Thanks,
My first attempt at the firewall reinforcement looked like that despite the
fact that I had scuffed it - obviously not enough - which taught me the
lesson.
And David I did wash it first because you put the warning about the release
agent on an earlier post. I find the forum extremely useful given that I
am a long way from in person advice.
Will
William Daniell
LONGPORT
+57 310 295 0744
On Mon, Jan 25, 2016 at 9:06 AM, Nigel Graham <nigel_graham@m-tecque.co.uk>
wrote:
> I just want to second David's comment (2) on scuff sanding.
> The wing mouldings are very thin and it's easy to inadvertently cut
> through the structural weave if you're over zealous. Use only 200 - 400
> grit "wet and Dry" abrasive and look to achieve a "flat" finish.
>
> All the pre-moulded components were delivered with small amounts of
> release agents still coating the surface. If you are in any doubt as to how
> effective this is, take a look at the attached picture of a de-laminated
> firewall to tunnel reinforcement. There is no sign of the firewall having
> been prepared - it is still "shiny" and the resulting lamination has not
> bonded. I was able to slide a steel rule under one edge and "unzip" it.
>
> This aircraft was built by students studying for a degree in aerospace
> engineering at a renowned university ..... which doesn't say much for the
> quality of instruction or inspection.
> I can't really name the university, but if Sir Geoffrey was alive today,
> he'd be turning in his grave!
>
> Nigel
>
>
> On 24/01/2016 15:30, davidjoyce@doctors.org.uk wrote:
>
> Will, as far as the factory gel coat goes two very important principles:
>
> 1. Make sure you wash all the gel coated bits very, very thoroughly. The
> release agent used in the moulds has a great ability to induce potentially
> serious allergic reactions, if you just sand it off. (That speaking with my
> medical hat on!)
>
> 2. You need to fine sand the gel coat until you cannot see even a hint of
> any shiny patch, even with a magnifying glass. Any shiny bits however small
> will give imperfect adhesion of your covering coat.
>
> Regards, David, GXSDJ
>
>
> On 2016-01-24 13:43, William Daniell wrote:
>
> Ummm....you got me there.
>
> I am talking about the white finish of parts that come from the factory.
>
> Will
>
> By that way david...nice pun
> On Jan 24, 2016 6:50 AM, "Jan de Jong" <jan_de_jong@casema.nl> wrote:
>
>> There may be confusion re what we call gel coat?
>>
>> On 1/24/2016 12:12 PM, davidjoyce@doctors.org.uk wrote:
>>
>> Will, on the principle that extra weight is a definite downer and always
>> think light or lighter, I would remove as much as you can without damaging
>> the fibreglass, subject to getting your perfect profile. If the gel coat
>> was properly applied in the first place it should be pretty much in
>> chemical continuity with the FG resin.
>>
>> Regards, David Joyce, GXSDJ, with gel coat finish I would not change if
>> you paid me!
>>
>>
>>
>>
>> On 2016-01-23 22:12, William Daniell wrote:
>>
>> Is it ok to fill on top of gel coat orovided that its scuffed up. In
>> other words is it necessary to go down to the fiberglass?
>>
>> I am dealing with the wing skin join and the fuselage join
>>
>> Thanks
>>
>> Will
>>
>>
>
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