| Copper-Top Hall Table -- Copper Panel and Patina |
From "Wood Works"
episode WWK-111 |
|
|
|
advertisement
|
With the base and frame for the table made, the next phase of the hall-table project is to create the inset copper panel and begin work giving it the blue-green patina finish that is the highlight of this piece. The copper itself is relatively thin, so it is mounted on a plywood substrate cut to fit precisely into the tabletop frame. Materials: Birch plywood stock
Copper sheeting
Band saw
Table saw
Disc sander; 80-grit sandpaper
Handheld router; flush bearing-bit
Epoxy glue
Woodworking glue
Clamps
Bronze-patina solution (available from crafts centers)
Cheesecloth; sawdust
Carpenter's pencil
Saftety glasses or goggles
Note: Cut sizes may vary. For exact measurements, please contact David Marks through his website -- information below under Resources. Safety Alert: Always wear safety goggles or safety glasses when working with wood, saws, drills, routers, etc. Gluing the Copper Panel Steps: - The plywood substrate, made from Baltic birch plywood, is cut to size on the table saw so that it fits into the rabbet cut into the tabletop frame (figure A). In our example, a hand plane was used on the rough-cut piece to get a glove-tight fit in the rabbet. An exact fit is also important because the plywood substrate will serve as a template for cutting the copper panel.
- To cut the copper sheet to size, it's best to use a bimetal blade on the band saw (figure B).
Important: Always wear eye protection when cutting metal, as metal shavings and slivers can cause eye injury. - Once the copper sheet is cut to size, use a disc sander with 80-grit sandpaper to rough up the bottom surface of the copper sheet (figure C). Roughing up the surface gives the metal a "mechanical tooth," to which the glue can adhere.
- After roughing the copper's bottom surface, spread epoxy glue onto the rough surface (figure D) as well as the plywood substrate.
- With a coating of glue applied to both surfaces, place the plywood panel on the copper sheet (figure E). Lay a piece of 3/4" MDF on the plywood and, using metal strips to even out clamping pressure, clamp the pieces together firmly (figure F).
- Leave the pieces clamped together overnight so that the glue can fully harden.
.Gluing the Frame to the Base While the glue is hardening on the copper panel, the tabletop frame can be glued onto the assembled base. The long grain of the base is glued to the long grain of the frame, resulting in a strong bond that won't require any mechanical fasteners. Steps: - For glue-up, apply yellow woodworker's glue only along the top edge of the table's base (figure G). It isn't necessary to apply glue to the frame.
- Blue tape placed earlier on the corners of the frame helps to align the frame and get it into position (figure H).
- Plenty of clamps are used to make sure there is even pressure all along the length of the aprons and frame (figure I), leaving no gaps.
Cutting the Copper Panel and Patina Finish With the copper top firmly bonded to the plywood substrate, the insert can be cut for an exact fit in the walnut frame. The plywood substrate serves as a ready-made template for trimming the copper. Once cut, the copper panel can be treated to begin the process of giving it a patina finish. Safety Alert: Patina solutions contain toxic chemicals. Carefully follow any directions and precautions that come with the chemicals that you're using. Safety Alert: Always wear protective gloves when working with toxic or caustic chemicals. Steps: - Excess copper is trimmed away from the copper panel using a handheld router with a flush bearing-bit. The bearing rubs against the edge of the plywood substrate as the blade of the bit trims away the copper edge (figure J). This will allow the entire panel to fit precisely into the walnut frame.
- With the panel cut to exact size, work can begin on the patina finish for the copper surface. This is achieved through a process known as cold patina. Techniques and chemicals for this process may vary. For details on various methods, check with your library or crafts center for information pertaining to "bronze patina." In our demonstration, the chemicals that David Marks selected were mixed with sawdust and cheesecloth to create an interesting pattern on the surface of the copper.
- To achieve a flowing, nonuniform pattern, the cheesecloth was torn into pieces and laid out in random shapes on the copper surface (figure K).
- The patina solution was then mixed into the sawdust and spread across the copper surface (figure L).
- A spray bottle was used to spray additional patina solution across the panel and sawdust (figure M) to dampen it thoroughly.
- Once the copper panel is thoroughly covered with the texturing materials and chemicals, the entire panel is sealed in nonabsorbent wrapping paper (figure N ) to trap moisture and assist the oxidizing process that will ultimately cause the blue-green patina to appear.
- Once sealed, the panel is set aside for about three weeks as the chemical process takes place.
In the following and final segment of this project, the patina finish is revealed, the copper tabletop is installed and finishing touches are applied to the table. Sponsored Resource
> Click here to order your tools and materials for this project from Woodcraft!
RESOURCES :
Fine Woodworking
A magazine devoted to high-quality craftsmanship in woodworking.
The Taunton Press Inc.
Website: www.taunton.com
The Small Wood Shop (The Best of Fine Woodworking)
Author: Helen Albert (Editor)
Publisher: Taunton Press
ISBN: 1561580619
Woodworking Techniques: Best Methods for Building Furniture from Fine Woodworking
Author: Editors of Fine Woodworking magazine
Publisher: Taunton Press
ISBN: 1561583456
Mastering Woodworking Machines (Fine Woodworking Book)
Author: Mark Duginske
Publisher: Taunton Press
ISBN: 0942391985
David Marks Website
David Marks, DIY's Wood Works host, is a master woodworker. For more information on cut sizes and project details, please contact him via his Website at www.djmarks.com
The Complete Woodworker's Companion
Author: Roger Holmes
Publisher: Watson-Guptill
ISBN: 0823008665
Advanced Woodworking
Model: 0783539126
Author: Editors of Time Life Books
1998
Time-Life Books Inc.
Website: www.timelife.com
Popular Woodworking
F & W Publications, Inc.
Website: www.popularwoodworking.com
| 
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
