Rubbed-Out Finishes and Durability
A discussion of rubbing-out technique and the nature of the final finish. November 27, 2007
Question
I am using polyurethane on a tabletop and as expected, a dust free final finish is impossible. I was wondering if I would have adhesion problems if I used a gel varnish or other wipe-on after going over the top with 2000 Abralon. I would like to use the wipe-on to help disguise orbit marks and leave a more scratch resistant finish without dust problems. By the way, I'm not using CV because I don't have a proper spray booth and I've never used it. And I'm not using waterborne because I want max water/heat resistance.
Forum Responses
(Finishing Forum)
From contributor B:
Rather than take the chance of an adhesion problem by adding a coat of gel varnish, why not continue with your rubbing process and bring it up to the sheen and desired smoothness you want with the 2000, then 4000? Or hit it with the 2000, then change to a buffing pad and Finesse-it or Perfect-it from 3M. When doing a high gloss on a grand piano, I will use 600 and 800 grit wet or dry paper, then switch to waffle type foam buffer pads and Finesse-it. You can take it to the sheen you want, even to the point of being able to read the wattage on the overhead light bulb in the reflection! I am assuming you are using a poly that is not for exterior or boat work, as it is more flexible and does not buff up as well.
From the original questioner:
The whole reason for adding the final thinned coat of varnish is because when I buff to the semi-gloss sheen I like, the surface is then less resistant to water marks, possibly food stains, and especially scratches. I think leaving the final surface un-rubbed will help provide a more durable finish. This is for a kitchen table. The poly I'm using is indoor type. I have never used Perfect-it or any of the pads you mentioned. Do these products help with the problems I have with rubbed semi-gloss finishes? From my understanding those products are used for full gloss.
From contributor B:
Rubbing a finish does not make it less durable or resistant, but putting the gel varnish over poly will possibly lead to an adhesion problem. The bond will not be as good as you want. The pads and material I mentioned will give you a high gloss, if you take it there. It isn't the product as much as it is the operator.
Whoever gave you the info that a rubbed finish is less durable is off base. In order for it to be true, you would have to change the chemical structure, which you are not doing. Steinway obtains a satin sheen by rubbing; they also obtain a high gloss mirror sheen by rubbing. Think of rubbing compounds like Finesse-it as Liquid Paper in multiple grits. Remember this, all surfaces will damage, scratch, or dent eventually and will have to be cared for.
From the original questioner:
Thanks for the info. My experience has been that if I rub to satin or semi, it will mark (not sure if it's a scratch) very easily if you drag a fingernail across. The same finish applied in a satin or semi sheen doesn't do this. Also, having all those fine scratches (from the rub) makes a more porous surface that smudges and seems more susceptible to water or food stain. I don't really like high gloss, but don't see it having these issues. Maybe it's my technique. I understand what the compounds do, but I never use them because I never intend to go to full gloss. Maybe I am mistaken when I just leave the finish at 2000 without using a compound.
Currently my rubbing process is to flatten with 600 around a block, then 1000 and 2000 Abralon. This looks a bit hazy when compared to un-rubbed semi-gloss, so that's why I thought to put a very thinned wipe on. Almost pure thinner would leave me haze free and 95% dust free with less chance of marks when in use. Perhaps I'm just missing some steps in my rubbing process. Do the waffle pads have a brand name? What would your process be for rubbing to a semi-gloss?
From contributor B:
I understand your problem better with your added explanation. What poly are you using? What you describe sounds like a spar urethane poly or some other type also made for exterior use. Exterior use poly is softer and flexible, which makes it scratch more easily; the chemistry is different and does not rub, polish, or react the same.
I use mostly satin materials, whether lacquer or poly. The lacquers I use will be either standard, pre-catalyzed, or post-catalyzed, depending on what I need the surface to do. I only use poly on exterior work like doors or boats. Either way, the rubbing is the same technique and I rub everything that goes out of the shop, then wax it. Many times I will start with the Abralon, 360, 500, then switch to steel wool (#0000). Other times I start with 320 no fil paper, then go to steel wool. My last passes with wool are done with a lubricant which makes the wool less abrasive. Sometimes I use wet or dry paper (400-800), then compound to high gloss.
I had hoped to help you with your problem, but it seems that I have fallen short. I still feel that you will be making a mistake and open the way for problems by doing the thin coat of a dissimilar material, unless it is a paste wax...
From the original questioner:
The poly I use is indoor
Minwax and GF arm r seal. I am aware of the differences in long and short oil varnishes, so that's not a problem. I agree waxing after rubbing helps with the haziness left by oooo wool or something similar. I haven't tried using a lubricant with wool - I'm sure that could help too. Do you ever have problems with wax contamination if you need to do a touchup? I can't believe you rub and wax everything you make. For most applications I get great results from waterbournes off the gun. Dining tables with filled grain are probably the most demanding type of finish, especially without a good booth.
From contributor B:
Wax I use contains no silicones or non-drying oils. Never a problem later this way. I am one of those people that believes in rubbing out finishes no matter how nicely it comes off the gun. To me, there is a definite difference in look and feel between an off the gun finish and a rubbed finish. I know others may disagree, but that is okay. Yes, full filled high-gloss finishes are the most demanding to do correctly.
