Core Bond, Pint
Quantity in Basket:
Catalog No.: CCB-16
Shipping Weight: 2.00 pounds
Corbin Core Bond CCB-16 is a pint fluid flux that bonds
lead cores to copper or brass alloy bullet jackets. The
process requires only a drop of flux in each jacket.
Core Bond is designed to have a fairly neutral pH at room
temperature, and to drop its pH radically when heated. This
makes it safer to handle and to ship and conventional zinc
chloride, ammonium chloride, and hydrochloric acid fluxes.
How to Bond Cores:
- Clean the jackets in solvent to remove oil or lube.
- Support the jackets in a heat-proof holder, such as Corbin's
ceramic foam heat treatment bricks.
- Make the cores for your jackets.
- Put the cores into the jackets loosely.
- Put a drop of Core Bond in each jacket.
- Using a propane torch, melt the lead in the jackets.
- Let the lead cool (don't drop into water)
- Inspect the lead. If it forms a cup shape, with a shrink hole,
it is bonded. If it forms a dome with no shrink hole, it is not bonded.
- Wash the seated cores in hot water with a little baking soda added.
- Dry the seated cores by spreading on a towel.
The secret of bonding is clean jackets, a loose fit between core and jacket ID,
and heat that is applied quickly so the flux is not boiled away before the lead melts.
If the heat is applied too slowly, the lead will not melt until after the flux has
boiled away. The idea is to have hot vaporized flux while the lead is molten, so the
lead will be able to penetrate into the jacket walls because the surface tension of
the lead is lowered by the flux and the surface oxides and carbonates are carried to the
top as a slag.
When the lead cools, it should be stuck to the jacket walls such that the only
place for the lead to go when it shrinks is to pull away from the center. This makes
a shrink hole. If the lead is not bonded, it will pull away from the jacket walls