Scratch Building Tutorial

This is the piece I will be building during this tutorial. It has five components; Styrene base, 2 styrene rings, rectangular greeblie, and drill holes.

For this particular piece, the first thing I did was figure out how thick I needed my styrene sheet to be. I did this by holding different thicknesses of styrene up to my master pattern, and seeind which one was closest. Simple technique, but it works. As it turned out, the master piece was about .05" thick. I didn't have any stock that thick, but I did have .03" and .02". I used plastruct cement to glue these two stock sheets together. That's what you see in the first picture. I use plastruct cement because it's very thin, and is easy to apply. It doesn't leave any globs like "testors" cement would. Stay away from that stuff. Once I glue the two pieces together, I press them together using the table and the palm of my hand. Then I leave them to dry for about 15 minutes. Ok, so now that I've got my styrene stock all set, it's time to move on.

One of the interesting things about the piece I am building here is that the two pieces that are seen on the master are not identical. Yes, they are mirrors of each other, but there are many differences between the two. One is longer, one is wider, the curve along the top is different on both, and the placement of the greeblies is different. I hope to eliminate these differences between the two, because I am building an idealization of the original, not an exact replica.
I chose to use the piece on the drivers side of the car for the length and width of the piece, while using the piece on the passenger side of the car for the shape of the arch on the top.
I started by measuring the width of the original piece I am attempting to build.

With that measurement, I mark off on my .05" piece of styrene some cutting guides. I use my micrometer to measure off the marking points on the styrene. I really value uniformity and precision, so I always try to use a clean edge that was cut by the manufacturer as a leading edge. In this case, you can see that the edge on the left hand side of the photo is perfectly straight. I measure the distance from there, confident that I have a solid baseline from which to make my measurements. I typically use a pencil to mark off where i want to cut, and mark three or four points along the path. This helps me line up my ruler for cutting.

Now it's time to cut the styrene. Notice that I'm going to cut a big long strip of the stuff at the desired width. This will allow me to not only cut out the two pieces I need to complete the model, but will also leave me some extra stock, in case I screw one piece up and need some extra.
I use a metal straight edge as my cutting guide. I carefully line up the ruler along the marks I made in the previous step. Before cutting, I confirm the placement of the ruler by using my micrometer to measure the distance from the rulers edge to the factory cut edge of the styrene. This ensures that my cut will be as accurate as possible.
One technique for cutting styrene is the "Score and bend" method. Basically, you make a light cut in the styrene (not going all the way through) and then bend the styrene along that cut to break it off. It's a property of styrene that allows it to break in a reasonably smooth way. However, this technique does have its drawbacks. The main one is that you lose a lot of control over the way the styrene breaks. For example, the styrene may curve away under your cut, making the cut line not perfectly perpendicular to your top surface. I recommend this technique for larger parts, or for rough cuts that you plan on sanding down.
Because of the precision involved with the making of these pieces, I'm going to skip this technique, and simply cut straight through the styrene. However, I'm going to use numerous small cuts, rather than try to do it in one deep cut.
Here's the way it works. When you have the ruler laid down on top of your styrene, there's nothing holding it in place other than gravity and the pressure of your hand. When you press down hard on the ruler, you run the risk of moving it out of position, and screwing up your cut. So what I do is I press down lightly on the ruler, and do a very gentle cut with my x-acto or box knife. Because I'm cutting gently, I dont' run the risk of accidentally repositioning the ruler, and therefore ruining my cut. After that first cut, I'll do another gentle cut, but this time with a tad more pressure. Once the blade has cut a trough in the styrene, the heavier, deeper cuts are less problematic, as the blade is less likely to wander.

This step could probably be skipped, but because I'm such a perfectionist, I went the extra mile on this piece.
Once I cut the strip from my stock, I measured the ends of it to see how accurate my cut was. In this case, one end was a TINY bit fatter than the other end. I fixed this by placing my piece down on a piece of sand paper, and gently pushing it across it. Notice the position of my grip on the piece. I am grabbing it towards the end that needs to be thinned down, and leading with that end. In this photo, I was dragging the piece from left to right. This way, the fat end is the end that gets most of the pressure, and thus most of the drag. I dragged it across the sand paper once, then measured again. It was perfect!

