# not sure if I have this quite right (wipe on technique)



## LMHmedchem (Dec 16, 2010)

I have been applying thinned poly to an oak plywood desktop. I have 6 coats or so applied and it seems to be coming along. I used 1:1 for the first two coats, then 2:1, 3:1, and am now using 4:1. I have been sanding with 320 and 400 between coats. I clean up the sand residue with a soft brush, then a microfiber dry tack cloth, and finally wipe with shop paper towel with some mineral spirits.

I am trying a wipe-on technique to apply the satin poly. I have tried using both a microfibre cloth, and a cotton t-shirt. I have basically been poring some poly on one end and wiping toward the other. I am treating this more of less like applying tung oil. It seems that most of the finish is ending up in the application cloth. It is certain that the finish builds up faster when I apply with a foam brush, but wiping on is definitely giving a smoother finish. I don't care that it's taking somewhat longer, but I don't really like wasting as much finish material as it appears I am.

Would it be better to apply with a foam brush, foam roller, or microfiber roller, and then wipe smooth with a cloth, or should I stick with what I am doing?

There doesn't appear to be any difference between using a microfiber cloth and t-shirt. I can pretty much clean the microfiber cloth completely, which I can't seem to do with the cotton, so I will probably stick with the micro.

The coats seem to dry very fast when using the wipe method. I am still only applying coats about every 12 hours. Can I apply more regularly, or should I keep with the 12 hour interval?

LMHmedchem


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## jack warner (Oct 15, 2010)

you dont want to us mineral spirits to wipe yur fresh finish with . use denatured alcohol. dries faster and wont leave a residue.

i dont use foam pads/brushes they tent to give you bubbles.

if its a large surface a mohair roller is best, then tip it with a good natural/black bristle brush.

buy just thinning poly, that doesnt really make it a wipe on. your better off buying one. watco is not bad. i spray 99.9% of my poly and am not a fan of wipe on poly, i prefure an oil/varnish wipe.

if your gonna stay with what your doing i would add abit of penetrol or maybe blo.

although wiping puts on lighter coats i would still stick with the recoat time recomended for the product.


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## cabinetman (Jul 5, 2007)

I would just continue with the "T" shirt application. I wouldn't pour the media on though. I would use a wet pad (not dripping), and wipe with the grain. It should draw enough that you don't need to "tip off" with a brush.

Twelve hours lets it dry, but it isn't cured. Depending on the temp and RH of your finishing area you may want to wait. An application covers the previous one and will delay the curing time for it.












 









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## LMHmedchem (Dec 16, 2010)

jack warner said:


> you dont want to us mineral spirits to wipe yur fresh finish with . use denatured alcohol. dries faster and wont leave a residue.


This doesn't seem to make sense to me. I am cleaning up the last bit of dust and then putting on a coat of poly thinned with mineral spirits. Why would it matter if there was a residue of mineral spirits left on the surface? All non-synthetic alcohol has some water in it. The driest you can get ethanol by distillation is 90%-95%. I would think that even a small amount of water would be the last thing you would want to get on the surface between coats of oil based poly. Did I misunderstand what you said?



jack warner said:


> buy just thinning poly, that doesnt really make it a wipe on. your better off buying one. watco is not bad. i spray 99.9% of my poly and am not a fan of wipe on poly, i prefure an oil/varnish wipe.


I have some wipe on poly that I will switch to for the last few coats.



cabinetman said:


> I would just continue with the "T" shirt application. I wouldn't pour the media on though. I would use a wet pad (not dripping), and wipe with the grain. It should draw enough that you don't need to "tip off" with a brush.
> 
> Twelve hours lets it dry, but it isn't cured. Depending on the temp and RH of your finishing area you may want to wait. An application covers the previous one and will delay the curing time for it.


By "use a wet pad" do you mean the folded up t-shirt, or a foam pad? It seems that applying with a foam pad and then wiping smooth with a cloth gives good results. I don't seem to get air bubbles that way. Is this what you mean, or should I dip the folded up t-shirt in the poly to apply it? Is there some reason to use a cotton t-shirt instead of a microfiber cloth?

 LMHmedchem


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## jack warner (Oct 15, 2010)

dna consists of ethyl alcohol, ethyl acetate, methyl ketone, and methyl alcohol. theres no water.
mineral spirits are a petroleum hydrocarbon solvent. petroleum=oil
thinning poly/varnish with ms is diferent from using it straight. poly/varnish's are made from resins thinned with dif types of thinners. the thinners evaperate from the resins giving you your finish coat. when you use ms it can/may/will soften up the surface and can give a softer bond between coats. poly doesnt stick to its self that well anyway, thats why your shouldnt sand with finner paper than 220.

the proper app. for poly is dilute first coat 30-40% for bonding to wood. second coat dilute 10-15%. then straight from then on. usually 3rd coat is good.

i would be very carfull mixing product, dif brand use dif solvents. not all compatible. i allways finish with the product i started with.

thats just my 35 yrs of finishing.


