NateOlsen Posted October 4, 2011 Report Share Posted October 4, 2011 I'm currently building a cradle for my new nephew (due in 2 week! Uncle Nate is excited.. ) and I ran into a strange issue that I've never heard mentioned before. This is my first major project so it could very well be something simple that I don't know, but that's what learning's all about I guess. Anyways, my issue here has to do with some black spots that showed up on my project. What happened was I started sanding my project up to 120 grit. I sprayed it with a little water before I went to hit it with the 220 grit. About 2 or 3 minutes later black spots started appearing all over my project! I've attached a couple pictures to show what I'm talking about. The third photo is from my first dry fit before any sanding. I was able to get rid of the black spots by bringing it back down to 60 grit and working my way back up, but now I'm worried about getting into the finish. If I hit it with a water based finish, do you think it'll do this again? What about something oil based? I was going to try to do a dark stain, like maybe something in the range of espresso to match my sisters furniture. Do you think a dark stain will cover these spots up if they do come back? Is there something I should have done or should do to prevent this? Basically........ Help!!! Thanks for any help you can offer. Nate Quote Link to comment Share on other sites More sharing options...
wingarob Posted October 4, 2011 Report Share Posted October 4, 2011 Looks like iron particles that have gotten wet ... have you used any steel wool on or around your project ??? I think oxalic acid removes those spots, but it's far better not th have to deal with them. A dark stain will make them less noticeable, but they will still be there when water hits them unless you get rid of the cause. Quote Link to comment Share on other sites More sharing options...
AceHoleInOne Posted October 4, 2011 Report Share Posted October 4, 2011 It appears your are working an oak wood? If so, the water you sprayed onto the wood possibly had a reaction to the natural tannins in the oak. Water based finishes can sometimes bring this out due to high PH. A wash coat of alcohol cut shellac first will help. However, if using an oil based stain, you should be fine. Curious...why wet the wood down between sanding? Are you going to stain with water-based or oil based? -Ace- Quote Link to comment Share on other sites More sharing options...
NateOlsen Posted October 4, 2011 Author Report Share Posted October 4, 2011 Well, looks like I could have a couple of causes here. I haven't used any steel wool around my project, but I did sharpen my chisels on my workbench the other day. I thought I had cleaned the surface pretty well but maybe there was still some residue? Ace's response made me think of something else. I have super hard well water in my house and it's got all kinds of minerals and such in it. I never think about it because it's just something we live with. Both of those possibilities are kind of dumb now that I think about it, but lesson learned! I think I'm going to do an oil based stain and probably a couple coats of de-waxed shellac as a top coat. I had hit it with the water because I had heard Marc talk about pre-raising the grain and I really wasn't sure until this morning if I was going to be using a water or oil based finish. Are there only certain types of wood that I need to worry about doing that with? I thought it was one of those things I should just kind of do all the time but maybe I'm wrong there? This will be my first time finishing something so I'm really not sure what standard practice is. 1 Quote Link to comment Share on other sites More sharing options...
Rapid Roger Posted October 4, 2011 Report Share Posted October 4, 2011 Just a suggestion.....If it is minerals in your water, you might try distilled water that you can buy by the gallon at the supermarket to use for wipe-down in the future. We have a water softener in the house so, I've never seen that problem before. My first thought was steel from steel wool also. Rog Quote Link to comment Share on other sites More sharing options...
NateOlsen Posted October 4, 2011 Author Report Share Posted October 4, 2011 I totally agree! Think I'm going to stock up when we go grocery shopping this evening. I also think I'm going to scrub the crap out of my workbench tonight. I haven't done anything with steel wool in a long time so it's tucked in the back of my finishing shelf but I have been doing some sharpening on my bench so there could be some residue there. Looks like I've got a good excuse to build a dedicated sharpening station! Quote Link to comment Share on other sites More sharing options...
AceHoleInOne Posted October 4, 2011 Report Share Posted October 4, 2011 Not an expert on wood tannins, but oaks seem to be the worst or just most talked about. I believe all wood has tannins, just some has more of it than others? Bottle water should help. When I find it necessary to raise the grain. I use 50/50 water to denatured alcohol. The alcohol will help the water to evaporate faster. You don't want to soak the wood. I get a rag good and wet (not sloppy wet) and wipe the wood. Like wiping the kitchen table after a meal. Then when dry, scuff the wood with 320. -Ace- Quote Link to comment Share on other sites More sharing options...
NateOlsen Posted October 5, 2011 Author Report Share Posted October 5, 2011 Thanks Ace. I'll give that a try on my next one. I'm hoping to get the finishing done this weekend. I'll throw some pictures up and let you guys know how it goes. Thanks for the help! Quote Link to comment Share on other sites More sharing options...
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