Now I have a strip of the correct width stock, so it's time to cut it into the proper height pieces. I begin by measuring off the desired height using my micrometer.

I mark off the correct length on my styrene strip and use a critical tool to do the cut, a T-Square. This tool allows you to make perfect 90 degree cuts. It does this by laying the long side of your piece along an affixed arm, with the ruler running at a right angle to it. This is another good reason to use the "factor cut edge" as your guide. This allows you to take full advantage of the benefits offered by a t-square. Without the perfectly straight edge, your piece would wiggle around in the t-square.
Anyhow, I marked off the cut using my micrometer, and loaded the styrene into my t-square. As before, I confirm the distance by putting my micromter against the rulers edge and the edge of my styrene to ensure proper placement.
I also employ the "multiple shallow cuts" method to get a nice clean, perpendicular cut on this piece. I repeat this process twice to get my two pieces of styrene.

I now have two styrene rectangles that are just about the right size.

This is a little trick I picked up a while back. Because I want my two pieces to be IDENTICAL, I'm going to do the final shaping of the two pieces simultaneously. This will ensure that the are as close as possible. To do this, I'm going to glue the two pieces together using a tiny dab of plastruct cement. I glue the two pieces together back to back. This way, when it's time to cut the two halves apart, any residue or distortion created by the cement will be hidden after the pieces are installed.
Once glued together, I gently run the newly formed piece over some sand paper to ensure that the edges all line up perfectly.

As mentioned earlier, I prefer the arch found on the passenger side piece, so I pull out my master and sketch the arch onto my styrene block. This will act as a guide for sanding and filing.

I did a bunch of sanding using my sketch as a guide, and realized that I had gotten it wrong. Fortunately, not too late! I ended up placing my styrene piece on top of my master pattern and simply filing away material one stroke at a time. It was fairly time consuming, but I ended up with great results. The arch now matches the passenger side greeblie exactly.
My next step before separating the two halves is to drill holes into the styrene. I drew some guild lines using my straight edge to indicate where I want the holes to end up.

I cut a few disks off a piece of plastruct rod, and sanded them down until they were even. I glued these on using plastruct cement.

To finish, I used my chopper and some strip styrene to cut out the little rectangles that sit flat on the sides. I glued them on, and now it's all done.

