not work, as it is to understand what does work.

And perhaps seeing the progression from blunders to consistent castings will help others see that things can be rough in the foundry world when one is trying to learn the methods.

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My first attempts to melt metal were very crude, so don't laugh too hard.

I first tried charcoal and coal in a steel pipe, with a leaf blower for combustion air.

I held an iron rod into the heat, but no melting.

1st Iron Attempt: Fail

Edited By PatJ on 03/07/2022 08:46:11

I bought a crucible, and built a very heavy (ludicrously heavy) cast refractory furnace, and a naturally aspirated propane burner.

Bought a 100 lb. propane tank.

Tried to melt iron.

2nd Iron Attempt: Failure (no combustion air blower used; I had no idea one was required)

This was my first attempt at melting aluminum, and I think this was my first casting ever, and before I built the furnace above.

I stacked some bricks in a circle, welded up a steel crucible, and melted some aluminum.

I purchased some aluminum ingots.

I carved out a crude flywheel pattern from wood, and a circle pattern, just so I could try to melt and cast something/anything.

I purchased some petrobond sand.

This is called an open-face pour, where you just pour molten metal into a cavity in the sand.

1st Aluminum Casting Proof of Concept: Success

1st Metal I Ever Melted: Success

I succeeded for the first time in creating molten metal, making a sand mold, pouring molten metal into the sand, and not dying in the process.

2nd Aluminum Casting Attempt:

I had a 3D printed pattern made for my green twin engine build, and so I started trying to see if I could cast that piece.

I got the wise idea that I could improve the surface finish of the casting by spraying the petrobond mold with a mixture of alcohol and graphite.

This was my first attempt at a two piece mold, using the cope and the drag, and vertical sprue to feed metal to the mold cavity.

Result: The alcohol flashed and created a "surface of the moon" casting.

MAJOR Failure. Learn from my mistakes, and don't repeat these blunders.

2nd Aluminum Casting Attempt:

I had a 3D printed pattern made for my green twin engine build, and so I started trying to see if I could cast that piece.

I got the wise idea that I could improve the surface finish of the casting by spraying the petrobond mold with a mixture of alcohol and graphite.

This was my first attempt at a two piece mold, using the cope and the drag, and vertical sprue to feed metal to the mold cavity.

Result: The alcohol flashed and created a "surface of the moon" casting.

MAJOR Failure. Learn from my mistakes, and don't repeat these blunders.

3rd Attempt to Cast Aluminum:

I tried to cast another green twin flywheel in alumimum, and this time I used straight petrobond.

This flywheel turned out pretty decent.

Result: First usable cast aluminum part that I made.

A bit rough in places, but I called this a SUCCESS, relatively speaking.

Edited By PatJ on 03/07/2022 09:18:40

Edited By PatJ on 03/07/2022 09:19:15

I made some long ingot molds, and melted a damaged aluminum car rim.

This casting is what I consider in the "disaster" category.

I was just blindly stumbling along, trying to figure out exactly what I was doing.

I call this my "CLUELESS" phase.

Edited By PatJ on 03/07/2022 09:22:08

Edited By PatJ on 03/07/2022 09:22:34

I made a pattern for the base of the green twin engine I was building.

I discovered sodium silicate could be used for a core, and so this core was made from sodium silicate and hardware store sand.

The remainder of the mold was made using petrobond.

I had no idea that hydraulic forces can lift the cope up off the drag, and so I did not use weights on top of the flask.

The cope lifted, some of the aluminum ran out.

The core was not secure, but it did not actually float.

The hardware store sand produced a dreadful finish on the inside of the casting.

Result: Failure on many levels. (No Pain, No Gain, as they say.)

I was trying to learn 3D modeling, and learn how to make 3D printed patterns, and so I printed the frame for one of my dad's small oscillators.

At the time, I didn't even know how to machine metal, and so it was sort of like a blind man hiking through a mountainous region full of cliffs and crevasses. If you fall down, you get up and keep hiking.

Result: These two castings actually turned out relatively well, with just some slight porosity on the top of the bearing supports. I never used these castings because at the time I didn't know how to machine or build engines.

I did learn how to fill a flat 3D printed pattern to give the surfaces a nice concave shape.

Edited By PatJ on 03/07/2022 09:42:16

Aluminum Casting Demonstration:

A friend of my brother's got all excited about my new casting abilities, and insisted on a demonstration.

I was a bit nervous, for good reason, because I still had very little idea of what exactly I was doing.

I discovered (after the pour) that if the same diameter pins were used on either side of cope and drag, then the cope could be installed in a position that was 180 degrees off, and thus the upper part of the casting is shifted over about 1" from the lower part of the casting.

My brother's friend was not impressed, and he never came around again for any more castings sessions,LOL.

One of those fair-weather casting friends I guess; always there for the glory; never to be seen for the failures, LOL.

