PPG Paint

[skippydiesel]

Cautionary Tail;

 

My Sonex has been undercoated with  PPG Industries DeSoto 515X349 and then top/final coat of PPG Industries Protec White (recommended by PPG Paint Power House)- Top coat applied by professional painter, in down draft, temperature controlled, spay booth.

About 12 months or so ago, I started to notice that neat little circles of paint was disappearing of some rivet heads (these are solid not pulled rivets). Both top & undercoat lifted off.

 

Then top coat started to flake from edges of "sheet" aluminium (skin).  In this case the undercoat remains attached.

 

 

• Before you suggest holding the painter to account, you should know, as a friend of my Son, he did a "love job"  so no recourse in that direction.
• Further - As a partially completed project, most of the undercoat came with the aircraft. I have reason to believe that as sections were completed, they were undercoated. The build took in excess of 10 years, so undercoat age may have varied from say 6 moths -10 years. No idea what effect age may have on subsequent top coat adhesion but from my own expertise, I am aware that some paints require further preperation when left to "mature".

 

Over a month or so , up to this day, I have been trying to get PPG Industries to inspect & advise.  Not only are they very slow to respond to correspondence (eMail) I have been passed from one department to another & back again, without receiving an inspection.

 

This day the verbal/phone advice, PPG would not be inspecting the problem.

 

I presume liability concerns may be at the crux of the refusal, even though I said I would put in writing that I would not claim/sue  and that all I wanted was informed advice as to what may have happened and what may be the way forward.

 

Without an inspection, the phone representative speculated the following possible causes/remedy to the paint failure;

 

• PPG do not have any data sheets suggesting Protec White is a suitable topcoat over DeSoto 515X349. I should have been directed to PPG Aerospace for their recommendation (Inference being - a different paint may have been recommended)
• Its possible that the undercoat was applied to the, correctly prepared,  aircraft skins, before assembly BUT the subsequent fixing rivets were not prepared, leading to the undercoat to not bond effectively with the aluminium rivet head = delamination of undercoat & with it the top coat.
• Remedy - complete removal of Protec White. Cleaning & light abrasion of all rivet heads. Seek advice from PPG Aerospace as to retention/removal/replacement of DeSoto 515X349 and subsequent top coat.

 

The Sonex is flying well. Its a shame about the appearance but fixing it is a huge /expensive job that will not deliver a better flying platforme. I think I will leave as is, for now.

 

It's a lot easier & less costly to do it right the first time.

 

I hope that any prospective aluminium aircraft painter, takes a lesson from my experince and questions (second & third opinions) all advice about the covering material and application techniques required.

I am sure I am not the first to make such a mistake & will not be the last.

 

😈