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View Full Version : How do I get varnish smooth and glossy


MrFantsyPants
03-11-2007, 09:39 AM
I've made a table for my daughter out of beech. It is my first real attempt at "good" furniture. Thinking back to previous attempts at varnishing wood, I always ended up with a slightly bumpy matt finish. Not the kind of finish that you'd get on a piece of furniture you'd buy.

So, what tips can you suggest to get the finish that I want?

Crafter_Man
03-11-2007, 09:43 AM
Rub wood with very fine (000 or 0000) steel wool.

MrFantsyPants
03-11-2007, 10:16 AM
Rub wood with very fine (000 or 0000) steel wool.
Presumably that is after a couple of coats of varnish? The wood is sanded now with 320 grit. No varnish yet.

I had tried previously sanding after varnish with a very fine sandpaper, and got the matt finish.

Sal Ammoniac
03-11-2007, 11:27 AM
The principle is that you need to sand the finish, just as you would sand the wood -- only you have to use much, much finer abrasives. Even 0000 steel wool will give you a matte finish.

A couple of factors: The kind of varnish matters. Polyurethane is hard to rub out to a regular, glossy finish. Other kinds of varnish are better, but you always need to buy the gloss. Matte and semiglosse varnish contain flatting agents that will prevent you from ever rubbing out to a high gloss. In any case, make sure each coat dries sufficiently before you level it.

With a close-grained wood like beech, you're probably okay with three or four coats. Level each one with 400 grit wet-dry paper (which you can get at the auto-supply store), maybe lubricated with a bit of mineral spirits, or water and dish detergent. Put the last coat on as smooth as you can, let it dry well, then level it as above. Then you need to rub it down with finer and finer grits. You can get an even matte finish with 0000 steel wool, then rub with rottenstone and water for the final polish. It takes a lot of elbow grease. Or alternatively, at the same auto supply store, you can buy buffing compound and use an electric buffer.

Getting a good finish isn't easy, in short. Commercial furniture manufacturers almost always use sprayed lacquer or conversion varnish, and probably mechanical buffers.

The Flying Dutchman
03-11-2007, 11:44 AM
I'm coming at this question as a boat builder, not a furniture maker, and based on the wording of your question, a couple of items come to mind

1. Steel wool is banned in a lot of high end boat building facilities, because the residue from steel wool can create stubborn rust spots.

2. Your experience with the matt finish can be a result of your choice of varnish. You can buy varnishes specifying high gloss or matt.

3. If you expect a high gloss finish after sanding, You will always be disapointed.

It is my recomendation that you count on at least 6 lightly applied coats and block sand by hand with 220 g in between coats after they've cured. Block sanding takes out the little bumps, and subsqent coats fills in the little holes. Sand with low pressure but quickly. You can jump to 320 grit for the last two coats. Be careful to remove all dust from the work.

I'm sure there are quicker procedures, but this is proven.

AskNott
03-11-2007, 02:07 PM
The varnish articles in Practical Sailor magazine showed that there's a lot of folklore, art, and maybe magic surrounding varnishing. They also set out some rules nearly everybody agrees on.

1.) Find the best brush you can afford. Then put that back on the shelf, and buy one better than that. There's a plethora of mythic stuff about the best way to maintain your mighty brush.

2.) If you need to stir or shake the varnish, let it settle for 3 hours before starting to apply it. Bubbles will make it bumpy.

3.) Dust is evil. Go over everything with a vacuum, then a tack rag before each coat.

4.) Is it a humid day? The answer is important, but I don't remember why.

BJMoose
03-11-2007, 02:51 PM
Humidity increases drying time, giving dust more time to settle on the finish.

I can't really improve on the advice given above, just pass on an anecdote from my own experience this past week (I'm working with shellac which is rarely used now -it's not terribly durable - but hey, I'm trying to match 90-year-old woodwork). The key really seems to be sanding between coats after the first couple to level off "mistakes" and things like dust nibs and air bubbles. The coat I put on after sanding was much more glossy than previous coats (which I then "ruined" with 4-aught wool because I wanted a matte finish).

cornflakes
03-11-2007, 05:52 PM
Humidity is also bad because it can cause the finish to "flash" and have a milky haze. It looks a little like how varnish looks after a wet cloth has sat on it for a while. Finishes will also flash in colder weather.