Results: Abject Failure, but important lesson learned. Use a 1/4" pin on the left side of the flask, and a 3/8" pin on the right side of the flask. Orientation problem solved.

Edited By PatJ on 03/07/2022 09:50:40

Here was a 2nd attempt to cast the green twin base.

This time used petrobond in the cope and drag, with no core, and that worked pretty well.

I was unaware of the correct pour temperatures for metals, and so my melt was too cool (pehaps a little under 1,300 F).

Result: Failure, incomplete mold fill. ( I think the correct term is "cold shut"?).

Lesson learned: Measure your pour temperature, and know what the correct pour temperature is (1,350 F for aluminum).

Also note that there was no reason to use a follower board for this pattern.  That shows just how clueless I was at the time.

Edited By PatJ on 03/07/2022 09:57:48

Another attempt to cast the green twin base.

I was still making rookie mistakes.

This time the melt was too hot, and so the metal degraded the petrobond, and ruined a lot of the surface finish.

Result: Failure, very poor quality surface finish, but complete mold fill.

Another green twin aluminum casting attempt.

Result: This one I consider a partial success, but with some heavy flash, which is most undesirable.

I see some shrinkage in places along the rim too.

Edited By PatJ on 03/07/2022 10:05:30

Having had some limited success with casting 356 aluminum, I decided to set my sights on casting gray iron.

I made my own siphon nozzle burner using a cutting torch tip, with the oil flowing through the center tip hole, and the compressed air flowing through the outer ring of holes.

This burner actually worked very well, but unfortunately I had no idea about what the optimum fuel/combustion air/compressed air levels where, and so I literally just stumbled through this melt with blind luck.

This was my first iron pour, and I used petrobond.

Petrobond can be used sometimes with iron, but it does not stand up to iron temperatures well, and so I did have a few sand inclusions in this casting, which I filled with JBWeld.

Result:

For a first attempt at an iron pour, I considered this a success, with a few defects that could be repaired.

I opened the mold while the iron was still hot (after removing my facemask), and the cloud of smoke burst into flames just as I leaned forward to look at the casting. I saw the flames coming and closed my eyes, and that is the only reason they don't call me Stevie Wonder now. Petrobond smoke is highly flamable; remember that.

The iron machined easily, even though I did not use ferrosilicon, being unaware of it at the time.

I made a pressurized diesel fuel tank from a NEW 40 lb propane tank (don't cut or drill into a used propane tank; it will explode), and this helped stabilize the burner.

I went to the used sporting goods store and purchased several weights to use on the top of the flask.

Crucible was a Morgan Salamander Super B30 (bilge shape).

Iron was Class 40 iron bar stock.

Fuel was diesel with home-made siphon nozzle burner.

Edited By PatJ on 03/07/2022 10:24:45

Edited By PatJ on 03/07/2022 10:25:28

Pat,

The most interesting post I've seen for a long time.

Thankyou

PS Aren't you supposed to pour metal on a dry sand floor??

Thanks Dave-

I get asked that question a lot.

I fear the moisture that would be in the sand more than I fear the concrete exploding.

I have spilled a lot of metal including iron on my driveway, and since it is rather old concrete, it does not explode.

Spilling molten metal on wet sand could definitely explode, and you would only need a slight amount of moisture in the sand.

I know of an iron caster in Australia who has poured iron over concrete for 20 years, with no sand, and he agrees with me that sand is not necessary.

I have seen someone spill aluminum on some relatively new and hard concrete, and it did spald the surface.

I also saw someone use concrete to build a furnace, in lieu of castable refractory, and that furnace did explode violently.

The sand would probably serve more as a protection for the driveway, but my driveway is not so great, so I don't worry about it. And sand gets tracked everywhere, and gets into everything, and so I never use it.

Glad you like the posts. I have learned as more from looking at casting failure photos then from looking at casting successes. With casting failure photos, you can sometimes identify what is causing your problems.

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A buddy of mine in Canada asked me to cast a plaque for his UK canal boat.

I needed foundry experience, so I decided to try and cast it in brass.

I had heard about the zinc fume danger when melting brass, so I wore a powered respirator.

Results:

The results were sub-par in my opinion.  I consider the plaque with the larger letters a marginal success, and the plaque with the small letters not acceptable quality.

Lots of zinc fumes.  This melt sort of cured me of the desire to pour brass.

I build a soft-fire-brick furnace for this small melt, and used propane for fuel.

Edited By PatJ on 03/07/2022 11:26:32

Anybody who reads all the threads and posts on foundry work that have been put on here will be way ahead of where I started from ! Almost all you need to know is contained here, apply it diligently and you will succeed ! Another valid point Dave ! Noel.

Here was another attempt at the boat plaques.

I think this was an open-face pour.

Resut: Total disaster. I forget exactly what happened; perhaps the crucible slipped in my poorly constructed pouring shank.