38-31: Canopy Fibreglass Fairing - Round 6 - Sanding back the skim coat / first & second coats of primer

Sanding Back the Epoxy Skim Coat

The epoxy skim coat was wet sanded back using 240 grit - the aim is not to remove all the shiny surface, but to sand to a shape. If you aim to sand for a smooth looking surface, you end up with a surface which looks average once primer is applied (wavy). So i used the curved blocks as before, and sanded until the surface was the correct shape. The forward edge was again sanded to a feathered edge with the skin. 

Forward edge was sanded to a feathered edge

Here you can see how i sanded to a shape - with only a few low spots remaining.

The shiny patches are the low spots.

First coat of Primer

The Stewart Systems primer which i have been using to prime the airframe components has a number of advantages when doing fibreglass work - it is water based (so easy to clean up, and won't affect the canopy), it is very high build (so fills holes well), it dries very fast, and wet sands easily. So it was a good choice for the finishing of the fairing. 

I decided to use a paint roller for the first coat thinking it would go on nice and thick, and would save me having to mask everything up - this ended up being an erorr. The paint went on with some texture, which took a fair bit of sanding to get off. The second coat was done with the spray gun (and lots of masking!). 

I applied paint to the whole of the forward skin / fairing. I wanted to get a nice fair curve from the skin to the fairing and make the front of the fairing totally dissapear.

Here you can see the texture left by the foam roller.

Masking and spraying would have been a better choice.

The texture is really evident in this photo.

Fortuantely the Stewart Systems primer dries in only a few hours, so i can paint and sand on the same day - it's great stuff.

Most of the first coat of primer was sanded off. You can see how it is left in the low spots, doing it's job nicely. All sanding was done with a block - no finger sanding whatsoever.

Despite looking patchy, this was a very smooth surface after only one prime.

Here you can see the little grey dots - this is where the paint has nicely filled some pinholes.

Once sanded, the second coat was applied with a spray gun.