3 Steps To a Successful MobyShield Finish

As discerning craftsmen, we know that the success of our work is based on 3 interrelated elements: Inspired Design, Quality Materials, and Careful Fabrication. We also know that the application of a quality finish is the step that unites and highlights these elements and on which lasting impressions and enduring quality are founded.

Just as there are 3 elements to the overall success of our work, so too there are 3 steps to a successful finish:

  1. Proper preparation of the substrate
  2. Proper cleaning and calibration of equipment
  3. Careful mixing and application of a quality product

Whether out of excitement at wanting to see our work completed, or out of the need to hurry the production process, we are all at times tempted to rush the finishing process – often to our detriment. No matter what product you choose, following these 3 steps will help to prevent costly or annoying problems and best, ensure the highest quality finish for the product you choose.

Step 1: Substrate Preparation

1) Sand & Fill

  1. Putty gaps and imperfections. Remove any excess material immediately.
  2. Sand all surfaces, with the grain, to a consistent and even texture. Check for any imperfections and correct them. Remove dust.
  3. Apply paste wood filler if desired. Read and follow product application recommendations and allow to dry thoroughly.
  4. Sand to 220 grit sandpaper. (Always use aluminum oxide paper – never use steel wool!) Check for sanding marks after thoroughly removing sanding dust. If wood species is prone to blotching or end grain is exposed, apply a wood conditioner or 2 pound cut of shellac. Sand lightly with 280 grit paper or a fine (white) abrasive pad. Remove dust.

2) Stain & Seal

  1. Before applying, always test the stain/dye on a generous sample prepared in the same way as the actual project (use the Sanding Sealer afterward for the most accurate color comparison; topcoat is not necessary on the sample). Testing will provide an opportunity to correct color tone and to ensure even penetration. Repeat test until desired results are achieved.
  2. Because of the variety of stains and dyes available, we recommend following the stain/dye manufacturer’s directions for specific application advice and/or consulting with the manufacturer. MOBYSHIELD has performed well overall stains tested that have cured per their manufacturer’s directions. [NOTE] Stains containing polymerizing oils, e.g. tung or linseed oil, require an extended curing time and we recommend they be avoided.
  3. After applying the stain, allow 12 hours minimum for the stain to dry.
  4. Apply one or more coats of MOBYSHIELD Sanding Sealer on top of a dry, stained surface. Lightly sand between each coat, allowing 30 minutes cure time per coat (test an area with hand or machine-held sandpaper – if dry, sanding will yield fine white powder with no gumming). If brushing on Sanding Sealer, allow MOBYSHIELD to level itself. Do not over brush!
  5. Remove all sanding dust with compressed air or with wax and silicone free tack rag. Topcoats may be applied as soon as dust removal is complete.

Step 2: Cleaning and Calibration

1) Work Environment

  1. Housekeeping: The work area must be clear of dust and debris.
  2. Elevate the work: If possible, work should be off the floor to prevent contamination from foot and tool movement as finishing proceeds.
  3. Clearance: Provide clear access to all sides and the top of the work. Continuity of motion assures even film disbursal.
  4. Airflow: A positive air draft, filtered if possible, prevents dust and overspray from settling on the wet coating. Air must pass over and around the piece rather than directly onto it. Direct contact can cause premature curing.

2) Clean and Organize Equipment

  1. Required accessories include fine mesh cone filters; clean stir sticks; lint-free rags; a container of clean water; and brushes of various sizes to ‘tip out’ drips. All these items should be conveniently available for immediate use.
  2. Brushwork requires good quality synthetic bristle brushes in sizes appropriate to the work. Provide a clean, elevated surface for placing these brushes when not in use. A stretched wire or rigid edge placed on the finish container to aid in unloading the brush will be useful.
  3. Spray equipment must be fastidiously cleaned to provide good performance. If solvent-borne coatings have been used previously, all fluid lines and equipment must be flushed with a solvent like acetone followed by a water flush. Clean the gun – including the body, airways, air cap, fluid tip, and needle. The airline should have a moisture trap located at least 20 feet from the compressor and below the compressor air outlet. The moisture trap and compressor tank must be drained before shooting. Placing an inline filter/dryer located as close to the gun as possible is recommended.

3) Equipment Calibration

  1. As with any fine finish, an HVLP conversion or conventional external mix gun is recommended.
  2. Fluid tip and needle. Under most conditions, using either HVLP or conventional equipment, a .055 fluid tip and needle is suggested when spraying MOBYSHIELD finishes.
  3. Each spray system, indeed each spray gun, performs differently. It is, therefore, better to discuss the spray gun output or ‘fan’. The fan is the result of the interaction of fluid delivery and the air pressure applied to it through the air cap. MOBYSHIELD is a medium viscosity lacquer that requires a comparatively heavy coat. The ideal fan is achieved by setting a moderately high fluid delivery flow and then increasing air feed to acquire acceptable atomization. Test the fan by directing it horizontally onto a vertical surface from a distance of 6 to 8 inches. Adjust the airflow until the excess lacquer drips down evenly from the horizontal line of finish.
  4. Test the fan by spraying a sample on a horizontal surface, make small adjustments in air and fluid delivery until an even pattern, approximately 4 inches wide, is observed while shooting from about 6 inches above the sample.

