Willbury Report post Posted February 14, 2012 Hello, This is my first time posting here, although I trawl about this forum regularly and pick up lots of great information. I have been experimenting with moulding over the last while and have noticed that I am frequently getting these little dark spots appearing in the leather after taking the piece out of the mould. The leather looks totally clean and clear of spots before it goes into the mould. I have used moulding leather from both Herman Oak and Wickett and Craig and it's happened with both. Is this normal? I have attached a picture to illustrate what the spots look like. Oh and I have been using hardwood moulds that are waxed so as not to take in water. Cheers, Will Quote Share this post Link to post Share on other sites
WinterBear Report post Posted February 14, 2012 I could be wrong, but it looks like the leather picked up a little iron contamination somewhere. A little invisible speck of rust can cause that to happen. There are some expert molders on the site, I'm sure they'll be along shortly with some pointers and will have a few ideas on how to keep it happening again. Nice molding job, by the way. Future cigar case maybe? Quote Share this post Link to post Share on other sites
Willbury Report post Posted February 15, 2012 Hmm interesting, if that's what's causing it I wouldn't be too surprised. I'm sure there are lots of small bits of iron laying around my shop, I build steel bicycle frames as part of my living. Thanks for the praise of the moulding, it's for pens/pencils on the inside of a sketchbook case. I'll post up some pictures when it's finished. Quote Share this post Link to post Share on other sites
gringobill Report post Posted February 15, 2012 Hello, This is my first time posting here, although I trawl about this forum regularly and pick up lots of great information. I have been experimenting with moulding over the last while and have noticed that I am frequently getting these little dark spots appearing in the leather after taking the piece out of the mould. The leather looks totally clean and clear of spots before it goes into the mould. I have used moulding leather from both Herman Oak and Wickett and Craig and it's happened with both. Is this normal? I have attached a picture to illustrate what the spots look like. Oh and I have been using hardwood moulds that are waxed so as not to take in water. Cheers, Will Pretty sure Winter Bear is right about the iron/steel filings being the culprit. I've got that t-shirt too, it's one of the pitfalls of a mulitpurpose shop/work area. The good news is a little oxalic acid/wood bleach or maybe lemon juice will remove those pretty quick. Bill Quote Share this post Link to post Share on other sites
Willbury Report post Posted February 15, 2012 Hi Bill, Thanks for the tip. How should I apply the the oxalic acid/wood bleach? Just wipe a little bit of it over the affected area? Will Quote Share this post Link to post Share on other sites
Sylvia Report post Posted February 15, 2012 Pretty sure Winter Bear is right about the iron/steel filings being the culprit. I've got that t-shirt too, it's one of the pitfalls of a mulitpurpose shop/work area. The good news is a little oxalic acid/wood bleach or maybe lemon juice will remove those pretty quick. Bill Hate to butt in but I have been wondering for some time now if vinegar would work since Lemon Juice might work? Quote Share this post Link to post Share on other sites
stef73433 Report post Posted July 27, 2013 Bumping this up. I have spots all over my leather like this.didn't notice until I got it wet and formed it for a saddle seat. Could it be hard water? I don't think I have any iron or steel in my work area. Anyone know about the lemon juice trick? When and how to apply effectively? Quote Share this post Link to post Share on other sites
bruce johnson Report post Posted July 27, 2013 I have never tried vinegar - might work, but is also the carrier for vinegaroon which is iron soaked in vinegar to MAKE a black dye effect so I'd be a bit doubtful. Lemon juice works straight, but I have found you need to work the whole piece or I'd get spotting where I used it. I use oxalic acid on big pieces and sponge the whole piece when I am done and before finishing. Sources of the iron can be your water. I used to fill my dunk tub from an outside spigot. Lived with spots all the time. Water from the house and I never spotted. Outside spigot had enough rust in the pipes to do it I guess. Quote Share this post Link to post Share on other sites
stef73433 Report post Posted July 27, 2013 I get water out of my base ment faucet. I'm not sure if that's before or after it goes through water softener, but probably doesn't matter. Perhaps I will try water from bath tub for a while Quote Share this post Link to post Share on other sites
SteelcityK9Cop Report post Posted July 27, 2013 Grab a gallon of distilled water from the grocery store to see if it's your water. If you have well water you may have high iron content. Quote Share this post Link to post Share on other sites
benlilly1 Report post Posted July 27, 2013 I agree with WinterBear...it's metal. Quote Share this post Link to post Share on other sites
BondoBobCustomSaddles Report post Posted July 28, 2013 Like Bruce says lemon juice or oxalic acid will do the trick,. If you can't find the source of the metal, it may also be the beginning of mold, in either case, it will clean off with the use of the mentioned ingredients. Bob Quote Share this post Link to post Share on other sites
