Tee Box Marker Match Plate – Model Hand Pump

Discussion in 'Pattern making' started by Al2O3, Jul 26, 2021.

  1. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I posted this originally at AA in 2017. Just thought I’d reconstitute it here.

    The local golf club was built on an old family farm in 1924. There were a number of wells and the club adopted the well pumps as its logo. The original pumps were also manufactured by a local company. One of the members has an outdoor ornamental lighting business with an aluminum foundry and powder coating line. I offered to make a multicavity pattern to suit his production equipment if he’d cast and powder coat model pump tee box markers. There are five sets of tees (pairs of markers) for eighteen holes so that’s 180 pieces. Plus figure some shrinkage through theft and breakage. They also intend to offer them for sale as souvenir at the pro-shop. First run probably ~250 pcs. Based upon their preferred flask size of 20” x 14”, I proposed a four-cavity mold. I’m happy to cast a few but not 250!

    They sent me a black & white photo copy of the pump profile which I enlarged and printed to scale. The first model I made was 5” tall. After looking it over the golf club board of directors decided they wanted something closer to 8” tall. Though it made for a little more material it also made it and better casting that was easier to clean up and do the finish work.

    The lower pump post is about 11/16” diameter. The bulge is about 1 ¼” diameter. The smallest diameter under the handle is 3/8”. I usually make patterns like this split but since the diameters were fairly small, I elected to turn it as one piece and make a follower board to pull silicone molds from the master pattern so I could pop proofs and reproduce them on a multicavity tool. To make the master true and concentric, I used a piece of 3/8” steel tube and epoxied three pieces of urethane modeling board (two around the slender body and a disc for the base) onto the tube. This made it easy to mount and dismount between a chuck and live center on the wood lathe for turning and sanding. I also incorporated the 3/8 tube as the smallest diameter feature in the pump body pattern which made it a sturdier piece to turn.

    1 Turn Pump.JPG

    I cut the handle out of the same modeling board on a band saw and used a small spindle sander and some hand work to shape the profile. For draft, I just took the blade from a utility knife and hand scraped about 5 degrees of draft either side of center around the entire perimeter. Afterward, a couple minutes of sanding finished it up. I simplified and modified several of the pump features to make them mold easily, help miminize flash and finish work, and still be consistent with the logo profile. For the spout, since I was already going to make a follower board, I was just going to flare and bend a piece of ½” copper tube but the radius was too tight so I made a small router template and used a ¼” radius bearing guided round over bit of my overarm router for each half and this worked well. I chucked a small disc of modeling board on a nail and turned the chamfer and some radial draft for the flare at the end of the spout.

    2 Spout.JPG 3 Spout Handle Pump.JPG

    After some detail work, primer, and polishing, here is the completed master.

    4 Finished Master.JPG

    Here is a crude follower. I initially routed it out to fit the main body and base, and then traced the rest of the features and some hand guided work on the over arm router. It was close enough that I could close the gaps with wax and a 1/16” radius fillet tool.

    5 Follower.JPG

    To conserve on silicone, I traced an enlarged silhouette of the pattern and freehanded the mold frames in the overarm router with a dovetail bit to retain the silicone. I match drilled registration holes in the follower and each mold frame and then cast the silicone around each side of the master. Here are the completed molds of the master pattern.

    6 Silicone Master Molds.JPG

    I then laid these out on a board set up for a 14x20 flask. I just used the registration holes as the drill template for aligning the mold on each side of the board and then screwed the molds to the match plate. After casting the four copies, I plugged the registration and screw holes.

    7 Reproducing Cavities.jpg

    There was some debate about how to layout and gate the match plate. I thought it would run without issue and probably didn’t even need a riser before the pump base, at least for shrinkage, but the extra head provided by the riser couldn’t hurt. The debate was over pour temp to avoid shrink at the bulge yet still have enough fluidity to flow and fill the handle when gated in the base. Since it was already made, I suggested the molder just use the master pattern and follower to hand mold a couple test pieces. That settled the debate.

    I added a few alignment buttons, pouring well, runners, gates, a couple vents, a riser, and a couple generous coats of KinKote, and she was ready for the foundry.

    8 Drag.JPG 9 Cope.JPG

    The castings also get a ¼” diameter mounting spike added to place the tee marker on the ground.

    I placed the master pattern in the silicone molds for safe keeping. The Tin catalyzed Silicone is fairly high durometer and has very long library life, especially with the master stored inside.

    I made a box to store the pattern.

    10 Pattern Case.JPG

    ….the first production samples.

    11 First Castings.jpg

    Fore on the Tee!

    12 On the Tee.JPG

    Best,
    Kelly
     
  2. Petee716

    Petee716 Gold Banner Member

    Whew! I thought you were doing it again!
     
  3. That was a great project! Very nice to copy it here.
     
  4. Chazza

    Chazza Silver

    Nice work Kelly and very interesting for someone who has never used this technique.

    After you made the silicone moulds, what material did you use to make the 8 patterns?

    Cheers Charlie
     
  5. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    It's Repro casting resin. That is a Freeman Manufacturing product but it is just a two-part urethane casting resin you can get it with different cure times. I use between 15-60 minute gel time depending upon the project.

    Best,
    Kelly
     
    Chazza likes this.

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