Well Pump Trophy

Seems like I always have a half dozen or more projects going at he same time. My golf club was founded in 1924 and resides on an old family farm. The water wells were still present, and the Club adopted the pumps as its logo. I made a 4-on pattern for Tee box markers here.

http://www.alloyavenue.com/vb/showt...ourse-Tee-Box-Marker&highlight=tee+box+marker

I was asked if I could make trophies for this year’s club championship. They are 18” tall versions of one of the pumps. They only wanted four. I made six patterns hoping to net them all but no less than four. It’s purely ornamental but with a little effort, could have been made functional…..or a garden ornament that flowed water. It seemed like a fun project…..an ornament but really just a scaled down machine so I took it on.

Here’s one of the real pumps. The base, spout and tube were cast as one piece on the original. I decided that was a little risky, so I opted to break down into pieces as shown.



The rest of this post is my attempt to make what turns out to be about 1/3 scale models.

I added a new set of tooling to my foam machining arsenal. These are woodworking plug cutters and wow, do they work great. 3/8” through 1” diameter by 1/8” increments and can cut 2”+ deep plugs. Here are the cutters and the marshmallows they cut, pictured as machined with no finishing. I hotwire or razor blade them to length. They make bosses and small round rods in seconds. You can see I put them to good use on these foam patterns.



I started with the spout. I’m getting quite a library of different diameter guide discs for my overarm router so I used several that I already had and added a couple new ones to the collection. There are nine separate pieces in this pattern. It’s a lot of piece work but went fairly fast. The round embossments are for a ball marker that I will glue on and use as an emblem. I was going to try to make a wax of the marker and cast it into the piece but the detail was so fine I thought it a bit risky, so will just glue them on.



Next, I made the handles. They will likely present the most challenge to pour.



Then the handle mounts.



Next up were the bases. They were made with a mash up of existing guide discs and router bits but I knew it would be easy so I saved it for near the end.



Last were the knuckles. I used my new plug cutter to make these…… very simple parts.



......and

 

So with all that, here’s what a set of patterns looks like.



Here’s what the whole sha-bang looks like.



……and what a trophy might look like. The post is just 1” aluminum conduit I fished out of the scrap bin at work.



So the pattern work is done……time to sprue and prep them for casting.



Coated with drywall mud



….you know what comes next fellas.

Best,
Kelly

 

They are going to be really cool when done.

 

Here are the results of round one. These were the 2-on trees; I still have 4-on of all parts left to pour. Everything poured fine except the handle……it poured short.




Here are the castings de-gated and cleaned up.




Here’s the short pour of the handle.



Certainly not surprised. It has a small gate, a very small contact area with the gate, and is a long thin part with the web only about 3/16” thick……sort of like a fluidity test in progress. The portion that filled sure looks nice LoL. I already have that 4-on tree for the handles prepped and gated the same way. I’m going to have to throw more heat and vacuum at it…..and maybe some high silicon piston alloy.

Best,
Kelly

 

Sunday, I got out to the shop in the early morning to have another go at the handle. I decided I would just try it with a high silicon alloy, some additional head pressure, and no vacuum so I trimmed the diameter of some Sonna-Tube to extend my flask height, made a tall aluminum sheet metal sprue, and prepped the mold as shown below.



Then disaster struck. I had just done a final skim and the melt was at temperature and ready to pour. As I was rolling the flask out into position, a pebble lodged under the wheel and over the top-heavy bugger went. It broke the foam pattern into pieces otherwise it could have just been repacked.



I guarantee the words coming out of my mouth were never any my mother taught me. I had to pour the melt off into ingots and after cleaning up the aftermath, still mumbling a few choice words, I marched straight to my over arm router and made six more handle patterns. I finished, sprued, and mudded two of them. I fattened the main web on the handle up from 3/16” to ¼” thick, increased the contact area, and redesigned the gate.



So tonight I rigged it up just the same as the mold I dumped with the new 2-on pattern and poured some piston alloy I believe to be about 12% silicon. It poured short too….maybe a little worse but certainly no better. These were all poured at 1575F-1600F. Rats!



