PianoLac

PIANOLAC®

Making A Closed Pore Piano Finish With The PianoLac High Build Waterborne Finishing System

High Build Waterborne Finishing System

A publication of StarHawk Laboratories,
31 Memorial Avenue, Pawling, NY 12564
845.855.0996

Just about any finishing sprayer will work with PianoLac. If you have high pressure equipment that has been used with lacquer, it must be “de-contaminated” before spraying PianoLac. Here’s how:

Pressurized fluid pots should be treated as above. Fluid lines should be replaced. Rustable pots should be lined with a plastic pot liner, and steel stems should be replaced with stainless steel. Aluminum spray cups should be replaced with Teflon coated, plastic or stainless steel cups.

If you have no spray equipment and are looking to get some, there are four choices:

HVLP conversion gun/compressor--efficient, minimal overspray. The compressor can be used for other work, and a good HVLP conversion gun is lightweight and comfortable. Requires good water and oil filtering.

HVLP/turbine--efficient, minimal overspray. Most HVLP guns have thick handles, can be unwieldy over long term use. The handle can get hot with long use. The air supply is always dry and oil free. Some HVLP/turbine guns have limited adjustments.

Contact StarHawk directly for more advice on equipment maintenance and selection.

Get A Thermometer

Maintain adequate air circulation and ventilation and wear respiratory protection (NIOSH/MSHA TC23C or equivalent) when spraying PianoLac.

This is a very important step. Sand carefully with the grain by hand (or with a random orbit dust removing sander) with # 100 grit.

Use a random orbit sander on the lids and flat parts of the case; this will assure they are well sanded and level. If you spend the same amount of time with each grit, the wood will be flat and scratch free. SPECIAL NOTE: Hand sanding with the same grit with the grain is advisable after r.o. sanding. This will prevent swirls from becoming visible when mahogany or walnut is stained. Hand sanding is not necessary on bare wood when making a black finish. Be careful around the edges; it’s easy to sand through the veneer with an r.o. sander, so sand up to, but not on the edges.

Blow off the sanding dust with a high pressure air gun. Place the nozzle right up against the wood and expel the dust from inside the grain. If you don’t have compressed air, wrap a layer of masking tape around the edges of a shop vac hose and vacuum off the dust by holding the hose right on the wood.

Apply a thin coat of PianoLac Paste Wood Filler Cream with a plastic body filler applicator. You can use a metal 3” putty knife if you round off the edges with a file.

Remember: always use a filler that is as dark if not darker than the stain color.

Sand with #150. After blowing off the dust, look closely at the pores. If there are a lot of open pores, fill again. You can thin the filler with a few drops of water Wait 30 minutes, then sand with #220. Spend the same amount of time with each grit.

Round off the edges with #150 paper. Sharp edges don’t take stain or finish: they will rub through.

If you’ve never spray-stained, give it a try. Master’s Magic and Mohawk make glycol based stains that look like aniline dye stains and spray easily. Here’s how: spray on a flood coat, wait a few minutes, and wipe off with paper towels or rags before it dries. After an hour’s dry time, observe for light areas. These can be misted with the spray gun without wiping.

An area that comes out too dark can easily be lightened by gently rubbing it with a medium grade Scotchbrite® type pad. Blow or vacuum off the dust after padding.

Be sure to test for adhesion if you use oil base stains. Here’s how: stain the wood following the instructions on the can. Wait at least 24 hours before sealing, then proceed as below. Wait at least 3 days, then cut a checkerboard pattern of lines ¼” apart with a razor blade. Apply a piece of duct tape using enough pressure to assure it is stuck on well, then rip it off quickly. If none of the finish comes off, adhesion is adequate.

Waterbased aniline dye stains look great under PianoLac. If you get grain raising, it’s no problem. Just spray SS/BC or SS/BC/PF without sanding between coats and the grain raising will be sealed in.

BLOTCHING

Certain woods, notably cherry, figured mahogany and curly maple tend to blotch when stained. This can be avoided by spraying 2 or 3 very thin coats of Stain Blocker before staining. Sand lightly after the third coat, tack off with a damp cloth, then stain.