Step 3: Mixing and Application

  1. Product Preparation
  • Mix and work with the product in a clean location. One a container has been opened, the product may become contaminated until the product has fully cured. To prevent contamination, ensure mixing surface, space above the work surface, and personal attire is free of dust, cigarette ash, loose hair, etc. before opening can and applying product.
  • Mix and work with products in an organized location. Have all mixing tools at hand before starting, including lid pry, stir sticks, funnel, fine mesh cone filters, an empty container to receive the filtered product, and a damp, lint-free rag to clean spills. Searching for these items after the opening can is frustrating and will increase the likelihood of contamination.
  • Open the can and place the plugin a clean location. Stir carefully from the bottom up to ensure solids are evenly distributed in the vehicle. Never shake product. Colorants or tints may be added to the sealer if desired while stirring. Always introduce color by premixing with a small quantity of Reducer before stirring into the sealer or topcoat.
  • After stirring, filter the product into a clean container and cover it to avoid contamination.

2. Product Application

  • Ensure the temperature of the work environment is maintained between 60 and 90 degrees F. Relative humidity should not exceed 70%. If humidity exceeds 70%, add 1-3% Anti-Moisture Additive.
  • For Brush: Load the brush by dipping only 1/3 to1/2 of bristle body into the product. Apply with long, even, strokes proceeding with the grain, laying a full, wet film. When brush fails to fully coat, reload and proceed from the fully coated point. Overlap strokes as you work towards yourself. On vertical surfaces, work from top to bottom, completing one strip before moving to another. Do not over brush! Instead, allow the product to level itself.
  • For Spray: Adjust to an even, wet fan on a vertical piece of scrap, holding gun about 6” to 8” from work. When spraying a 3-dimensional piece (e.g. a table or chair), coat vertical surfaces first to avoid overspray on the top or seat. Spray vertical surfaces from high to low. Spray horizontal surfaces from near to far. Overlap strokes by about 1 inch. Trigger a stroke before entering the surface and release only after finishing the pass. Maintain an even distance of 6” to 8” from work. Never pause during a pass! If puddling occurs, or debris then falls on the surface, complete the surface, let it cure, and then sand it out. Don’t attempt to repair a wet surface with finish or fingers. (Note: pitting with open-pored species can be avoided by reducing the sealer and applying a series of thinner coats.)
  • Allow a minimum of 30 minutes for the Sanding Sealer to cure before sanding with 220 grit aluminum oxide or garnet paper. Never use steel wool or papers with silicone binders with waterborne finishes. Avoid sanding through the seal coat – reseal if this occurs. Once sanded, the sealer may be recoated immediately. Multiple coats of reduced sealer will provide the fill desired with open-pored woods. Carefully remove all sanding dust and debris before proceeding to topcoats.
  • Apply a minimum of 2 topcoats, allowing no less than 1 hour curing time between coats, cool or humid conditions will slow the curing process. MOBYSHIELD may be recoated at any time after curing, scuff between coats for optimal adhesion. Remember that sealed substrate is less absorbent than raw wood – lighter coats will reduce the risk of runs on vertical surfaces. Exercise great care to ‘proof’ the finish before the final coat is applied, using both your hands and eyes to detect any flaws in the finish to be corrected before proceeding.

Cleanup and Post Production Considerations

  • Cleanup of brushes or spray equipment is easily accomplished using clean water only while the MOBYSHIELD finishes are still wet.
  • Brushes, material hoses, and containers require rinsing under a stream of water. Dry and block the brushes after rinsing to maintain their shape.
  • Spray guns should be cleaned by removing the air cap and soaking it while running water is passed through the material inlet. Repeatedly triggering the gun while rinsing should adequately clean the needle and fluid tip.
  • Blow compressed air through air cap openings and gun body before reassembling.
  • Shooting clean water through the gun after reassembly completes routine cleaning. Equipment should be completely disassembled and cleaned with solvent and a soft brush weekly if the equipment is under heavy use. Always flush the gun with running water after the solvent has been used.
  • Remove the masking tape.
  • Cured finish must be removed with an aggressive solvent like acetone or MEK, so clean up immediately after each use!
  • Wash your hands and arms with soap and water after working with the finish.
  • MOBYSHIELD reaches 95% of complete cure within 24 hours, complete cure in 7 days. Wait 72 hours, minimum, before stacking or packing. Finishes should not be exposed to standing water or cleaners until full cure is reached.

If a ‘rubbed’ effect is desired, abrasive pads, wet-dry sandpapers, or rubbing compounds may be used. Wait a minimum of 48 hours before rubbing out to achieve ideal results.