Hope someone can help us. We have applied numerous coats of polyurethane varnish to an old oak table. The table was throughly sanded with 400 and 600 paper between coats and vacuumed. (Trying to fill in some of the grain for a smooth top) The last couple of coats were with thinned varnish (turpentine) and now the table is streaked. The streaks appear to have a different gloss (or lack of) . All varnish was applied in only one direction using a soft, clean natural bristle brush. Any suggestions? Will the next, and hopefully last coat, take care of this? Help!!!!!!!!!
Thanks, Su
Edited 4/12/2005 5:01 pm ET by pbillsu
Replies
A few questions:
1) what brand poly did you use?
2) were all the coats with the same brand, and the same gloss level?
3) How much did you thin the later coats?
It is often advisable to thin the first coat (kinda like a sealer), but not the subsequent coats (unless the stuff is too thick and gloppy to brush effectively).
"I would never die for my beliefs because I might be wrong."
-- Bertrand Russell
Hi Nikkiwood, Thanks for your response. We used minwax. We started with satin but are ending with semigloss. The varnish was thinned to try to get a really even coat. Any ideas?? Su
Yeah, the streaking probably was caused by the thinning you did and using two different sheen levels.I would suggest you do the final coat full strength, with whichever sheen level you prefer. I have used Minwax poly, and I have found it very brushable, without thinning. The other trick is to be sure you put on a full "wet" coat. Some of the modern polys are very fast drying, which can create streaking problems if you don't "flow" the varnish onto the surface. And of course, you must work quickly. Good luck."I would never die for my beliefs because I might be wrong."
-- Bertrand Russell
I think Nikiwood has the basics pretty well covered. I'll just add this:Don't thin Minwax with turpentine. Mineral spirits is the correct thinner. I'm not sure that Turps does any harm, but it sure won't work any better, and why take the risk.Just sand with 220 or 320 between coats, preferably 220. Poly has enough trouble adhering, and sanding finer than necessary just makes the problem worse.Thinning doesn't necessarily make any product level and flow out better, especially varnishes, and especially when you use the wrong thinner.Michael R
Lots of good info but let me just add that heavily thinning a finish that contains flatteners to make it into a non-gloss allows the flatteners to quickly fall out of suspension. Frequent and constant stirring may not help. The flatteners end up in your rag and are unevenly deposited as you wipe.When using a wiping finish, it is best to use only a gloss finish and dull the finish using other techniques after it has cured.Howie.........
Hi Howie, Thanks for your reply. We started out with a satin finish but decided that we preferred a semi-gloss so we switched. I added terpentine at about a ratio of 1 to 10 for the most recent coat. We are really working under adverse conditions- basement, poor lighting, bristles come out of the brush, etc. I would prefer to wipe rather than brush on the final coat but I am afraid of lint. What type of cloth do you recommend? Thanks, Su
Use an old white sock, T-shirt, or an old sheet. Most often I use non-embossed paper towels like the "shop towels" you get in the big box.Howie.........
Per previous posts:
Stir slowly often with a thin vertical stick. Do not shake.
Thin with mineral spirits or with naptha which is my preference. Naptha flashes off FAST. Mineral spirits flashes slower.
Gloss to satin in OK. Satin to gloss is not OK.
Just my experience.
A bad day woodworking is better than a good day working -- yes, I'm retired!
Hi Howie, Thanks for your suggestion. I used an old sheet once when applying tung oil and had lint all over the finish. Won't that also happen with poly? Thanks, Su
Anything with lint will be a problem.Howie.........
I'm not completely clear on the sequence of coats of which sheen but I think one potential problem was stirring your product. "Semi-gloss" (satin?) has flatting agents that must be kept in suspension.
Hi...
You've had some really good feedback. Lemme add a little, if I may.
The flatting agent in most clear finishes, unlike those in paints, are refractive solids - usually fume silica. The fume silica's crystal structure tends to scatter incident light when reflected, helping to dim the perception of gloss. Further, since the fune silica consists of sub-micro solids, it will to some small degree hide the surface beneath, making its characteristic grain appear to be less sharply defined. No fume silica = gloss, some = semigloss, more=satin. Since it doesn't affect the actual surface of the coating, there's no such thing as flat.