I'm no expert and I'll admit that I usually cut corners when finishing something, but I recommend applying several coats, block sanding after each and running a tack rag over the surface. For the finish coat and maybe the one before it, I usually French polish the surface, applying the varnish, slightly thinned, with a pad made of cheesecloth.

I have heard of people using rottenstone, but usually for harder finishes like shellac.

Chief Pedant
03-11-2007, 06:33 PM
I've made a table for my daughter out of beech. It is my first real attempt at "good" furniture. Thinking back to previous attempts at varnishing wood, I always ended up with a slightly bumpy matt finish. Not the kind of finish that you'd get on a piece of furniture you'd buy.

So, what tips can you suggest to get the finish that I want?

Seal the wood first with a coat or two of thin sealer--commercial, or thinned shellac.
Use a very good brush.
No dust. Minimal humidity.
Fine sanding between multiple coats.
I think spraying is easier for a perfect finish but I am not good w/ brushes. There is technique to spraying as well.

R. P. McMurphy
03-11-2007, 07:02 PM
Any truly smooth finish that you see has been sprayed and not brushed under conditions that control humidity and dust.

If brushing is the only option then it has to be polished with really fine polishing compound. Then the finish has to be waxed. The wax will bring out a gloss that is lost in the polishing process.

rocking chair
03-11-2007, 07:24 PM
how 'bout the stuff that claims to be hundreds of coats of finish in one shot? it seems very shiney and thick.

Lynn Bodoni
03-12-2007, 04:36 AM
Tack rag, tack rag, tack rag. Oh, and use a tack rag.

I had some very good results with patiently sanding my dried finish each time I applied another coat. My main problem is always finding a place to apply the finish and let it dry...the place has to have adequate ventilation, yet it must be relatively dustfree. And cathairfree. We have a couple of outbuildings, but they're pretty dusty.

Mangetout
03-12-2007, 04:59 AM
how 'bout the stuff that claims to be hundreds of coats of finish in one shot? it seems very shiney and thick.
I've never heard of it, but it sounds like it is probably a polyurethane varnish; these go on thick and produce a nice glossy finish, but it's unlikely to be a level glossy finish - the end result usually has a sort of bumpy orange-peel texture. This might be OK for things like windowsills, but it's never going to look nearly as nice on furniture.

There really aren't any worthwhile shortcuts.

Fir na tine
03-12-2007, 09:07 AM
I always use the cheap foam disposable brushes. Makes a nice even finish.

First, decide if you want a glossy finish or a satin finish. Buy what you need.

Apply varnish running with the grain. Nice thin coat. Let it dry at least 24 hours.

Use 0000 steel wool to smooth out the finish and provide a texture for the next coat to stick to. Vacuum up the dust or use a tack rag but get the piece absolutely clean.
For my taste sandpaper is too rough for the work between coats. Even the superfine grits cut too deeply into the previous layer.

Repeat this process 3, 4 or 5 times. Works every time.

Whe you're done apply paste wax for protection.

Fir na tine
03-12-2007, 09:09 AM
I've never heard of it, but it sounds like it is probably a polyurethane varnish; these go on thick and produce a nice glossy finish, but it's unlikely to be a level glossy finish - the end result usually has a sort of bumpy orange-peel texture. This might be OK for things like windowsills, but it's never going to look nearly as nice on furniture.

There really aren't any worthwhile shortcuts.

I've seen this at the BORG and it's mostly plastic. Useful for bartops or other projects where a lot of liquid will be spilled on a regular basis. Not sure how it was applied but it was about 1/8 thick and glossy as hell. Resembled a bartop with a piece of plexiglass melted to it.

Harmonious Discord
03-12-2007, 09:42 AM
Lynn Bodoni adds in the important thing you must use a tac rag before each finish. It will remove all dust sized residue. Having a super clean room is important. The multiple coats with steel wool sanding between coats is important. Doing the sanding in a different room than the finishing is important. Picking a glossy finish is important if that's what you hope to achieve. The finish needs to be aplied in dry conditions, for a fast, non-milky finish. There are easier finishes out there that I haven't used. I found Formby's finishing kits with tung oil finisher, worked so much easier and gave me better results than varnishes. Remember the tac cloth, the finish won't turn out as good without the tac cloth wipe downs.

Alway finish a scrap piece of wood from the project, to see the finished result. It's too late to change stuff after you start finishing.

