Avoiding White Haze

By Matt Yonkey, Yonks Custom Rods, Midland, MI

I was reading through some of the Rod Maker Tips on your website, and had some information that other readers might find useful. One of the comments on the site was from a man having trouble with 2 part flex coat epoxy curing, and also a white hazyness.

A tacky finish is almost surely caused by not thoroughly mixing the two parts (Resin and Hardener), or inaccuractely measuring the two parts. It is crucial that a 1 to 1 ratio of hardener and resin be measured to achieve a proper curing.

Your guide wraps can be recoated with a fresh batch of epoxy and it will cure out the tacky coating. If you are concerned about getting a high build up then you will need to remove the tacky epoxy and then recoat.

The white hazyness the man is experiencing is called Polyamine Blush.The two parts, resin and hardener, parts A and B, contain molecules called 'amines'.

When mixing the resin and hardener the amines in the hardener are looking for an amine molecule of resin to bond with. A blush problem comes from not mixing the two parts as thoroughly as possible, epoxy curing in a cold temperature, and/or exposure to moisture in the air during cure. After the curing reaction has taken place there are amine molecules that do not bind and rise to the surface appearing as a greasy, waxy layer. On contact with high humidity or water, this coating turns into an opaque white smudge, which turns into dry chalky powder with time.

You need to clean off this haze (by sanding with ~220 grit paper) before recoating to get a good bond between coats.

I recommend using syringes as the measuring devices for finish epoxy. This helps to accurately measure equal amounts of hardener and resin. ~ Matt Yonkey

Publishers note:
If you have any tips or techniques, send them along! Help out your fellow rodmakers! ~ Publisher, FAOL

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