Technical Procedures Disclaimer
Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.
We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.
STRIPPING DETERIORATED VARNISH FROM WOOD HANDRAILS AND REFINISHING
A. This procedure includes guidance on stripping and refinishing wood handrails where the varnish is deteriorated or has been damaged.
B. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:
1. Safety Precautions
2. Historic Structures Precautions
4. Quality Assurance
5. Delivery, Storage and Handling
6. Project/Site Conditions
7. Sequencing and Scheduling
8. General Protection (Surface and Surrounding)
These guidelines should be reviewed prior to performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO).
1.02 PROJECT/SITE CONDITIONS
A. Existing Conditions: Determine that surfaces to which finishes are to be applied are even, smooth, sound, clean, dry and free from defects affecting proper application. Correct or report defective surfaces to Contracting Officer.
B. Field Measurements: Take all required field measurements and verify profiles and installation conditions for work of this section.
A. The Sherwin Williams Co.
NOTE: Chemical products are sometimes sold under a common name. This usually means that the substance is not as pure as the same chemical sold under its chemical name. The grade of purity of common name substances, however, is usually adequate for stain removal work, and these products should be purchased when available, as they tend to be less expensive. Common names are indicated below by an asterisk (*).
A. Varnish: Linseed-tung modified phenolic spar varnish such as "Rexpar" (Sherwin Williams), or approved equal.
B. Solvent: Mineral spirits, turpentine or denatured alcohol.
1. A petroleum distillate that is used especially as a paint or varnish thinner.
2. Other chemical or common names include Benzine* (not Benzene); Naphtha*; Petroleum spirits*; Solvent naphtha*.
3. Potential Hazards: TOXIC AND FLAMMABLE.
4. Safety Precautions:
a. AVOID REPEATED OR PROLONGED SKIN CONTACT.
b. ALWAYS wear rubber gloves when handling mineral spirits.
c. If any chemical is splashed onto the skin, wash immediately with soap and water.
5. Available from construction specialties distributor, hardware store, paint store, or printer's supply distributor.
1. Typically used as a solvent and thinner.
2. Potential Hazards: TOXIC AND FLAMMABLE.
3. Safety Precautions:
a. Work in a well ventilated area.
b. Observe safety rules as turpentine is flammable, and the fumes can trip an ionization smoke detection system.
c. Store soiled cloths in a metal safety container to guard against spontaneous combustion.
d. Available from hardware store or paint store.
1. Other chemical or common names include Methylated spirit*.
2. Potential hazards: TOXIC AND FLAMMABLE.
3. Available from hardware store, paint store or printer's supply distributor.
4. Denatured alcohol should be a satisfactory substitute for ethyl alcohol for stain removing purposes.
C. Alternative Solvent: a mixture of 75% toluene, 24% acetone and 1% butyl acetate.
1. A liquid, aromatic hydrocarbon that resembles benzene but is less volatile, flammable and toxic; is produced commercially from light oils from coke-oven gas and coal tar and from petroleum; and is used as a solvent, in organic synthesis and an antiknock agent for gasoline.
2. Other chemical or common names include Toluol.
3. Potential Hazards: TOXIC AND FLAMMABLE.
4. Available from chemical supply house, hardware store, paint store or printer's supply distributor.
1. A volatile fragrant flammable liquid ketone used chiefly as a solvent and in organic synthesis.
2. Other chemical or common names include Dimethyl ketone; Propanone
3. Potential Hazards: VOLATILE AND FLAMMABLE SOLVENT
4. Available from chemical supply house or hardware store.
D. Steel Wool: Grade 000 steel wool.
E. Clean, soft cloths
F. Sandpaper: 3 grades, finest grade 00.
G. Shellac burn-in sticks
3.01 ERECTION, INSTALLATION, APPLICATION
A. Stripping Deteriorated Varnish:
1. Make sure work area is well ventilated and wear protective clothing and rubber gloves. Do not allow smoking in the work area. Place a fire extinguisher for Class B fires at entrances for emergency use.
2. Always rub along the grain of the wood.
3. Change cloths as often as necessary to be effective in cleaning.
a. Wet steel wool with solvent and rub over the wood to remove varnish buildup and smooth out checked surface. Replace soiled steel wool frequently and continue the wiping process until a smooth evenly colored surface is achieved. Use no water on wood surface under any circumstances.
b. Work only one 4' square area at a time. Work area should be within a comfortable arms reach. Protect areas of wood and adjacent surfaces not to be refinished from solvent and other stripping operations.
c. This process is to remove the varnish buildup only. If solvent affects the stained color of the wood, discontinue use and use Alternative Solvent mixture listed under 2.02 Materials.
d. Allow surface to dry thoroughly, no less than 24 hours.
5. Fill scratches and gouges with shellac burn-in sticks matching the color to the wood stain.
1. Apply full wet coat of varnish. Allow to dry thoroughly.
2. Sand out roughness with 6/0 open coat abrasive paper. Dust off thoroughly with air jet or vacuum and wipe with a tack cloth to remove all dust.
3. Apply final full wet coat of varnish. Follow manufacturer's instructions for obtaining final satin finish.
C. For guidance on cleaning and maintaining woodwork, see 06400-02-P, 06400-01-R, and 06400-01-P.