chemically reactive, two-part polymerizable cements such as Weld-On 40* are best. The cure is brought about by a chemical reaction. Polymerizing adhesives are polymers dissolved in monomers which cure when a hardener is added. Polymerizing adhesives fill better and, therefore, impose fewer demands on the accuracy of fit between the parts. They must be used where high strength and good resistance to environmental conditions are required. A bonded part should be heat conditioned (annealed) before finishing the adhesive joint. If not, it could form constrictions when it is later heat conditioned and the constrictions would impair the bond strength.


Solvent cements are better for bonding thin sheets with a blunt edge. Most small tanks, sumps and displays are fine built with capilary methon solvent cements, all large tanks and structural pieces should be bonded with 2 part polmerizable cements