Once satin or semi has been applied, there's no erasing its effects save to sand and have another go at it (you can go "duller", but brighter ain't in the cards.) Because of the hiding effect, it's recommended that all coats save the last one or two be gloss.
9% dilution (1:10) doesn't seem like very much, though I don't know the chemistry of MinWax products well enough to comment as to compatiblity with various thinners. If the varnish isn't absolutely uniform, you may well see variable light scatter as streaks. Are the streaks in color? Surface texture? Are they visible at every angle?
It sounds possible that you may have a problem with over-brushing, to the extent that thinned material may not flow as expected and become very sensitive to additional brush passes. The one thing you have to do with varnish is get it on and get away from it. If there's a goof, leave it - sand later and repair, as re-brushing is likely to do even more damage. As Nikkiwood stated, you must work quickly.
Your description of poor light and shedding bristles has made its own contribution, I'd surmise. Suggest you get one of those inexpensive double halogen work lights, and set it up so that you can look across the surface to the light as you work. The reflection will "tell you everything." If you're not paying $15-$25 for your *natural bristle* brush, then you may be the victim of a quality problem with the brush itself. Sherwin-Williams' best house brand of natural bristle brushes are about the finest I've found locally (out here in the sticks.) Even those need a little judicious shaping of the tips to get rid of uneven bristle extensions. (If you're tempted to do that, use a razor and cut bristles at a slant so their ends are at least tapered - scissors will wreck 'em.)
I'm not a MinWax fan, and can't comment knowledgeably about its usefulness in padding techniques. Usually, such varnishes are too slow drying and too sticky to go on easily with a pad. If they can be so used, they should be thinned to the max allowed by the mfgr, and may benefit from a tad of boiled linseed oil. Apply *sparingly*, rub 'til tack is gone, and wait a day for the next coat. Someone who's done it successfully with that specific product may help you with better info.
My own approach to varnishing those "sacred objects", be they heirlooms or just a table that's in everyone's line of sight, is to use all gloss with wet-or-dry sanding after the first couple of coats. Need to be sure, of course, that no water makes its way under the surface onto unsealed wood! With that put-it-on-take-it-of approach, you'll fairly quickly fill all the pores. Once the whole can be wet-sanded with no visible bright spots (depressions) it's time for one more coat. Final coat is sanded very lightly - just enough to remove brush marks or other oddities -with 600, 800, and 1200 girt paper. Each successive grit is used only enough to eradicate scratches from the previous grit.
Using *white* automotive rubbing compound, rub the surface to a shine. The trick it to use compound sparingly on a damp rag, and rub 'til it's not leaving a film behind. In the basement, my preference is to chuck up a sanding disk in the portable drill, cover it with a lambswool bonnet, wet the bonnet, add compound, and use that for the rubout. Caution - it'll sling white stuff everywhere! Once done, do the same with Meguiar's automotive Swirl Remover for the final polish.
If you've used satin or semi for the last coats (adjust how you count, as you've been sanding most of it away), you'll arrive at a surface that appears to be semi (e.g.), but is dead smooth and a joy to touch. If you've used all gloss, you can modify using the lightest touch with 0000 steel wool, rottenstone in oil on a felt pad, etc., to achieve the degree of surface dullness you prefer - the secret lies in unform application of the process used.
Finally - varnish is a bear to apply to perfection on large surfaces - brushing nearly inevitably leads to visible imperfections, especially if the surface is horizontal. If you've an air compressor, you might consider buying a conversion HVLP spray gun (e.g., Porter-Cable makes one for about $85) so as to make application significantly faster, and free from intruding brush contact.
Hope this might have helped a little. Best of luck with the project!
---John
Another trick I've used for large surfaces is to add a bit of Penetrol - it helps maintain the wet edge and promotes leveling.
Hi, Ed...Agreed, although I'm reluctant to any retarders because of the increased "wet" exposure time. Dust and those darned bugs seem to even get into lacquer, much less varnish!
