Hello,
I have been trying to read the threads on wipe on methods using poly or spar varnish. I have seen it mentioned that one of the problems with this method is film thickness. I know you can build the total thicknes up to anything you want but does the last thin layer cause problems with scratching easily? If I brush on three or four coats at full strength the last coat is thicker than a wiped on coat is. Does this add to the protection of a heavy use item? Do any of you have problems associated with the last thin layer….can’t rub out, will sand through and show the next layer thus causeing an ugly blimish (sp)? I guess what I am wanting to know is ……..is a thick last coat protect better than a thin one (stand up to heavy use, ect)?
Thank you for your advice.
Replies
Matthew - there's no loss of durability with thin coats as lon as you apply enough to build a protective film. Though if you tried to rub out the finish there's a good chance you would see the witness lines where you cut through the various coats.
But, varnish and polyurethane are poor candidates for a rubbed finish anyway and I wouldn't even try rubbing them out beyond a light buffing with steel wool (and paste wax if you prefer) if you want the hand-rubbed look. Spar varnish contains more oil than standard varnishes and is even less of a candidate for a rubbed finish.
There's and article on rubbing finishes at this link - http://www.alan.net/prgfeat/jjrubbing.html - with some good info on the subject and some recommended products.
If you want a hand rubbed finish, use a finish that will do a good job. If you want the ease of application of a wipe-on oil finish and the durability of varnish or polyurethane, then don't plan or doing a full scale rub-out.
Paul
F'burg, VA
Paul; I think there is some confusion as to terms here; when I speak of a hand rubbed finish, I am meaning one in which the finish was rubbed into the wood as it was applied and as it was beginning to dry or cure. You are speaking of a polished finish and referring to it as a hand rubbed finish. Finishes may be polished (either by hand or machine aided) but when they are polished after they are fully dried or cured rather than before and during that process they are more commonly referred to as polished finishes, while hand-rubbed (which originally referred to a now rarely used linseed oil finishing system) is more commonly taken to mean a finish in which the finish is manipulated during its drying process.
Clay - because so many people use so many terms to mean different things when it comes to finishing, I don't focus on the term used, rather the technique described. In the future, I may not rememeber that you were the one that uses the term "hand rubbed finish" only when applying an oil finish; in which case I'll ask if I'm unsure of your meaning.
If you take a look at the article in the link from the previous post you'll see that the title is "Rubbing Out Finishes." This is the standard term that I've been exposed to, whether rubbing by hand or using a machine. I generally try to make sure I explain the technique involved (or provide a link) and not rely soley on the terms that I know, in order to avoid this sort of confusion.
If you follow the posts on Woodweb, you see that the same sort of exchange occasionally takes place among professional finishers regarding the meaning of terms. Some folks learned that a certain technique is called one thing while others know it as something else. In the end, we have to agree to focus on the technique rather than what we choose to call it.
Paul
F'burg, VA
One of the benefits to using a wiping varnish is that you do not have to sand or scuff between coats as long as you apply subsequent coats as soon as the prior coat is no longer sticky. Wipe on 3-4 coats at a time and you will equal a brushed on full strength coat. If you wait more than a few hours before recoating, a light scuff sanding with 320-400 paper will set you up for your next series of coats.
So, as long as the last coats are applied as soon as the prior coat is non-tacky, you can build up the final coats to the same thickness as one full strength coat.
If you wiped on correctly, there should not be a need to work the final coat much depending on what degree of sheen you want for the final look.
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