I am refinishing a coffee table. (I posted earlier about a fish-eye problem and followed the recommedation to use a shellac barrier coat and it seemed to work.) But now I have another “rookie” question. I intend to use 5-6 coats of wipe-on poly. After the first coat I got some “dust nibs.” Should I remove those now, ie between each coat, or can I wait until the final rub out of the last coat? If I should remove now (which I suspect is the correct answer) how is the best way? I did try sanding with 600 wet dry but had to go all the way through that coat to remove the dust nib. Thanks for any help.
Frank
Replies
You should be sanding each coat which will take care of the nibs.
Getting dust nibs on your first coat of wipe on may indicate you needed to wipe your surface better with mineral spirits. The beauty of wipe on is that it dries so quickly that things don't get trapped. A good regimen is to wipe on 3 coats (re-coating before the last coat has had time to cure--maybe a coat every 3 hours), then lightly sand with 320, apply 3 more coats. If you don't let the finish fully cure you should not need to sand between every coat. After sanding wipe down with mineral spirits again to remove the dust. Or vacuuming is also a good way--use the brush tool and really rub it hard to get the dust off.
Frank,
As someone else said, you must scuff sand between every coat. That should easily get rid of any dust nibs. If it doesn't, something else is wrong. In addition to the other suggestions: look for chunks of dried varnish in the can; carefully clean the area in which you varnish; clean the piece with a vacuum, a tack rag, and then rinse it with naphtha or spirits; give the dust time to settle before you begin; and if possible, wet down the area where you work.
Be careful (don't) recoating before the first is dry. All kinds of bad things can happen trying that. In fact, that is one way charlatans "fake" a craze on a piece they want to sell as an antique.
An aside: I don't see the sense in wiping on coats of varnish. It makes for more work, and adds more steps in which things can go wrong--dust, for example. With a badger/fitch brush and very little practice you can easily flow on full strength coats that build much faster.
Another aside: POLY! Yeeeccch. Horrible stuff. Plasticy looking, hard to rub out, and has a greenish cast to it. Can you tell I don't like poly?
Alan
In addition to dust it appears I am getting little bits of what may be lint. I use a piece of cotton bedsheet to wipe-on the poly. Is there something better? Before each coat I clean with mineral spirits and a piece of terry cloth towel. Is that perhaps causing a lint problem. What is the best material to use to wipe-on?
Alan. I see that you don't like poly. I am open to any type that gives me a good smooth luster with some sheen. I have tried shellac but can't seem to get it to work right. It goes on pretty good but dries with either an orange peel look or with ridges. How do you avoid that, and get it to go on smooth?
Frank
Go to Star Finishing Supply (on the web) and buy some of their lint-free cloths, cheesecloth, etc.
I've had good luck with old T-shirts.
Edited 8/11/2004 7:40 am ET by cstanford
In addition to dust it appears I am getting little bits of what may be lint. I use a piece of cotton bedsheet to wipe-on the poly. Is there something better? Before each coat I clean with mineral spirits and a piece of terry cloth towel. Is that perhaps causing a lint problem. What is the best material to use to wipe-on?
Yes, there are a lot of things better than that, up to and including non-embossed paper towels. Oh, and the terry towel is absolutely WONDerful. WHY would you use the most lint full piece of material to do this. DON'T. You do not "dry" the mineral spirits. You wipe your piece with a piece of cloth or paper towel barely moistened with mineral spirits TO GET RID OF ANY SANDING PARTICLES--MOISTENED. Let that dry--probably 10 minutes will do it. Apply another coat of thinned varnish. AND use a non-embossed paper towel to apply your thinned varnish. Use shop towels, or some such.Gretchen
Last night I lightly sanded the work piece, wiped clean with mineral spirits (didn't use terry cloth) Then applied another coat of thinned varnish using an open weave automotive polishing cloth. This kind of cloth worked great because it doesn't seem to have any lint and it holds a lot of varnish so you can apply quite a bit in a short period of time. I then left the room and didn't return until this morning and to my surprise, no dust nibs of any consequence. I think my constantly going in and out of the room before, and in fact staying in the room cleaning up while the finish dried may have contributed to the dust nibs. I've learned a lot about finishing lately ( and quite a bit of it from this forum.) I'm a beginner and have read a lot but to really learn you have to just jump in and try it.
