Wash/Rinse/RP – Can You Use the Same Chemistry?

Explore the challenge of cleaning without corrosion.
–Chuck Sexton

Read the condensed Q&A below and watch our full 10-minute presentation video for in-depth advice from one of our techs:

What kind of storage are your targeting for your corrosion protection?
I think I mentioned in one slide, it’s inside protection in a warehouse but not air conditioned and with open doors, typically. That’s where we see most of our corrosion problems and sometimes during transportation. Usually, parts are made and then they go in the inventory in the warehouse that doesn’t have a controlled environment.

Do you recommend different chemical concentrations for winter and summer?
Yes, the products that I’m showing or the group of products, normally run between 2 and 4 percent in the winter. It’s sort of 4 to 6 percent in the summertime, obviously the conditions are a little more demanding in the summer regardless of where you are around the world. So, about a 2 percent higher product in the summer.

Do these products leave a visible film on parts?
Like most corrosion inhibitors, they will if you let the concentration get too high. With these products, as long as we keep them at the concentrations I just mentioned, mostly below 6 percent, you see none or very little film left on the parts. It depends on the type of part, if it’s a really highly machine smooth surface or stainless steel sometimes you will see the encroached inhibitor film left behind.

I understand nitrite RPs can be measured even after intermixing with alkaline cleaning chemistries, how are these different than your combination products?
Well that’s very good question. We sell some sodium nitrite corrosion inhibitors and where the customers choose to use them; they’re good corrosion inhibitors. They’re not accepted in many areas, mostly not in Europe, many companies who have EH&S issues with the nitrite, we do provide a titration that’s specific to sodium nitrite. So, what you just said is exactly right, you can carry in even an acid product into those baths and measure the concentration with the sodium nitrite titration. One of the problems is you can’t automate that process as a titration. You can’t do with it what you can do with conductivity in particular with the combination products that I’ve been referring to today.

Will these combination cleaner RP products pass salt spray testing?
Normally not, salt spray is mostly for coatings, for powdered coatings or for liquid paint coatings. Most corrosion inhibitors, especially water-based corrosion-based inhibitors, which is what I’ve been talking about, are water soluble. The salt is dissolved in water so when you start spraying the salt solutions onto the part you wash off the corrosion inhibitors and we normally fail fairly quick. It’s a good question because a lot of companies ask us about that and the salt spray test is really designed, in my opinion, for more solid coatings, a light powdered coat.