Ball Hopper Monitor - Casting Project

You have lost me Pat, one post you won't use spray on filler primer as you are working indoors. Next you want to spray things thinned with Alcohol.

Gypsum based products like the drywall filler need water to get the setting action as when they are made the water is removed and it is the hydration when it is added again that will cause it to set

Pattern halves used to make the permanent aluminum patterns will look like this.
Gate/runner system is in the drag, and the pattern is in the cope.
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Jasonb said:

You have lost me Pat, one post you won't use spray on filler primer as you are working indoors. Next you want to spray things thinned with Alcohol.

Gypsum based products like the drywall filler need water to get the setting action as when they are made the water is removed and it is the hydration when it is added again that will cause it to set

Click to expand...

Yep, I just found that out.
No water, no set.
Well I had to try it.
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Edit:
As I recall, when I mixed shellac with wall patch, it became about like Durham's filler, ie: very hard.

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The runner/gate system for the full casting is similar to the one used for the half casting.
Gate/runner system is in the drag, and pattern half is also in the drag.

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My apologies for the high Jack, but I thought my post might be relevant.


We are currently working on patterns for a 1920’s Petter ‘ Apple top ‘ , a model that my old friend Vincent had been making, very secretly in his backyard foundry and workshop.
We managed to save it and the patterns just before his sister sent everything to the local tip, after his passing.

We have printed the two halves as seen in the attached picture and are currently drawing up the core box. A special pattern is being made, out of house to produce the lettering.

Welcome to the Ball Hopper/Apple Top thread.
These engines have such a distinct look to them, and I recall admiring them as a teenager when I first saw them at an engine show in Iowa.
The are so rare that I don't think I have seen another one since at a show.

That is a great little Petter engine.
I have always admired that brand.
It is interesting to compare the designs.
The Petter appears to have the head built into the water hopper ?

Looks like it is going to turn out very nicely.
Keep us posted on your progress.
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Lets talk about filler hardness.

Durham's Water Putty:



Durham's putty is as advertised, which is "Hard as a Rock".
Durhams is so hard that it is very difficult to sand it down without damaging what is around and under it.

DAP spackling compound is very good filler material, but it dries out in the container before I get a chance to use it more than one or two times.

The material I use now is Fastpatch 30, also a DAP product, and comes in powder form, and is mixed on demand.

On an unscientific hardness scale of 1-10, Durham's is a 10 in hardness, and not really of much use as far as I am concerned with filling patterns.
Durhams is so hard and inflexible that it can expand and contract at a different rate than what it is applied to, and can chip/flake off.
Durhams is like concrete; once it sets, you are pretty much done with it.


DAP Spackling Compound:



DAP spackling compound is about a 2 on the hardness scale, and so very easy to sand, and easy to level with a soft surface without gouging into the surface. I coat the sanded spackling compound surface with shellac to give it some surface hardness.
The downside is that the shelf life in the container is way too short.
It must be used in perhaps a week after purchasing it.

The Fastpach 30 wall filler is very good material.
It is easy to mix, sets quickly, and is nice to work with.
The downside is it is a little on the hard side, and more like a hardness of 6.
It is not excessively hard, but is about twice as hard as it needs to be.
I filled the inside of my hopper pattern halves with a rough coat of Fastpatch, just to make it easy to pull these patterns from the sand.
In some places the filler is 1/4" thick, and this requires a surprising amount of work to sand out flat, even when using a coarse 2" sanding disk in the variable speed drill.
Fastpatch is very tough material, and it feels a bit more flexible than spackling compound.
Fastpatch will take a lot more abuse than spackling compond after it hardens, but I will still coat it with shellac.
Sanding Fastpatch takes 2-3 times longer than sanding spackling compound.

All of these products are waterbased, and I use these products because I can use them inside without annoying fumes.

Bondo:

I have used Bondo, and the fumes are bad.
Bondo is too hard for my preference, and I consider it about a 7 on the hardness scale.
Bondo is somewhat flexible, which can make it a bit odd to sand if it flexes under the sanding tool.
Bondo costs a lot more than wallpatch material, and it tends to get on everything, permanently.
The cleanup with waterbased fillers is very easy.

Skim Coat:




Automotive skim coat is like thin bondo, and I have tried two types of this material.
I was not pleased with the skim coat.
It sands like bondo, which is it has a bit of a rubbery feel to it, and no doubt make to be a bit flexible for auto body use.
On a hardness scale, I would say skimcoat is about like bondo, and a 6-7 on the hardness scale.

Wall Patch:



So far the Fastpatch 30 is working pretty well manually applied as a thick putty on the inside of the pattern halves.
I will use it on the outside of the coreboxes also, to basically insure that these items can be pulled from the sand when molding for permanent aluminum patterns.
The interior of the pattern halves, and the exterior of the coreboxes does not have to be perfect, and so a coarse 2" disk in the variable speed drill works pretty well in leveling out these items.

For the exterior of the pattern halves, and the interior of the coreboxes, I am going to try spraying on Fastpatch 30 in a thinned form.
I only need a very thin coating, but the key is that the coating has to be very even, so that when I sand, I don't gouge through the filler and expose the plastic lines below.