Re: PenetrolI have used this stuff a lot for alkyd paints, but never considered using it in poly. What qualities does it impart to the poly that you don't get by a moderate thinning?My favorite poly is Ben Moore, and sometimes it is just too thick and gloppy to brush straight from the can. A little paint thinner does the trick, but now you have me wondering about Penetrol (which I have never regarded as a "thinning" agent)."I would never die for my beliefs because I might be wrong."
-- Bertrand Russell
LOL, I guess first I should say, "Cuz that's the way I wuz taught!"
I think there is probably a lot of "stuff" we do by instinct, belief, and habit, LOL. However, I believe adding Penetrol to varnish and poly helps to maintain the wet edge, which promotes better leveling, and allows the stuff to flow better in general, helping to hide brush strokes, etc. In short, I've always done it that way. ;-)
The flatting agent in most clear finishes, unlike those in paints, are refractive solids - usually fume silica. The fume silica's crystal structure tends to scatter incident light when reflected, helping to dim the perception of gloss. Further, since the fune silica consists of sub-micro solids, it will to some small degree hide the surface beneath, making its characteristic grain appear to be less sharply defined. No fume silica = gloss, some = semigloss, more=satin. Since it doesn't affect the actual surface of the coating, there's no such thing as flat.
Once satin or semi has been applied, there's no erasing its effects save to sand and have another go at it (you can go "duller", but brighter ain't in the cards.) Because of the hiding effect, it's recommended that all coats save the last one or two be gloss.
I think you've received some bad information. If flattening agents didn't affect the actual surface of the coating, they wouldn't alter surface reflectivity, i.e. reflectivity at relatively low ancles of incidence. Yet they do, indeed. Just look at a gloss finish from a low angle, then look at a dull (off the gun) finish from the same angle and you'll see what I'm talking about. With your engineering background, that should be apparent.
A flat finish may contain as much as 15% silica, equal to half the resin content or more.
You can also polish satin finishes to a high level of gloss. You can't reduce the internal scattering and loss of clarity, but you can sure alter the surface reflectivity (gloss), especially with lacquers.
As to flatness, I consider the dead flat clear finishes with less than 10% reflectivity that I use to be definitely flat. That's as flat as any dead flat paint. I sure wouldn't call it semigloss. One thing about dead flat clear finishes: one of the biggest problems with them on furniture is that they develop shiny spots from wear where people rest their arms. I get called on to take care of this problem frequently, and expect this fashion to run its course pretty soon.
As a pro finisher for over 35 years, I can also tell you that a halogen work light doesn't help when finishing. It's way to harsh and contrasty. A more diffuse light works much better. Every pro finishing setup I've ever seen uses diffuse lighting.
Most alkyd varnishes pad very easily if you reduce them 50% or so with mineral spirits. You just wipe it on evenly. No rubbing back needed, and adding linseed oil just softens the final finish, which may or may not be desirable
There's no need to wet sand between coats unless your finish isn't dry and you are getting corning on your sandpaper. 220 grit stearated paper is fine. Wet sanding is typically reserved for cutting and rubbing the final finish.
Finally, while I spray over 90% of the finishes I do, I don't spray varnish. I prefer to brush. The slow drying overspay from oil based varnish is a bear to deal with even in a good spray booth. It can of course be sprayed, but at a cost.
Michael R
Edited 4/14/2005 12:17 pm ET by Woodwiz
Hi, Michael...
<<<<<<<<<<<<
I think you've received some bad information. If flattening agents didn't affect the actual surface of the coating, they wouldn't alter surface reflectivity, i.e. reflectivity at relatively low ancles of incidence. Yet they do, indeed. Just look at a gloss finish from a low angle, then look at a dull (off the gun) finish from the same angle and you'll see what I'm talking about. With your engineering background, that should be apparent.
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With varnish (at least what I'm using), I get a smooth surface - did with the older oil-based urethanes, too. If it's sprayed dry enough, any liquid will make for a barely less-than-flat finish, yielding the appearance of surface disruption as a function of drying. Furniture lacquers, in my opinion, are among the worst for it. With automotive lacquer, you at least expect to color-sand before "varnishing" with clearcoat. Furniture lacquer can't be smoothed by sanding after the final coat unless you expect to restore with rubbing.It does depend on the manufacturer's approach. There are "not glosses" that will level smoothly, and others that have an additive contributing to surface disruption. For furniture and cabinets, I personally prefer the slick stuff because it stays clean and feels better (to me.) We all know how easy it is to mar flat paint.<<<<<<<<<<<<<<<<<<
You can also polish satin finishes to a high level of gloss. You can't reduce the internal scattering and loss of clarity, but you can sure alter the surface reflectivity (gloss), especially with lacquers.
