Installing upgrade parts?

[jowman]

What is the best way to cut out plastic from model kits for installing upgrade kits or parts (without mangling the kit).

[BProbst]

What is the best way to cut out plastic from model kits for installing upgrade kits or parts (without mangling the kit).

Well, there's no single best way, because sometimes you need to use different techniques for different types of parts (and depending what it is you want to cut out, and where it is on the part -- it's easier to cut off something on the edge of a part than it is to cut it out from the middle).

If you don't already have them, you need to get yourself a sharp hobby knife (with plenty of fresh blades available) and a razor saw. For the latter, I heartily recommend the JLC Razor Saw (see a review here).

For relatively thin parts, a knife should be sufficient. Probably the most important thing to remember is that you don't need to make the whole cut in a single pass! Take it slow and easy. Several shallow cuts are better than a single deep cut. Trying to rush it can result in you cutting where you didn't want to cut, broken blades, missing pieces and perhaps a great deal of blood. When the plastic is thick, use the razor saw. Don't "saw" back-and-forth like you're cutting a log, the plastic will probably flex and ruin the cut -- draw the saw in a single direction and then lift it up before making another pass.

A metal ruler will be handy for when you are cutting straight lines. For curved lines, you may find some sort of thick tape (e.g., Dymo label tape) useful, to give the knife a "guide". Otherwise, a steady hand and make multiple small cuts!

Another useful tool is a micro-chisel. I use one from Mission Models. It's not essential and it's a bit pricey, but if you have one it makes a lot of tasks easier.

To remove whole sections from the middle of a part, use a finger-drill and make small holes at the corners of the section you want to remove. Then cut between the holes. Drill as many holes as you need to "perforate" the section.

Finally you should make sure that you have some fine-grade sandpaper (or similar) to clean up the parts after you have cut them.

I think that covers the basics, any specific questions?

[Tankmodeler]

To add to that, it is also not a given that you do or do not assemble the kit parts before cutting them. I've found that it's usually better to do the cutting before any assembling, but sometimes it works better to assemble and then cut, expecially if you need to make an even cut across a major joint.

Paul

[Richard Baker]

When cutting a hole or removing a section go smaller than the final desired result. It is easier to chop a smaller hole then slowly widen it the final size with scraping, sanding or filing than to cut it the exact size then have to fill gaps if anything turns out rough or not perfect.

[Mr. Badwrench]

You can also cut odd curves with cotton thread. I've seen auto modelers saw the doors off cars with thread. It takes some time, but it is a really neat trick.

[ajmadison]

When cutting a hole or removing a section go smaller than the final desired result. It is easier to chop a smaller hole then slowly widen it the final size with scraping, sanding or filing than to cut it the exact size then have to fill gaps if anything turns out rough or not perfect.

Also, use a trick the woodworking guys use. Where possible, put the resin replacement up against the model and as closely as possible and use a marker to draw around the resin. If the marker will potentially stain the part, you can use pencil, and in some ways a sharp pencil will make a better line, but pencil has the bad habit of rubbing off. As you make your initially cuts, only go up to the edge of the line. Then refine the hole with sandpaper to get a perfect fit.