On 3/3/2019 12:08 PM, Martin Gregorie wrote:

Snip...

I've been told to never use silicone based polish because it is said to
make repairs to fibreglass or carbon structures very difficult or
impossible to repair.

In fact I remember reading that here, so it must be true!

OTOH I've not seen any publications that mention the effect of silicone
contamination on repairability. The only article on repairing FRP
structures I've seen, in a search I just carried out, that even mentions
contamination in any detail is:

https://compositesuk.co.uk/system/files/documents/
repairoffrpstructures.pdf

It has a short section about contamination (half a page in a 33 page PDF
document) that mentions "fuel, oil, hydraulic fluid, etc" and moisture, but
says nothing about the perils of silicone-based polishes.

The other 2-3 publications my search turned up that didn't turn out to be
pushing supplier's products either did not mention contamination at all, or
gave no details apart from describing how to sand through surface finish.

So, what's the deal?

Are silicone-containing polishes etc to be shunned?

Can anybody recommend an FRP repair publication that gives any more details
about dealing with contamination than the one I quoted above?

Lordy, it must be winter in the northern hemisphere!

Certainly there's no harm in avoiding 'silicone-ingrediented' waxes, but IMO
'commonly-held views' on the subject border on religious arguments in that
'proof of one's beliefs' is rarely part of the discussion.

So while we're polling, let's not forget including FRP repair shops' inputs.
My own direct shop-input querying-experience - *not* repairs, sardonic chuckle
- includes a mere 3 (4 counting a long-ago RAS post by JJ Sinclair), and, so
far, each puts "Silicone = Bad!" into the urban myth category. Further, who
can point me toward an accident report involving structural failure of a
repaired FRP glider, that has 'fingered' silicone as a contributing factor?

N.B. For the disputatiously-inclined, I am NOT recommending spraying every
accessible surface of your bird with silicone spray (a little common sense can
go a long way), but rather positing that 'fretting over its presence in wax,'
arguably falls into the urban-myth/anally-self-inflicted worry category.

YMMV, of course...

Bob - last night's low -1 deg F. here - W.

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