…inhibits electrolytic corrosion of dissimilar metals
 

Description: Duralac is an anti-corrosive jointing compound for use between joints of dissimilar metals.

Form Duralac Jointing Compound is a yellow paste prepared from an elastic varnish medium of low

moisture permeability, a corrosion inhibiting material barium chromate and an inert filler. It

conforms to specification DTD 369B.
 

Properties: Barium chromate is only very slightly soluble in water and hence is not leached out of the joint

even in the presence of a considerable flow of water. It is however readily decomposed by

acids with the liberation of chromic acid so that it is brought into action only in the presence of

corrosive influences. It is tough and flexible, absorbs little water and is resilient to seawater.

Uses: Duralac is indispensable for the sealing of joints between dissimilar metals of all types

including magnesium and its alloys. It is also valuable for the protection of metals in contact

with wood, synthetic resin compositions, leather, rubber, fabrics etc. When the components

of a structure are of different materials, it is essential that the points or faces of contact should

be treated with corrosion inhibiting materials because in the presence of electrolytes

considerable differences of potential arise, not only where different metals are in contact, but

also where components of the same metal under different stresses are in contact: for

example as between the aluminium alloy plates or extrusions and rivets or bolts used in

building up the structure, in industrial areas where structures are exposed, in flue ducts and

acidic vapours. In close proximity to the sea where a salt laden atmosphere will be met with,

structures will need the maximum attention to prevent corrosion due to the electrolytic cells

set up by the salt laden moisture deposited upon the structure.

Application: Duralac is supplied ready for use and must not be thinned. It is best applied by brush. When

Duralac is applied to metal or other surfaces the volatile solvent evaporates and the

compound sets to the touch, but remains tacky for a considerable period. It is important that

the joint should be closed while Duralac is still tacky – so that it is in such a condition that it

will flow sufficiently under pressure to close the gaps in the joint. It will harden somewhat if a

thin film is left exposed to the atmosphere for a long period and this will prevent the making of

a close joint.

Availability: Duralac is available in the following packaging:

Supplied in 250ml, 500 ml, 1 litre, and 5 litre tins. Also supplied in tubes.