How to Make Copper Cap Boppers
By James C. Keffer
1. Copper plumbing caps, sizes 1/2" to 2"* (available at most major hardware stores).
Tools and Materials:
The objective is to get the copper cap as round and smooth as possible. The more round the
cap is the better control you'll have in striking flakes. You want to be able to strike the rock
with a single point of the bopper end as shown below.
Next clean the inside of the cap with sandpaper or a small sandblaster (I use either a small
cabinet sandblaster or an inexpensive siphon sandblaster).
Level the cap and secure (I use a vice and bubble level).
Then melt some lead and pour into the cap. Leveling the cap helps to balance the weight
distribution of the lead creating a more consistent bopper.
sufficient area on the handle and inside the cap for the epoxy to adhere and also places the
weight forward making the bopper more efficient at delivering the energy to the platform on
Let the cap/lead cool. There is a high degree of probability that the lead will not adhere to
the copper, particularly if using hard head. I find the easiest way to secure the lead to the cap
is with epoxy applied when attaching the cap.
lead. This doesn't work as well with hard lead containing either zinc or antimony (the two most
common alloys used to harden lead).
using a blunt punch (or carriage bolt), hammer the lead to where is swells within the cap
thereby creating a tight fit. Again, this also doesn't work as well with hard lead. Since epoxy secures the lead to the cap and the hardened lead doesn't deform, I prefer to use harder lead and epoxy.
any residue or glazing cause by the hot lead. This will help insure the epoxy has the best
opportunity to create a strong bond.
personal preference but most are usually 3-5 inches in length and made of hard wood. Oak, walnut, maple, alder, fir or any other wood that does not contain oils (such as teak which does not take glue well) will work for a handle.
A wood lathe allows for fast and easy turning of custom-fit handles. A variety of shapes,
Turning a handle on a wood lathe:
Checking the fit:
Mix a good two-part epoxy according to the directions. Use only enough epoxy for the
Liberally coat the inside of the cap (if using the epoxy to secure the lead, coat the entire
Clamping the cap:
One the finish is dry you have a bopper!
Drying Boppers (a drying block helps!):
All that is require to maintain the boppers is to occasionally re-seal the handles with your finish of choice.
When a copper cap wears through - and if you use it a lot - it will, you can remove the cap from
From what I've observed the primary reasons for caps becoming loose:
2. Too smooth surface on cap/handle. Solution - roughen the inside of the cap with sandpaper
3. Wood shrinkage - wood shrinks or expands with humidity. Solution - seal the handle with
4. Too much lead in the cap resulting in insufficient glue surface area. Solution - fill the cap just to the top of the domed area.
5. Too tight of a fit between cap and handle, not enough glue area - solution - make sure the gap
©2010 J Keffer