Recutting an already painted case (how not to damage the paint?)

[kimochii72]

My case needs a larger cut. The problem is I've already had it professionally painted and clear coated with real autopaint. I'm concerned that when I use the 36 TPI jigsaw that it might lift of the autopaint a few millimeters to the side of the line cut. I know that the blue Painters tape is supposed to reduce this paint tearing but are there any more measures I can take to completely prevent it?

[nvidiaOCmaster]

Work around the insufficient cut?

[Deadbot1_1973]

masking tape and prescore the line where the cut is. Take a razor and cut down to the metal(plastic?) under the paint before you cut with the jigsaw. Cross your fingers and pray.

edit...Cut inside of where you want to end up and FILE out to the profile you want?

[kimochii72]

It's basically 3 layers of Sikkens clear coat and Sikkens auto paint. I have rubber trim that will hide up to 3mm of the paint ripping from the cut edge. Do you think the paint ripping will extend further than that from the cut edge? It's basically a recatangle on the top of a CM Stacker that fits an old fan controller and the USB/Power panel. But I have a new fan controller that I want to go there and it needs 3-5mm more on the length and width. Should I use an X-acto blacde or a good quality straight edge razor? Also, I am supposed to completely cover the cut with the blue painters tape (cut right through the tape and case), as opposed to just making the tape's leading edge end where the cut line begins?

[54lariat]

I would mask the whole top of the case overlapping the tape just a little, this will keep the Jigsaw from scratching the rest of the surface. Then I would mark the cut out (pen/pencil) and then like Deadbot said PRESCORE down to the surface. And of course plunge drill a start hole for the saw.
Just dont bind up and be steady, it will be fine.

[RIG RIDER]

I 100% agree with Deadbot and 54lariat about scoring the paint to the metal along the new cut line that you need with a razor blade or blade that YOU can control very well.
Mask the whole top so you can not scratch you new paint job with the jigsaw.
Good luck and take your time.

[54lariat]

Thanx RIG RIDER

[kimochii72]

Which is easier? An exacto or a razor by itself, or a razor in a blade holder, and which type of razor.... the one with the 90 degree angle or the one that has the 45 degree edge. This is a big issue to me because as I remember everytime I've used an exacto to cut a line I could not control the blade well. Never really used a normal blade in a holder to even know. THanks

[54lariat]

Your cut out is square right? So use a straight edge get a nice FISKARS brand metal ruler, flip it upside down so it is smooth and flat on the surface and use it for a guide, I prefer an X-acto with the 45 degree angle, just practice on something first, and remember you still have to cut it out and you do have a seal for it, you will be fine. Just remember to score it deep enough, but not so deep where you cut it out with out the jigsaw...LOL

Good luck, take pics