Checking for scratches

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Forum topic by moke posted 02-06-2013 09:25 PM 1351 views 0 times favorited 22 replies Add to Favorites Watch
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1175 posts in 2777 days

02-06-2013 09:25 PM

Way too many times in my woodworking, I have sanded more than what I thought was an ample amount, only to apply the stain and have it highlight a scratch or two. With plywood almost having a top layer these days, I have always been afraid of sanding through it. I know I have have talked with several folks who wipe their project down with something ( but what I can’t remember) to check. Can some of your share your process to insure the finish looks good?
Thank You
Mike aka Moke

-- Mike

22 replies so far

View BinghamtonEd's profile


2298 posts in 2370 days

#1 posted 02-06-2013 09:37 PM

I’ve used a good wipe of mineral spirits to highlight problems before finishing.

-- - The mightiest oak in the forest is just a little nut that held its ground.

View kdc68's profile


2657 posts in 2277 days

#2 posted 02-06-2013 09:46 PM

moke..BinghamtonEd is right on with mineral spirits. Mineral spirits won’t raise the grain and too is a good indicator for what your project will look like with a clear finish. Another method is to use a bright (500w) light (like the type on tripod stand) with light shining as close to even with the board and perpendicular to the grain. Sight the down the board and look for shadows. It will show any scratches or other imperfections.

-- Measure "at least" twice and cut once

View Picken5's profile


254 posts in 2692 days

#3 posted 02-06-2013 10:18 PM

Moke—I’ll echo the other replies—mineral spirits works great—and it dries pretty fast. It’s also good for highlighting anywhere where you may have left a bit of glue on the wood. I’ve occassionally wiped on mineral spirits just before applying a clear finish—it deepens the colors of the wood slightly and seems to enhance the grain a bit.

-- Howard - "Time spent making sawdust is not deducted from one's lifetime." - old Scottish proverb

View Gary's profile


9331 posts in 3433 days

#4 posted 02-06-2013 10:23 PM

.....not to mention it helps get rid of any particles of sawdust left on the wood…..

-- Gary, DeKalb Texas only 4 miles from the mill

View AandCstyle's profile


3052 posts in 2258 days

#5 posted 02-07-2013 01:02 AM

You can also use naphtha (dries faster) rather than mineral spirits and with a raking light as has been mentioned.

-- Art

View RussellAP's profile


3104 posts in 2287 days

#6 posted 02-07-2013 01:20 AM

I use painters alcohol, it dries real fast.

-- A positive attitude will take you much further than positive thinking ever will.

View Cosmicsniper's profile


2202 posts in 3159 days

#7 posted 02-07-2013 01:22 AM

Good points all. Good point on the naphtha, Art. Denatured alcohol can be used as well, though it will raise the grain slightly. I’ve heard that some use acetone too, though I haven’t tried it personally. I prefer mineral spirits because everything else just dries too quickly in Texas. Paint thinner (which is just merely less refined mineral spirits) and turpentine are options as well.

The key, though, is the raking light.

-- jay,

View moke's profile


1175 posts in 2777 days

#8 posted 02-07-2013 06:04 PM

Thanks all….Mineral Spirits and light, sounds like the best way to go. I will try to find some Naphtha though…

-- Mike

View mds2's profile


310 posts in 1945 days

#9 posted 02-07-2013 06:28 PM

Moke, all of the big box hardware stores carry naphtha by the gallon.

View moke's profile


1175 posts in 2777 days

#10 posted 02-11-2013 09:14 PM

I was at a Lowes and I found they had a lot of Naptha, so I bought some and tried it….it works awesome…
Thank you very much.

-- Mike

View HorizontalMike's profile


7757 posts in 2914 days

#11 posted 02-12-2013 12:28 AM

Geez Moke, you have been reading my mind! This has now happened to me TWICE!... in just the half dozen or so projects that my ‘WW hobby’ has produced. Great question! I ended up putting on SEVERAL more layers and sanding in between layers, to eliminate it.

-- HorizontalMike -- "Woodpeckers understand..."

View lumberjoe's profile


2899 posts in 2249 days

#12 posted 02-12-2013 12:46 AM

I wipe down with some sort of solvent compatible with whatever finish I am using. I recently found out (here in another thread) raking lights make a HUGE difference. With a raker on each end of the bench, I have yet to be surprised when I wipe a piece down.


View Straightbowed's profile


717 posts in 2298 days

#13 posted 02-12-2013 12:51 AM

I use just a flaslight at differ angles turn the lights low in my shop and start lookin and sanding at the same time but really most of the time Im really asleep so its like Im dreaming

-- Stevo, work in tha city woodshop in the country

View kdc68's profile


2657 posts in 2277 days

#14 posted 02-12-2013 01:17 AM

As I, and others have mentioned in this forum, a bright 500w light (raking light), does a great job to look for scratches and imperfections. You could do this each time before switching to finer grits of sandpaper. This way you know before you reach for that 120 grit, everything looks good after sanding with 100 grit. These raking lights can be used in the finishing process as well. Look right after finish sanding and right before the next topcoat of finish.

-- Measure "at least" twice and cut once

View moke's profile


1175 posts in 2777 days

#15 posted 02-12-2013 04:28 AM

There is little in life that is much more frustrating than have imperfection in a finish of a project that you have worked so hard on. This happening on a couple of projects drove to not use any plywood, because it would be impossible to fix with as thin as the top layer is….so I thought I would ask the experts!!!!!

In 1990 I became the 3rd owner of a 50 year old Photographic Studio, which I still own and operate during the day. The basement of the building is full of old “retired” lighting equipment, so I have MANY lights I can use. I tried it Sunday and I think I have looked it all over and I am ready for stain!!!

Thanks to all for all the great advice…It is nice to have a “brain trust” to rely on!!!

-- Mike

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