Mangetout
03-12-2007, 10:16 AM
I've seen this at the BORG and it's mostly plastic. Useful for bartops or other projects where a lot of liquid will be spilled on a regular basis. Not sure how it was applied but it was about 1/8 thick and glossy as hell. Resembled a bartop with a piece of plexiglass melted to it.
I wonder if it's one of those two-part gelcoat finishes like they use on boats - you mix the resin and hardener thoroughly, slap it on (more like spreading than painting), then it cures chemically to a solid layer of plastic, rather than curing/drying by evaporation of solvent.

Kalhoun
03-12-2007, 10:25 AM
I just saw a thing on how to make a piano (it was very cool). They finished the finishing process (all the steps everyone has already outlined) with a mirror gloss wax of some sort. You may want to look on woodworking sites to see if they offer something like that.

BJMoose
03-12-2007, 12:24 PM
Re dust control: I've found that a large air cleaner in the room helps.

Mangetout
03-12-2007, 12:29 PM
Re dust control: I've found that a large air cleaner in the room helps.Do you run it while drying is taking place? I'd have thought that a bad idea only because the filtered air coming out of the vent might stir up more dust - and if you try to overcome this by venting outside, more air will come in under a door or something to replace the air you're venting.

Running the air filter for a few hours, then switching off before wiping over with a tack cloth and recoating might work quite well.

BJMoose
03-13-2007, 11:13 AM
I have and it seems not to have been a problem. But I agree it would be better to run it a few hours beforehand and shut it off while actually working - you room's airflow patterns will vary, to corrupt a phrase.

Harmonious Discord
03-13-2007, 11:19 AM
I hope you'll update use when you're done, to know if the advice helped, and maybe a picture.

Skipper Too
03-13-2007, 01:45 PM
The Bar Top finish that has been mentioned is a Two part epoxy product like this (http://systemthree.com/p_mirror_coat.asp)

In boat varnishing some people use a two part epoxy or polyurethane to get the build and depth with a product mentioned above or something like this (http://bristolfinish.com/) A bit of caution, if the piece will be outside use an exterior grade product. Epoxies are not UV stable and will still require a coat or two of Exterior varnish to keep the Epoxy from breaking down in UV.

A couple of other tips that have not been addressed

Do not dip your brush out of the can/container, pour enough varnish for the coat you are applying through a fine paint filter into a clean cup and work out of it.

Selecting the right brush is only half of the battle. Proper brush maintenance is the other half. One school of thought is to not let the brush dry, to keep it in solvent or cleaner suspended so it is not touching the bottom or sides of the container, the thinking and from my experience is that it is difficult to get all the solids from the varish out of the brush, if given the chance to dry, they will come out of the brush with the next use leaving particles in the surface you are finishing.

Skammer
03-13-2007, 02:53 PM
Someone gave me this tip when I built my wife a bookcase: instead of using fine steel wool or sandpaper, I used brown paper (from a brown paper bag) on my sanding block, after each coat of varnish. It came out great.

Sal Ammoniac
03-13-2007, 03:55 PM
The problem I've found with using steel wool between coats is that it doesn't really level up the coat you're working on. If you have any dust embedded in the varnish, the steel wool will round it over a bit, but not bring the whole surface level, though you tend not to see that until you apply the next coat. That's why a sanding block (felt is nice) with fine sandpaper is good -- though it's a little unforgiving. If the wood surface underneath isn't flat, you can sand back to bare wood on the high spots really easily. And edges are always a problem.

Suffice it to say that getting a great finish isn't easy.

casdave
03-13-2007, 05:32 PM
It helps to put the varnish on in very thin layers.

You first layer on the raw wood is what will seal it, and this needs to be especially thin, it depends upon the specific varnish type, but you might also find it is better to have the first layer thinned out. Let this layer dry out good and hard and then when you rub it down it will take away any wood roughness.

Stand your varnish pot in warm water and let it warm up.

Varnish becomes considerably thinner, allowing it to spread more easily and so there is much less chance of runs.

The varnish will cool quickly when it is applied, but it does stop you overloading the brush.

You are best to put on one layer and let it dry for 24 hours if you can, you may well need 10 coats of varnish done this way as each coat is so thin.

Don't get too ambitious with the fine abrasive, it should not be much more than a wipe down.

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