how to paint the edge of a business card

The good way.

Go to an A.C. Moore / Michaels and buy an airbrush, small compressor, and airbrush paint. You’ll then have this for future jobs, but it makes the first one expensive.

Trim your cards out VERY carefully and keep them in the same stacks you cut them in so the sides are very straight.

Use a clamp and something to protect the tops and bottoms (I have business card sized pieces of masonite). I also sometimes use bookboard on the top and bottom of the cards as I cut them out and use that.

Clamp them tight and airbrush the sides. Doesn’t hurt to sand the edges a bit, but not critical if you have a good sharp blade (which is in itself pretty critical).

DO NOT OVER SATURATE. It will bleed between the cards or the cards will be hard to separate. Several lighter layers is better than one heavy layer. Even if the color is a bit uneven you cannot tell it when you are holding only one card.

It is surprisingly fast to do the cards.

A critical issue to me is that you need to trim the cards on all four sides so you get a good vertical cut along the sides of each card.

…

Less good, but cheap, is to just handroll the edges with the same letterpress ink you printed with. Sanding the edges maybe more critical as you really need a smooth surface.

Shall I wax the edge with bee wax afterwards?

I’m with LG on this one…. stack ‘em up and spray them.

If you a cheapo like me, and VERY careful, you can can get by with spraypaint…. but that’s not the “professional way to do it”. No matter how you do it, the key is to not over-saturate the cards.

For business cards, I wouldn’t wax them. for a book or other fine work, i’d consider it.

Bleed can be reduced by sealing them with acrylic matte medium before airbrushing.

Good day!
Thank you very much for your answers and ideas!
You are very helping me!
Thank you that there is a forum and people like you!
I still have a few questions:
1) After cutting the cards I understand that it is necessary to polish the edge! They get very sharp on the back side after cut! What instrument do I polish the edges of the paper? Sandpaper? Polishing machine? Ideas?
modernman - Thanks for the great idea with acrylic lacquer. Say what paint to use? Normal from the store for creativity or balloon under pressure?
Thank you so much for your help!

Normal from the creativity stores works fine for me, I use the cheap generic stuff.