I changed the gate for round three as shown below and will use vacuum assist. Gonna get it somehow.



Best,
Kelly

 

Should have mentioned the evening wasn’t a total loss. I did cast the 4-on handle mount while I had heat in the furnace. Batting 1000 on the rest of the pieces so far…..that handle is a different matter.



Best,
Kelly

 

Double bummer!!
Lil voice in my head says you might need to lay them down flat and gate in the middle.. But that voice says a lot of things...

 

...was thinking the same thing and... maybe multiple gate contacts too. If vacuum doesn't get it that is next. Back when I was doing my molten metal travel tests I was getting 12-13" of travel length at these pour temps in my makeshift-behind-glass-fluidity-tests with no vacuum. -We'll see.

Best,
K

 

It's not that I'm not a fan, just not currently set up to do it but agree with you. Still some challenge to fill the mold even in GS.

Best,
Kelly

 

It all looks amazing, other than those darn handles... Looking forward forward to seeing how you'll solve that one.

Jeff

 

I think I've had an epiphany. It's not what I have prepped and queued up for vacuum pour, but since it is ready, I'll give that a go too for grins before I switch from guns to missiles.

Best,
Kelly

 

First is A356. Second is cast automotive piston. Both poured at 1575F-1600F. The A356 shrinks more than the piston alloy (probably higher melt point) because I can pull the kush cup off with my hand on the A356 and had to beat the piston alloy out.

There is really no way to vent a lost foam casting other than through the surface of the mold where the foam pattern has already been evaporated. Beyond that, the rest of the mold is full of closed cell pattern (or molten or frozen metal), so if there is still foam between the molten metal front and the intended vent, the vent is not a vent.

While pouring in lost foam, the pattern actually exists in three states; solid liquid, vapor. When things are working properly, the metal doesn't touch the foam because the radiant heat of the front has already evaporated the foam prior to contact and that vapor sits with advancing molten metal on one side, and on the other side, liquid then solid foam.

Vacuum assist pulls the vapor layer into the mold media faster and creates higher differential pressure in the feed system, both of which speed the flow of metal and extend the distance the metal can travel for a given pour temperature before it freezes.

In lost foam you're probably more limited to what can be filled compared to GS because the two phase changes of the foam take heat from the melt. I say probably because you have no binder in the sand in lost foam, and especially no water which also produces gas (steam), so it is much less thermally conductive than green sand but you have to get the gas out in either case. The byproducts of expended Polystyrene are not soluble in aluminum. H2 dissociated from water vapor is soluble in aluminum.

The only place that must/can/should lose gas during a lost foam pour is where the metal and foam are meeting, so there is not a lot of area to pull it from at any point in time.

On this part, the way it is gated, the cross section where vapor exists is so small it just cant vent fast enough so the metal sits there insulated by the vapor layer and freezes (this lead me to my epiphany). Net affect is same as your GS observation and comment.

Best,
Kelly

 

Had a go with vacuum pulling 7” Hg. Still poured short.....but close.



In the words of Maxwell Smart, “Missed it by that much”.



I did successfully pour the 4-on spouts and knuckles. Besides the handle I just have the four bases left to pour.



Here’s round four for the handle. It’s personal now. Generous gate and ¼” contact the length of the part. It will require a little additional effort to de-gate and clean it up but at this point I need a win. It will need to be packed well to avoid any destabilized sand leakers under the rib of the handle.




Best,
Kelly

 

Got home after a short business trip mid afternoon today and couldn’t wait to get at it. Charged the crucible, fired up the furnace and proceeded to mold up round four of the handle and the rest of the pieces.



I poured and…….Success!



I proceeded to degate. Made a few relief cuts and the cut down the 1/4” section of the gate.



Then ground off what was left on the top drum of my 6"x48" belt sander, fine tuned it on the spindle sander, and colored it up with a soft stainless wire wheel. Came out nice.




Here’s the family photo.



So now with the recipe in hand, I’ll cast up the remaining handle patterns and start assembly…..havin’ some fun now.


Best,
Kelly

 

Whoot Whoot! Happy dance time