Thanks for your help.
Frank
You might try Norton's new red tack cloth, made of micro fiber, and dry. Picks up dust through static electricity, I think. Works great, and is washable. Since there is no finish in it, there is no contamination. Toolsforworkingwood.com has them. $3.50 I think.
Alan
http://www.alanturnerfurnituremaker.com
Frank, almost all dust nibs occur from dust in the air, not dust on the surface.
The best way to get ready to apply finish is to let the air settle down, get your supplies and tools ready for finishing vacuum the project and the space you will use for finishing, turn on your air filter and get out of the area for at least two hours. Change you cloths and go back and again vacuum the project, wipe it down with a rag dampened with mineral spirits and go to work being careful not to stir up the air any more than necessary. Then get out of the room again while the finish sets.
Too often folks finish sanding, brush off the dust and then immediately start finishing. Then, they wonder where all the dust nibs came from. The came from the air and from the clothes you were wearing when you were sanding.
Using the wipe on method of finish application saves you in a couple of ways. Because the finish is thinned, it becomes tack free faster than a full strength coat. This means that airborne dust has less time to settle on the surface. Second, you only have to worry about the dust nibs before you put on the last coat and sanding is not required between coats for adhesion.Howie.........
Frank,
Excellent! It sounds like you solved your problem.
But as to your questions:
The choice is not between a poly varnish and some other kind of finish such as shellac. There are other varnishes that are not a "poly" varnish, e.g. an alkyd varnish.
Alkyd varnishes are getting a little more difficult to find. I'm not sure why. Homestead has them, as does Waterlox.
All varnishes, even poly, need to be rubbed out to look and feel right. The various additives that make varnish semi-gloss, egg shell, etc., also soften it a bit. So you can use the hardest varnish--gloss--and then rub it out to any surface sheen you want, from matte to high gloss.
An old T-shirt, one that's had all the lint washed out of it, is great for use with finishes. Stay away from terry-cloth, sheets and newer T-shirts. If you don't wear underwear, cheesecloth also works fine, but has a very open weave.
Shellac from the store is something of a crap-shoot, you're never sure what you'll get. Mixed shellac has a shelf life of no more than six months. So far I've not seen a date on a can of shellac, so there's no way to tell if it's too old.
You're much better off mixing your own shellac. The flakes are available just about everywhere, and the only other ingredient, denatured alcohol, can be gotten at your local hardware or paint store. The flakes come in different grades, different colors, all the way from coffee brown to darn near clear.
I'm not too sure what might have gone wrong with your shellac. Orange peel can be caused by trying to put on shellac that's too thick. The first coat should be very thin, a 1/2 lb. or 1 lb. cut; it should flow on almost like water. I almost never use any more than a 2 lb. cut. A thinner first coat and a good brush may solve your problem.
I'm heard, but never experienced, old shellac can cause orange peel. Again, I don't know that to be the case. Taking way too long to dry, or not drying at all, is what usually happens when mixed shellac is too old.
Remember too that shellac is probably the easiest film finish to get right. Any mistakes can be fixed in a flash with steel wool dipped in alcohol or thin shellac. If you don't like the surface it leaves you can rub out shellac just like varnish. A "French polish" is the ultimate rubbed-out finish--it's like glass.
Again, experiment. My one and only maxim on the subject: when finishing there should be no surprises.
Experiment!
Alan the longwinded
Here is a process for wipe on finishing that has stood the test of time with me and many others. It was originally developed by a friend of mine and I present it with attribution to him but with some of my own recommendations. Note particularly the part about defect removal and that between-coat sanding is not required.
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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.
If you are making your own wipe-on the mix is scientific - thin. I suggest 50/50 because it is easier to type than any other ratio and easy to remember.
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 pimply 16 year old kid working as a busboy at Denny's you have sent over to wipe off a table. The applicator can be a paper towel, half a T-shirt sleeve or that one sock left after a load of washing. Then leave it alone. 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. It 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 ligthtly 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. Keep going till you are tired of it. 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 will have dust, lint and, if you live in Texas, bug legs. Use the 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. 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 agressive sanding to flatten out the surface and starting over.
Jim Kull
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