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You bet, and boy are they nice under the fingers! Works well with a good hard poly, too. Lacquer is my last alternative - it tends to dry so quickly as to bond only fairly, and may chip or just slough off if stressed. Also prefer (some) poly because of its inherent flexibility e.g., it will deflect slightly under a hard blow without chipping. For fineness of quality to the touch, I prefer to polish and then cut the surface if a lower gloss is desired. That's a spendy method for contract work, and I realize that not every customer is going to want or appreciate it.<<<<<<<<<<<<<<<<<<<
As to flatness, I consider the dead flat clear finishes with less than 10% reflectivity that I use to be definitely flat. That's as flat as any dead flat paint. I sure wouldn't call it semigloss. One thing about dead flat clear finishes: one of the biggest problems with them on furniture is that they develop shiny spots from wear where people rest their arms. I get called on to take care of this problem frequently, and expect this fashion to run its course pretty soon.
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I'm not a pro, and have never attempted to even look for such a varnish. Actually, I wouldn't - just seems contrary to what seems right (any traditionalism here...?) On the other hand, I've applied an awful lot of finishes over the last 50 or so years, and am finally beginning to get one or two coats on right once in a while.I'm not surprised to hear about shiny wear areas - they're just knocking down the high spots!<<<<<<<<<<<<<<
As a pro finisher for over 35 years, I can also tell you that a halogen work light doesn't help when finishing. It's way to harsh and contrasty. A more diffuse light works much better. Every pro finishing setup I've ever seen uses diffuse lighting.
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I find they work OK if they're set high enough, and far enough away not to be blinding. If too close, they can bounced off the ceiling. Too little light is worse than too much, methinks! I don't really care how well I can see the object itself, just that the finish surface is highlighted with sufficient brilliance that every flaw is crying out for help - before it's too late to react.<<<<<<<<<<<<<<<<
Most alkyd varnishes pad very easily if you reduce them 50% or so with mineral spirits. You just wipe it on evenly. No rubbing back needed, and adding linseed oil just softens the final finish, which may or may not be desirable
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The "usual" 50% wasn't a given for me in light of the prior discussion about MinWax' particulars, about which I'm ignorant. You're right - about 50% dilution should do the trick with most of whatever the devil is "normal" these days.<<<<<<<<<<<<<<<<<<<<
There's no need to wet sand between coats unless your finish isn't dry and you are getting corning on your sandpaper. 220 grit stearated paper is fine. Wet sanding is typically reserved for cutting and rubbing the final finish.
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Right. The only reason I like to wet sand early is because the water tends to more or less "glue" the entire paper surface down to yield slightly more uniform cutting with minimal pressure. I hesitate to steer (apparent) beginners to 220 for fear it will lead them to color breakthrough on the stain. I figure if they know enough about sandpaper, they'll discover on their own that they could go coarser.<<<<<<<<<<<<<<<<<
Finally, while I spray over 90% of the finishes I do, I don't spray varnish. I prefer to brush. The slow drying overspay from oil based varnish is a bear to deal with even in a good spray booth. It can of course be sprayed, but at a cost.
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Amen, mostly. I'm using a water-based poly that acts like it thinks it's an oil, but is touchable in 10-15 minutes and sprays beautifully.I really appreciate your having taken time to reply, Michael - thanks.---John
Edited 4/14/2005 2:05 pm ET by John
With varnish (at least what I'm using), I get a smooth surface - did with the older oil-based urethanes, too.
I'm not talking about a smooth surface. I'm taking about specular reflectivity or sheen. Let me try a different approach: Put a paint can on a high gloss surface and look at its reflection from a low angle, say 30 degrees. You will have a mirror like reflection in which you can read the (backwards) reflection of the printing on the can. Then place it on a smooth satin finish, either rubbed or off the gun. The image will be blurred and unreadable. That is purely a function of surface condition and is produced by the flattening agents.
