The Engineer Artist - Encaustic Fusing DoE

I am an Artist. I am also an Engineer. I am always both but today the engineer really took over in the art.

I read a lot about how on encaustic (wax) paintings you must fuse the wax or it will flake off. There are as many ways to fuse as there are artists - heat gun, torch, heat lamp, the sun, red lamp, just until the wax shines, it needs to melt, slow, fast, 3 inches, 12 inches, or any number of processes. It all seems like a bit of hocus-pocus, but not disingenuous. The artists believe that they need to do whatever it is that they are doing. Some even hide their "secrets". My experience is that the wax seems pretty "fused" immediately without any additional fusing.

As an Engineer I know that I can get to the bottom of this. So I get out my DoE knowledge. This is short for "Design of Experiments" and is an engineering and statistical approach to figuring out what impacts a result and what does not.

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The factors that I decided to investigate are:

1. Degree of Fusing. None, Melted

2. Type of Pigment. Oil Paint, Dye

3. Amount of Danmar in the Wax. 0%, 15%

4. Temperature of the Substrate Wax When Applying the New Layer. Room Temp, Warm.

5. Temperature of the applied layer wax. 200 degrees F, Medium, hard enough to just adhere to the substrate

6. Temperature of the final art work. 65 degrees F, 35 degrees F

I did a Taguchi Main Effects DoE to find which factors are important and which are not.

I did 3 samples of each run.

The test for flaking was just to try to get the wax to separate using a scalpel. The possible results were:

1. Falls off on its own

2. Flakes off easily

3. minor flakes

4. some separation but need to work at it

5. Fully adhered

I did all the test runs, compiled the data, ran the statistics and had some interesting results.

Observations from the analysis:

• No noticeable flaking due to any of the factors when tested at room temperature

• No noticeable flaking due to any of the factors when the applied wax was hot or medium.

• At near freezing there was some flaking on the wax that was applied "cold" and not fused.

• At Freezing there is an interaction between fuse temperature with with danmar ratio and pigment type.

• There is no impact on flaking from the wax substrate temperature.

• Frozen work, with no fusing, applied cold, had statistically significant flaking. Oil Pigment and increased Danmar made this slightly worse.

Next Steps:

• Investigate further into lower levels of fusing.

• Investigate temperature cycles on finished work. freeze, warm, freeze, etc.

• Look into other pigment types

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Conclusion

• Fusing is not really that big of a deal for flaking for the type of works that I do as I apply wax when it is hot.

• If you apply wax on the colder side of things then fusing is important especially if you use a high Danmar wax ratio or use oil paint as a pigment.

This all makes a lot of sense as there are encaustic paintings that are 1000's of years old with no flaking. It just can't be that hard to make a robust encaustic painting.

Recommendation

• Apply wax hot and you will be fine

• Fuse to a slight level (just shiny) to make sure the wax layer is adhered. You don't need to fully melt the wax when fusing.

Has anyone done similar experiments? Anybody want to try to reproduce my experiment results?