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Re: Envirotex Lite coating tips

Original poster: "Scott Hanson" <huil888@xxxxxxxxxxxx>

Matt -

I'm not sure where you see any "disagreements on key issues" between Terry's and my epoxy application processes .....certainly not anything that should induce anyone to stick with solvent-based coatings instead of at least trying epoxy.

Here are the differences that I see between Terry's procedure and mine, and the reasons behind my suggestions.

1. Application brushes:
Terry suggests a 1" wide bristle brush, I suggest a 3-4" wide disposable "foam brush". I used the cheap disposable bristle brushes in the beginning, but found that they continuously shed bristles into the coating. The foam brushes shed nothing, and using a 3-4" wide brush just makes leveling the coating go faster since you are leveling a wider section of the coil. Obviously, using a wider application tool requires you to pay more attention to keeping the edge of the brush perfectly parallel to the axis of the coil. Also, the single, flat edge of the foam brush seems to introduce less bubbles than the bristle brush. Remember that in the final stages of smoothing, only the very tip of the brush is contacting the coil, with only a few grams of pressure.

2. Use of Co2 to magically pop bubbles in the coating:
I think this is actually stated in the Enviro-Tex literature. However, there is no mechanism (physical or chemical) that I can think of that could cause Co2 to make bubbles expand or rupture. Nevertheless, I had lecture bottles of pure Co2 and nitrogen available to me when I was first experimenting with Enviro-Tex coatings, and I tried flooding bubbles in the coating with direct streams of C02 and nitrogen. There was absolutely no effect on the bubbles. However, the more conventional process of applying mild heat from a heat gun or hair dryer (at LOW VELOCITY) instantly pops the bubbles and allows the heat-thinned epoxy to flow back into the low spot created when the bubble pops. Remember, we're talking about bubbles smaller than the head of a pin. I also tried vacuum de-gassing of the mixed resin, which works very well while the liquid is still in the mixing container, but I still found that bubbles were generated when pouring the resin onto the coil form and smoothing it out with the brush. In the end, I stopped vacuum degassing as an unneeded complication.

3. Smell:
Terry found the smell disagreeable enough to recommend the use of a fan during application, I suggest applying the coating in a completely sealed, draft-free room. The uncured material does have a distinct "epoxy resin" smell, but I didn't find it objectionable. My reason for suggesting a damp-mopped and draft free room is to eliminate (as much as possible) any lint or dust in the air. This is to eliminate any dust from settling on the coil while the resin is curing. Dust and lint settling on the coating will leave nearly microscopic (but still visible in the right light) little lumps and bumps in the coating, just like they will on a varnished coil. It just depends on how much of a perfectionist you are. Because of how perfectly glass-smooth the rest of the surface is, any little dust motes or lint embedded in the coating stand out visually. Regardless, any lint that does get embedded can be easily sanded out with very CAREFUL use of #400 or #600 grit silicon carbide "wet-or-dry" paper, used wet with a little dishwashing detergent added to the water as a lubricant. After final sanding with #600 paper, the epoxy can be polished to a high gloss using any polish designed for acrylic or polycarbonate, or even just an automotive type polish.

So, there you have it: really very few significant differences between Terry's and my processes. Like anything in Tesla coil construction, you will need to develop your own application process, based on the experiences of others who have tried it and recorded their results. I can absolutely guarantee that anyone who has the skills to build a functioning Tesla coil will get better results with an epoxy coating than with a multi-layer varnish coating.

Scott Hanson

----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Saturday, July 01, 2006 7:43 AM
Subject: Re: Envirotex Lite coating tips

Original poster: Mddeming@xxxxxxx
Hi All,

Since the two people with expertise in the use of Envirotex Lite (Terry and Scott H.) seem to disagree on a number of key issues concerning its application, I think therefore that I will stick with polyurethane until enough trials (disasters?) have occurred for a consensus to emerge. ;^)

Matt D.