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-   -   Cutting A Hole Through The Paint? (http://www.hotrodders.com/forum/cutting-hole-through-paint-214001.html)

StreetKruzer 02-04-2012 09:55 PM

Cutting A Hole Through The Paint?
 
I'm changing over the fuel cell that was in my 33 Ply for an aluminum tank with vent, sender, etc, and want to put in an outside fill. What is the best way to cut the hole without messing the paint. Do I just tape it up and have at it with the hole saw? I have the location pretty much figured out and it is flat and the stainless fill has an outside flange so the fill spout part should not be too difficult. Bob

jjack010 02-04-2012 10:23 PM

I would lay down some masking tape in the area to be cut. Place the hole saw on top of the area to be cut. Trace the outside with a pencil. Keep the hole saw in place. Use a good exacto knife to "cut" along the outside of the hole saw. Be careful not to stray away from the circle and damage paint. Do this several times in an attempt to make a destinct line, paint that stays, paint that goes. Happy hunting......

stich626 02-04-2012 10:31 PM

yup tape it up and go nuts.. then add some paint to the cut to stop any rust..

HVAC Phil 02-05-2012 03:23 AM

Just a thought, maybe start cutting with the holesaw in reverse first, it won't walk as bad pulling the metal. Once a "groove" is cut in reverse, switch to forward, should make a clean cut. I do this all the time when cutting vents in on alum sided houses.

shine 02-05-2012 05:05 AM

forget the tape. wont stop a hole saw or anything else from going through but most likely will pull up paint when removed. if you get the paint hot it will loose adhesion.
drill your pilot hole then change the drill bit to a piece of rod the same size. the drill bit will wallow out the hole and let the saw walk. first turn the saw backwards slowly to cut the paint. then cut the hole very slow to keep the heat down. heat is the thing to avoid. good luck .

StreetKruzer 02-05-2012 07:00 AM

Quote:

Originally Posted by shine
forget the tape. wont stop a hole saw or anything else from going through but most likely will pull up paint when removed. if you get the paint hot it will loose adhesion.
drill your pilot hole then change the drill bit to a piece of rod the same size. the drill bit will wallow out the hole and let the saw walk. first turn the saw backwards slowly to cut the paint. then cut the hole very slow to keep the heat down. heat is the thing to avoid. good luck .

Thanks to all. Shine, looks like that is how we'll do it. Never thought that the tape might be the bad guy! :thumbup:

shine 02-05-2012 07:03 AM

just remember the heat. hole saws cut better at a slow speed. when metal heats it tempers itself and gets harder. go slow and monitor the temp . i'd rather take all day to cut a hole than repaint a fender . :(

stich626 02-05-2012 08:49 AM

heat.. ya I guess if you are use'n a dead hole saw..
a sharp hole saw will not heat the metal anymore than the summer sun does..
I'd still use painters tape and if you're worried about heat.. light stream of water from a hose.. if heat lifted paint, we'd be repainting every fall..
it's sheet metal not 1/8" plate he's cutting.. as long as the saw isn't dull..it never build enough heat.. nowa dull saw.. well.. :spank:

shine 02-05-2012 08:57 AM

i'll stick to what i know .

MARTINSR 02-05-2012 09:47 AM

Quote:

Originally Posted by shine
forget the tape. wont stop a hole saw or anything else from going through but most likely will pull up paint when removed. if you get the paint hot it will loose adhesion.
drill your pilot hole then change the drill bit to a piece of rod the same size. the drill bit will wallow out the hole and let the saw walk. first turn the saw backwards slowly to cut the paint. then cut the hole very slow to keep the heat down. heat is the thing to avoid. good luck .

Absolutely brilliant Shine! As soon as I started reading this I am thinking NOOOOOO on the tape. Then thinking, drill a pilot hole! LOL Your idea on replacing the drill with a piece of rod was worth coming to my computer and reading this stuff, that will be written on the inside of my hole saw box, that is a good one!

Brian

MARTINSR 02-05-2012 10:00 AM

And of course another tip would be to have a new or at least very sharp hole saw. If it's old it's going to "rub" on the panel and heat it up instead of cutting thru.

