Troy
I go along with what John says, though did not find any thinning was
necessary. Matthew Russell who did the top coat for me had misgivings
about putting polyurethane on top of smooth prime but it worked fine and
I am very pleased with the result.
By the way when it came to doing the doors the gelcoat affected the top
coat somehow, resulting in a very pale grey instead of the "pure" white
elsewhere. After drying for week and a rub down to provide a key the
second attempt did the trick I am pleased to say. With the advantage of
hindsight I would be inclined to rub as much of the gelcoat off as
possible, if only to save a bit of weight. It was very generously
applied!
Paul
On Tuesday, September 10, 2002, at 01:30 , John & Paddy Wigney wrote:
> Hi Troy,
>
> Am hesitant to give opinions here as I am not an expert on painting.
> However,
> here goes.
>
> TroyMaynor@aol.com wrote:
>
>> I am priming the fuselage. Question; is slightly less than a gallon of
>> Polyfibers UV Smooth Prime about right for three coats rolled on? It
>> seems
>> like I am going through it too fast. I only thinned it enough to roll
>> it on
>> easily and to prevent it from drying too fast as temps are a little
>> warm in
>> my garage this time of year. I will sand these 3 coats and if I don't
>> sand
>> through too much maybe only one or two coats more is sufficient. I
>> suspect I
>> put it on too thick by not thinning it much.
>
> I followed the Polyfiber instructions and rolled 6 coats of Smooth
> Prime. Can't
> remember clearly but am pretty sure I used at least 2 gallons of Smooth
> Prime for
> the whole plane, maybe more. Somewhere in the archives is a paint
> quantity
> estimate. If I had used less than 6 coats, I do not believe I could
> have done a
> good job of sanding it out smooth. Recommend you do not try to put it
> on too
> thick, 6 regular coats work fine. I thinned mine just a little so that
> it did not
> dry and flake at the edges of the roller.
>
>> Also, how much paint should I plan to buy for the entire aircraft? I
>> will use
>> an automotive paint like DuPont Imron or PPG polyurethane.
>
> Recommend you let the fellow doing the spraying do that estimate. If he
> can't
> estimate it, then it may not be a very good testimony to his abilities.
>
>> One more; the fellow that will be spraying it suggested using some of
>> the
>> primer that is normally used under the same paint when he paints cars.
>> What
>> have others done? I have already talked to the Polyfiber folks and if I
>> remember correctly they said more primer was not necessary. But I was
>> just
>> wondering what others had done down this avenue.
>
> All manufacturers declare that you should use their primer with their
> topcoat. If
> you use somebody elses primer and then you have a problem with the
> topcoat, they
> will just say : " You are on your own." Smooth Prime is an excellent
> primer and
> is compatible with the Polyfiber 2 mix Aerothane catalysed polyurethane
> which is
> what I used with success considering it was my first spraying job.
> Imron and PPG
> autobody paint are 2 mix catalysed polyurethanes. By the way, by the
> time I had
> finished the plane, I was getting pretty good !
>
> One option is to have a hybrid primer, i.e 3 ? coats of SmoothPrime
> and then ?
> coats of DuPont or PPG primer. Be careful though, more paint = more
> money = more
> weight. As a plus, if you do use the automotive primer, your sprayer
> man does not
> have any excuse not to do a good job. Some kind of rotisserie for the
> fuselage is
> a definite asset, so spraying before the engine is mounted is probably
> easier. I
> was not that smart.
>
> Lots of luck.
>
> Cheers, John
>
>
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