OT, but someone here will know about paint.

Some of my recent posts don't show up on my webtv so if this is a repeat forgive. I have two gallons of hi-gloss dark green acrylic enamel. Lorraine likes the color but not the shine for her new 'fern room' and I hate to waste the enamel. Is there a way to make high gloss enamel into flat or at least low satin? TIA.

Turn to Safety, Arch Fortiter

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Arch
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You can buy a flattening agent to add to the paint but it may be less expensive to just buy the color in the sheen desired.

Interlux is one manufacturer of a flattening agent. See:

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Reply to
Nova

May sound silly, but try a little corn starch.

(Well, Does sound silly.)

Reply to
Lobby Dosser

Thanks Jack & L.D. I think I'm better off buying some flat paint or first trying a package of corn starch. My wallet and I know the Searsport, Me. Hamilton Marine store very well. Funny coincidence.

BTW, what makes an enamel or lacquer gloss or semi gloss or a flat paint flat?

Turn to Safety, Arch Fortiter

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Arch

Visit my site at:

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Reply to
Canchippy

"Arch" wrote: (clip) BTW, what makes an enamel or lacquer gloss or semi gloss or a flat paint flat? ^^^^^^^^^^^^^^^ Finally, a question I can answer. In the can the paint consists of a liquid with suspended particles of pigment. As the paint dries, the liquid phase shrinks, due mostly to evaporation of the solvent. If, after drying, the "liquid" surface still covers the particles, the surface will be smooth--thus, high gloss. If the particles stick up through the "liquid" surface, the reflected light is scattered, so the gloss is reduced or lost completely.

If you paint a piece of bare wood, the penetration of the liquid varies from point to point across the grain. On the hardest parts, the gloss will be retained, while on the soft parts the liquid soaks in, leaving more of the pigment esxposed. This is why the grain shows up as a gloss/flat pattern.

So how do they make semigloss or dull varnish? The pigment particles are transparent--have the same index of refraction as the liquid.

Reply to
Leo Lichtman

I turn for fun, but finishing my work/projects of part of what I do for a living. If I were you I would use the paint you have for primer and put a finish coat of new paint on at the correct level of sheen you want. Changing the sheen of paint is a pain in the butt.

But you can indeed put in a flattening agent to reduce the reflectivity of finishes. I shoot a lot of a particular conversion lacquer, and when in touch with the tech support guys at the factory (it is a small specialty company) this very subject came up when talking to one of the chemists in charge of formulation.

The flatteners in use today are NOT organics of any type. They are ground crystalline products that are ground so fine that they use another measurement that I am not familiar with to describe how small the particles are. The chemist told me that their flattener was about he equivalent of a 50,000 grit sandpaper grit, or finer.

The powdered crystals sometimes go to the bottom of the bucket on >his< stuff, and when I am trying to get them back in solution I can pull some of it up on a stick. One time I let a blob of it dry, and it easily broke open and and I could see that it looked like the finest sawdust I had ever seen. I actually thought it was something foreign in the lacquer (duh)so I called the factory to find out what it was. Then came the explanation, along with the chiding for not stirring their semi gloss material >really< well.

And quite simply, the more flattener, the less shine. They use the same formula for all but dead flat to achieve their interpretation of gloss, semi gloss and satin. With this in mind, I was able to uncover the fact that the little boutique mixed the resins and solvents to make a batch of finish, and simply pours that finish on top of the pre measured flatteners that have been measured dry and dropped into a can before filling. It is our job in the field to get the flatteners into the resins.

Flatteners work the same with most oil base paints, but since paints are thicker they hold the flattener in suspension and you don't see it. Also, at the huge factories they mix the flattening agent in the batch of paint and dispense the mixed product into the cans so chances of complete separation are almost nil.

Probably more than you ever wanted to know...

Robert

Reply to
nailshooter41

Thanks to Leo and Robert, I and probably several others here, know a little more about the coatings that we apply to our turnings. That's on topic for woodturners and not their first good answer for us.

I had it wrong. I thought that something is added to make the coating glossy instead of something being added to flatten it. Sort of like I thought for years that hi-test gas had something added to make it burn faster, not to retard it. (actually I thought the gas worked by exploding, not by burning) That's not on topic. :)

Turn to Safety, Arch Fortiter

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Arch

I noticed painting metal with auto paint that more coats meant more sheen to a point. Granted they were thin coats, but at two not much sheen, at four a lot of sheen. I was thinking this might be a measure of how thin the coat of paint was on tools in the store. No soaking in on metal, I don't think.. Maybe something else at work..

Reply to
Jim Hall

More coats of finish mean more resin solids. As you build coats, more resin solids mean a smoother finish as all the tiny, tiny voids and imperfections are filled in, making the reflectivity of the finish less scattered.

Robert

Reply to
nailshooter41

Seems like you would build voids at some number of coats?

Reply to
Lobby Dosser

You mean make new voids, or build up existing ones? I am talking about the micro-tiny pores left in metal primer after being sanded to the proper grit, or the same on wood that has been sanded smooth. I am not talking about hammer dents, nail holes, or chips in bondo.

Robert

Reply to
nailshooter41

You mean make new voids, or build up existing ones? I am talking about the micro-tiny pores left in metal primer after being sanded to the proper grit, or the same on wood that has been sanded smooth. I am not talking about hammer dents, nail holes, or chips in bondo.

Robert

Reply to
nailshooter41

ALL those coats are sanded to a fare-the-well, too. My hands ache just thinking of it.

Can't do that with wood, by and large, but you can burnish to make the pores smaller, and buff to make the rough edges rounder to get more direct return on your light.

Reply to
George

I'm talking make new voids. Say you fill the last of the voids at coat X, do you add voids if you continue with coat X+1? Or do you just reach a point of diminishing returns?

Reply to
Lobby Dosser

On wood, the tiny little voids left when sanded to 220 are what allow to properly adhere to the surface. The coatings will fill the voids left behind, but to get a really mirror smooth finish, several coats must be applied, then polished down with several grits (600 - 12,000 or so) to remove all imperfections. Look at your finish before you stop finishing, and you will see how rough it is; polishing the surface really just flattens out all texture and tiny scratches left from previous sandings.

To look at it another way, look at using the old fashioned pore fillers. They were used widely on opened grained woods such as furniture grade mohagany many years ago. The reason they were used it that the voids caused by the tubules would never fill by themselves, no matter how much finish you put on them. You can try this yourself by putting several coats of finish on another open grained wood, oak. Put all the finish you want on it, and you may evnetually cover over the pores nicely, but you will still see the grain.

To continue to add finish is as you say, X+1. At some point you need to stop adding and start taking off if you are looking for a mirror shiny surface. Worse, if you start with a bad substrate, you will always have to deal with it. All the imperfections are just amplified (including improperly applied previous coats of finish!) when you add more coats.

My auto finishing friend uses a term called "color sanding". He never worries about stuff in his finish, voids, orange peel, fisheye, or anything else. He puts on so much poly enamel (as per manufacturer) that he has a thick coat to work on to sand and polish off all the imperfections. He polishes and buffs off about 1/3 of what he applies. Then he puts on a light coat of clear and just buffs it out.

The guy I buy my finishing stuff from is a professional refinisher and teacher. He has advised me that I need to start with 9-10 mil of finish in order to polish out the finish correctly. This allows the finsher to cut down all the finish needed to get to the bottom of any small voids or orange peel without cutting through the finish.

But if you are NOT going to buff, sand or polish out your voids, then you will indeed wind up with the X+1 effect.

Robert

Reply to
nailshooter41

Thanks Robert, good explanation.

Reply to
Lobby Dosser

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