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Peeling or flaking plywood spars

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JasonKing

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Jul 22, 2020
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Hi , I hope someone can help me determine if this is of concern. I acquired my dads fisher flying koala fp-202 and I discovered these few areas on plywood spar facing. Just little pieces of outside of plywood appear to be flaking off. Is there a way to fix/repair this? Glue another piece of plywood over problem areas? Just lightly sand flaking parts off? Add epoxy?
 

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TFF

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The purple throws me off. What is it preserved with? I see the scars. Those look like tooling issues from when the ply was made. To me depends on where it’s located along the span on if I would do something or leave it.
 

JasonKing

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The purple throws me off. What is it preserved with? I see the scars. Those look like tooling issues from when the ply was made. To me depends on where it’s located along the span on if I would do something or leave it.
Preserved with a varnish of some sorts, think your seeing the dust on it that makes it appear purplish. And the scars are on the outer few feet of the spar.
 

mcrae0104

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Are you familiar with AC 43 13 1b? Chapter 1, section 4 seems to address situations very similar to this.

You might also reach out to @Pete Plumb to see if he would be willing to render an opinion.

Also, it that an intercostal stiffener just to the left of the delaminated section of the web?
 

BBerson

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It might be cheap interior plywood, like door skin. Can't tell without inspection of end grain.
 

BBerson

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Why would aircraft plywood do that? Can't see much from a photo. I suggest a wood Tech Counselor visit.
 
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Marc W

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I would worry about it having been wet. The purple stain is from the glue and might be caused by moisture causing the glue to bleed to the surface. I would inspect everything very carefully.
 

JasonKing

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I would worry about it having been wet. The purple stain is from the glue and might be caused by moisture causing the glue to bleed to the surface. I would inspect everything very carefully.
Never been wet, been hung in Morgan building. Nothing is purple, it’s just the dust, should’ve got better photo i guess. Think I’ll just get in touch with local EAA members.
 

Pops

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What would be wrong with sanding and scraping the varnish off with a razor blade and cut a piece of 1/8" plywood ( same as the web) one inch larger on each side than the damage and to the top and bottom spar caps and re-varnishing. To me it looks like the plywood surface was gouged with something with a sharp edge.
 

TFF

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It’s interesting it shows as purple on the monitor while the other wood looks like wood and the fabric looks like fabric. To me it still looks like an anomaly like a plainer knife dig during ply manufacturing. If not, it’s the layer grain was more burl than straight. Time had it pop. Has this flown or is it still in the build stage?
 
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