I am one to cut small too, cut small and using a quality burr cutter (rotary file) to slowly open up the hole to size. You can do this very slowly (with a GOOD cutting burr cutter)

http://web.tradekorea.com/upload_fil...4fbe895773.jpg

And I mean picking the right one, in your case the largest cylindrical one like the sixth one from the left in the photo. I picked up a selection of these twenty years ago that were very high quality, I think I spent $20 each one them. Outside of a few that I have lost ( :mad: double :mad: :mad: ) they are still in top not working condition. Buying the best REALLY pays off.

But anyway, having a good selection lets you chose the RIGHT one for the job .

I am thinking Shines tip on removing the drill bit and replacing it with a piece of rod may take care of this somewhat. But a how saw will walk a little, it often will open the hole just a bit larger than the hole saw size. Just a tad understand, but there are times that "tad" may kick your ars.

The other day at work one of the guys (he should have known better) used the exact size hole saw on a plastic bumper to put the holes for back up sensors. The correct saw but the hole had to be EXACTLY right for the funky plastic sensor bracket to clip into, with it's little tiny clips, it needed to be very precise. Well, the hole saw opened the hole just a tad too much, wham, the sensor wouldn't say in!

The moral of the story is if you are cutting a hole exactly the size you need run a test and see if it is in deed going to work for you. If not, go to the one smaller and open the hole up to perfection with a rotary file.

And of course the one thing you have to be careful of is when using the rotary file to open that hole, don't come out of the hole and ruin the surrounding paint!

Brian

MARTINSR 02-05-2012 10:03 AM

Oh and on your idea Shine, I am thinking of getting a short piece of 1/4" drill stock today and putting it in the hole saw box so I don't get tempted to do without because I can't quickly find some when I am ready to drill a hole. :welcome:

Brian

shine 02-05-2012 10:19 AM

i have no bits in my hole saw drawer . just a few rods with flats filed on them. also use the rods when working on wood. makes for a much truer hole.
and the heat is worse than the saw walking. takes very little drilling to create enough to loose adhesion around the edge. any tape will pull up paint .

MARTINSR 02-05-2012 10:21 AM

Quote:

Originally Posted by shine
i have no bits in my hole saw drawer . just a few rods with flats filed on them. also use the rods when working on wood. makes for a much truer hole.
and the heat is worse than the saw walking. takes very little drilling to create enough to loose adhesion around the edge. any tape will pull up paint .

Very good tip! I will be doing the same. :thumbup:

Brian

Old Fool 02-05-2012 05:39 PM

Quote:

Originally Posted by MARTINSR
And of course another tip would be to have a new or at least very sharp hole saw. If it's old it's going to "rub" on the panel and heat it up instead of cutting thru.

I am one to cut small too, cut small and using a quality burr cutter (rotary file) to slowly open up the hole to size. You can do this very slowly (with a GOOD cutting burr cutter)

http://web.tradekorea.com/upload_fil...4fbe895773.jpg

And I mean picking the right one, in your case the largest cylindrical one like the sixth one from the left in the photo. I picked up a selection of these twenty years ago that were very high quality, I think I spent $20 each one them. Outside of a few that I have lost ( :mad: double :mad: :mad: ) they are still in top not working condition. Buying the best REALLY pays off.

But anyway, having a good selection lets you chose the RIGHT one for the job .

I am thinking Shines tip on removing the drill bit and replacing it with a piece of rod may take care of this somewhat. But a how saw will walk a little, it often will open the hole just a bit larger than the hole saw size. Just a tad understand, but there are times that "tad" may kick your ars.

The other day at work one of the guys (he should have known better) used the exact size hole saw on a plastic bumper to put the holes for back up sensors. The correct saw but the hole had to be EXACTLY right for the funky plastic sensor bracket to clip into, with it's little tiny clips, it needed to be very precise. Well, the hole saw opened the hole just a tad too much, wham, the sensor wouldn't say in!

The moral of the story is if you are cutting a hole exactly the size you need run a test and see if it is in deed going to work for you. If not, go to the one smaller and open the hole up to perfection with a rotary file.

And of course the one thing you have to be careful of is when using the rotary file to open that hole, don't come out of the hole and ruin the surrounding paint!

Brian

A trick I do when I need to hole saw a hole and think it might "hog" out the hole out a bit is to chuck the hole saw on an arbor and put it in the drill motor. Go over to the belt sander and turn on the belt sander and run the drill motor. Hold the hole saw side parallel to the belt sander. In a few seconds I can sand the "set" off the outside teeth.

This accomplish 2 things, the OD of the hole is reduced and by not having teeth looking to pull to the out side of the circle the saw will be more self centering.


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