Rod(NH) and others

• MP series

Here's a direct link. I have no idea if any formulation has changed. If any has changed, I would think they would have given it a new numerical designation. But they might not. I see that the dry time for one coat is now said to be 15 min instead of 30. Perhaps that's the result of subtracting out the 15 minute induction period time - or not. So we are left with not knowing if the "new" MP175 catalyst can be used with the "old" MP170 or vice versa. My guess it that there probably has been no formulation change and both MP170 and the 175 are the exact same products as before. But it's just a guess. I suspect they added an induction period as a precaution - perhaps they have had a problem with application too soon after initial mixing. When I used the PPG DP epoxy there was only one catalyst for it and there was a 30 minute induction period after mixing and before application for the ingredients to "interact". It was a surprise to me when I changed over to the OMNI MP170 that there was no induction period at all. While I consciously observed the period with the DP, I didn't make any effort to wait any specific time period for the MP170. I haven't had any problem that I have noticed. I guess now I will be a little more careful about application too soon. With the newer DPLF epoxy, there are now two different catalysts - one with a shorter pot life and a faster cure with no induction period and one like the old catalyst with a longer pot life and a 30 minute induction period.

The change from 1 coat to 1-2 coats is not surprising to me. It's now the same as both the old and new DP. I always use two coats anyway - a carryover from my familiarity with the DP. In fact with the DPLF, there is a requirement for a film build of 1.2-1.5 mils if there is no prior treatment with a metal cleaner/conditioner (phosphoric acid treatment in two steps) or a wash primer (etch primer). Since the film build is said to be 0.5-0.75 mils per coat, it follows that two coats should be applied for the best corrosion protection if no specific pretreatment is used. I use the same reasoning with the MP170 and always use two coats anyway.

Rod