Sanding edges/ends without going through finish?

[KingwoodFan1989]

I'm pre-finishing some parts for my current project before I put them together...I want to sand the finish relatively even with 400 grit, then 600, and then polish up the finish by hand with micromesh until I get a medium gloss. However, I'm finding that with sanding the ends of my rails, I'm going through the finish...I wiped *16* coats on. What am I doing wrong? I'm using Polycrylic like I did with a previous project, and on there I only used 8 coats and didn't have this issue. What do I need to change this time around to get the end parts sanded even without sanding through to the wood?

[Stwood_]

End grain.....what type of wood? Maybe the end grain is sucking the finish on in?
That's a lot of coats though.

[KingwoodFan1989]

Oh no...not the end grain. I mean the ends of the face right before the tenons. That edge seems really easy to sand through. The wood is Jatoba. I have no idea why I needed that many coats, but even 3 just barely sealed off the grain. I just wanted to make absolutely sure I didn’t sand through anything again. I need to practice finishing on scrap after this project is done, that’s for sure.

[jteneyck]

Oh no...not the end grain. I mean the ends of the face right before the tenons. That edge seems really easy to sand through. The wood is Jatoba. I have no idea why I needed that many coats, but even 3 just barely sealed off the grain. I just wanted to make absolutely sure I didn’t sand through anything again. I need to practice finishing on scrap after this project is done, that’s for sure.

When that happens to me I set the 400 grit aside and use 600 or even 1000 grit.  All you are trying to do is eliminate the dust nibs.

John

[KingwoodFan1989]

Okay, I’ll try starting with a finer grit on the ends. I usually don’t apply the finish very evenly, so sanding is also for evening out the finish in my case.

[jteneyck]

Okay, I’ll try starting with a finer grit on the ends. I usually don’t apply the finish very evenly, so sanding is also for evening out the finish in my case.

Maybe you need to modify your process.  Try putting on several coats of finish before you do any sanding.  I might brush on 3 or 4 wet coats before sanding, or 6 or 7 wiped on coats.  Then you can sand it flat with minimal (but not zero) worry of cutting through it.  When it's dead flat, apply one or two more thin coats and then it's done or ready for rubbing out, depending upon what you are trying to achieve.  

John

[Cooler]

You are probably tipping the sanding block slightly as you extend over the edge.

Make a 12" long sanding block and use either adhesive backed sand paper or use 3M 77 adhesive to adhere the paper.  I like using melamine laminated particle board for this purpose as it allows easy cleaning.



It is sometimes easier just to buy a small shelf than a piece of melamine laminated board.  

Make sure your hand remains over the main work surface while shifting the sanding block over the edges.  This will yield a flat result.

I have made much wider sanding blocks and used adhesive backed sanding paper in rolls.  But you will not find the very fine grits in rolls from my experience, though 2-3/4" wide is available in 320 grit from automotive body work suppliers:

http://www.ebay.com/bhp/adhesive-backed-sandpaper