Goblin Nosecone Mold

Discussion in 'Other Builds' started by Adam, Feb 5, 2016.

  1. Adam

    Adam Administrator Staff Member

    **Note: If you want to see more up to date photos of this project as it progresses, check out Lonny's instagram: lonny.dfkitcar

    As you all probably know, the Goblin is getting a new nose. Unlike the old nose, the new one is two pieces. The rear section of the old nose is staying the same and from now on will be called the hood. The tip of the old nose is now cut off and will be replaced by the nosecone.

    In the future we hope to make the nosecone, hood, side panels, engine cover and fenders via vacuum-forming a plastic called TPO (Thermoform PolyOlefin). From ProductivePlastics.com:

    "TPO is the plastic material of choice for replacing fiberglass parts. This material is more durable, crack resistant, UV resistant, conductive, and lighter when compared to its fiberglass counterpart."

    We want to prototype the new nosecone now, so instead of taking the time to build a vacuum forming machine now, we are just going to layup a fiberglass test piece. To do so, we have to make a mold.

    The wooden buck
    The first step in the mold making process is to build a wooden buck. The buck will be machined, primed and sanded to the exact shape of the final nosecone. The we will layup a fiberglass mold over the buck.

    Making the rough buck
    Instead of starting with a giant block of wood, we sliced the model into 3/4 inch layers and then glued together the rough shape out of particle board and 1x4 planks. Here's a shot of the layers before gluing.


    And then after gluing and clamping it together:


    After letting the glue set overnight, we clamped the piece to the CNC mill table and started machining. The surface matches the model at this point but is very rough. When machined like this, particle board has tons of pits all over it, but we will take care of that later.

  2. Jkean949

    Jkean949 Something witty

    That is looking pretty awesome! Great job guys!
  3. Adam

    Adam Administrator Staff Member

    Thanks John.

    Making the rough buck, continued
    Yesterday while I was figuring out wheel options and doing clerical work, my dad made a lot of progress on the buck. After finishing the top portion of the buck, he moved on to the most elaborate piece, the front/grill section.

    In the photo below, you can see the machine doing the final passes of the front and upper lip. It first did a rough cut which was still visible on the upper lip. After finishing the front and upper lip, the machine cut the flat on the bottom.


    After finishing the front piece we held it up against the top piece to get an idea of how it was going to look. Even after doing CNC work for years, its still neat when pieces look just like the model.


    Next the sides and a floor were cut. Then we clamped, screwed and glued the pieces together and let the glue set overnight. Before starting on filling pits, sanding and priming we grabbed the cut off section of the old nose for a comparison.


    The new nose is considerably shorter and in my opinion looks way cooler. The fiberglass will wrap under the lower lip and go back a few inches before terminating.
  4. rallyracer

    rallyracer Well-Known Member

    Wow, I love the looks of the new nose so far!!!
  5. EcoRich

    EcoRich Member

    It's really nice how you are willing to show production "how-to" on the forum. How many kit companies do that? Practically NONE.

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