[djg]

I had stained (after Wood Conditioner) the top of my cabinet yesterday only to realize I had some sander scratches throughout the whole top. I had labored over the top with various grits and I thought I had done a thorough job. Not being able to accept the results, I spent over an hour this morning sanding off the finish (thank goodness I hadn't used Poly yet). I clogged up tons of paper and discs, but I am now done with the 80 grit paper. I ran over the whole top with 100 Grit RO discs, which surprisingly only took 10 minutes. The paper cuts much faster without any finish getting in the way.

I think there is a trick (correct me if I'm wrong) to wipe on mineral spirits or paint thinner (which I have) to be able to view any remaining scratches at that grit. Do you do this after every grit or just after the final sanding?

I guess I could do it after every grit and then let the top set out in the sun for a short while to speed up the drying.

Thanks

Edit: I should say, my eyes aren't what they use to be and I don't want to miss the scratches again. Also I don't want to put anything (mineral spirits, etc) on the surface if I don't have to.

 

[djg]

I didn't do any liquids in between grits, but I did use a light held at a low angle - and cleaned my glasses. It almost looks like pine have microscopic rays or flecks like white oak in between the grain. Looks kind of deceiving, like microscopic scatches. I went over these areas with the sander and they did not disappear, so I guess it's in the grain.

Can I use paint thinner to check for bad spots or should I only use mineral spirits?

Edit: I went ahead a did it; no scratches found.
I couldn't figure out how to delete this thread, so there's no reason to resond.
Thanks

 

[Rick Mosher]

You don't say what species of wood and that does make a difference, however 100 grit is far too coarse no matter what species. Hard wood like oak or maple 150 to 180 softer wood like pine 220.

 

[djg]

What? You can't read my mind?:icon_smile:

It's pine, and the first time I had finished it, I went up 180 grit. Then I noticed the problem.

So today, I sanded off the old finish with 80 grit and then progressed back to 180 grit. I checked with the light as I mentioned after each grit and then I flooded the surface with paint thinner, and with the light, checked for scatches. None were found this time. I dried it outside in the shade for 15 minutes, brought it back indoors, treated it with wood conditioner and then stain. It came out good this time.

Problem solved.

 

[Steve Neul]

I think lacquer thinner would have been a better solvent to wipe off a conditioner or stain. You never get it all though and it does ruin a lot of sandpaper no matter what you do. When you are sanding if you would wipe the wood off with a damp cloth between grit changes and raise the grain it would make your sanding more effective.

 

[HowardAcheson]

>>>> I think there is a trick (correct me if I'm wrong) to wipe on mineral spirits or paint thinner (which I have) to be able to view any remaining scratches at that grit. Do you do this after every grit or just after the final sanding?

Yes, it is quite common for an experienced finisher to dampen a rag with mineral spirits (paint thinner) and wipe the surface. This will highlight and sanding miscues or other surface blemishes. It will also preview the appearance of the wood if you plan to apply an oil based clear coat. The mineral spirits will evaporate and you can then continue your preparation.

I personally only do the above just prior to my initial application of my finish. But, I also set up a light so I can see most all sanding miscues as I am sanding. There is not reason not to do it after every grit if that helps you get a surface properly prepared for finishing.

Oh, you can also use lacquer thinner or alcohol to wet the surface. These chemicals will evaporate more quickly so you can get back to your finishing.

 

[cabinetman]

Can I use paint thinner to check for bad spots or should I only use mineral spirits?

Paint thinner, is basically the same as mineral spirits. Mineral spirits is just a more refined version. Using 80x initially will leave some very deep scratches. Although you sanded further with smoother grits, some scratches may prevail. You have to check carefully. As once you start to apply finish, by that time it can be a PITA to fix.

.

 

[djg]

Thanks all for your replies. What you suggested is basically what I did. I was so PO when I saw the initial fish I just wanted to fix it. So I started sanding on it. Then I found out how dificult that was to do. Plus I didn't have any stripper on hand. And what would that do to the wood?

As far as mineral spirits vs paint thinner, you, I believe, had explained that to me before. I have a short memory; sorry for that. I just wasn't sure if the heavier impurities would effect the wood.

To sum it up, the cabinet top came out looking pretty good, a nice even finish and no scratches.

On a side note about wood conditioner (MinWax), the can says apply stain up to 2 hours after the excess conditioner has been wiped off. I waited about an hour, but would you get more of the stain to penetrate it you waited less (10 minutes) or the other way around. Or does it not matter?

 

[cabinetman]

On a side note about wood conditioner (MinWax), the can says apply stain up to 2 hours after the excess conditioner has been wiped off. I waited about an hour, but would you get more of the stain to penetrate it you waited less (10 minutes) or the other way around. Or does it not matter?

Minwax has a conditioner for waterbase stains and one for oil base stains. Make sure you're using the correct one.

.

 

[djg]

Both stain and conditioner where purchased years ago before the VOC craze, so they are both the same. But that's good to know for in the future, because I'm about out of conditioner and will need more for future projects.