PianoLac® Sanding Sealer/Barrier Coat/Grain Filler® and Black Primer can eliminate the need for a second coat of paste wood filler. They have outstanding qualities:

SPRAY VERY LIGHT COATS, one pass per coat. If the coats look cloudy when wet, you’ve sprayed too heavy. Wait 30 minutes between coats, or until the surface is dry to the touch.

Don’t be shy about spraying multiple thin coats of SS/BC/PF®. It is intended to close out the pores and is totally transparent, so you won’t see the cloudiness normally associated with standard sanding sealer. Closing out the pores with SS/BC/PF® means fewer topcoats, no grain suck down, no pinholes, no orange peel, and no shrinkage.

STIR GENTLY BEFORE USE. DO NOT SHAKE. The pore filling solids settle to the bottom and are easily stirred back into the liquid.

Spray a mist coat over the stained surface. Wait until dry to the touch, and spray another mist coat. Wait 30 minutes, spray another mist coat. DO NOT SAND BETWEEN COATS, unless dirt particles are trapped in the sealer.

Grain raising rarely occurs. If it happens, DO NOT SAND IT OUT. Sanding a grain raised area will only cause more grain raising. Just keep spraying until you see a satiny gloss.

Most veneers will be filled after four coats. Here’s how to test: wait overnight, sand with #220 lubricated paper. Remove all the dust with a damp, lint free cloth. If you see open pores, spray another coat. Caution: if you leave any white sanding dust, it will show up as white particles trapped inside the finish. Test sand again, re-spray as necessary.

Don’t sand if you see any deep open pores. White particles will not melt in if left in the pores.

Alternative procedure: If the surface is relatively smooth after 3 or 4 sealer coats, don’t sand at all. Wait overnight and start spraying topcoat.

When the pores are substantially filled, sand with #220 after an overnight drying period. Sand again with #320. This will make it easier for the topcoat to fill in the sanding scratches.

Special Hint: Sanding large areas by hand is laborious and time consuming. A random orbit sander with vacuum dust removal does a great job of sanding and leveling SS/BC/PF. If you use a random orbit sander for this purpose, skip the #220 and go right to #320..

PianoLac is high solids, but easy to atomize. A one mm tip or smaller makes for a fine spray. If you use a larger tip, you will likely get excess overspray and orange peel.. Experiment with keeping the air pressure low, with the fluid volume high. PianoLac has excellent defoaming (air bubbles break before it dries) but too high pressure can create excess foam. Spray several scrap pieces and pay attention to the gun settings to get a feel for how to lay down a slightly wet, even coat.

Don’t be surprised when you spray your first coat. You’ll see bubbles and orange peel. If you spray a light, well atomized coat, they will flow out in 5-10 minutes, leaving a smooth surface. After a little practice you’ll sense how fast to move the gun and how close to keep it from the surface.

Spray one slightly overlapped pass, up, then down. Don’t make multiple wet coats. SPRAY THIN COATS, NOT THICK! The greater the humidity, the thinner the coats. Keep the air circulating with adequate exhaust.

The surface should look dull, not shiny after it dries. As the coats build, a certain degree of gloss will develop.

Special hint: Spray a light coat on the edges and into the corners before spraying the surface. This will help prevent “rubbing through” during the polishing process.

THERE IS NO NEED TO SAND BETWEEN COATS. PianoLac has 100% burn in and adheres perfectly to itself and to its sealer. Sanding between coats should be done only if dust or dirt particles are embedded in the finish.

If you must sand between coats to eliminate foreign particles, remove all the sanding dust with a damp, lint free cloth or paper towel. DO NOT, UNDER ANY CIRCUMSTANCES, WET SAND BETWEEN COATS.

Spray as many as needed to close out the pores, wait overnight, then level sand with 320. Carefully remove all sanding dust, then spray 2 more coats without sanding between them.

Special information for high gloss finishing: you will remove a lot of material when you wet sand and polish for a high gloss finish. It is always a good idea to spray extra coats to avoid rubbing through to the undercoat. How many extra? Approximately 4, giving a total of 9, one pass coats (HVLP sprayer, or 9 two pass coats with conventional sprayer). If you want a perfectly level, mirror like surface, start the wet sanding with #320, then proceed to #400, #600, and if the ultimate polish is desired, #1000 and #1500 paper. If this is done evenly and thoroughly, a flat, wave free factory finish can be achieved.