If it's sprayed dry enough, any liquid will make for a barely less-than-flat finish, yielding the appearance of surface disruption as a function of drying.
That has nothing to do with the point. A dry top coat is considered a defect among finishers. A full wet final coat is normal, although some finishers reduce the final coat with thinner, with the aim of getting better flowout.
Furniture lacquers, in my opinion, are among the worst for it.
I have no idea what you are talking about here. I used to buy and apply lacquer by the 55 gallon barrel, and never saw anything like what you are talking about. Can you give an example?
With automotive lacquer, you at least expect to color-sand before "varnishing" with clearcoat. Furniture lacquer can't be smoothed by sanding after the final coat unless you expect to restore with rubbing.
Again, I don't understand what you are talking about. The normal process of cutting a finish involves sanding to level the finish, then using progressively finer abrasives to get the desired degree of sheen. You can get a good satin or dull finish by sanding alone, with steel wool with wool lube, or with pumice and oil, among other techniques. Using any kind of compound often gives an unwanted effect. Higher glosses do generally require compound and polish, although some finishes can be polished with only a dry buff. Polishing and then dulling back is a complete waste of time and does nothing to enhance the finish.
It does depend on the manufacturer's approach. There are "not glosses" that will level smoothly, and others that have an additive contributing to surface disruption. For furniture and cabinets, I personally prefer the slick stuff because it stays clean and feels better (to me.)
This doesn't correspond with anything in my experience. Perhaps you could give an example? Manufacturer and product name of an example of each? Or perhaps a reference?
<<<<<<<<<<<<<<<<<<You can also polish satin finishes to a high level of gloss. You can't reduce the internal scattering and loss of clarity, but you can sure alter the surface reflectivity (gloss), especially with lacquers. >>>>>>>>>>>>>>>>>>You bet, and boy are they nice under the fingers! Works well with a good hard poly, too.
Then why did you categorically say earlier that it couldn't be done?
Lacquer is my last alternative - it tends to dry so quickly as to bond only fairly, and may chip or just slough off if stressed. Also prefer (some) poly because of its inherent flexibility e.g., it will deflect slightly under a hard blow without chipping.
Lacquer is known for its ability to bond, and for the fact that one coat melts into the next. Fash time and drying time are easily controlled. Poly is notorious for its difficulty in adhering even to itself. Also, there are all kinds of lacquers, and only the cheapest resins are "chippy". You can formulate almost any kind of performance you like. In manufacturing over a million board feet of pine furniture, I used an acrylic modified NC lacquer specfically because of its flexibility. In contrast to your experience, with oil based poly, I have found it to be hard, and not particularly flexible.
I'm not a pro, and have never attempted to even look for such a varnish. Actually, I wouldn't - just seems contrary to what seems right (any traditionalism here...?)
50 years ago, an "eggshell" finish was all the rage in my neck of the woods. I remember rubbing out my Dad's varnished table tops with pumice and paraffin oil to get an almost dead flat finish. Finishes in the 18th century and before were generally pretty flat, too. Gloss finsihes first became popular with "vernis au tampon", French polishing, starting around 1820. Traditionalism? There is no absolute "right" in finishing, just what meets your requirements or expectations.
I'm not surprised to hear about shiny wear areas - they're just knocking down the high spots!
Not so. They are actually polishing the surface.
I find they work OK if they're set high enough, and far enough away not to be blinding
Halogen lights are not as bad if you bounce the light off the ceiling to duffuse it, but it's still pretty harsh, in my experience. Sometimes it's just as bad as having too little light. Direct illumination doesn't work at all. I find, as do most others, that a diffuse light source makes it a lot easier to spot flaws.
The only reason I like to wet sand early is because the water tends to more or less "glue" the entire paper surface down to yield slightly more uniform cutting with minimal pressure. I hesitate to steer (apparent) beginners to 220 for fear it will lead them to color breakthrough on the stain. I figure if they know enough about sandpaper, they'll discover on their own that they could go coarser.
A proper sanding block will achieve the same end better and with a lot less cleanup. Spend $5 and treat yourself to a good cork block. If you're paper is glued down you're probably not using enough water. Its function is to jubricate and carry away the swarf.
