Sanding down the plug ready for its next coat of epoxy before that next coat is sanded and polished ready to be gelcoated and the tank made

The plug covered in low density epoxy filler which was left to cured over two days 

The filler was then sanded back until the surface was smooth all over 

A few places that needed extra filling with fine filler 

The sides coming smooth after a lot of careful sanding to get a smooth finish ready for the next coat of thin epoxy resin 

The fine filler appeared to the areas as it was needed, just a few places, however, generally a fairly smooth finish  

So it is just a matter of a quick sanding and then on to epoxying the surface after sanding back this fine filler