Making Plaques

The Making of a Vespa Plaque

(or what to do with your left-over pastel colored spray paint)

After discovering that my brother Eric had put a Vespa link on my site, I decided I had better make some Vespa stuff. Here's how I made a Vespa plaque from cradle to grave:

After learning about the need for Vespa articles, I decided to make a plaque. I took an image and traced it onto a piece of plexiglass with carbon paper. I set the scroll saw table at about two degrees and started cutting.

Once I finished cutting out the logo, I began working on the frame. Because there are straight lines on the frame, I needed to slow down my reflexes by having a few beers and turning on a good Mozart string quartet on my Hi-Fi. I honestly believe that most naturally occurring things are chaotic because it was easier for God to make weird curves and angles rather than straight lines. I'll cut out weird lettering all day long, but straight lines, that's hard!

I found a piece of scrap plexiglass of a contrasting color for the back of the plaque.

I glued the frame (which I had only cut the inside of) to the backing plate.

I then set my bandsaw blade to about one degree which is less than the two degrees I had set the blade for cutting out the lettering. Angling the blade is very important when making patterns to avoid your pattern tearing the sand as you withdraw the pattern from your mold—unless, that is, your hands are steadier than mine. But I play banjo, so your hands probably are steadier than mine.

I then cut around the frame through both laminated sheets of plexiglass.

After I finished cutting, I glued the back of the logo, centered it, and put it within the frame.

After pulling the paper coating off the plastic, I mixed up some plastic resin. Not fiberglass resin because fiberglass resin is too thick and sets up quickly. Casting resin works very well. Not having a small brush, I took my toothpick and ran a fillet of resin around the perimeter of all the cut surfaces. This smooths out the saw cut and provides a nice fillet. If you do this, don't stick the toothpick back in your mouth. After overnight curing, everything needs to be wet sanded with 220 grit paper. I listen to music like Phillip Glass' Fog of War while doing monotonous work. Listen to samples:

Sample 1 .....Sample 2 .....Sample 3

After everything is smoothed out from the sanding, I placed the pattern on the mold board, put the Cope (top flask) on the board and dusted it with a layer of plumbago. Most any dry dust will work. Some people use Talc. Just make sure it isn't silica dust. You can get rid of a headache due to beer and plastic resin fumes, but you can't get rid of Silicosis.

I then ran about a 1 inch layer of sand through the riddle (sieve) over the patterns. This breaks up any lumps and provides uniform sand density close to the pattern.

I rammed sand into the mold in two inch layers.

I struck off the top of the sand level with the top of the cope.

I then rolled over the mold, put the drag on (bottom flask), put the sprue base in and dusted the bottom of the patterns. The dust keeps the top and bottom of the mold from sticking to one another and also acts as a release for the pattern.

I rammed sand into the mold similar to the first half.

I struck it off similar to the other side.

I then rolled the mold over and opened it. Note, it is not always necessary to roll over the mold the 2nd time. But in this case, I get a better pattern draw when lifting the Cope off pattern rather than the pattern out of the mold. I can use the guide pins to steady my draw whereas lifting a pattern out of the sand, especially one with lettering is a very delicate matter. Note that my sprue base has built in gates in it. This is a real time saver.

I then twisted a hollow tube thru the sand to cut the sprue and cut the gates in. It is a better idea to have the molten material go though some turns. This reduces washout and helps trap loose sand. In this case, the melt goes from the sprue base, into the gates attached to the sprue base, then to the gates in the cope leading to the mold cavity.

I smoothed the outside of the sprue with a sprue spinner. This helps keep loose sand to a minimum.

I then charged the crucible with some scrap aluminum and fired it up).

After about 25 minutes, it was at about 1400 degrees and I poured off the molds. Unless you know how to degas, you should not pour aluminum any hotter than 1400 degrees. Most parts are done at about 1350° F. But in this case, I needed a hot melt as plaques are thin castings and cool quickly. I didn't want to have the melt solidify before everything was filled. And I was not too concerned with gas porosity in these plaques. At this time I had about 1 hr 45 minutes into molding and pouring. I had to meet my friend Bruce at the bar so I left.

After I got back from the bar, I shook the casting out.

And deburred them with a 60 grit wheel.

I needed to select an appropriate color for the plaques. I had Ford Engine Block Blue left over from my working on my Ford and Lilac left over from my Super Glide. Sometimes smoke and resin fumes influence your color choices and when you're out of seafoam green, you're out of seafoam green. I just go with the flow.

I hope this has been helpful to people wishing to make their own Vespa regalia.