Re: Ironman Mk III - First Build - Pic Heavy (UPDATE 19/2/11)
You can lightly key the resin, although both filler and fibreglass resin are polyester, so they will bond together naturally. I would try to skim over the whole helmet. You will sand back through to the fibreglass anyway in places as you block over the curves.
For the best finish, you will need to work through ALL of the grades. Start at 80/120/180 depending on your filler skimming, then 240, 320, 400, 600, 800, 800 wet, 1000 wet and finally 1200 wet. Use the 1000 and 1200 once you have some primer on...this will give you a glass-like finish. Skip any out and you'll more than likely have scratches you can't get rid of....you can go on heavy with a decent high-build primer to fill the scratches, but this is a bit of a bodge (I do it all the time :LOL). I'd use 1200 on your top coat too...between coats. Then you finish up by polishing. T-Cut will do the job, but there are some better compounds out there.
Yep, the David's is good stuff. Halfords do a UPOL too...I prefer it.
