Once I had the clean “egg” halves, I used a hot-wire cutter to cut off the wings. This ended up being kind of a disaster* - the wire was too short and not hot enough to cut through 12"+ of foam. My plan was to gracefully guide the wire across a form in front and behind the egg, but in reality I ended up sawing the wire back and forth for an hour. The wire also bowed back significantly as I pressed it into the foam, so when I got to the area with a sharp corner, I had to pull it tight and hope that it would melt its way into that area. Another problem was that many of my foam slices were only stuck to one another near the MDF core, so when I cut them away they just fell apart.

After I glued the broken wing parts back together, I cut off the leg notch areas very easily with a Japanese pull saw. The “scrap” from the leg notch is actually re-used to create the Turret's kneecaps. You need to cut each scrap piece in half, glue 2 together to create the back kneecap, and then also fill in the concave areas with more foam.



Now that all the parts were created in foam, all I had to do was fiberglass over them. Foolishly, I decided to cheap-out on fiberglass and re-use my scraps for the in-between reinforcing layers. This lead to a really lumpy and bubble-filled surface that took FOREVER to fix. I'm sure I spent at least half of my time fussing over the surface imperfections and voids in the fiberglass. If I had just used larger pieces and been more careful when laying them down, things would have gone much smoother. (Pun!)

This method for applying fiberglass is a little different than how you would do it in a female mold. With a mold, the neatness of the layers is less important because the outer surface of your finished piece is pressed up against the mold and the back side will show any changes in thickness or lumps. Typically a mold is treated with an anti-stick coating, then the fiberglass is laid in, making sure that everything is thoroughly 'wetted' with epoxy poured and applied with disposable paint brushes. Then the fiberglass is covered in 'peel & ply,' a cotton batting like 'breather' layer, and sealed inside a bag that is loose enough to not tear as it is drawn into all the nooks & crannies of the mold by a vacuum compressor. This is a good method for two reasons: first, it presses the fiberglass into all the details of the mold; second, the peel & ply will help draw out extra epoxy, leading to a lighter & stronger part. When fiberglassing over a positive core you can't vacuum bag without distorting the parts and it's very hard to keep the layers pressed down.

I was only able to fiberglass about 2 major surfaces a night simply because I didn't have enough room to store all the parts as they cured, so doing all the parts took a long time. I started with the main body halves and the outside of the wings. I needed to wait until the main body was cured and somewhat smooth before I could shape the inside of the wings where they would need to sit flush with the surface.

On the outside of the wings is a small slit, which I believe is intended by the game designers to be used as a carrying handle. Before I glassed the outside of the wings, I carved a small trench and made sure to cut pleated holes in the fiberglass so it could fold into the trench. I also took a few strips of foam core poster board wrapped in saran warp and jammed them in the slit to help shape the edges of the hole as the epoxy cured. This turned out better than I expected even though I had to pick out scraps of plastic that got folded over and trapped in the glue.

On the sides of the main body, there are two large square recesses where the mechanical guts & wires of the Turret would be exposed when the wings are extended. To create this feature I cut through the fiberglass and foam and punched out that section before slicing off 3/4" from the backside and then glued it back in place. The sharp edge that this created turned into a nightmare of bubbled fiberglass that I kept breaking through as I did the finish sanding. I think it would have been better to line the edges with stops of plastic or pre-cured fiberglass and then just strengthen the corner areas.

Another major piece of the Portal Turret were the gun-pods. I glued up foam and carved it to match the profile of the front and back frames I made from thin strips of craft wood. I then spread a couple whole sheets of fiberglass over this and trimmed it along the wooden edge. These relatively simple boxes were easy to create, but I probably didn't need to use fiberglass and foam - I should have used the same wooden frames, but then covered the in-between area with a sheet of bent styrene or sheetmetal.

The foam kneecap parts were in pretty rough shape due to the extreme stair-stepping in that area of the original form and the fact that they are made from several tiny pieces of foam. I covered the main faces with fiberglass and waited until the wooden legs and metal tubes were attached before finishing off the rest.



* Assuming that cutting off the wing areas would be simple was the first of several tasks that were more difficult that I had originally planned because I was thinking about doing things in the real world like they were a CAD program. Making an extrude cut or cut with a surface in SolidWorks is just a couple of mouse clicks, but in the real world you have to worry about the blade thickness, flexing, not cutting perfectly straight, etc. Cutting the pockets in the sides of the main body was another situation where I assumed I could cut through something, push it aside by an inch and then re-glue it. Now I'm positive there are better ways.