Wipe on poly process

[Cesar Vega]

Hi,

I'm about to finish a furniture with polyurethane. I plan to apply it wiping it and I have a couple of questions.

First.
I've heard a 50%/50% proportion is usually good enough. Now, the poly I'm using says that to apply with brush it has to be diluted at 25%-30%, though I think I had to use up to 35% when I did it with brush.
It is so thick, that I think it would have to be diluted to 60% just to be the consistent of a Minwax brush poly out of the can.
The question: is there any other way to measure a proper proportion to dilute the poly to wipe?
Related question: If the usual dry time when applied with brush is about 30 minutes, then, when wiped, how fast it would be reasonable to expect it to dry?


Second.
What exactly do you use to apply it?
I know it is needed a lint free cloth, but what?
I've been using old white t-shirt underwear made of pure cotton, and they have made a good job in other works.
But I'm running out of old t-shirts and if I buy new cotton cloth like fannel, it will lose a lot of fluff.

Third.
Do I still need to sand between coats?
I kind of think that the coats will be so thin that I will be removing it all with a 220 grit sand.

[Quinn McCarthy]

I use minwax wipe on pretty often. It is a great finish. I have never diluted it before hand. Seems to be thinner than brush on to me already. I use Scott brand shop towels that I get in the big yellow box. I always scuff sand between coats. There are 2 advantages to scuff sanding. You get a smoother finish and you fill the pores in the wood a bit every coat.

I hope that helps.

Quinn

[Jeff Monson]

I apply wipe on poly with a good soft cotton cloth or old t-shirt. It dries quite fast as you are not putting on much material. I make my own 50,50 mix as that is all you get with the premixed wipe on. I usually dont sand until I have 3 coats on, as stated earlier you are not applying much poly per coat, sanding through coats is very easy.

[Howard Acheson]

Here is something that should help. A friend of mine who was an early advocate, put it together years ago and it has worked well for many. It should answer all your questions.

QUOTE

There are a number of suggested application regimens that are totally subjective. The number of coats in a given day, the % of cut on various coats, which coat to sand after, when to use the blade and a whole host of other practices are all minor differences between finishers. There are some things that I consider sacred when applying a wipe-on finish.

First, you can use any full strength oil based clear finish. Polyurethane varnish or non-poly varnish is fine.

If you are making your own wipe-on the mix is scientific - thin. I suggest 50/50 with mineral spirits because it is easier to type than any other ratio and easy to remember. Some finish formulators have jumped on the bandwagon and you can now get "wipe on" finish pre-mixed. If you use a pre-mixed, thinning is generally not necessary. But making your own is cheaper and you know what's in it.

The number of coats in a given day is not important. Important is to apply a wet coat with an applicator and merely get it on. Think of a 16 year old kid working as a busboy at Denny's you have sent over to wipe off a table. Sort of rub/swirl the the material on like you would if you were applying a paste wax. Don't attempt any straight strokes. The applicator should be wet but not soaked. The applicator can be a non-embossed paper towel shop towel, half a T-shirt sleeve or that one sock left after a load of washing. Once applied,leave it alone. The surface should not be glossy or wet looking and, if applied correctly, there should be no "brush stroke" type marks. If you have missed a spot, ignore it - you will get it on the next coat. If you try and fix a missed spot you will leave a mark in the finish.

Timing for a second coat involves the pinkie test. Touch the surface with your pinkie. If nothing comes off you are ready for another coat. If was tacky 5 minutes ago but not now, apply your next coat just as you applied the previous coat. Remember, you are wet wiping, not flooding. After applying the second coat, let it fully dry for 48 hours. Using 320 paper and a sanding block lightly sand the surface flat. Now, begin applying more coats. Do not sand between coats unless you have allowed more than 24 hours to elapse since the prior coat. The number of coats is not critical - there is no critical or right number to apply. For those who need a rule, four more coats on non-critical surfaces or six more coats on surfaces that will get abraded seems to work.

After your last coat has dried at least over night you will have boogers in the surface. You should not have marks in the surface because you ignored application flaws. You may have dust, lint and, if you live in Texas, bug legs. Use a utility knife blade at this point. Hold it between your thumb and forefinger, near the vertical, and gently scrape the surface. Gentle is the important word - no harder than you would scrape your face. If you start scraping aggressively you will leave small cut marks in the surface. After you have scraped to the baby butt stage gently abrade the surface with 320 dry paper or a gray ScotchBrite. Clean off the surface. Now, leave the area for two hours and change your clothes. Apply your last coat with a bit more care than the previous coats and walk away.

An anal person is going to have a tough time with this process. Missed spots have to be ignored. Wet wipe, don't flood. Scraping to babies butt smooth means scraping no harder than scraping a babies butt. Ignoring any of these will leave marks that are tough to get out. Getting these marks out requires some aggressive sanding to flatten out the surface and starting over.

Jim Kull

END QUOTE

Finally, It works better to use a gloss varnish for all coats except the last. The flatteners in semi-gloss and satin tend to rapidly fall out of suspension when the finish is highly thinned. If you want a non-gloss finish, use it only on the final coat or two and be sure to stir the material frequently or you will end up with cloudy streaks.a

[Cesar Vega]

Thank you very much for such detailed information :)

[Prashun Patel]

Great explanation, Howard. Thanks.

[Steven Hsieh]

Howard

I find that its more difficult to wipe in swirls than straight. It shows brush storkes.

Maybe it's me, I am new using it.