best tool for cutting fenders?
 

greetings,

So I'm ready to cut the gaps behind fender vents in order to make them functional. Got my replacement grills ready.
I've searched around and seen reports of some tools burning or crazing the paint near the cuts.

Those of you who have cut the fenders, what tool works best, with least chance of damage?
Dremel?
Die Grinder?
Recip. saw?
Any advice on cutting disc type or blade type?


I will be cutting the fenders on the car, and I'd rather not screw it up.

thx...

canyons.

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"Oversteer is where the back of the car hits the wall first; understeer is where the front of the car hits the wall first."

scissors :popcorn:

I would stay away from the saw since one catch of a tooth and the fender is toast. Any of the spinning discs should do the job. Just take it slow and easy, do small sections at a time and stop to let the heat dissipate frequently and you should not have any issue. I personally would go the Dremel route with a heavy cutting disk.

And breath !!!

I used a pneumatic cutting wheel on one side and decided to use tin snips on the other just to see how they worked. The tin snips worked remarkably well when used in the proper direction(at some angles it is impossible to snip in the correct direction). The cutting wheel was superior tho. Just make sure you are prepared for the sparks to fly!

I would NOT use any sort of cutting disc / jigsaw / dremel just to easy to make a mistake .

I used a compact Nibbler which attaches to a drill ( I used a cordless 18v ) and it worked a treat with no chance of cutting into anything behind the fender plus no heat/sparks or chance of slipping .

I'm using a Dremel, and it works fine. Just be sure to take your time and work slowly. And don't try to cut the tight corners, just make a rough cut and grind them down.

Fender vents completed
 

This the process and end result.

The functional vents started out as new oem vents which I cut out, painted and backed with black wire mesh.

The fender cuts were done with a CBN wheel on a dremel (link here). This wheel works fine as long as you go slowly and guard against the dremel's chuck touching the bodywork.

I used two layers of tape holding a plastic ruler along the bottom of the vents. If you do this, try to keep intact the receptacle for the rear-most press clip; it helps align the new piece.


After cutting the fenders, I put two coats of flat black on the edges of the cuts to minimize potential rust. I also blacked out the inner body panel just behind the vent, which was still showing a lot of primer ( see 2nd photo.)

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FYI The 'supercharged' sticker is from ebay. I wanted some subtle bling.

Very nice. Great job!

That has to be the cleanest set of functional vents that I have seen so far.

Awesome job Canyon!

Looks amazing. How did you remove the center fakegrill plastic piece?

I bought two extra OEM trim pieces to work on. The black trim bit pops off. The center opening was a time consuming task of drilling and dremellng to leave the center spar in place. I filled the back of the center spar ( it's normally hollow) with a cut down chunk of plastic and lots of body filler. It's now solid. The mesh screws to it as well as being stuck at the edges with 3M trim adhesive.

Rear surface painted black. Then several coats of priming, sanding and more primer on the outward facing surfaces. Then final paint and clear coat.

Lots of work but it turned out great. I spread out the prep over a few weekends.

Can you confirm that your hood no longer "lifts" at high speeds because of these vents?
Also, is there a noticeable increase in wind noise or any whistling from the added air flow around the side mirrors?

I have not seen hood lift at freeway speeds. Definitely no more wind noise. A bit more engine noise now.

This area of the fender is a fairly neutral pressure area ( see other posts on this topic) meaning it does vent heat once positive air pressure builds in the engine bay.

I am thinking there is enough room to fit a small 12V blower fan above the battery as well to provide ~30CFM of active airflow even when stopped. Haven't determined yet whether same is actually necessary....