This article focuses on applying a flat paper dial to a convex dial pan, including stretching techniques, wet-application methods, adhesive choices, and practical alternatives when the curvature is too great.
Understanding the challenge of convex dial pans
Why flat paper wrinkles on curved surfaces
Paper cannot naturally conform to a convex surface without stretching. When forced into a curve, it forms creases or buckles, especially on Sessions mantel clock pans with noticeable curvature.
Original construction of Sessions dials
Many Sessions black mantel clocks originally used silvered metal dials, not paper. These metal dials were formed to match the convex pan, making paper replacements more difficult to fit.
Effect on hand clearance
Dial pan curvature is matched to arbor length. Replacing a convex pan with a flat one may cause the hands to sit too far from the dial or bind against the glass.
When a flat dial pan is appropriate
If the curvature is shallow, a flat pan may work. If the curvature is deep, a flat pan will cause mechanical alignment issues and should be avoided.
Methods for fitting a flat paper dial to a convex surface
Using wet-application to stretch the paper
Soaking the paper in water softens the fibers, allowing gentle stretching over a convex pan. This method works best with laser-printed dials sealed with matte lacquer.
Applying wallpaper paste
Thinned wallpaper paste provides even adhesion without over-wetting the paper. Once applied, the softened dial can be pressed outward from the center to conform to the curve.
Working out air pockets and wrinkles
Finger pressure or a soft tool can push excess paste and air toward the edges, reducing creasing as the paper stretches into shape.
Using absorbent or flexible paper
Thinner, more absorbent paper stretches more easily than heavy cardstock. Heavy paper is more likely to crease on convex surfaces.
Alternative solutions when stretching is not possible
Switching to a flat dial pan
If the convexity is too great, replacing the pan with a flat one may be the only practical option, provided hand clearance remains correct.
Printing directly onto a prepared dial pan
Some restorers experiment with printing onto a gessoed metal pan, though this requires specialized equipment and careful surface preparation.
Using transfers or decals
Rub-on transfers or decals can be applied to curved surfaces more easily than paper, though they require precision and may not match original styling.
Creating a custom curved dial
For highly curved pans, a professionally made curved metal dial may be the most accurate and durable solution.
FAQs
Can any paper be stretched to fit a convex dial?
No. Only thin, absorbent papers stretch well. Heavy cardstock will crease.
Will lacquered paper still stretch?
Yes. Light coats of matte lacquer protect the print but still allow the paper to soften when soaked.
Is wallpaper paste safe for dial applications?
Yes. It provides even adhesion and does not overly wet the paper.
Can a convex dial be flattened?
No. Dial pans are formed metal and cannot be flattened without damage.
Is replacing the dial pan a common solution?
Only when curvature is too great for paper. Many convex pans can accept stretched paper successfully.
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