PLA Filament (3D printer filament):

PLA plastic is quite hard, and I would rate it perhaps 9 on the hardness scale.
PLA cannot easily be power sanded, since it tends to melt and streak, instead of getting cut cleanly.
PLA is not easily hand sanded, but it can be done.
PLA can be buffed somewhat smooth with a 2" fine sanding sponge operating at a very low rpm, with is good for an initial smoothing of the surface and edges.
I prefer patterns made from wood, but the advantages of 3D printed patterns make PLA the pattern material of choice for me these days.
PLA has little or no odor while 3D printing, and that is a real bonus for me, since some of the filament material I tried years ago had very noxious fumes.



Once the filling work is complete, I can start thinking about casting permanent aluminum pattern halves and corebox halves.
The gate/runner prints are ready for use.
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This is the interior of the pattern halves rough filled with wall patch.
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This is the interior of the pattern halves after some sanding work.
A bit more sanding and filling will be required.
The interior of these prints just needs to be smooth enough to be able to easily pull the pattern half out of the mold.
The interior will not be a cast surface on the final casting.

The Fastpatch 30 is tough material, sort of like bondo, and requires a coarse sanding disk in the angle drill.

I ground off the bosses, since they will be defined by the core/corebox, not by the inside of these patterns.
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The cleanup of the interior coreboxes has begun, and I am using the fine sanding sponge for this work.
These will need a light coat of filler, since this will be a finished interior surface on the final casting.
I will try the airbrush on most of this surface.
I need to fill behind the bosses in the direction of pull, and use some draft angle on this material.
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The window was a real challenge to model in Solidworks.
After the 3rd redesign, I finally found a shape that was close enough to be manually corrected after printing.

I don't like cutting this deep into the wall of a 3D print, because you get into the infill area, but I think this will turn out ok in the end.
The problem is that there is not quite enough draft angle on a few of the window walls.
I will go find my Dremel with the long bit, and clean this up.
PLA likes to melt instead of cut, and so you have to move the tool pretty fast if you need to take off a lot of material.

The base shape of the window is good, but the walls need a bit more draft angle.
An analogous amount of filler will be added to the interior walls of the window inside the corebox, so that we don't have a section of wall that is too thin.

The interior of the pattern halves has been filled, and this is basically complete, except for some light sanding.
I sanded off the bosses to give an easy pull from the sand.

The exterior of the coreboxes is also basically complete, and ready for final sanding.
I filled in the window on the corebox half that had a window, since it is not needed on the exterior of the corebox.

Now I just have to wait for the airbrush, and see if that is going to work for applying a thin coat of filler to the exterior of the pattern halves, and the interior of the coreboxes.
Not much I can do until I get the airbrush at this point.

These pieces will be cast as permanent patterns and coreboxes in 356 aluminum.
I could be ready to cast these pieces very shortly.
I may use my small furnace and propane burner, since I can carry that furnace outside, and the propane burner is very simple.





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In the past, I have used my small semi-temporary furnace to melt aluminum for permanent patterns.
It is made from vertical hard firebricks, and used a kiln shelf as a lid.
It is a crude affair, but works well for its intended purpose, which is quick one-off aluminum melts.
This furnace is somewhat slow to heat due to the density and low insulating value of the walls.




I built a mini-iron furnace a few years ago, and it will have a thin high density hot face in it when completed.
It is made from 2,500 F insulating fire brick.
I think I will use it to melt the aluminum for these pattern halves and coreboxes, since it will heat up much faster due to the insulating value of the lightweight bricks.
It is designed to melt iron in a #5 crucible, but I think I can squeeze a #10 in there since I don't have the hot face installed yet.
The exact fit of the crucible and the clearance around it are not critical when melting aluminum, and I can use a kiln shelf for the lid.



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I am going out to the shed to do reconnaissance for wood to be used for the flasks for these pattern halves, and to see if I can locate the mini-furnace.
Last time I was out there, a racoon had gotten in through a rotted space in the floor, and he walked down the shelfs that run down the left wall, pushing everything off the shelf, ate his way into my corncob sandblasting material, chewed up an entire roll of paper towels, and then crossed over to the shelving on the other side, and pushed about half of those boxes off onto the floor.
It was like some sort of messy frat house post-party scene, with stuff scattered everywhere.
If they make a movie about this, the title will be "Racoons Gone Wild !" (in my shed).

I saw this critter go waddling down my driveway, and he is a chunky cheese for sure, probably pushing 40 lbs.
Probably got fat eating my corn cob material.
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I found some 15"x15" flasks.
I can tack on some temporary wood to make these work, and add some filler blocks inside.
No sense creating new flasks when I can make these work.

I found the mini-furnace.
I think it will work with a #10 crucible, assuming I don't use a plinth.

