Spraying

3 Spraying Events

6 Spraying FAQs

Troubleshooting Guide for Spraying Water Based Finishes

ROUGH, DRY SURFACE
This is called dry spray. You may have sprayed too lightly.

Re-sand the finish with 320-grit sandpaper and apply a heavier coat. Keep your gun at 6-8" from the surface.

DIMPLES IN THE FINISH
This is called orange peel, caused by spraying in temperatures that are too cool. Cooler temperatures will adversely affect how the finish will level and harden.

Water-based finishes must be applied at temperatures above 65 F. If it is cold enough to wear a sweater it is too cold to apply a water-based finish.

The surface of the wood must also be warm. If you turn the heat on when you enter your shop in the morning, the air heats up quickly but your furniture will still be cold for some time. Check the surface to see if it is warm.

Also, check the temperature of the finish. Warming cold finish by setting the can next to a heater or setting the container in some hot water for 5 minutes will improve the ease of application.

NOTE: Larger dimples are called "fish-eyes" or "craters". Cool temperatures can cause these, but the more likely source is contamination of the finish with either wax or silicone.
 

BLUSH
Blush, the term for a cloudy, milky appearance in the finish, has two causes

1. The most common reason is an incompatible stain. For example, using a water-based topcoat over a heavy oil-based stain. When the top coat is applied, the oil in the stain seeps up through the finish and reacts with the acrylic causing a chemical blush.

To prevent this,

  • Increase dry times when changing from an oil-based finish to a water based finish.
     
    • Allow an oil-based finish to dry 72 hours before a water-based finish.
       
    • Allow a water-based finish to dry 24 hours over an oil-based finish.
       
  • Use a quick-drying water-based stain. If you choose to use oil based stain, seal the stain with a coat of shellac or lacquer sealer. This will provide a barrier between the oil and the acrylic. Proper drying time between the oil stain and finish coats is essential! The other cause for blushing is high humidity.
     
  • Spraying water-based finishes in humidities of over 75% may cause blushing because moisture becomes trapped beneath the finish and cannot evaporate.

    You can prevent this condition by increasing air movement in the finishing area with a fan. All water needs to evaporate is sufficient air movement. You can also improve drying conditions by increasing the temperature in the drying area.
     

2. The surface is not leveling out. In hot temperatures (85°F - 100°F) the finish may dry too fast.

Use General Finishes Extender to open (increase) the dry time. Finishes that dry too fast may not completely level out before all the water evaporates from the finish.

How Do I Prevent Orange Peel from Occurring When Spraying High Performance Gloss with a 2.0 Spray Tip?

The 2.0 tip is too large for General Finishes High Performance Gloss when working with an Earlex 5500 sprayer. We recommend that you use a 1.5mm tip instead. 

One of the causes of orange peel is the application of too much fluid and not enough atomization to break the product up into smaller droplets. It's similar to putting your finger over the end of a garden hose.

High Performance Gloss is going to be the most finicky of the sheens to spray. Both Critter and the Earlex devices are suitable but atomization can only be increased with smaller fluid tips or larger spray units

 

GF University FAQ: Orange Peel While Spraying High Performance Gloss

Orange Peel Occurring While Spraying General Finishes High Performance Topcoat Gloss

Why Does GF Milk Paint Look Different When Applied with a Spray Gun Versus a Brush Application?

Milk Paint is not like a filler-based wall paint. It is engineered for high-use applications such as tabletops and cabinets that require considerably more durability than a wall. The resins that make Milk Paint durable change the properties of it, so you have to handle it differently.

The type of applicator you use will change the thickness of the film and affect the appearance GF Milk Paint.

When refinishing kitchen cabinets, our contractor customers often roll the face frames and spray the doors. If there are any corners or edges that need to be filled in with a brush, they will fill in before spraying or rolling. Then, they will complete the entire section with one type applicator.

With this approach, you will notice a slight difference between the frame and the cabinet door, but the difference is considerably less obvious than it would be if you sprayed and rolled on this same surface. 

Secondly, always stir the can well just BEFORE and DURING use. When working with a large project, we recommend continuing to stir during use to keep color properties consistent. If there is any delay, the ingredients will start separating.

Color separation is a condition that the paint industry calls "float". This is very typical with specific colors such as grays because of the large variance in gravities of the pigments required to create the color. In gray for instance, Ti02 (white) is 3.4 and black is 1.62. The lower density will float. This phenomena will not occur in colors that have less variance in densities.

Here is an example of Milk Paint color separation:GF University FAQ: Milk Paint Color Separation

 

How to Spray Water Based Finishes

General Finishes water-based products can be sprayed through compressed air, HVLP, airless or C.A.S. units.

SURFACE PREPARATION:

All surfaces should be clean and free from dirt and oil and sanded.

Indicated below are instructional videos we have for preparing a surface for a new coat of paint or finish:

SPRAY APPLICATION OF GENERAL FINISHES WATER BASED FINISHES:

All General Finishes water based topcoats and wood stains are ready to spray from the container without additives with the exception of Conversion Varnish. Always strain material through a medium to fine mesh filter before spraying. If necessary, in hot or dry climates, reduce 10 to 15% with General Finishes Extender to extend the open time.

PRE SEALING:

Softwoods such as Pine absorb stain at an uneven rate and may respond better to staining if the wood is pre-sealed. General Finishes Pre-Stain Conditioner Natural can be applied to raw wood to condition the surface for uniform penetration of the stain. Pre-sealing will cause the final stain to be lighter so you may need to use a darker color. Always test your color on a hidden part of the furniture. Allow the Pre-Stain Conditioner to dry 30 minutes before applying your final stain color.

