Sanding between coats...

[Ralph Morris]

What do any of you guys use to "sand" between the coats? I used 220 grit and go by hand. Minwax's Polyurethane brushed on with the poly-brush didn't give me "lines" free looking finish. I didn't like the finish and had to lightly sand it but it still shows streaks from the brush. I thought about the cabinet scraper and tried that on the coat and it did "level" out the "ridges" and "dried on drips" very easy. I started to use General Finishes' Polyacrylic Blend on that Minwax, it did blend out the "mistakes" very nicely. I always liked General Finishes better than Minwax's. Ever thought of using the cabinet scraper on between coats?

[Brian Buckley]

Ralph,

I usually use a 3M pad between coats. It is the equivelent of 0000 steel wool. They are gray on color. I dont think they would work on drips, but do a good job smoothing out the coat.

Brian

[Scott Parks]

As far as your ridges, I've used light sanding with anwhere from 220-320 or 400 grit with a block to cut down the ridges flat, but never a scraper. Although between coats, I slice off drips and imperfections with a razor blade.

I hate to say this, and I hope this insn't too negative, but... I've used Minwax years ago with the same results that you've descibed, and I was not happy at all. Just recently LOML picked out a minwax color for her bath vanity. I was reluctant to use it due to prior experiences. After applying the minwax, we were so upset with the results that I planed and sanded the entire cabinet and started over. I vow to never look at minwax again.... (IMHO)

[Keith Christopher]

I use 320 - 400 and then last some rottenstone or wet sand at 2000 grit if I want a HUGE shine.

[Mike Cutler]

Ralph. I've never had real good luck with MinWax Polyurethane either. I've tried all sorts of methods, and just never got the result I was looking for.
I been using General Finishes, Arm-R-Seal as of late and have got great results with it.
I sand to 150 or 180, apply a flood coat with the grey synthetic pad from 3M, let it dry overnite, then go over it again with the 3M grey pad, or 220 grit on a rubber block. The next coat is lightly applied with a lint free rag, and allowed to dry overnite, and then buffed out with a 3M white pad. The final coat(s) are lightly applied with a rag and allowed to dry for a few days, the hit with a yellow 320 grit, Norton pad. It takes me about a week to finish this way.
I gotta admit I've never considered using a scraper before. If it works for though, keep using it.

[Jim Knauss]

Ralph,
Im no expert on finishing for sure but I never have any luck bushing on poly nomatter WHO makes it. I always use wipe on poly and lightly sand between coats with 400 grit paper. Steel wool leaves pieces behind for me.
I wipe lighly with a tack rag also. Matter of fact I am just finishing a horse for my niece for x-mas. It has one coat of BLO and 5 coats of wipe on poly (satin). I dont care for high gloss usually. Here a pic......... I hope

[Alan Turner]

Evey piece I make seems to call for a slightly different finishing schedule. But, if possible, I start with shesllac, sanded between coats with 320 grit 3M No. 215 fre-cut, which is sterated, and will not clog easily. Great finishing paper. Jeff Jewitt sells it. It is a bit more expenisve than the Mirka, but since it does not load, it lasts for an awfully long time.
If I have a wear surface, such as a table top, I then overcoat with a wiped varnish, being sure it is quite fresh. 2 or 3 coats. They actually sell varnish in 1 or 2 oz. packets, like little foil pouches, and they are great since there is no waste. Between coats of the varnish, I use Liberon 4 - 0 steel wook, which has no oil. Great stuff. I don;t think I know anyone who enjoys brushing varnish. I do not use poly.
Alan

[Dennis McDonaugh]

Ralph, I prefer to use BLO and Tung oil just for the reason you mentioned. I but do use poly occasionally and here's my recipe. I sand between coats with 220 after the first coat, 320 after the second and spray the third coat out of a can. Then I use 0000 steel wool between the third and fourth coat which is sprayed on. It was the only way I could get a smooth finish with minwax gloss poly and a brush. I usually only use this method on pieces I know are going to see hard duty like kitchen tables.

I wipe on 3-4 coats of poly and sand with 0000 steel wool on pieces that aren't going to see a lot of hard use like entertainment centers and occasional tables.

The wipe-on poly coats are a lot thinner than the brush on coats so 3-4 coats of it are thinner than two coats of brush on.

[Jim Becker]

The problem with sanding finishes like polyurethane varnish is that they go on the project in layers...and sanding can expose those layers. You might want to try thining your varnish a little prior to brushing or switch to wiping it on by thinning 50-50 with mineral spirits. Wipe it on quickly and DO NOT revisit an area...if you miss a small spot, it will get picked up on the next coat. Wiping requires many more coats, but you can virtually eliminate brush marks. Dust nibs can still be an issue because varnishes dry so slowly...nature of the beast. Knock them off very carefully with 320 or 400 wet and dry paper lubricated with mineral spirits after the current state of your finish is cured.

You might also consider using a non-poly varnish as they tend to be easier to get uniform results and usually have harder finishes. (Poly is softer to be "abrasion resistant") Pratt and Lambert #38 and Sherwin Williams Fast Dry Varnish are good examples of alternatives to consider. The former is also soya oil based and is lighter in color...desirable for some woods.

[James Giordano]

I like Jims' plan. Thin the poly and wipe it on. I think that the sanding pads are great too . I don't like the Steel wool though because I have found ,when I use it, it leaves a mess of fibers in my finish. Then wet sanding to even it all out.
I have recently used this method and it came out great. It took a lot of coats to finish but it is worth the extra time.

[George Tokarev]

Two or three problems going on here.

First, "levelling" the finish. That's removing brush marks, sags, pullback on the arrises. Means using a firmly backed abrasive - or scraping - so only the high points are removed. Stearated paper is nice, because it loads less, though I use SiC 320 and mineral spirits to keep it cutting aggressively. Dip paper periodically in solvent to clean. Tack off well, of course, after the solvent evaporates.

Second, removing captured particles. If they're captured early (or left by poor tacking), they tend to have a little pullback ring, so I consider it a levelling process. Late capture can be removed by buffing with a Kraft paper bag.

Third, "toothing" the finish. That's the process of making a rough enough surface so that the next coat may adhere mechanically. Oil-based finishes do not chemically bond to a great degree, so this is the answer to the bond. You can do this with steel wool (if you're a masochist) or plastic substitute, but it doesn't level where needed too well, preferring to run up and over, so why use it?

Why indeed? Last stage. Some people don't like glossy finishes, so they introduce a relatively small random scratch pattern to scatter light at the surface. Good use for the woven pads, in my opinion, as I am not a masochist. Even here I like a bit of lube - preferring to put the wax on with the scuff.

I use dilute. Minwax haters can take their favorite and dilute one part spirits to two parts varnish as a start point, Minwax lovers can use the back of the Wipe-on-Poly can to determine, from the amount of solids in this self-levelling finish, how much to dilute the full strength stuff.

[Terre Hooks]

What I have found to produce some great slick results with poly is to scrape the flat surfaces with a new utility knife blade before the final coat. Say, if you are wiping on, after lightly sanding the nibs out of the first coat, and the second dries (preferrably overnight), take a blade and lightly scrape the surface. Wipe this down with mineral spirits and let it dry.

Then, take a pad charged with poly and make ONE stroke across the surface in ONE direction. You want to strike the surface like an airplane landing and taking off. Never stop the pad.

Should end up with a great surface.