Applying a Sacrificial Coating to Wrought Iron, Cast Iron and Steel
- Procedure code:
- Maintenance, Repair & Alteration of Historic Buildings, GSA PBS
- Metal Materials
- Last Modified:
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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.
APPLYING A SACRIFICIAL COATING TO WROUGHT IRON, CAST IRON AND STEEL
A. This procedure includes guidance on applying a sacrificial wax or linseed oil coating to wrought iron, cast iron and steel features.
NOTE: CLEAR, NATURAL COATINGS ON EXTERIOR WROUGHT AND CAST IRON SURFACES ARE NOT RECOMMENDED EXCEPT IN EXTREMELY LIMITED CASES. WHEN EXPOSED TO THE ELEMENTS, THESE TWO MATERIALS WILL RAPIDLY DETERIORATE. CLEAR, NATURAL COATINGS SHOULD BE LIMITED TO ORNAMENTAL PIECES ONLY. EVEN LIMITED USE REQUIRES A HIGH DEGREE OF DILIGENCE IN MAINTAINING THE COATING. IDEALLY, SUCH COATINGS SHOULD BE LEFT TO INTERIOR WROUGHT AND CAST IRON SURFACES.
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).
C. For guidance on cleaning and paint removal of wrought iron, cast iron and steel, see 05010-05-R, 05010-16-R and 05010-17-R.
A. Butcher Polish Company
A. Paste wax such as Butcher's "Boston Polish Wax" or "Bowling Alley Wax" (Butcher Polish Company), Trewax Clear, or approved equal.
D. Linseed oil: Available from hardware or paint store.
E. Emery cloth
F. Soft cloths
A. Fiber bristle brushes (1/2 to 3/4 inches long)
B. Portable propane torch
A. Before recoating, remove all traces of rust, corrosion, scale and old paint leaving the surface completely clean. For guidance on paint removal, see 05010-05-R, 05010-16-R and 05010-17-R.
3.02 ERECTION, INSTALLATION, APPLICATION
A. Refinish with Wax:
1. Wax metal piece with paste wax, or a mixture of beeswax which has been dissolved in a bit of turpentine.
NOTE: DO NOT USE EMULSION TYPE WAXES.
2. Let sit for fifteen (15) minutes.
3. Buff with soft cloth.
4. Rewax every one to three months depending on the severity of the exposure.
Refinish with Wax and Linseed Oil:
1. Gently heat piece with a portable propane torch.
2. Wipe with emery cloth.
3. When cool, rub a combination of beeswax and boiled linseed oil into the surface with a soft cloth.
4. In exterior locations the beeswax and boiled linseed oil should be renewed yearly.
A. Protect cleaned or final finishes from damage during building or project cleaning period by use of temporary protective coverings approved by RHPO. Remove protective covering at time of Substantial Completion.