Ask the Expert Question-and-Answer Archive

by Ron Joseph

September, 2001

Painting Steel for Wine Making

Q. I have made a wine press that has some metal parts which will have minor contact with acidic grape juice. Could you recommend a paint for these steel parts? Where stainless steel was not cost effective I've used regular steel with hopes of using a coating to protect. One store recommended aliphatic polyurethane enamel by Insoltron (Inslx) which is a two part paint. And finally, will this paint have to have a special primer or will regular spray can primer be sufficient? Thanks in advance.

A. Thanks for your email. If you are not concerned with the appearance of the coating you should be able to use an epoxy primer followed by an epoxy topcoat. If appearance (color and gloss) are important, then use an epoxy primer followed by a polyurethane topcoat.

Please bear in mind the following:

1. You will need to prepare the steel extremely well before painting. Follow the vendor's recommendations.

2. All of the coatings that I have mentioned are two-component products. They are relatively expensive and sophisticated products, therefore read the instructions carefully before you start the project.

3. If the wine or ingredients will come into contact with the coatings, insure that the coatings you purchase are nontoxic in the cured state. The paint vendors can give you this information.

4. You are STRONGLY advised to wear a suitable respirator when using these coatings. Please follow the vendors' recommendations, especially if you intend to use a polyurethane. The respirators that are available in hardware stores are usually not adequate for these coatings, and especially not suitable for polyurethanes.

5. If this project seems too onerous for you, consider taking the steel to a custom coater in your area and have him apply the coatings for you. Most reputable custom coaters also have the necessary equipment to prepare the surfaces appropriately.

6. You will be able to purchase the coatings form an industrial paint supplier in your area, but in all likelihood you will not be able to get these products from a hardware store or building supply store.