Michael R
Hello, Michael..Apologies for having been out-of-pocket for so long. Will attempt to respond to your comments:(If a past comment by myself is included, I've added JOHN/WOODWIZ identifiers to keep it form becoming hopelessly confusing. Otherwise, beginning comments are by WOODWIZ, and responses by JOHN.) <<<<<<<<<<<<<<<<<<<<<<<<
I'm not talking about a smooth surface. I'm taking about specular reflectivity or sheen. Let me try a different approach: Put a paint can on a high gloss surface and look at its reflection from a low angle, say 30 degrees. You will have a mirror like reflection in which you can read the (backwards) reflection of the printing on the can. Then place it on a smooth satin finish, either rubbed or off the gun. The image will be blurred and unreadable. That is purely a function of surface condition and is produced by the flattening agents.
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Absolutely correct. And, as the angle of incidence lessens, the reflected image becomes more clear. Even a piece of (hand) planed, unfinished wood will reflect something of an image if the angle of incidence is low enough. A truly flat finish may reflect a hint of shape or color, but with virtually no clarity. Other fit somewhere in between.<<<<<<<<<<<<<<<<<<<<<<<<<
A dry top coat is considered a defect among finishers. A full wet final coat is normal, although some finishers reduce the final coat with thinner, with the aim of getting better flowout.I have no idea what you are talking about here. I used to buy and apply lacquer by the 55 gallon barrel, and never saw anything like what you are talking about. Can you give an example?
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Agreed. That's my practice, as well. More difficult with lacquer in a closed cabinet because overspray is considerably more difficult to control.<<<<<<<<<<<<<<<<<<<<<<<<<<
The normal process of cutting a finish involves sanding to level the finish, then using progressively finer abrasives to get the desired degree of sheen. You can get a good satin or dull finish by sanding alone, with steel wool with wool lube, or with pumice and oil, among other techniques. Using any kind of compound often gives an unwanted effect. Higher glosses do generally require compound and polish, although some finishes can be polished with only a dry buff. Polishing and then dulling back is a complete waste of time and does nothing to enhance the finish.
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We are somewhat in disagreement here. I prefer if possible to leave some of the wood's character visible, but without abrupt discontinuances, e.g., as might result from a small pit arising beneath an air pocket. Polishing to a higher sheen than the intended final product will highlight even the smallest imperfection, which can be corrected if needed.From the standpoint of personal preference, I prefer to avoid pumice altogether, as modern sandpapers are more finely controlled in particle size. Rottenstone can be useful for true hand-rubbing, though I've come to prefer the automotive compounds.Depending upon hardenss of the finish, an approach as simple as a dry buff may indeed be exactly what's needed.<<<<<<<<<<<<<<<<<<<<<<<
JOHN: It does depend on the manufacturer's approach. There are "not glosses" that will level smoothly, and others that have an additive contributing to surface disruption. For furniture and cabinets, I personally prefer the slick stuff because it stays clean and feels better (to me.)WWODWIZ: This doesn't correspond with anything in my experience. Perhaps you could give an example? Manufacturer and product name of an example of each? Or perhaps a reference?
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Sure. A very gross eample would be wrinkle paint. Fortunately enough, Chris Minick in the June 2005 FWW confirms that Danish oil doesn't dry to specular brightness because of its chemistry. Any oil or resin liquid (or others - even water) will tend to surface homogeneity because of surface tension. That is, it "wants" to be smooth - glossy by extension. A less-than-glossy surface is rendered through addition of chemical or mineral modifiers. If the surface isn't glossy, then it's been disrupted from that natural tendency to smoothness, even if on a nearly microscopic scale."Level smoothly" was meant to suggest a varnish with internal diffraction modifers only, and which dried naturally to a relatively high level of specular reflectivity.In the last several years, the range of water- and solvent-based finishes, some with catalysts, has become so broad that it's undoubtedly inaccurate of me (playing old tapes) to specifically categorize either.<<<<<<<<<<<<<<<<<<<<<<
WOODWIZ: You can also polish satin finishes to a high level of gloss. You can't reduce the internal scattering and loss of clarity, but you can sure alter the surface reflectivity (gloss), especially with lacquers.
