Optimus Prime Truck Process

Construction of a Semi

Side view of the Optimus Prime upon completion


Before the start of any cake, I research the theme rather extensively.  I gather books, photos, toys, anything I can get my hands on that will help me understand fully what I am creating.  Being a mother of two boys gave me the great advantage of having an endless supply of truck paraphernalia.  When my research portion is completed, the walls of my work space are generally covered.  This is my work space for the Optimus Prime project:


Images of truck from various angles are included from various books and photos gathered during my research phase.

I could not have been more excited when I found the front and side view truck renderings.  Using my printer, I blew up the images to the dimensions that I needed for my cake and cut them out.  These are what I use to constantly check the scaling of each piece of the truck.


Blueprints printed, resized to scale and measurements taken.


After I know the general dimensions of the cake, I can work on the pieces that will have to be  constructed out of gumpaste.  In this case, I knew the side view mirrors, front window frame, grill, bumper, muffler thingy (yeah, I’m most definitely not an authority on what the individual pieces are called), etc. would have to be constructed out of gumpaste and then painted with silver luster dust.  I went ahead and made the rims first since they looked REALLY cool.  I measured the diameter on the rim of the truck on my blueprint to get the size circle cutter I needed and proceeded to cut 6 circles out of white gumpaste and used a round piping tip to create holes around the edges of the rims.  Now, the front two tires of the truck had rims that were convex and the back 4 rims were flat.  To make the two circle convex, I laid them on top of an upside down plastic painting pallet to dry.  The other 4 rims just dried laying flat.  As they were drying, I measured the center portion of the rim and used small round cutters to cut out 6 circles for the inner circle on the rims.  I again used a small piping tip to make the small circles around the edges.  Last, I used another piping top to cut the center circle of the rims.  I assembled them all and let them dry.  The other pieces I made according to the dimensions on my blueprint.  Here are the pieces drying in this photo below.  Just disregard those Lorax tree trunks on the left.  :)



After the pieces dried, I painted them with silver luster dust mixed with some vodka and set them on parchment paper to let dry overnight.


I also completed the wheel wells ahead of time:

I knew that I wanted the truck raised off the cake board so I had to enlist the talents and skills of my wonderful husband.  I gave him dimensions for the board including where I wanted the dowels places under the truck portion of the cake board so they would be hidden by the tires.  He made the board and while he did that, I baked the cakes and whipped up some peanut butter swiss meringue buttercream. Once the board was done, I wrapped it in foil and began to cut and position the cakes on the board.


Here is the board my fantastic husband made for me:


 In hindsight, it should have been more narrow in the front but this worked well enough for what I needed.  I layered cake with buttercream and cut the cake down until I got the dimensions and the basic truck shape.  I crumb coated it and let it chill and harden in the refrigerator.

And here’s the fun part!  I covered the bottom board in black fondant, attached the tires and wheel wells, covered the hood in red fondant and attached the grill and headlight pieces.

Coming along now, isn’t it?!  See?  I told you this was the fun part!  I covered the cab with blue, attached the windshield, muffler thingies and all those other random pieces of metal stuck to the outside (Yep, still don’t know what any of it is called) and made holes to place the rear view mirrors.  See those white poofy things near the bottom of the picture?  I used marshmallows covered in fondant for the air tanks.

Basically after this, it was just adding flames and detail where I thought it needed it.  And there you have it!  Easy peasy!


  1. Looks great!! And, I happen to have a CDL, so I can tell you what those things are. The “muffler thingys” are called stacks. They’re for exhaust. The two “air tanks” on each side are actually called air breathers. They’re to bring air to the engine and they have a filter in them. If you have any other questions, let me know! :)

    • I love how you know all the correct terms for the intricate truck parts. From here on out, I’m totally calling them “air breathers” and “stacks” That should freak my husband out! :)

      • Too funny, Rachel!! I can give you some other “trucker” tips if you’d like. When I met my husband, he was a truck driver. I got tired of missing him all the time, so I quit my job and learned how to drive a truck. We were a team for 2 years, till I got pregnant (I had been told by doctors I couldn’t have children. By the time you’re 39 and childless you figure they are right. Boy, were we shocked!). I needed to do something with a little one at home, so I turned to cake baking.

  2. Joyce Larmore says:

    Wonderfully detailed description! I noticed there were no pictures of your chief critic doing his assessment of your truck making.

  3. How long did it take you to make it?

  4. Amy Munroe says:

    How did your husband construct the support system?

  5. Jocelyn says:

    Could you estimate how much cake was used for this particular design? Thank you so much.

  6. Hi Rachel,
    You did a fantastic job with this cake. What are the dimensions that you used? Also, I am VERY new to fondant/gum paste and am curious how you attached the wheels, and air tanks?

  7. On this cake can you please give measurement on how far apart everything is.thank you.

    • Hi Randi! Thank you for your kind words! The bottom tier was completed in wafer paper and I did some further highlighting with metallic petal dusts.

    • Kristy, sadly, I don’t remember the exact measurements or the number of servings I designed the cake for. My memory clearly needs to improve! :)

  8. gloria knapman says:

    fantastic love it

  9. The cake looks amazing!!! Where did you get the blueprint from??

  10. Hi there,
    Cake looks AMAZING! I just wondered where you got the blueprint from?
    Thanks, Jess

  11. Heddy B says:

    Hi Rachel, Ive plane to make a John Deere truck for my husband birthday end of this month. I can not figure it out how to print the blue prints after I change the dimension I want to. Pls kindly advice me. TIA

    • Hello, Heddy! I apologize for the lack of response till now. My business materials, computer, etc have been in storage for the past 6 months while we moved. I hope that you were able to get your dimensions printed and scaled for your husband’s John Deere cake.

  12. Jolly well done thanks for all the help im doing a green monster truck OMG

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