EPOXY BASICS ~ by Russell Brown
Excerpt from “Epoxy Basics ~ Working With Epoxy Cleanly & Efficiently” by Russell Brown www.ptwatercraft.com
Copyright ~ not to be reproduced without written permission of Russell Brown
EPOXY
Epoxy technology is relatively new. As such, it’s not as much of a taught art as other building methods. An art it is though, and there are many techniques for using these materials efficiently.
To achieve the full potential of these materials, one needs a warm and dry place to work.
The viscosity of epoxy is greatly affected by temperature, so mixing, coating, and glassing are faster and easier at room temperature. Cure times are faster as well and this helps overall progress.
If working in winter, most heat sources (not Propane) will help keep your workplace dry.
If working in a damp environment, a shop that can be closed to keep out night air, fog, etc., is
recommended. Electric dehumidifiers (the kind used in basements) work great for keeping a shop dry.
MIXING A BATCH OF EPOXY
This seems pretty simple, and it can be, but it’s a deep subject. Epoxy is a two part, fairly viscous material that needs to be metered accurately and mixed thoroughly.
Epoxy must be metered accurately to the correct ratio.
Epoxy mixed inaccurately may get hard, but it will not be nearly as strong as it would be if it was mixed to the prescribed ratio.
Never add extra hardener, and always discard a batch that you are not sure about.
If you decide to use mini pumps and the temperature in your shop is not always warm, you will need to keep the epoxy jugs warm. Keeping the epoxy warm will do two things; it will greatly increase the speed of pumping for mixing large batches, and it will make the two parts much easier to mix thoroughly together.
A drop light with a 40 watt bulb clamped close to the resin jugs or pump is one way to keep the epoxy warm.
CUPS AND MIXING STICKS
You will be mixing many batches of epoxy. It helps in many ways if you get the right cups and sticks, and learn how to do this part well.
We think of epoxy as liquid gold. Properly mixing it is like adding value.
To mix all the epoxy in your cup, you will need cups with straight sides and a flat bottom, and stir sticks with straight edges and square ends. With this combination you will be able to scrape the unmixed epoxy off the sides and bottom of your mixing cup, so that your whole batch gets mixed together thoroughly.
We use lots of 12 oz paper coffee cups. If you buy coffee in paper cups, wash and dry the cups. Get your friends to do the same, and then you will only have to buy the quart size paper cups. Quart sized cups will be used for glassing and large coating and filleting operations.
Try snipping off the tops of the cups with scissors.
This makes a sharp edge you can scrape your mixing stick and other tools on, keeping epoxy inside your cup, and not running down the outside. Try it, you’ll like it.
Stir sticks of different sizes can be cut on the table saw. They must be wide enough to get the batch of epoxy moving, but light (thin) enough to not tip the cup over when it is empty.
The edges of the sticks should be straight and the ends square.
MIXING
Hold the bottom of the cup in the base of your palm. Stir the two parts so that you get the whole batch moving around in the cup. Stir some more.
Now scrape all the unmixed epoxy from the walls of the cup with the stir stick held vertically. The edge of the stick should contact the walls of the cup all the way around.
Next, holding the stir stick horizontally, scrape the unmixed epoxy off the stir stick, and into the cup. Stir again, repeat the above process, and stir again.
Excerpt from “Epoxy Basics ~ Working With Epoxy Cleanly & Efficiently” by Russell Brown www.ptwatercraft.com
Copyright ~ not to be reproduced without written permission of Russell Brown
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