Edge paint durability

[dring]

Hi all!

I'm looking to move towards painted edges in my leather items. I mainly work with small items such as wallets, card holders, passport covers  etc. They all have quite thin edges 1-2,5mm (0.04-0.1") and I usually use vegetable tanned shoulder for the leather. Some likely contain small amounts oil but don't think very much. Mostly they are quite dense or hard tempered leather because I need to have some rigidity in the products.

I have tried two different edge paint brands, Tarrago and Giardini. Tarrago is very thick and doesn't require base coat. Giardini requires base coat and I have tried it with their Adhesion Aid, which supposedly helps the base coat to adhere better. With both of them I can use my finger nail to scrape the paint off. The point is that I want to do some destructive testing to see how well edge paints protect the edges because a product like wallet can be rubbed against a zipper of a pocket in clothes or bag when in use. I kind of have to really try to scrape the paint away by pushing the nail hard in the paint, but when it starts to come off, it just seems like the paint didn't bond with leather but is just dried on top of it. I have also tried different grits to sand the edges. Even tried with 80 grit to make it really coarse and get the edge a little fuzzy for the paint to stick. I have used different applicators like roller pens with different heads and awl. Every time my test edges have failed the finger nail test. They could get more durable if I'd just add more layers of paint but still the first layer is the one that counts and if that doesn't adhere properly, then it's pointless to continue.

Has anyone else tried how well different edge paints can take scraping and rubbing without making it come off? I now have like 150e worth edge paint products and I feel like I want to stay with burnished edges because I can't seem to get the durability I expected.

As a side note I also have some Liquitex acrylic mediums used in acrylic painting which is one of my hobbies. I mixed gloss and matte medium to make satin surface and applied to leather edge. To my surprise it's almost impossible to scrape that thing off without tools! It's also flexible after drying, can be colored by mixing it with acrylic inks, comes as gloss, satin and matte but the down side is that it doesn't give that beading that happens with edge paints.

[TonyV]

If the paint you're using doesn't stick to the edges, it's not the paint I would want to be using.  I use sandpaper on edges when it is to help smooth the edges for painting, and I think 80 grit is way too coarse on edges.  I start at 220 grit and up to 400 or 600.  depending on the look I want, I'll smooth it with 220, paint the edge and let it dry, sand with 400 or 600 to smooth it out some more, then paint it again.  IN rare cases I might include a step to 1200 grit then another coat of paint.  Paint doesn't really need a very coarse, rough surface to hold, just not a polished surface.  

If different acrylic paints are adhering to the edges better than the fancy stuff, I vote for the acrylics (which are used on all sorts of leather products anyway_).

But any paint will rub off the edges of items like wallets and belts, sooner or later.

Edited July 22 by TonyV

[Northmount]

@dring  Moved your post to Dyes, Antiques, Stains, Glues, Waxes, Finishes and Conditioners