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I seen you had planned to split your pattern as you have. But I was looking at my 6 hp today, it appears to me the parting line is on the low side of the ring.
It is very clear, with no vertical line.
I plan to turn my ball pattern on a lathe. I like the 3D, if one could do it in a way that the inside is as the outside, one could use it as a split pattern, standing on end and ram a green sand core.
I have done this, one opens up the mold and removes half the pattern then just turns the mold over, then opens the mold again, and removes the other pattern half.
I also planned a cheek mold where I would use a tall sprue and pour from the bottom.
I like bottom pouring and do not like pouring iron as a ball, as you plan.
So far, besides the drawings, all I have made is a flywheel.

Someone posted a couple of Baker catalogs on fb, and the vertical engines are listed as 2,4, and 7 hp, and the horizontal engines are listed as 3, 5 and 8 hp.
This is a 1924 catalog.
I am not sure about the hp differences, but I noticed that the horizontal seems to have a hemi-style head, with valves at an angle, so perhaps better flow and more horsepower for the same bore size.





I also see in one of the fb photos that the recess for the valve on the 7 hp engine is flat across the top, horizontally, and that would seem to lend itself to a horizontal parting line at the bead.
The 7 hp window is pretty much just a rectangular shape, whereas the 4 hp window shape is quite a bit more complex, especially when you start adding in draft angles.
(not my photo)



And on the 7 hp, there is an opening in the side of the cylinder near the top for intake (intake passage), and there is another opening below that.
What is the lower opening for ?
It is as if they are allowing cooling water to contact the side of the valve chamber, to cool it.
I only see one intake passage on the 2 and 4 hp vertical units.

There are so few remaining Baker Ballhopper Monitors, and so few photos of these engines disassembled, that it is difficult to figure out all the nuances of every part.
A fellow named Barney Kedrowski (on ytube and fb) has provided me with photos and measurements of his 4 hp, which is how I have been able to get as close as I have with my 3D model.
The factory brochures are also helpful, and thanks to the individual who found and posted those on fb (I forget the name at the moment).

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Since the Fastpatch is a dry powder - have you ever tried adding a filler to it, such as talc or maybe even cornstarch, to see if that makes it easier to sand?

Fidlstyks said:

I seen you had planned to split your pattern as you have. But I was looking at my 6 hp today, it appears to me the parting line is on the low side of the ring.
I plan to turn my ball pattern on a lathe. I like the 3D, if one could do it in a way that the inside is as the outside, one could use it as a split pattern, standing on end and ram a green sand core.
I have done this, one up opens the mold and removes half the pattern then just turns the mold over then opening the mold again, and removes the other pattern half.
I also planned a cheek mold where I would use a tall sprue and pour from the bottom.
So far, besides the drawings, all I have made is a flywheel.

Click to expand...

So I think you are correct that your engine has a horizontal parting line.
I think a horizontal parting line would be easier to mold, especially with a simplified recess in the side.

I have studied the Soule Speedy Twin steam engine a lot, and it appears that all Speedy Twins were made from the same patterns.

The Dake engine design changed noticeably over time, and the later designs have been simplified from the original.

The Cretors line of popcorn engines seem to have been made from the same pattern set, but there are some oddities.
The Cretors No.06 all seem to have identical flywheels and other castings.
The Cretors No.01 all seem to have identical flywheels, with some variations in bases, gear drive, etc.

The Cretors No.02 was produces in two styles of flywheels, with one style having spokes that are more curved than the other.
Why did Cretors use two flywheel patterns on the No.02 ?
Did they lose the original No.02 pattern ?
Cretors patterns were made from bronze, and so they did not wear out, and the original Cretors patterns that Bob Pearson has look perfect after all their use.

The Frisco Standard engines are all very similar, but not identical.
There are some design differences, such as the length of the water jacket on the cylinder, and a few other items.

So it would make sense that they would change the molding for the Baker 7 hp water hopper, since there were many other design differences between the 2 and 4 hp, and the 7 hp anyway.
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ddmckee54 said:

Since the Fastpatch is a dry powder - have you ever tried adding a filler to it, such as talc or maybe even cornstarch, to see if that makes it easier to sand?

Click to expand...

That is a good idea.
I have seen people add things to the core material, such as flour, to assist in it breaking down after the casting work is complete.
It would have to be very fine material.
I will have to see if I can requisition some of my wife's corn starch.
She probably won't know I took it; I will do a late-night kitchen raid, if the dogs don't start barking and alert her to what is going on.
She is a bit touchy about her kitchen stuff, expecially after I used her oven to temper some aluminum castings.


And she was not happy about me requisitioning her Hobart mixer either, and I eventually had to purchase her a new one.
My wife really does not like me going near the kitchen.
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Edit:
As it is, the Fastpatch is at least three times as hard as the spackling compound, and so the sanding is much more difficult than it should be, and it is much harder to get a completely flat surface when you have hard high and low spots.

Given the amount of surface filling work I have to do on this engine, an easier filler would same a lot of time and effort.
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Well, before you try the moonlight requisition.....

The next time she goes to the store ask her to get a box of cornstarch. Tell her you need some for an experiment, which ain't a fib. Tell her she can have the new stuff and you'll take the old stuff, also not a fib. Happy wife => happy life.