Ask the Expert Question-and-Answer Archive

by Ron Joseph

June, 2004

Epoxy Primer on Aluminum Surfaces

Q. Are epoxy primers limited to Aluminum surfaces? Are there any for Stainless? Is there a standard operating temperature for these types of primers?

A. Thank you for your e-mail. Epoxy primers are used on virtually all substrates including aluminum, steel, stainless steel and more. You need to determine whether a pretreatment is necessary before applying the epoxy. In the case of aluminum it is advisable to apply a chromate or non-chromate conversion coating such as Alodine which is manufactured by Henkel. Equivalent pretreatments are available from other companies. In the case of stainless steel it is recommended that a pretreatment primer, such as a vinyl butyral wash primer be applied before using the epoxy primer. However, the wash primer must be formulated specifically for purposes of slightly etching the stainless steel. You should contact your local industrial paint store (not your local hardware store) to identify the most appropriate wash primer for your application.

If you have a production line in which you already treat aluminum then you might be able to avoid the use of a wash primer by passing the stainless steel through a chemical etching process.

Please bear in mind that it is extremely important to rinse the stainless steel well and then allow it to thoroughly dry before applying the epoxy. Epoxy primers should not be applied at temperatures below 60°F or above approximately 100°F. At the higher temperature the potlife will be dramatically shortened.

In service epoxies can be used at both low and high temperatures, but I would imagine that you would not want to expose it to temperatures much above 300°F for any length of time.

I hope this email answers your questions.

Best wishes,

Ron Joseph