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MasonRE® S-305 Heavy Duty Paint Stripper


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This water based paint remover extremely effective in removing the tough, high performance coatings. S-305 Heavy Duty PS will effectively lift highly cross-linked urethane and epoxy top coats and primers, alkyds, non-skid coatings (100% solid content) and the toughest of industrial coatings as well as most graffiti.  It is also capable of lifting fuel resistant primers, inorganic zinc primers and coal tar epoxies.

Features and Benefits

  • Water Based
  • Easy clean up
  • Low and inoffensive odor
  • Will not burn skin
  • Cost Effective:
    • Reduces man-hours
    • Reduces down time since other work at site can continue while stripper does its job
Application Procedures

Test Area
Always prepare a test area prior to full application.  This will indicate the time required for project completion and suitability of product for the paint and the substrate.

Equipment and Tools
This product is engineered for airless spray application.  Use only airless equipment with chemical resistant packing, such as a Titan 440i or larger pump. Equip the sprayer with a tip size of 0.019 inches or larger. (Example: a 519 or 425 tip).  Other equipment: brushes, rollers, scraper, masking tape, plastic (polyethylene) sheet, pressure washer, electric drill with mixer, empty pails for clean-up, water.  Roller application should be used ONLY for horizontal surfaces.

MASKING: Cover / protect areas where stripping is not desired, including adjoining surfaces where over spray may travel.  Plastic (polyethylene) sheets make a very effective barrier.  If using masking tape, apply two layers of tape and remove the top layer immediately after application as the remover may soak through the tape, damaging paint under it.  Plants should be covered during application.

MIXING: Thoroughly mix the stripper with a drill. DRILL MIX ONLY.  DO NOT DILUTE.

EQUIPMENT:  Ensure application equipment is free of any previously applied products or chemicals or solvents (especially mineral spirits).

Apply a thick, even layer of stripper onto the coating being removed.  An airless sprayer is the most effective means of application.  Always start the sprayer pump at the lowest pressure setting and slowly build up the pressure until an adequate fan pattern has been generated.  The minimum wet film thickness should be 15 mils (300 microns).  The stripper must be applied 30%-50% thicker than the coating to be removed, i.e., 10 mils of coating requires 13-15 mils of stripper to be removed effectively.  High pressure is neither required nor desired.  High pressure and narrow tip sizes will break the stripper’s emulsion and will reduce its effectiveness.  When trying to build up films thicker than 30 mils (600 microns), it is advisable to build the stripper film in two separate applications.  First apply a light coat of approximately 10 mils (250 microns), allow it to dwell for about 30 minutes and then build the rest of the stripper film thickness in the second application.  Once applied, leave the stripper alone, as agitation slows down penetration.  Brushing and rolling should be avoided because these methods produce a lower film build and inconsistent thickness of stripper.

Dwell Time
The time required for penetration varies according to the type of paint, and the temperature.  Most paint systems require 1 to 6 hours.  Leave the stripper overnight for best results.

When there are multiple layers of paint, it is quite likely that there is poor intercoat adhesion between some layers.  Premature lifting may occur at this interface.  If this happens, remove the lifted layers and reapply the stripper.  Do not allow the stripper to dry out.  The stripper is designed to remain wet and effective over extended periods of time (up to 48 hours), but excessive sunshine, windy conditions or insufficient stripper thickness can cause early drying.  If the stripper starts to dry, reapply a light coating and allow extra time for completion.

Removal and Cleanup
Removal of lifted paint can be completed by scraper, squeegee, wet/dry vacuum suction system or by pressure wash.  The stripped surface must be rinsed with water or denatured alcohol to remove all chemical residues before repainting.  When rinsing, always work from the bottom to the top. Any water that runs down the substrate will deactivate the stripper and allow the paint to re-adhere, therefore never work from the top to the bottom.  Collect lifted paint and dispose of in accordance with local, state and federal government regulations.  Do not collect and/or store removed paint and stripper waste residue in metal containers.  Clean up spray equipment by running water or denatured alcohol through the equipment soon after the spraying has been completed.

Safety Requirements
Proper safety procedures should be followed at all times while handling this product. Refer to the Material Safety Data Sheet for important health/safety information before use.

Surface temperatures should be 65° to 95°F (20° to 32°C). The product performs effectively at lower temperatures (even at 32°F, O°C), but the dwell time increases.

Packaging and Coverage
Packaging: 5-gallon pails
The product is engineered for thick film build up on vertical and overhead surfaces.  The desirable wet film thickness of stripper is approximately one and a half times the dry film thickness of the paint.  Minimum wet film thickness should be 15 mils (300 microns).  The stripper must be applied 30%-50% thicker than the coating to be removed, i.e., 10 mils of coating requires 13-15 mils of stripper to be removed effectively.  Typically, coverage is approximately 40 to 90 sq. ft./ US gallon (1 to 2.2 sq. m/L)



Notice: The information contained herein is based on our own research and the research of others, and it is provided solely as a service to help users.  It is believed to be accurate to the best of our knowledge.  However, no guarantee of its accuracy can be made, and it is not intended to serve as the basis for determining this product's suitability in any particular situation.  For this reason, purchasers are responsible to make their own tests and assume all risks associated with using this product.

Technical Data
Appearance Blue foamed emulsion
Specific Gravity 1.03
Boiling Point 100°C 212°F
Freezing Point 0°C 32°F
pH (direct reading) 3.0 4.0
VOC content 76g/L 639 lbs./gal
Flash point 100°C 212°F
Viscosity (cPs) 4,000 11,000

Scientific Breakthroughs in Masonry Restoration Seminar

We will be holding a Scientific Breakthroughs in Masonry Restoration Seminar and Repair Workshop on March 25th 2015 at our facility in Hanover, MD.  Hurry and register soon as only the first 25 participants to enroll will be eligible for the Open House.  Cost will be $25 for the day which will include lunch and AIA credits.  For more details please contact the front desk.


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