Here’s part 2 of my Porsche 356 coupe resin kit build project! When we last left our little Poorsh, we had trimmed the window insert to fit and then test-fit the chassis, checking the wheel base accuracy. After you’ve done your initial test fitting and looked very carefully at everything to make sure nothing is rubbing, the stance is right, and you’re going to be happy with the look of the finished product, the next step is to drill the screw posts. This is a delicate operation that is VERY easy to “screw up” (guess how I know!) The resin is fragile, and its essential to drill in the dead center of the post, and as close as possible at a right angle to the base. If you have a drill press, this would be an excellent use for it. I myself do not, and have to rely on my bad eyes and a level to get it right.
The best drill bit size to use is 1/16”; while you may be able to use a larger one, I don’t recommend it, since it doesn’t take much to split the post and shear the side of it off; if that happens, you’re done right then and there. You also want to make sure not to drill down too deep; the drill bit goes through the resin like butter, and its very easy to poke right through the top of the body if you go too deep! For this reason I set my bit very deep into the drill chuck, although wrapping the bit with a piece of electrical tape to mark it for depth will also work.
If you get away with drilling both posts without breaking them, congratulations! You’re now ready to slowly, carefully, insert your first screws. If you encounter resistance, back them out and go in again, allowing the threads to cut their way through the resin, as forcing the screws in too fast is also a sure-fire way to break your post.
Once you’ve got the screws run all the way down, tighten them to final torque, because there’s one more thing you need to check for.
One thing I commonly find with these kits is that the posts, which are of course added after the mold of the die-cast body on which they are based in taken, are often not completely square in relation to the body. In addition, try as you might to drill those posts at 90°, you probably didn’t get it exactly dead-on. Both of these conditions can result in a fit where the body will lean to one side or the other on the chassis once the screws are tightened. All the wheels may still clear the wheel wells and turn freely, but when you look at your car from the front or the back, it will look like it needs new springs! That’s not a good look, especially for a sports car!
I’ve used 2 ways of dealing with this: one thing you could do is add shims to the posts that you can shape and grind at an angle to compensate for the lean of the chassis. What I prefer to do is use my Dremel tool to “shape” the base of the post, grinding it at an angle opposite the side the body is leaning to in order to straighten it out. In almost all cases, you will have to do this to both the front and the rear posts, although often to varying degrees. This can be a tedious process that naturally has to be done incrementally and carefully, refitting your chassis frequently to make sure you haven’t overdone it. The danger of this method is that, if DO overdo it, you’re now grinding material off the other side of the post to “re-tilt” it, and obviously you can’t do this too many times before you’ve got a new problem. So… be careful!
With patience and care, you’ll eventually have a body mounted on a chassis that has all the right clearances and the right look. The last thing to do as part of this “second step” is to track test the car. If this seems premature, believe me, it isn’t; this is the best way to find out if there are any other problems, such as the car being poorly balanced, “top heavy,” or other performance issues, or if something is rubbing somewhere that you haven’t yet detected. If there are problems, chances are you can do some additional grinding and shaping on the body to work them out, but NOW is the time to find them; you don’t want a surprise on the track after you’ve spent days painting and finishing your car!
If your track test goes well, at this point you can now be confident that the resin kit you’ve chosen is going to be a viable build. You are now ready to take the car back apart and start working on making it look the way you want.
In our next installment, I’ll discuss paint and finishing, and again tell you about all my screw ups so you can avoid them!