No more than three. Wait an hour or more between coats. You shouldn’t need more than 5 topcoats after filling and sealing for a rubbed out finish.

PianoLac hardens enough for polishing in 3 to 10 days, sooner if cured with warm, circulating air. It will also be print resistant (you can sit on a finished piano bench) 24 hours after spraying and not leave a mark.

Black PianoLac requires two weeks to achieve its complete “jetness”. It gets blacker as it cures. It can be rubbed out within 7-10 days without any problem.

For a satin look: Try white Scotchbrite® pads lubricated with a along the sanding with medium grit orange compound will give a satin look, as will cheese cloth with orange compound..

Wet sanding up to #1500 or #2000 paper without any compounding results in a smooth, satiny look.

If you do a lot of this kind of work, a straight line air sander is a good investment. It will make the job go faster and the scratch pattern will be perfectly even and flat.

High Polish: See the illustrated manual “High Polish Rubbing With PianoLac.”

If you don’t want to go through the entire polishing process, you can make an excellent finish in less than half the time.

Spray 3 to 5 coats of SS/BC. Wait overnight and carefully hand sand with #320 paper. Tack off all the dust with a damp cloth. Spray a slightly wet coat of PianoLac® Rub Effect Satin. Wait one hour, then spray another coat. It will dry smooth and satiny, with a waxed feel to the touch.

ORANGE PEEL: Pores are not completely closed out. Don’t spray sealer over topcoat. Level sand with 320 lube paper, tack off, then spray sufficient topcoat to close out the pores. Another cause: Insufficient atomization. Increase air pressure, decrease tip size, or add enough PianoLac LV® to eliminate orange peel. Adding PianoLac LV® will reduce the viscosity without reducing the solids content. Sprayed too thick. Sand with 320, then spray a thin coat.

PINHOLES: Micropores aren’t filled. The first coat of SS/BC/PF should be misted on. Enough should be sprayed to close out the pores. Do not spray SS/BC/PF on top of topcoat. Instead, sand down the pinholed area almost to the bottom of the pinhole, and spray enough topcoat to close out the pores. Be careful not to sand too deep on a clear finish; you could remove color underneath the sealer. TRAPPED MICROBUBBLES—spray thinner coats.

STREAKS—Too heavy coats with not enough time between coats. Spray thinner, wait at least one hour between coats.

ORANGE PEEL AFTER RUBBING: Caused by using water a rubbing lubricant. Don’t use water. Use only PianoLac Rubbing Oil.

DRIES TOO SLOWLY: You’re spraying too thick a coat. If the wet coat looks cloudy, spray lighter. High humidity can also cause slow drying. Keep the air circulating or use a dehumidifier.

SAGS AND DRIPS: You’re spraying too heavy. PianoLac viscosity has been adjusted for good buildup on vertical surfaces. Spray thin coats.

FISHEYE: PianoLac has built in fisheye killer. Fisheye caused by surface contamination (usually wax left from paint stripper) can be overcome by adding PianoLac Fisheye Killer.

BLUSHING: Extreme humidity combined with no air circulation can cause blushing. Even a window fan giving minimal circulation is sufficient to prevent blushing in most cases. StarHawk Labs doesn’t provide retarder: its use slows down the cure time and reduces viscosity. Spraying thin coats with air circulation and a longer wait between coats eliminates blushing. Using a dehumidifier not only keeps out blushing, it promotes fast drying and cure.

Pour out the spray cup at the end of the day, wipe out the residue with a paper towel, and fill it with water. Spray the water through the gun.

It’s a good idea to filter PianoLac before spraying using the filter material supplied. Place the filter material in a funnel and pour through it into the spray cup.

If a part of the gun gets jammed with dried material, soak it for a few hours in lacquer thinner. Rinse the part with alcohol and water.

PianoLac sets up fast.. If you stop spraying for 30 minutes or more, spray water through the gun for one minute. Keep a separate can of water handy for this. Be sure to spray all the water out of the gun before spraying PianoLac again.