Help! Getting dark spots on my leather

[shadow2511]

I started making this picture frame for my son but these black dots have appeared on the leather. Each time I get it wet more spots show up...almost before my eyes. I don't think it is mildew because I have only wet it down twice and it dried the 2 days in between. Can anyone tell me what this is and how to get rid of them? I tried soaking it in bleach water. It didn't help.

I need to finish this before Christmas. Any help would be appreciated. Thanks, Barb

Edited December 16, 2006 by shadow2511

[bruce johnson]

Barb,

Those appear to be "metal" marks. Small amounts of metal (iron is the big culprit) will react with vegtan leather when wet and cause those marks. The metal can come from grinding flakes that are so small you can't see them if there is a bench grinder in the vicinity. Storing the leather or dragging it on a metal surface, flakes of metal coming off stamps as you hit them, or other sources of fine metalic flakes can cause the small freckles. Bits of iron from plumbing can freckle leather. I have that issue from a hose at home, but not the tap. Larger smudges usually come from handling something metal, like a bench anvil or head of a hammer, and then going back to the wet leather. That minute amount can transfer to your fingers, then to your leather and cause exactly what you see. Acids tend to neutralize these spots, but can make your leather harder to tool once you do that. Acids commonly used are either oxalic acid (available as wood bleach in hardware and home improvement stores) or citric acid from plain old lemon juice- fresh or concentrate. I use lemon juice, and just dilute it a bit and sponge it on. Use the lemon juice, or you will have so many warnings and different and conflicting pieces of advice it will take you until Christmas to figure out how to use oxalic acid.

Bruce Johnson

[ClayB]

I think Bruce is right about what could be causing the spots, and what to try to get rid of them. I use lemon juice right out of the bottle on a damp sponge. The spots wont dissappear right away, but should go away as the juice evaporates. You can also wipe down parts of your work area if you suspect they might be contaminated and causing the spots. If you are handling something iron like Bruce said, maybe an anvil, or filings from a drill press etc. you might try washing your hands with lemon juice also before you go back to working on leather. I hope your spots come out. It can be really frustrating when things like that happen.

Clay

[shadow2511]

Ok...thanks for the info. It is a relief that the spots can be removed. Could tools being old and not used for years contributed to this? They are kinda coroded from being in storage in the attic for maybe 15 years. Any suggestions about how to clean them? I ought to replace them but it gets expensive. Have a great day! Thanks for all the advise! Barb

[ClayB]

Ok...thanks for the info. It is a relief that the spots can be removed. Could tools being old and not used for years contributed to this? They are kinda coroded from being in storage in the attic for maybe 15 years. Any suggestions about how to clean them? I ought to replace them but it gets expensive. Have a great day! Thanks for all the advise! Barb

One suggestion from another site is to place your rusty tools in an aluminum pan filled with water and one tablespoon of Cream of Tartar. Let the tools cook on low heat. When the water starts to turn colors, it is the rust letting loose. You should then be able to brush the tools clean with a scrub brush. Other suggestions would be to use a steel brush on a bench grinder or dremel tool. I soaked some I had in vinegar once and it worked, but was told afterwards that this isn't the best idea. They said that if you leave it in the vinegar too long it will start to eat the tools.

Hope this will give you some options to try.

Clay

[abn]

Wow. I'm glad to see this topic. I sometimes use my leatherworking bench for home repairs, including some filing of metal parts. :warning: I guess I'll do that somewhere else from now on!

[shadow2511]

ClayB and bruce johnson,

Just a quick note to let you know I treated the marks with lemon over night as you had recommended and the marks are gone. I am so glad. thanks for the info! Barb H

[Johanna]

FWIW, for anyone else reading this, lime juice works almost as well as lemon, and orange juice does not work at all. Oxalic acid is strong enough to justify a warning or two, like follow dilution directions well, and don't let it in contact with your skin.

Barb, I'm glad your piece turned out all right. These guys are great, aren't they?

Johanna

[freak]

That's experienced knowledge, thanks for sharing guys.

I LOVE THIS PLACE !!

[Heavy Mallet]

Ok...thanks for the info. It is a relief that the spots can be removed. Could tools being old and not used for years contributed to this? They are kinda coroded from being in storage in the attic for maybe 15 years. Any suggestions about how to clean them? I ought to replace them but it gets expensive. Have a great day! Thanks for all the advise! Barb

Loose rust on tools is always an issue. This is particularly true if you work with antique tools (as some of mine are). I have used several techniques to restore such tools.

The most important thing to do first is to mechanically remove as much of the rust as is reasonably possible. This can usually be done best with a wire brush. Brass brushes are best, as they are softer than the tool steel and thus will not damage the steel itself (although they will remove paint and in some cases chrome or nickel plating). On smaller tools, use a brass brush in a Dremel tool, rather than a bench grinder. I feel that if the tool has a replaceable blade or bit, you are best off replacing it with a new one, unless it is an expensive tool, such as a splitter and the cost of the replacement blade is very high (Osborne Splitters, ~ $200 retail / blade!).

It is not advisable to paint or coat a cutting edge or bearing surface; however, as for the remainder of the tool, it should be painted with a good quality anti-rust pain, such as Rustoleum. If there was any surface rust remaining, before painting, use a phosphoric acid spray or gel (Rustoleum or Naval Jelly), which converts the rust to a durable, paintable phosphate coating. Always use a mask when spraying these products! I have used this technique to restore some very large, expensive Osborne arch punches. As I also do a lot of wrought iron work, I use these products a lot.

As a final note on restoration, consider that blades must always be very sharp to function properly and safely. It is worth the time to properly sharpen your tools. If you have not yet learned this important skill, consider one of Lie-Nielsen's excellent videos on sharpening using Japanese waterstones. If you are on a limited budget, look for a decent book on the subject in your local library.

Good Luck!

[shadow2511]

When I said corosion I was refering to some white corosion which I believe came from the tools being in a box with leather dye thinner which had over the years leaked onto the handle of the swivel knife I used. I was assuming that maybe that had flaked off and mixed with the moisture of the leather. I was just embarrassed that I had let my tools get in this condition and didn't want to expand.

And yes Joanne they are great! They hit it right on the head and told me how to fix it. (and with something simple I could easily get from the grocer). There is a lot of experience and knowledge on this forum that I will continue to tap into if I run into trouble with a project. Thanks again everyone!

By the way...my son loved the picture frame!! He didn't even realize that I had made mistakes and I didn't point them out!

Thanks again!! Barb

Edited December 28, 2006 by shadow2511

[WorldOfLeathers]

Hi Guys,

Need all your expertise advice and help. How do you get rid of these dark spots on my semi Aniline full grain leather cushion? They have penetrated the leather surface and I am not sure if they are mold spots. I tried using the tip of a sharp blade to "dig" them out but without success.

Many thanks in advance.

Edited October 9, 2015 by WorldOfLeathers

[Guitarist762]

Do what many people do for old axe heads, soak them in vinegar. The acid removes the rust, and then puts a patina on the metal that helps slightly with rust prevention. Other than that put beeswax on your tools to keep them from rusting.