----------------
JOHN: You bet, and boy are they nice under the fingers! Works well with a good hard poly, too.WOODWIZ: Then why did you categorically say earlier that it couldn't be done?
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Misunderstanding. I didn't. My comment was in reference to varnishes modified with internal diffraction modifiers such as fumed silica. Yes, you can attain high specular reflectivity with polishing of satin or semigloss varnishes of that type, but cannot regain a "dead clear" appearance short of complete removal of the modified varnish.<<<<<<<<<<<<<<<<<<<<<<<<<<<
Lacquer is known for its ability to bond, and for the fact that one coat melts into the next. Fash time and drying time are easily controlled. Poly is notorious for its difficulty in adhering even to itself. Also, there are all kinds of lacquers, and only the cheapest resins are "chippy". You can formulate almost any kind of performance you like. In manufacturing over a million board feet of pine furniture, I used an acrylic modified NC lacquer specfically because of its flexibility. In contrast to your experience, with oil based poly, I have found it to be hard, and not particularly flexible.
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That's highly dependent on the manufacturer. I use a poly that can be bent virtually in half without fracturing, yet is hard enough to polish. Every piece I've had to refinish (no million board feet, I can assure you) has been the victim of fractured or flaking lacquer - perhaps a factory fault in poor application or choice of materials - they do like to get 'em out the door ASAP.In contrast, I admit that lacquer I've personally sprayed "wet for sure" has evidenced no problems with regard to adhesion.<<<<<<<<<<<<<<<<<<<<<<<<
50 years ago, an "eggshell" finish was all the rage in my neck of the woods. I remember rubbing out my Dad's varnished table tops with pumice and paraffin oil to get an almost dead flat finish. Finishes in the 18th century and before were generally pretty flat, too. Gloss finsihes first became popular with "vernis au tampon", French polishing, starting around 1820. Traditionalism? There is no absolute "right" in finishing, just what meets your requirements or expectations.
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That, of course, is right. Again, my admittance of personal preference for (the appearance of) a moderately subdued French polish. I dislike the eggshell finishes for surfaces subject to wear because they tend to polish in spots and become non-uniform in appearance.<<<<<<<<<<<<<<<<<<<<<<
JOHN: I'm not surprised to hear about shiny wear areas - they're just knocking down the high spots!WOODWIZ: Not so. They are actually polishing the surface.
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Uhhh - that's what I said. Polishing levels a surface - including one that's microscopically disturbed, whether as the result of its chemistry/composition or the result of manual deglossing.<<<<<<<<<<<<<<<<<<<<<<<<<<<
Halogen lights are not as bad if you bounce the light off the ceiling to duffuse it, but it's still pretty harsh, in my experience. Sometimes it's just as bad as having too little light. Direct illumination doesn't work at all. I find, as do most others, that a diffuse light source makes it a lot easier to spot flaws.
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Yah - good daylight makes life better, eh? It's my experience that the width and internal angles of most (tubular bulb) halogen worklights' reflectors provides for considerable spread (not diffusion and not so the little individual bulbs.) I find that when coating, even a plenitude of individual incandescent lights will produce a series of bright halos, which can be a distraction in viewing the surface alone. True diffusion can be a challenge to create, even with diffuser panels. I find that extremely bright light will render the work surface virtually invisible, and highlight the liquid surface, thus helping me to better percieve the coating alone. That's why I prefer halogens during application. I'd never recommend them in the absence of space - they seem to be most useful for me at 12-15' distance. I agree that a softer and diffuse light is much better suited to "read" the quality of a surface being rubbed.<<<<<<<<<<<<<<<<<<<<<<<
JOHN: "The only reason I like to wet sand early is because the water tends to more or less "glue" the entire paper surface down to yield slightly more uniform cutting with minimal pressure. I hesitate to steer (apparent) beginners to 220 for fear it will lead them to color breakthrough on the stain. I figure if they know enough about sandpaper, they'll discover on their own that they could go coarser."WOODWIZ: "A proper sanding block will achieve the same end better and with a lot less cleanup. Spend $5 and treat yourself to a good cork block. If you're paper is glued down you're probably not using enough water. Its function is to jubricate and carry away the swarf."