	For this particular piece, the first thing I did was figure out how thick I needed my styrene sheet to be. I did this by holding different thicknesses of styrene up to my master pattern, and seeind which one was closest. Simple technique, but it works. As it turned out, the master piece was about .05" thick. I didn't have any stock that thick, but I did have .03" and .02". I used plastruct cement to glue these two stock sheets together. That's what you see in the first picture. I use plastruct cement because it's very thin, and is easy to apply. It doesn't leave any globs like "testors" cement would. Stay away from that stuff. Once I glue the two pieces together, I press them together using the table and the palm of my hand. Then I leave them to dry for about 15 minutes. Ok, so now that I've got my styrene stock all set, it's time to move on.
	One of the interesting things about the piece I am building here is that the two pieces that are seen on the master are not identical. Yes, they are mirrors of each other, but there are many differences between the two. One is longer, one is wider, the curve along the top is different on both, and the placement of the greeblies is different. I hope to eliminate these differences between the two, because I am building an idealization of the original, not an exact replica. I chose to use the piece on the drivers side of the car for the length and width of the piece, while using the piece on the passenger side of the car for the shape of the arch on the top. I started by measuring the width of the original piece I am attempting to build.
	With that measurement, I mark off on my .05" piece of styrene some cutting guides. I use my micrometer to measure off the marking points on the styrene. I really value uniformity and precision, so I always try to use a clean edge that was cut by the manufacturer as a leading edge. In this case, you can see that the edge on the left hand side of the photo is perfectly straight. I measure the distance from there, confident that I have a solid baseline from which to make my measurements. I typically use a pencil to mark off where i want to cut, and mark three or four points along the path. This helps me line up my ruler for cutting.
	Now it's time to cut the styrene. Notice that I'm going to cut a big long strip of the stuff at the desired width. This will allow me to not only cut out the two pieces I need to complete the model, but will also leave me some extra stock, in case I screw one piece up and need some extra. I use a metal straight edge as my cutting guide. I carefully line up the ruler along the marks I made in the previous step. Before cutting, I confirm the placement of the ruler by using my micrometer to measure the distance from the rulers edge to the factory cut edge of the styrene. This ensures that my cut will be as accurate as possible. One technique for cutting styrene is the "Score and bend" method. Basically, you make a light cut in the styrene (not going all the way through) and then bend the styrene along that cut to break it off. It's a property of styrene that allows it to break in a reasonably smooth way. However, this technique does have its drawbacks. The main one is that you lose a lot of control over the way the styrene breaks. For example, the styrene may curve away under your cut, making the cut line not perfectly perpendicular to your top surface. I recommend this technique for larger parts, or for rough cuts that you plan on sanding down. Because of the precision involved with the making of these pieces, I'm going to skip this technique, and simply cut straight through the styrene. However, I'm going to use numerous small cuts, rather than try to do it in one deep cut. Here's the way it works. When you have the ruler laid down on top of your styrene, there's nothing holding it in place other than gravity and the pressure of your hand. When you press down hard on the ruler, you run the risk of moving it out of position, and screwing up your cut. So what I do is I press down lightly on the ruler, and do a very gentle cut with my x-acto or box knife. Because I'm cutting gently, I dont' run the risk of accidentally repositioning the ruler, and therefore ruining my cut. After that first cut, I'll do another gentle cut, but this time with a tad more pressure. Once the blade has cut a trough in the styrene, the heavier, deeper cuts are less problematic, as the blade is less likely to wander.
	This step could probably be skipped, but because I'm such a perfectionist, I went the extra mile on this piece. Once I cut the strip from my stock, I measured the ends of it to see how accurate my cut was. In this case, one end was a TINY bit fatter than the other end. I fixed this by placing my piece down on a piece of sand paper, and gently pushing it across it. Notice the position of my grip on the piece. I am grabbing it towards the end that needs to be thinned down, and leading with that end. In this photo, I was dragging the piece from left to right. This way, the fat end is the end that gets most of the pressure, and thus most of the drag. I dragged it across the sand paper once, then measured again. It was perfect!
	Now I have a strip of the correct width stock, so it's time to cut it into the proper height pieces. I begin by measuring off the desired height using my micrometer.
	I mark off the correct length on my styrene strip and use a critical tool to do the cut, a T-Square. This tool allows you to make perfect 90 degree cuts. It does this by laying the long side of your piece along an affixed arm, with the ruler running at a right angle to it. This is another good reason to use the "factor cut edge" as your guide. This allows you to take full advantage of the benefits offered by a t-square. Without the perfectly straight edge, your piece would wiggle around in the t-square. Anyhow, I marked off the cut using my micrometer, and loaded the styrene into my t-square. As before, I confirm the distance by putting my micromter against the rulers edge and the edge of my styrene to ensure proper placement. I also employ the "multiple shallow cuts" method to get a nice clean, perpendicular cut on this piece. I repeat this process twice to get my two pieces of styrene.
	I now have two styrene rectangles that are just about the right size.
	This is a little trick I picked up a while back. Because I want my two pieces to be IDENTICAL, I'm going to do the final shaping of the two pieces simultaneously. This will ensure that the are as close as possible. To do this, I'm going to glue the two pieces together using a tiny dab of plastruct cement. I glue the two pieces together back to back. This way, when it's time to cut the two halves apart, any residue or distortion created by the cement will be hidden after the pieces are installed. Once glued together, I gently run the newly formed piece over some sand paper to ensure that the edges all line up perfectly.
	As mentioned earlier, I prefer the arch found on the passenger side piece, so I pull out my master and sketch the arch onto my styrene block. This will act as a guide for sanding and filing.
	I did a bunch of sanding using my sketch as a guide, and realized that I had gotten it wrong. Fortunately, not too late! I ended up placing my styrene piece on top of my master pattern and simply filing away material one stroke at a time. It was fairly time consuming, but I ended up with great results. The arch now matches the passenger side greeblie exactly. My next step before separating the two halves is to drill holes into the styrene. I drew some guild lines using my straight edge to indicate where I want the holes to end up.
	I cut a few disks off a piece of plastruct rod, and sanded them down until they were even. I glued these on using plastruct cement.
	To finish, I used my chopper and some strip styrene to cut out the little rectangles that sit flat on the sides. I glued them on, and now it's all done.