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does any one hav any experance using a solvent based paint over the stewart sys, glue/uv block? we are building a ss7 and are at the covering and uv block stage. love the glue and uv block but want to look at all top coat options. thanks for any input.
FYI, the guys out here in Kansas say the Water born systems just don't hold up to oils and chemicals on the Ag-cats. The last job only last 2 years.
Roger
So, if we're going to saturate our a/c w/insecticides and fertilizer, Stewart Systems is not a good choice?Quote:
Originally Posted by rogerh12
Seriously though, on our field trip to Stewart System last week, the topic of fuel and their top coat came up. We were told that while it wouldn't work as a "gas bag" (e.g. fuel leak allowed to accumulate in the fuselage), incidental contact (ie. minor slosh from fueling that is cleaned up) shouldn't be a problem.
The system is water borne, not water based.
(As an aside, how much longer, do the solvent based paints last on crop
dusters?)
Ok, you asked,,, 20 + years with the non-water born systems,,,,,
Food for thought?
I was going to use the Stewart system, but the old timers have warned me off, said to go only with proven long-term-true-&-tested fabric systems,,,, or else....
You can learn a lot from a group of 80 year old men... I'm just a kid to them at 46
Hope this helps
Roger
A sure way to have paint crack, peel and fail is to mix one system with another. I think it is important to note these covering processes are called Poly Fiber “SYSTEM” and Stewart “SYSTEMS”
.
Whether using Poly Fiber, Ceconite, Stewart Systems, or Randolph Products, the components of each are designed to work together as a system. They are not in any sense interchangeable or necessarily compatible. Regardless of what a supplier may tell you, they haven’t tested all paints with all coatings on aircraft. If different manufacturer’s products are mixed you may experience cracking and separation of the color coat.
Some problems may not appear for a year or more and then you will be facing a new cover job or have to live with a cracked finish. It costs about $2000 to cover a Kitfox. So why risk two grand just to cut a few corners? Stick with one system.
I prefer the Poly Fiber System. Here’s the process in brief:
Poly Tack. It is to tack down the fabric at the edges prior to shrinking. It is simply PVC solids in MEK. There’s nothing you can’t fix with MEK to loosen or re-glue fabric with Poly Tack. It's simple and fast.
Poly Brush is next. Poly Brush is to fill the weave. When dry it is slightly rubbery and cannot be sanded but bumps can be flattened with an iron. You apply one coat of brushed Poly Brush and two coats of sprayed Poly Brush.
Poly Spray is third. It is a UV blocker. All systems must use a UV blocker to prevent the sun from destroying the fabric in two years or less. Three coats of Poly Spray are sprayed on. You may sand Poly Spray lightly before the color coat. Poly Spray is also an adhesive to bond the color coat to the filler coat.
Poly Tone, AeroThane or Ranthane is the color coat. AeroThane and Ranthane have a wet look. Poly Tone has a semi-gloss look. Poly Tone is non-toxic and requires only a simple respirator for application. You must use a fresh air respirator with toxic fumes from AeroThane or Ranthane. I like the simplicity of Poly Tone.
If using Ranthane or AeroThane they are chemically resistant. PolyTone is AvGas resistant, but don't soak it.
What is the advantage of Poly Fiber system over Stewarts ? First it is almost always lighter. Sprayed finishes weigh less than rolled finishes. Second, If the fabric is damaged you can remove the coatings with MEK, patch the area, and re-coat the fabric to blend it in. Third, If the color coating is Poly Tone and it starts to get brittle as it ages, you can rejuvenate the coating without the need to recover. There is no rejuvenator for Ranthane, Aerothane or any waterborne systems.
Stewart Systems also makes some fine products but take care to note it is a system. Do not mix any of the Stewart System products with products from Poly Fiber; or, you may encounter problems.
What is the advantage of Stewart Systems? On the surface the system has no fumes to deal with and water cleanup. Because I've never used Stewart Systems I'll let the experts weigh in on this. I'm sure they can tell you many reasons why they prefer SS over PF.
John Pitkin
Greenville, TX