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Here again we disagree - depending. Some woods, such as oak, and many veneers will retain surfaces that aren't planar - that is, a little grain or surface "waviness" in the harder grain will remain, even after planing. I prefer to retain as much of that character as possible, especially on large flat surfaces, so as to ensure against "plasticky" appearance insofar as is possible. That is, I feel that wood needs to look like wood to the greatest possible extent, and I work to ensure that outcome.Sanding blocks tend to miss the small hollows, and thus to force a finished surface to become more nearly planar as sanding progresses. With a delicate touch, wet-sanding can be pursued without skipping the low spots.Intervention of a tool such as a sanding block removes the hands' sensitivity from the workpiece. Again, a delicate touch will reveal surface condition and evidence discontinuities that aren't even visible in the sanded finish.I do have a variety of blocks, and use them regularly on surfaces which are intended to be as nearly flat as possible.
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A small amount of digression to illustrate a point of practice...
As to "gluing down" - I'm sure you know that, for example, color-sanding custom graduated Candy auto paint requires considerable finesse and a light touch to avoid literally ruining the paint job. As well, no sanding block can be used in such a situation without high likelihood of breakthrough on contours. Learning to work with such delicate applications leads (finally) to development of considerable skill in "reading" the sandpaper by touch, and can considerably enhance one's ability to rub out wood finishes while retaining as much grain character as possible. With too much water, the paper just floats around and there's water, water, everywhere. With too little, it sticks and over-cuts. With too much hand pressure, it's a disaster with finger streaks and marked unevenness. But with a sensitive and very light touch, and just the right pressure and hand spread, a 1/4 sheet of conditioned (well-soaked) wet-or-dry paper will conform almost exactly to the surface being sanded and remain attracted to the surface by virtue of surface tension of the water itself - very weak but perceptible attraction. It's more or less an art, but it works beautifully and can be learned with practice. Doesn't work worth a hoot with coarser grades (340 and under) because the paper's too stiff. The finer the grade, the more reliable the touch feedback.None of that's an "I toldja so" - I hope that it perhaps adds a little clarity to the place I'm coming from. Every craftsman has his/her preferred ways and tricks, just as some folks prefer flat finishes. That's why they make red cars and green cars, ain't it ... ? At least in reading all of this, you might see another's approach, whether or not any part of it attracts you personally.Finally, I can afford to spend whatever time is needed in the (never complete) pursuit of perfection, as I've no product to sell and therefore no time to conserve. Many have told me that they thought I should do this professionally, but they don't understand that I couldn't make a living at it - no one would pay for the hours per square inch I'm willing to invest as needed. Professional finishers have the advantage, I think, in that they're competitively forced to find good methods that sell product profitably - may hat's off to them.---John
Well I sure know more about polyurethane now, thanks to you all. The only comment I have is that, to me, poly is a floor and trim finish, not a furniture clearcoat. I could be fairly happy with some of the wiping polys I've seen, but Minwax poly is rather "plastic-y" for a piece that has some craftsmanship in it. My opinion would be use spray lacquer, even if you have to buy aerosol cans. By the time you rub it out with 0000 steelwool and maybe some paste wax, you've got yourself a finish that looks great and has excellent wear characteristics, to boot. Just my opinion... there are many good ways.
Why don't you use a non-poly oil based varnish. Wipe it on, thinned 50/50.Gretchen
Thanks for all the info!! Su
I use Min Wax poly . I always thin mine with naptha. i have never tried turpentine but i have useb mineral spirits , but if there was any thinned poly left over sealed in the contaner it will s poil or get chunks of half dry poly in it.
Have a nice day Lee
Hi Lee, When you thin your poly, what is the ratio that you use? Do you brush or wipe it on? Thanks, Su
Hi. Sorrey i dident get back to you sooner. I thin my poly about 20 to 25 %
with naptha and i usualley brush it on, i tried spraying it for a while . I found i could brush it and end up with as smooth a finish as spraying it. .It takes a little longer,but you are putting a lot less voc,s in the atmoephere
Have a nice day Lee
Lee, Thanks to you and to everyone else for supplying all of the useful info!! Su
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