Build a Cast Tap Handle: Projects

 

In the January–February 2004 issue of BYO we constructed some very nice tap handles built of preformed wooden spindles. A few of you were kind enough to send photos of your improvements on our suggestions. To say those results impressed us would be a massive understatement — Congratulations! Yet there remained the ultimate custom tap handle. You’ve seen those outrageously decorative sculptures of mermaids, geese, pirates and all manner of fanciful testimonials to brewers’ eccentricity. We, as homebrewers could do no less . . . but how?

I’m a car nut and automotive journalist. Viewing a craft show on casting replacement tail lamps for old cars it dawned on me: Casting is casting, molding is molding and what comes out of the mold could be a tap handle as easily as a tail light lens.

Some molding companies sell casting kits for recreating plastic or metal parts. These everything-in-one-box kits include everything one would need to mold and cast at least one tap handle. Plus, the one I used came with an instructional video to teach novices how to construct a mold, pour the silicone molding compound and cast a new part.

The wonderful thing about silicone molding is that once the mold is made, multiple parts can be produced. Thus, if you make a really cool tap handle, you could give it to others as gifts or promote your brew! I decided to call my pal Mark Stucky who is a professional molder by trade. Together we made my first mold and casting, a graphic based on the BYO logo.

While some molders build a molding box from foam-core board and coat it with molding release, Mark convinced me to use an oil-based clay. That’s what you’ll see in the photos. To begin, you need the object to be copied. In other words, you have to create or possess a 3-D model of your desired tap handle. The kit provides a specific type of molding clay (Play-Doh does NOT work) that doesn’t stick to silicone. You must use clay that does not adhere to silicone.

Though your creation will be your own, and you may choose to recreate a favorite miniature sculpture, we’ll show you, step-by-step, how we created our original design.

If you’re copying an existing 3-D object (like an antique tap handle) the process is much simpler. Place the object into a box made of foam-core board, one that is very well taped together. You will create two molds for this object, a left and right or front and back. Orient the object correctly — you can use bits of clay or wire to hold the object — and follow our steps from pouring onwards.

The first step is to purchase the materials for molding and casting. The kit that we used (available from Eastwood Company at www.eastwoodcompany.com) was a good all-in-one starting point. If you can find a similar one, you can use it and then buy other resin (plastic) colors or silicone molding compounds when you have more experience.

Materials in hand, you have to create your tap handle, whether copying an existing 3-dimensional object or designing a new one. Not being the world’s best sculptor, I chose to stick with taking 2-D graphics into the third dimension. I modified the Brew Your Own logo, changing the orientation of the W (of the word Brew) to fit a narrow tap handle form, and drew it on paper.

Step by Step

1. Create your 3-D object in clay, or use an existing object.

2. Roll out molding clay to about half the total thickness you want in a tap handle (approximately 3/8” or 10 mm in our case). Smooth the clay and be sure there are no imperfections — any scratch or nick will show clearly in the finished object.

3. Cut out a tap handle shape, squat, oval or a narrow rectangle — the choice is absolutely yours. When finished, set this back aside for further finishing.

4. Adhere your paper pattern to another sheet of smooth clay. Use a needle or prick punch to transfer letter or other graphic shapes to the clay. Be sure to put a punch at each corner or sharp change of direction.

5. Once you’ve outlined your shapes, remove the pattern and cut out the letters or objects. I used table knives, a scribe, small bits of sheet metal and some dental instruments to cut out the logo. Each tool fits certain curves better than others. Make your cuts uniform, with a similar bevel or perpendicular edge. It looks better when every form is similar — if that’s appropriate.

6. Once the letters are cut, smooth the top and side faces meticulously. Silicone casting is accurate enough to reproduce skin texture, so any flaw — groove, nick or scratch — will be on display in your final casting.

7. Adhere the letters or graphics to the flat form. Press firmly and use a fine tool to blend the bottom of the shapes into the flat. I used a dental tool that resembles a tiny canoe paddle. You could add a slight bevel to the back of the flat and you can improve on it with a sander or file when the casting is complete.

8. This completes the 3-D object that will become your tap handle. Examine it again — absolutely everything that you see will be reproduced. When you’re satisfied that it meets expectations set it aside.

Step by Step: molding kit

1. You need a box into which you will pour silicone molding compound in order to surround the 3-D model. While my instructional video suggested a Foam-Core box, Mark’s experience was in building clay boxes . . . when in Rome.

2. If you make a clay enclosure instead of a box, be absolutely sure the clay sticks to its substrate. Even pinholes will leak silicone.

3. Following directions, mix the silicone. Some kinds have a short “open” time from mixing the silicone with an accelerant, others a long time. Viscosity will affect how easily bubbles migrate to the surface. Once the mold is poured, heating will speed up the cure, but slightly shrink the mold. If you are manufacturing products, mold fidelity is more important than speed. If you’re impatient, you can cure your silicone mold in the oven, following directions of course.

4. When pouring the molding compound, start in one corner and let it flow into every crevice. While instructions suggest painting molding compound onto the surface of your object (very complex molds might benefit), Mark says in his 10 years of experience it has never been necessary. Pour slowly to limit bubbles forming or being included in the mold, particularly near the desired surface.

5. Cure the mold overnight, or longer. The rubber mold can then be pulled off the original and is ready for casting. Be careful when removing the mold, especially where the thickness is minimal. I tore mine at one corner.

6. Another suggestion from Mark is to surround your mold with plaster of Paris to support the edges. This doesn’t make parting the object from the mold impossible, just a bit more challenging.

Step by Step casting

1. Casting resins are catalyzed liquids. Adding part A to part B in correct proportions results in a solid plastic. Different resins have different mix proportions and “open” times when you may pour. Misjudge open time and you’ll have a frozen waterfall of solid resin. Resins also come in different colors including transparent and translucent. Imagine how our BREW tap handle would look if clear and filled with fresh hop flowers!  Fortunately the resin can also be painted quite easily.

2. Before mixing resins you must prepare the attachment ferule and bolt for your tap handle. The bolt attaches the ferule to the tap handle; the ferule mates your tap handle to the tap. Many homebrew stores offer ferules, as do on-line merchants.

3. To attach the ferule to the tap handle I strongly suggest you use an attachment bolt at least 2” (50 mm) long — the longer is better. If you embed this steel rod into your tap handle, opposed to drilling and tapping the cast resin itself, your tap handle will be much stronger. If your design requires post casting bolt insertion, try to insert 2” minimum and secure with epoxy glue. Remember, tap handles normally crack at the base. A long rod welded to the attachment bolt will create an extremely sturdy tap handle, but you wouldn’t want it to show through a clear or translucent tap handle.
Once you have thoroughly mixed and poured your resin according to directions — I’d suggest starting a timer set 30 minutes or less than your open time — set the filled mold on a surface and wait. You may need to add wedges or bits of clay to make sure the mold is perfectly level.

4. It may take an hour or as little as 10 minutes for the resin to cure. The resins contained in my kit set solid in less than three minutes from mixing and generated significant heat. When cured, remove the object from the mold and clean up any imperfections. Smooth the back and evenly round the edges (if it suits your design) and buff out any nasty scratches with 300-600 wet-or-dry sandpaper. You might add texture with a rotary cutting tool or other sharp object. You can now paint and decorate the surface to your liking with epoxy-based paints. Your imagination is the limit!