What do u guys use?
Cut your Door (the metal) for example to put a large speaker in a small hole
Cut your Door Pannel (plastic) for example remove factory speaker grill so that i can use the momo ones, so in other words, make a perfect 6.5" cut, this what i would like to do the most :)
Cut your Door Pannel (plastic) for a flush mount
When making your MDF spacers, do u guys do it yourself or will homedepot do it for u if u give them the exact specs u want them?
Homedepot can only make straight cuts (that I know of). I use an airsaw for the door metal. If you want a perfect circle in plastic, you need to rough cut the hole with a saw (airsaw, jigsaw, utility knife) and attach an MDF template to the door (as best as you can without screwing it into the door panel) and use a router.
When you cut the plastic, tape the door up with masking tape and make your mark on that. Also it will protect the rest of the door from being scratched by the saw.
I am an old guy and whenever possible I use metal shears or tin snips to cut metal. Most of todays cars use very thin metal and the tin snips work quite well. If there is double steal, where metal overlaps, I use an air saw or a jig saw. To make a perfect cut you have to have a jig or a perfect circle device of some sort. If you have a flat door panel then you can do what ELOPLAYSPOLO suggested with the router. Better to have the router mounted and move the panel. If it is not flat then its going to be very difficult and take a steady hand. You can buy MDF rings from some web sites. To make your own and make them right you going need a plunge router and a circle jig. If the MDF rings are not going to be used for custom fabrication and you just need a spacer then use a jig saw and be sure paint it to protect it from the elements. A dremel tool is good for cuting plastics. It has many attatchments that provide you with many options. If you need a perfectly smooth cut that will be seen then you can use sand paper to smooth out the cut marks.
For plastic door panels, I've had good luck drilling multiple holes inside the circumferance of the area to be removed (to perforate the panel), then using a cutting bit in my Dremel to open things up.
I smooth around the inside of the hole with a Dremel grinding bit up to the outside diameter- the ground plastic beads up and after it's cooled you can snap it of with your fingers, leaving a clean cut line...emphasis on "after it's cooled" (ouch). Sandpaper cleans things up further for a nice edge.
To add to the sandpaper use , when the sanded edge will be seen . On plastics other than those white in color the sanded areas often show up as white scratches , solution - just heat them slightly with a heat gun and watch them disappear . You could also use a small torch but be very careful to not move to slowly and melt the plastic . Works well on plexiglass also .
Cordless dremel tool is very handy and would do the job. Metal shears would be difficult to use on installed metal because of wierd angles