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## LMHmedchem (Dec 16, 2010)

jack warner said:


> dna consists of ethyl alcohol, ethyl acetate, methyl ketone, and methyl alcohol. theres no water.


There is always water in alcohol, unless it has been specifically removed by a drying process, or was created by a synthetic pathway not involving water. It can be the devil itself to separate fully. Distillation will only give ~95% pure ethanol. It can be dried with agents like sodium sulfate, but that is expensive. I believe they use simple things like corn starch on the large scale. We have reagent grade 100% (200 proof) ethanol in the lab, but that is synthetic (not made by distillation), and is expensive compared to 95% (makes a hell of a martini though). I would have to look it up in the Merck or CRC handbook, but I believe that DNA is considered 95% ETH in water. This is usually not a problem, since ethanol is typically used as a polar solvent for water based systems. Even for applications like disinfecting, 100% ethanol has not effective at all. You need to add at least 5% water before it will kill bacteria. That is why over the counter iso is sold at 70%. It is also a fair detergent for co-solving greasy stuff in water, but water is almost always in the picture with ethanol. I suppose it is possible that the DNA sold for bulk solvent has been dried, but I don't know why you would bother when it is used for so many water based applications, plus I wouldn't expect it to be so cheep.

Since I take your word for it that it doesn't cause any issues when used to clean an oil based surface, the small amount of water must keep its association with the ethanol and not wet the surface. That would make sense with it being so difficult to disassociate with the ethanol in the first place. Either that, or it does wet the surface slightly but evaporates before it creates a problem.

The first person who told me to clean up with MS was a very good cabinet maker and wood carver. We were building a communion table and alter for a church and were in a place where we didn't have much access to supplies. That was long before the days of microfiber tack cloth. Maybe we were just cleaning up the sawdust after sanding and before finishing. It was long ago, and I don't really remember, but I have done it ever since. Alcohol seems to work just as well, so I will use that since you think MS could soften the surface.



jack warner said:


> the proper app. for poly is dilute first coat 30-40% for bonding to wood. second coat dilute 10-15%. then straight from then on. usually 3rd coat is good.


I never seem to get the look I want before 10 coats or so. Maybe I am sanding off too much? I like satin with a build up of many layers. It starts to get a bit glossy after many coats, but the wood still looks warm and rich. Most of what I have done are thresholds and things that I expect to get allot of wear.



jack warner said:


> i would be very carfull mixing product, dif brand use dif solvents. not all compatible. i allways finish with the product i started with.


Both products are the same brand (minwax). I have used the wipe-on minwax after many layers of regular minwax and I have not noticed any issues. Before, I always applied with a foam pad, and sanded out bubbles and such. I finished the last few coats with the wipe on to get a smooth final coat. I am quite sure that is not the best way to get from here to there, but that is why I am posting. The surface is much smoother sticking to the wipe on, but it is taking longer.



jack warner said:


> thats just my 35 yrs of finishing.


I've only been finishing for 35 years if you count the bookends I made in Cub Scouts.

LMHmedchem


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## cabinetman (Jul 5, 2007)

LMHmedchem said:


> By "use a wet pad" do you mean the folded up t-shirt, or a foam pad? It seems that applying with a foam pad and then wiping smooth with a cloth gives good results. I don't seem to get air bubbles that way. Is this what you mean, or should I dip the folded up t-shirt in the poly to apply it? Is there some reason to use a cotton t-shirt instead of a microfiber cloth?
> 
> LMHmedchem



When you fold up "T" shirt material into a nice creaseless square, you have a "pad", not a foam pad. I would not use foam pads or foam brushes. Yes, you can dip the pad into the poly to get it wet, but you don't want it dripping wet. Use only that pad to draw the finish out (with the grain). You don't need further rags to wipe off excess, as you will get the feel of how wet the surface is getting and how to draw a path out without bubbles.












 









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## jack warner (Oct 15, 2010)

thanx for chem lesson. even if there is a 5% water content, and ill take your word for it, im not a chemist. the tinny bit of water is evaperated by/with the alcohol, and leaves to residue. a good way to test is lightly dampen two cloths, one with dna, theother ms. wipe on a shinny surface and watch how much faster the dna evaperates compared to the ms. try it on a mirror, that should show the residue dif.


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