Help masking glass for paint

[Gio0300]

I plan to paint the glass on my cabinet. The glass is 1/4" thick real glass and I'll be using a modern LCD flat panel. I have a general understanding on the concept of masking the area where the monitor will show and then painting the glass from behind. My question is:

How do you make a mask that has sharp square corners? Do you lay the tape down a certain way? Do you over lap the vertical and horizontal strips of tape and then use a razor to cut the excess?

Please and thank you.

[BadMouth]

Dunno if it's the best way, but I cut the masking tape (usually Frog Tape) at an angle so it has a good point on it.
I lay that down with the point where the corner will be.  Then I cut another piece with the opposite angle for the piece that will be perpendicular to that one.
(like you're making a picture frame, but make the angles more than 45 degrees so they overlap.)
Lay that one down with the tip of the point touching the first piece.  Overlap is ok, you aren't trying to butt them up against each other.
Just get the tips of both pointy tips touching. 

If you want to get creative, get some fineline masking tape and round the corners.  (I like K-Tape brand, but in a pinch have used the pinstripe tape from the model building section of craft stores)

I'll throw this idea out there if anyone wants to use it:
I always wanted to lay out a design on the back of the monitor glass bezel area with fineline tape before painting it black.  Then peel the tape and spray another another color from the back.
It would look nice and flush from the front side of the glass.  You could do pinstripes, a grid, lines that get progressively smaller from bottom to top.

[bperkins01]

For the cleanest edge  - this is the best tape - it comes in a bunch of widths and its expensive.
https://www.amazon.com/Scotch-Fine-Line-Tape-Sand/dp/B07CL41HRP/ref=sr_1_3?ie=UTF8&qid=1544536013&sr=8-3&keywords=3m+fine+line+tape
But it works great.   

For overlaps - I use a razor and cut through the overlap and remove the tape that is not needed.  I get a perfect joint.

ex:  Miter joint with tape - vertical tape - then overlap horizontal tape - then use a blade and cut through both layers removing extra pieces.  You end up with a perfect corner and paint can't creep under the overlap - because you eliminated it..  (practice a little)

Added:  Store it in a sandwich bag.  As soon as dust and crap gets on the edge..  It messes up the fine line you wanted in the first place

HTH

[Gio0300]

Dunno if it's the best way, but I cut the masking tape (usually Frog Tape) at an angle so it has a good point on it.
I lay that down with the point where the corner will be.  Then I cut another piece with the opposite angle for the piece that will be perpendicular to that one.
(like you're making a picture frame, but make the angles more than 45 degrees so they overlap.)
Lay that one down with the tip of the point touching the first piece.  Overlap is ok, you aren't trying to butt them up against each other.
Just get the tips of both pointy tips touching. 

If you want to get creative, get some fineline masking tape and round the corners.  (I like K-Tape brand, but in a pinch have used the pinstripe tape from the model building section of craft stores)

I'll throw this idea out there if anyone wants to use it:
I always wanted to lay out a design on the back of the monitor glass bezel area with fineline tape before painting it black.  Then peel the tape and spray another another color from the back.
It would look nice and flush from the front side of the glass.  You could do pinstripes, a grid, lines that get progressively smaller from bottom to top.

Miter the edges of the tape, got it, thanks. Now regarding the length of each strip. Do you cut the tape to length (with each end pre-mitered) before laying it down on the glass or do you lay down the tape with a square edge and then cut the miter while the tape is on the glass?

[JDFan]

Do you cut the tape to length (with each end pre-mitered) before laying it down on the glass or do you lay down the tape with a square edge and then cut the miter while the tape is on the glass?

Either would work but if you cut after it is in place what is to keep the glass from getting scratched when cutting ??

[bperkins01]

Square edge and cut on the glass (be careful)..
that way the seam is perfect for no paint leakage

[BadMouth]

Miter the edges of the tape, got it, thanks. Now regarding the length of each strip. Do you cut the tape to length (with each end pre-mitered) before laying it down on the glass or do you lay down the tape with a square edge and then cut the miter while the tape is on the glass?

I cut it before laying the strip down.  Sometimes with a razor blade, sometimes with good scissors.
I've painted a grand total of 2 monitor bezels.
Those were plexi, so there was no option to cut it in place.
I have done this whenever taping off sharp corners in a half dozen other projects though.

Like I said though, I'm no expert.
If a pro who does this type of stuff for a living comes along and tells you to do it differently, you're probably better off listening to them.

[shaolindrunkard]

Here's a tip, use black spray plasti dip instead of paint, then you can take it off if you mess up.

[Ian]

Another quick industry tip. If using frog tape, (and this goes for any application) the way it seals the edges to provide a clean line is technology used in diapers. It is an absorbent powder lined on the edge of the tape that expands when wet. So to get the crispest lines possible on frog tape, do the following...

Lay the tape down on whatever surface like you would any painters tape.

Take a sponge or a paper towel and wet it until damp.

Then run the wet sponge across the edge you want sealed.

This  will activate the powder and give it time to really seal the surface it is stuck to. Then Paint as usual. You will find it leaves a better sharper line. And to avoid any razor blades I remove the tape when the paint is still wet.