sanding sealer for water base lacquers

[old_picker]

Hi all,
the product I usually use from the states is currently unavailable and am looking to use locally sourced stuff. The colortone S/sealer holds a good rate of solids and is great for filling and sealing open grain timber.

FYI I am building solid body guitars and am having excelent results using very unsmelly water base finishes.

Thanks in advance for any tips or suggestions.

[Tony Clarke]

My recent research indicates that the wear characteristics of water based finishes are not as good as turps based ones, at this stage of development. They do, however, have the advantage of a clear finish, rather than the light yellow/brown of the turps based lacquers.fficeffice" /><O></O>
On this subject I am wondering if a water based finish can be classified as a lacquer (going by definition of a lacquer). Any thoughts welcome.<O></O>
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[old_picker]

There re many definitions of lacquer but probably the one that best describes it is

"A finish material that dries as its solvents evaporate, and can be redissolved in its own solvents. Most lacquers are either nitrocellulose or acrylic base."

I tend to use the word lacquer in a generic manner describing any clear glossy finish that forms a hard skin over the base material which is a bit confusing and I apologise for the confusion.

Traditionally, guitars were coated in Nitrocellulous lacquer which is very toxic and very flammable. "Nitro" is quite soft and over time crazes. In extreme cases it will crack through and fall off exposing the underlying wood.

The product I have been using is an acrylic and mrketed as "guitar lacquer". I have also been experimenting with water base floor finish which is pretty tough and buffs to a good mirror finish.

Many in the [guitar] industry are moving away from "Nitro" because of either environmental or health concerns. Big companies are using polyurethane these days as are many boutique builders. I chose the water base way simply because it doesnt stink the place up and I don't have to clean up with tupentine and dispose of it.

[durwood]

Old picker is on the mark with his definition of a lacquer, lacquers have in them huge amounts of solvent which evaporates off at a huge rate. So much so its only really suitable to spray, when Nitro Cellulose was invented (WW1 when developing explosives -hense the Nitro part) it was seen as being a useful fast drying paint - enter DUCO they had to develop the spray gun to apply it up until then paints were brushed, dipped, rolled, or flowed on with a hose. The only spray devices then were similar to a purfume spray where you blew air over a vertical stem submerged in a liquid.

DeVilbus came up with the external mix gun which mixes pint and air after it leaves the gun making it impossible to dry out and clog the nozzle as happens is cheap guns like you get with a vacuum cleaner.

NItro cellulose lost favour when they discovered perspex (acrylic) N/C hates ultra Violet light and goes yellow and then cracks acrylic will not.

Acrylic lacquer paint has been used on motor vehicles replacing N/C since easly 1960"s. It won't yellow but dries a lot slower than N/C, being a lacquer it needs lots of thinner.

If a tin says its lacquer you need at least 50-50 paint thinner but it works best about 40 - 60 or 1 part to 1 1/2 parts thinner.

So much thinner means loads of solvent going into the air as all the solvent you added to mix it as well as that in the paint itself has to evaporate off. Thats why its now being banned.

If turps is added to lacquer it turns instantly into a lump of goo. Turps thinned paints are enamels. They dry by a little amount of thinner but mainly by oxidation ( oxygen makes them set hence the skin you get on the top.)

Water based paints are usually used in the house refinishing industry and hardness is not considered necessary. You may have noticed the paint companies suggest enamels on house trim doors etc especially if it may be rubbed and cleaned a lot by mum.

Lacquers arn't toxic neally as much as other paints. no one ever used a mask when lacquers were being painted.(though they probably should) it dries so fast it turns into dust and disperses quickly, the ones that are really poisonous are the two packs especially polyurethanes. Definately need a mask, it's law spray painters have to use an air fed hood as the normal face masks are not good enough. Don't spray any paint in an enclosed area alway have good ventilation.

Some paint companies have a water based clear which is used on motor vehicles, this stuff is weird you paint it on and its white and as it dries it turns clear. Overseas water based paints are compulsery in some countries but not here yet!!! If they can stand sun, rain washing scrubbing, scratching etc on a car they would excell on a Guitar.

[old_picker]

mmm Thats all good but we have digressed.
I still dont have a water base sanding sealer with high solids content

[durwood]

Sorry, I was going to mention the sealer at the end but was interupted and it slipped my mind.

I'm not sure a water based sanding sealer is available here, was the one from the states water based.

As water tends to raise the grain I would have thought it would not make a good sealer for following coats.

Lacquer sealers on the other hand work well, they dry quickly, fill and seal well and have been the backbone of woood finishing coatings for years.

Several companies make them here, mostly those supplying the furnature trade. Wattyl and Mirotone and Pheonix come to mind immediately but I havn't purchased any for ages.. A paint chemist told me once that there is little difference in formula for any of the brands, but often people rate one brand over another as they think they see a difference.

[echnidna]

It might be worth a bit of experimenting by adding stearite (talcum) to some topcoat and try it out.

Got no idea how much to add but I'd start at say 25% talc to topcoat by volume and see how it works.

p.s. Might be wrong but I think Neil stocks pure talc.

[soundman]

have a chat with receene, a kiwi crowd offices in aus.

they do a water based polyeurathane thet behaves more like a laquer.

cheers

[old_picker]

Yes, good suggestion.....
I can get industrial grade talc [300 mesh] at a ceramics supply place in the next suburb and they also stock silica which i have read can be used also. Talc BTW is calcium carbonate, sometimes called whiting, . Either of these minerals will stay in suspension and hopefully sand down easy in a mix with some topcoat. I reckon it will break the bond of the the hardened finish enough so that sands down nice and flat pretty easy. I guess if too much is added it will begin to opacify the mix. 25% by weight might be a little heavy handed. I would try it out like 5% 10% 15% 20% 25% 30% and see where it starts to cloud over.

When I sand the imported colortone s/sealer it comes off in a white powder which i bet is talc or silica or both.

I will give it a try and report back.

[ubeaut]

There is no reason why almost any commercially available sanding sealer can't be used under water based poly.

The white powder when you sand is silica.

By the way Talc is Magnesium Silicate Hydroxide.
Whiting is Calcium carbonate also known as chalk, a big difference.

You can use talc in a mix as sanding sealer as it is translucent and as a rule won't leave white in the grain unless you use too much.

Chalk on the other hand will act like a paint and will blanket out the grain of the timber.

Cheers - Neil

[old_picker]

of course
i worked in ceramics for most of my working life & used whiting, talc, silica, feldspar etc etc in glaze formulation. its amazing what a few years can do to the old memory banks.

general failure reading drive c:

must have had a seniors moment getting talc and whiting mixed up