Steel wool or sandpaper?

[Al Willits]

Another newbie question if I may..
I'm slowly getting futher into finishing, and I am now using a water based poly on the cabinet doors I'm making, directions say to sand between coats with a 300 (?) grit sandpaper, least I think it said 300 anyway, but I read where people use 0000 steel wool between finishing coats and am wondering are they interchangeable or ???

Is there a guideline as to when to use sandpaper versus steel wool?
tia
Al.....who see's a major chunk of learning curve coming...:D

[Steven Wilson]

I don't use steel wool on water based finishes. For the most part I use 3M pads (maroon, gray, white) in place of steel wool. Sanding between coats allows you to remove finish imperfections. Sanding is most effective when you back it up with a sanding block (the small cork ones are great).

[Jim Becker]

Don't use "real" steel wool with water borne finishes...small bits can remain and rust. Use synthetic wood pads if you want to use them for rubbing out, etc.

[Al Willits]

Thanks, looks like scotchbrites or sandpaper then.
Water and steel wool didn't really sound right... :)

Al

[Art Stratemeyer]

Al,

With Water Based clears ... the reason they say to sand between coats with 320 grit is so that you lightly give the surface a scuff sand. This is because with most WB finishes, if you wait more than an hour or so before the 2nd 3rd, etc coats they need to be very lightly roughed up to provide a mechanical bond between coats. This is "light touch" sanding .. not aggressive sanding

As others have said the maroon pads work great for this

[Joe Chritz]

The scotchbrite pads do work great. I use them often for irregular surfaces. For flat panels and doors, etc I use the sanding sponges available at lots of locations.

A quick once over and its back to the rack for round two.

Joe

[Al Willits]

Thanks, wasn't sure how much a light coat meant, but do now.
Figures I have a ton of Green scotch brites, but I'll go look for maroon...:)

Al

[Jamie Buxton]

I use sandpaper between coats. At least in my finishing process, I occasionally find little nits in a coat of WB varnish. They're bits of dust, or maybe a fiber poking up from the wood surface. You can't really see them, but you can feel them if you run your hand over the surface. Steel wool -- well, actually the plastic steel wool -- doesn't knock the nits down. It rides over the top, leaving the nit still there. Sandpaper knocks it down quite well.

For sanding in between coats, I use 600 grit. It isn't really sanding. It just takes a few light strokes to knock down those teeny imperfections.

[Al Willits]

Thanks, I'm wondering if sand paper for flat surfaces and scotch brite for uneven might be a nice way to go?

Al

[Tim Sproul]

With most finishes, you can skip sanding between coats if you apply subsequent coats quickly enough. If you apply a subsequent coat within 1 hour, you're almost for certain safe that you'll get excellent adhesion between coats even for finishes that don't burn-in (polyurethanes being one). Even within 12 hours you're pretty safe. 24+ hours typically requires a bit of sanding to get the best adhesion between coats for water borne finishes. One really good advantage of using products like Target Coatings or other finishes that I can obtain through Homestead Finishing is having expert advice readily available. This is advice coming from expert users (Jeff Weiss of Target Coatings or Jeff Jewitt of Homestead)...not technical support reading from a script on their computer monitor.

There are other reasons to sand between coats besides getting good adhesion. Removing major surface flaws is one.....I don't worry too much about dust nibs until the next-to-last coat. For water bornes, I typically spray 2-3 coats of sealer (can be the finish itself for some topcoats) and sand that to get a smooth feeling texture and then apply 1-3 additional build coats, sand once more and apply a final 1-2 coats. If I'm going to rub out the finish after the final coat, I won't bother with the second sandpaper session. I try to arrange my time so that I can spray the first 2-3 sealer coats in a single day. Then I can wait any number of days, sand the sealer coats whenever I have time and then arrange to have enough time to spray the subsequent 1-3 additional build coats in a single day. Again, I can wait any number of days and sand the build coats whenever I have time and then arrange yet again to have enough time to spray the final 1-2 coats in a single day.

[Howard Acheson]

>> Thanks, looks like scotchbrites or sandpaper then.

Let me suggest the following. Sandpaper is better to use in most cases. One of the primary things you want to do, especially after the first coat, is to flatten the surface of all flat surfaces. A flat surface is the most important characteristic if you want a professional look to your project. Use 320 paper mounted on a cork or felt bottomed sanding block. Do not just use your hand. Sand the first seal coat until the surface is flat. Then you can apply your addtional coats and will have a flat, smooth surface to work with. If you have to sand between coats, again use sandpaper on the sanding block to maintain your flat surface.

Use an non-woven abrasive pad like a gray scotchbrite pad for irregular surfaces but avoid using it for flat surfaces. Pads or flexible sanding pads will not flatten the surface as they ride up and down over the uneven surface.

[Jim Becker]

Caveat to Howie's suggestion is to be careful if you are sanding a film finish over oil that you don't sand through, especially on dark woods. DAMHIKT!

[Al Willits]

Thanks guys, I think I got it pretty close now.

Doing the cabinet doors and I'd put one coat one, let sit for half hour or so, add the second and let dry for several hours at least, then hit the flat parts lightly with a foam backed sanding block and 220 grit sandpaper, just couple of passes to knock the nibs and dust bunnies off, I'd gently use the maroon scotch brite (found a stack of them under the green ones) to go over the routered parts.

Seems to work well, and I'll switch to 320 after the 4th coat, no reason other than I don't have any 320, and slightly used 220 seems to work for now, will switch as soon as I make a sandpaper run..

So far the finish has turned out nice enough Beasty wants it left shiny instead of the satin finish.

I am wondering if I dare get the spray gun out...maybe wait till next time as this is enough learning curve to handle now...:D

Once again, thanks all.

Al