spraying water based finishes, help needed...

[mreza Salav]

I have worked a bit with waterbased finishes but have a very big job (a full house trim work) in front of me. I am using General Finishes RTM stains with their pre-cat (WB) Lacquer. The wood is (hard) Maple.
The process I followed is spray the stain, spray 1-2 coats of top coat, then sand the rough surface down very lightly with 400 (or 600) grit and then spray the final top coat.
No matter what, I can't avoid sanding as I think the water raises the grain and causes the roughness.

The problem I have is after a dark stain and the top coat is sprayed if I sand (even very lightly), the sharp corners are easily gone in no time (even one stroke with sand paper) and bare wood is visible, an ugly and hard to finish situation. So I have to be very carefull not to get to the edges while sanding, which, given the size of the task, is very difficult (imagine all the moulding/casing/baseboards and the profiles). I need to figure out an easier way of fixing the roughness.

Should I spray a light coat of stain, then top coat, then sand lightly, then tint the topcoat a bit and get to the desired color I want with the tinted topcoat with the hope that it will cover (at least somewhat) the damaged edges and get a close color (stain) over the entire piece?

What is your solution advice here?

TIA!

[Jason Roehl]

Raise the grain with water (distilled) and sand before applying stain. Also, a coat of a sanding sealer after the stain, something like SealCoat shellac (though this will impart some amber color) will help prevent the topcoats from raising the grain.

[mreza Salav]

So if I spray water, then sand down the grain, then follow up with spraying stain and topcoat I won't need sanding in between the stain/top-coat layers?
Essentially I move the "sanding" step before the stain? that would be great if it works.

[Scott Holmes]

You can only hope this is the case.

Seal the stain with the de-waxed shellac as stated then apply 2-3 top coats then lightly sand. I have found that the foam Norton Softouch Superfine Sanding Sponge work well for this step. NOT the 1" thick foam pads (these are for drywall) the 1/4" thick soft flexible sanding pads are what you want. http://www.woodcraft.com/Product/2083057/33838/Norton-Softouch-Superfine-Sanding-Sponge-500-600-Grit-20-pack.aspx

[John TenEyck]

I have never been able to get good results with WB stains; they just cause too much grain raising, whether or not I pre-raise the grain. Even when I've applied two coats of finish over it, I've either cut through it when I sanded or if I didn't cut through it was still rough. Maybe it works with really thick OB topcoats, but it doesn't work with the GF WB topcoats I've used. So I take a different approach. I either get the color I want by spraying toner coats (Transtint in Sealcoat shellac) or I use an OB stain and then a sealer coat of Sealcoat shellac, and then apply my WB topcoats.

I also use sanding sponges similar to what Scott mentioned, and they are far superior to sandpaper in helping to prevent cutting through to bare wood. Here are the ones I like: http://www.amazon.com/Grit-Norton-Contour-Sanding-Sponges/dp/B00FCE8YM0/ref=sr_1_5?ie=UTF8&qid=1407980327&sr=8-5&keywords=norton+sanding+sponge+320 Equivalent grit ones from 3M are much too aggressive and cut right through.

John

[mreza Salav]

Thanks folks. I got some ultrafine (800/1000 grit) sanding sponges and they worked great in smoothing the topcoat without going through the topcoat on the edges. I now applied my final coat and it looks great!

[Chris Padilla]

What steps did you employ, Mreza?