Re: Re: covering with mylar

From: Ken Achee <ken_at_achee.com>
Date: Sun, 1 May 2011 21:58:33 -0500

Thanks for the information Don.

On Thu, Apr 28, 2011 at 11:15 PM, Don Slusarczyk <don_at_slusarczyk.com> wrote:

>
>
> On 4/28/2011 8:29 PM, John Kagan wrote:
> >
> > y reference to "relatively heavy" was intentionally vague.
> >
> > I covered a wing and prop using the solution wicking method and surprised
> at how overweight they were (I remember something on the order of several
> hundredths of a gram too fat).
> >
> > The next set I did using the activation method and got better results.
> That's the extent of my scientific analysis.
>
> It is easy to get heavy for a few reasons.
>
> 1) to strong a solution
> 2) too much applied
>
> I found that for different films a different solution had to be used.
> For heavier films like polymicro (0.9 micro) I needed a stronger
> solution than for Y2K. What I would do is take one of those small jars
> that are about 1" in diameter and about 1.5" tall (~3/4oz or so) then
> spray 3M77 in the bottle for about 3-4 seconds. Then fill to about 3/4
> full with TCE then shake it vigorously. I would then take a piece of
> 1/16" sq wood about 3" long and lay it on the film. Then take a brush
> and apply the solution and let it dry for at least 30 minutes. Then pull
> on the piece of 1/16 to see how much force to pull it from the film. If
> it comes off easy then add a quick squirt of 3M77 and try again. Too
> strong add more solvent. Typically I would keep thinning until it became
> too weak then add in one quick squirt of 3M to bring it back up. For Y2K
> the solution was very thin like 10:1 or maybe even more. For heavier
> films I had to make a stronger solution like say 7:1. I recall that the
> stronger solution has a slight milky haze and the thinner solution for
> Y2K looked essentially like pure solvent. In either case, if you rub the
> soluton between your fingers you will not feel any tackiness.
>
> Where the weight really comes in is if you use a strong solution when it
> is not needed combined with over application. All that is needed is to
> apply a small drop from the end of a brush to the outside of the outline
> then let it wick a few seconds then apply another drop and so on. It is
> very much like how applying microfilm with water was/is done. If one
> drop wicks 1.5 inches in each direction then the next drop is applied 3"
> away. Then tendency is to apply the drops too close to each other or
> worse continuously along the outline. The excess glue just gets soaked
> up into the wood. You are better off to apply the drops farther apart
> then go back and fill in the missing areas. I cover wings upside down
> (with the film on a frame) so after I have gone around the outline with
> the solution, I flip the frame over and look to see if some spots are
> missed. You can see where the film is attached to the wood or not pretty
> easily if you look at an angle with good lighting. Once I am happy with
> everything, I let it dry for an hour or so before messing with it.
>
> Don S.
>
>
>
Received on Sun May 01 2011 - 19:58:34 CEST