If you are using a sprayer that has been used for oil based or lacquers, clean the unit thoroughly with acetone followed with hot water to purge the fluid passage. Apply a thin coat first that will dry and harden faster. Sand this first coat down to a smooth base on which to build your finish coats with a 220-320 grade foam sanding pad or #400-grit sandpaper. It is better to spray 2 thin coats rather than 1 heavy coat.

Contact your supplier to verify proper tip sizes for your specific equipment. GF's general recommended fluid tips for Wood Stains and Top Coats are Compressed air - .040 and Airless - .009. 

RECOMMENDED TIPS FOR GENERAL FINISHES PRODUCTS USING HVLP:

  • Milk Paint: 1.8mm-2.0mm
  • Chalk Paint: 1.8mm-2.0mm
  • Stain Blocker: 1.8mm-2.0mm
  • Pearl Effects: 1.8mm-2.0mm
  • Glaze Effects: 1.8mm-2.0mm
  • High Performance Topcoat: 1.1mm-1.3mm
  • Flat Out Flat Top Coat: 1.1mm-1.3mm
  • Enduro-Var  1.1mm-1.3mm
  • Water Based Wood Stain: 1.1mm-1.3mm
  • Water Based Dye Stain: 1.1mm-1.3mm
  • Exterior 450 Topcoat:1.1mm-1.3mm
  • Exterior 450 Stain: 1.1mm-1.3mm
  • Enduro Sanding Sealer: 1.3-1.4mm
  • Enduro White Poly: 1.3mm-1.5mm
  • Enduro Black Poly: 1.3mm-1.5mm
  • Enduro White Under Coat 1.5mm-1.8mm
  • Enduro Clear Poly: 1.1mm-1.3mm
  • Enduro Pre Cat Lacquer: 1.1mm-1.3mm
  • Enduro Conversion Varnish: 1.1mm-1.3mm

Air caps should be medium size. Contact your supplier to verify proper tip sizes for your specific equipment.

Break your work into sections such as dresser top or drawer fronts. Spraying too large of an area can result in a textured grainy surface. A correctly sprayed finish should appear even and glossy. It is important to spray enough material to allow proper flow and leveling of the finish.

Spray medium wet films at 3-5 wet ml thickness. Practice makes perfect. If you have never sprayed finishes before, take a large piece of cardboard and practice your technique first. Spray water on the cardboard to learn how the gun works. Check your fluid settings and adjust the controls to get comfortable with the spray angles and to develop your technique.

SPRAYING TOPCOATS:

Keep your gun at a 90* angle, 6-8" from the surface. On large flat areas, use wet, even patterns 6 to 8 wide. For narrow surfaces, reduce the fan pattern to 2-3" to reduce overspray. For topcoats, overlap each pass 25% to conceal lines.

Watch our video how to spray water based topcoats here.

SPRAYING WATER BASED WOOD STAINS:

Keep your gun at a 90* angle, 6-8" from the surface. On large flat areas, use wet, even patterns 6 to 8 wide. For narrow surfaces, reduce the fan pattern to 2-3" to reduce overspray. Overlap each pass of stain 50% for even coverage and wipe back the excess with an absorbent cloth. For narrow surfaces, reduce the fan pattern to 2-3" to reduce overspray. 

SPRAYING WATER BASED DYE STAINS:

Keep your gun at a 90* angle, 6-8" from the surface. On large flat areas, use wet, even patterns 6 to 8 wide. For narrow surfaces, reduce the fan pattern to 2-3" to reduce overspray. Overlap each pass of stain 50% for even coverage. If coverage is even, there is no need to wipe. If you have issues with uneven coverage, wipe back the excess with an absorbent cloth. For narrow surfaces, reduce the fan pattern to 2-3" to reduce overspray. 

What Sprayer Should I Use?

Although we spray product all the time in our workshop, with several sprayers ranging from airless to HVLP, we do not consider ourselves to be spray gun experts.

To get the latest information, we recommend you contact Jeff Jewitt of Homestead Finishing Products and/or Paint Sprayers Plus for the best advice.

Between these two resources, you should get the information you need.

SPRAYERS THAT WE HAVE USED IN THE SHOP

1. The Earlex Sprayer Station 5500 is an entry-level spray gun with a self-contained pressure system that sprays our paint quite well. It comes with a 2.0 mm tip for paints and a 1.5 mm tip for clears. You can learn more about this product by going here.

The Earlex Spray Station 5500 has been used for the following GF spray demo videos:

2. The 3M Accuspray HG18 16570 is also easy to use, It filters the material, and the spray head is disposable. This is one of the units we spray within the woodshop. It uses a 1.5-1.8 mm tip for paints and clears. Check out the 3M Accuspray product listing on Amazon here.

3. Home Decor Sprayer by Wagner is another entry level sprayer that is easy to use, saves time, and works well with GF products. You can purchase this sprayer directly through the Wagner website for under $100- here.

We have used the Wagner Home Decor Paint Sprayer for the following videos:

Can I Spray Arm-R-Seal?

Arm-R-Seal can be sprayed successfully, but we prefer hand application methods because it is very easy to spray too much in one area. If you choose to spray, use very thin coats and watch for runs (large drips that run down the side of your project).

If you notice a run, immediately wipe or brush it out. If you correct a run promptly, you will not see a mark. However, dried runs can be difficult to remove.

Wear a mask and work in a well-ventilated spray booth.

Size: Small Needle Nozzle (1mm)