Re: Repurposed old wing.
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I did some careful testing of solvents when I was building my Q. I ended up using what is called "Fabric Wash". It is formulated and sold by Air-Tech Coatings Inc. They specialize in finishes for fabric covered aircraft. To test it, I put a piece of blue billet Styrofoam in a jar of this liquid for a period of two weeks and I had no change in the foam, either softening or shrinkage. I believe the formulation is mostly alcohol (it is a proprietary formulation), but I know from testing, that it is safe to use on all the materials in a Q. It is also fully evaporative, so it does not leave any residue.
Even soap and water will leave some soap on the surface and in the pores. Soap film can cause delamination and epoxy is hydrophilic, so will soak up water affecting the cure.
If you are concerned about the health of the styrene foam and want to make sure there is no residue that will compromise a lamination after you clean an area, this is the stuff I can recommend. Here is the link to the product it is $39/gallon plus shipping from the US:
Sam------------- Good report. I don't know if I said before, but I am building a Glasair 2SFT. The airplane came with lots of parts missing, so I decided to build my own style wing tips.
I had some old pink dock foam so I made some templates and hotwired out some tips. Had them attached and sanded and ready for the micro and glass.
The Glasair used a Vynl Ester resin, so I mixed up some resin, added micro and did a fill. Waited a while for it to set before I installed the glass. When I came back all the foam was 1/4 inch smaller and had been eaten away. Tore it all apart and on to plan "B"
I am so used to using Aeropoxi, I didn't realize the problem Vynl Ester created with the billet foam.
I should of know better when I know that bondo, gas, and some thinners eat foam. That's why they say, prior to paint, soap and water wash and no chemicals.
Anyway. No harm done, just time and money,and another learning
lesson.----------- Chris in Canada
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