The Stovebolt Topper

Created by Rick "Whizzerick" Bacon
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          Welcome to this Stovebolt Special Feature. I've prepared these pages after getting many requests for an overview of the processes used for creating these tasty morsels...

           This has been a hobby of mine for two or three years and EVERYTHING in the foundry was HAND-MADE from information gathered through literature and the web ... from the sand formulation to the very effective sand muller. ~~ Whizzerick

           Let me add that SAFETY is a priority in our foundry. From eye protection to ventilation, every step is important.      

Casting the Stovebolt Topper

Every image is "clickable" to get a bigger view. Enjoy this pictorial, Bolters ...

The Artwork The Master Pattern Making Secondary Patterns - A Making Secondary Patterns - B
Every good piece starts with a good design. From the start, decisions are made based on castability, meaning draft, angles, detail sharpness, etc. Two negatives are outputed, each will serve in creating a 1/8 photoetched layer of the pattern.

We find that 99% of the art of the foundry is in the pattern.

A master cast is assembled, tweaked, sanded and polished. In this case, a rubber mold is pulled to create secondary patterns for multiple items per pour, for ease in production.

This is necessary ONLY for a 'high' volume job such as this one.

Catalyzed resin is poured in the rubber mold. It can be unmolded in 10 minutes. Shore hardness is 90. Secondary patterns are virtual clones of the master pattern. They will be tweaked, painted and polished. These patterns are highly detailed (with final sanding at 2000 grit) which will result in almost perfect aluminum parts with minimal flashing.
Preparing the Matchplate Patterns on Board Making the "cope and drag" Set Pattern Ready for Ramming

Patterns on furniture grade Russian plywood. A 5/16 thick "runner" is glued.

The runner feed the gates (they will be carved after ramming).

The finished pattern, after numerous coats of lacquer, wet sanding up to 1000 grit, polishing and waxing.

It is virtually IMPOSSIBLE for the sand to adhere to this surface, making unmolding that much easier.

A box is fabricated out of ash, for strength and to ensure trueness. Locating dowels and "lifting handles" are added.

In the foreground is my home-made, cast aluminum rammer.

Drag side: parting dust is applied to the pattern.
A Most Important Machine The Muller Head The Muller Drive Mechanism Sand Distribution

I'm very proud to show you this piece of equipment: my home-built muller. The muller is VERY important. The oil based sand NEEDS a "mulling" action to become chemically reactive.

We used to do it by hand, with a kitchen beater! No more.

Everything was fabricated from scratch. The wheels are regulation 25 lbs bench-press weights with snowmobile bearings adapted.

The lifting mechanism is made from a Honda car jack.

A 1/2 hp motor and $15 gear reducer from eBay. The muller head turns at a PERFECT 30 rpm.

I added this little trap to distribute batches of freshly mulled sand. The very fine sand becomes sticky and the details obtainable are incredible.

Ready for some more action? ... Read on!

           Meet "The Rammer" -- Before a job, I like to polish and wax the tip of the ramming tool so it won't stick to the sand. Ridling fine sand over the pattern ensures fine detail on the finished surface. Sand is 140 mesh synthetic olivine. Next step is to ram the sand in the drag. The sand is incredibly compact. It takes a LOT of energy from this 38 year old fella. The cope section -- the cope side has been rammed on a flat board. This is the back of the toppers. A sprue is cut (middle) and two vents.

          The mold is clamped (metal pressure is high) and the mold rests on the pouring bench. Sand will safely catch any running metal.

Meet Lil' Bertha, The furnace

           This furnace is home-built from scratch, with sheet metal and refractory cement. It is propane fired and can reach 2200 degrees Fahrenheit. The furnace blower: a hairdryer (not needed anymore -- I'm almost bald) and 1/4 inch propane line.

           The Aluminum alloy scrap is ready for recycling. Aluminum alloy NEVER loses it's initial properties.

           Introducing: Wheelium! Wheels are primary source of quality 356 Aluminum alloy. These are NEW, mismatched display wheels bought from a bankrupt autoparts store. The wheels are then transformed in ingots by melting and pouring it into steel muffin pans (Thanks, Mom ). Gathering up the scrap ... reclaimed Aluminum from previous jobs. These are Whizzer's sheave centering fixtures.

          HOT HOT HOT! Here is the red-hot crucible with five pounds of molten aluminum at +/- 1350 degrees. The melt is de-gassed and fluxed prior to pouring.

On to the pour!

We are ready The Pour The Sand The View

The molten Aluminum is ready. A stainless steel asparagus cooker makes a great crucible.

The pour will take approximately 450 grams of 356 Aluminum Alloy. The pour is fast and steady. Molten metal can be seen exiting the vent. A good sign. Mold is filled. Excess is poured in muffin tin.

The sand is a home-made recipe. Traditionally mixed with 3% water and Bentonite, this "green" sand is oil-based and uses Bentone 38, a derivative of Bentonite.

Here the mold sits outside. The sun is coming down on Sunday night. In the distance are maple trees. Some of the best maple syrup comes from around here. This is 20 minutes from the Eastern Townships. Here is the south view from the shop.

And the harvest


           Opening the mold reveals a smoking-hot batch of perfect Stovebolt toppers. Here is how they look when we pull them out of the mold. In this close-up, you can see how the runner is connected to the toppers. And here they are all nicely stacked and ready for finishing and painting.So, do you know which one is yours?

           The photo above right is actually a preliminary piece cast from the MASTER pattern, not the secondaries. The piece was bead blasted, the upper letters where polished and the raised portion of the mid section was polished. Two colors where applied, in keeping with a 1950's theme, a maroon and black combo was chosen. Other DARK colors are available for the text portion (the 6 is always black!). Guys, pictures DO NOT do it justice.

           Man, Rick has talent galore!! And yes, the picture looks great but the actual topper is incredible!

           Last year, Rick offered to make up a limited batch of these Toppers to help raise funds for our much needed Stovebolt second (backup) server in Texas. These toppers went like hot cakes and after covering his costs, Rick was able to send over $300 to Stovebolt. He included in this generous gesture a topper for each of our volunteer staffers. HQ got a mounted topper which hangs proudly in the living room! It IS impressive and we know people are chomping at the bit to see Rick open his shop again and start another batch. But don't rush the man. He needs a break (and probably some help). Stick around and you'll see when he's ready to fire up again. Thanks to Rick and all of you for this show of support! ~~ Editor

July 2007

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