however are not to be considered as limiting the invention to their details all parts and percentages in the examples as well as throughout the specification are by weight unless otherwise indicated the following examples show the effect formaldehyde has on lowering the ph of an aqueous cationic composition and how the ph can be stabilized by the addition of a formaldehyde scavenger this example shows the effect of formaldehyde on lowering the ph of a cationic electrodepositable composition the composition was in the form of a resin concentrate which was contaminated with about 0 3 percent by weight based on resin solids of formaldehyde the film forming resin was prepared by reacting a polyepoxide with n methylethanolamine and the methyl isobutyl diketimine of diethylenetriamine the reaction product was combined with a fully blocked polyisocyanate and then solubilized with acid as generally described in example b of u s pat no 4 419 467 with the exception that aqueous lactic acid 91 2 percent was used in place of acetic acid the resin had a solids content of 36 6 percent the resin 2220 grams was thinned with an additional 300 grams of deionized water and contaminated with 6 63 grams of 37 percent aqueous formalin the ph of the uncontaminated resin was 6 5 the resin was then heated for about 2 hours at about 65 u00b0 c the ph of the resin dropped to 6 23 a sample of the resin treated similarly but with no formaldehyde contamination had a ph drop.