Buffing gelcoat to match the original

I've made several small gelcoat repairs, but can't seem to get the gelcoat to buff out to the original gloss. I sand with 360, 400, 600, 1000, and 1500 to get as smooth as possible. Then I buff with a 7" buffer at about 2000 RPM using compound from West Marine. It seems a little better if I use the 3M Finess compound. It just doesn't buff out as glossy as the original. Are all manufacturer's gelcoat created equal? Should I add white pigment to the gelcoat? What's my problem, am I expecting too much from my repair?

 

Are you talking shininess or color?

 

Shininess, I guess getting the exact shade of white is another issue.

 

If the repair is not fully cured you may not get a good gloss and if you do, it may not last long. Make sure you catalyze it at 2% and it needs to be warm for it to cure correctly, 70F + if poosible. If you thinned the gel coat to spray it, or thickend it to use it more like a putty, it can (may) reduce the gloss. There are differences in gel coats, some repair very easily, some don't, when you buy gel coat at most retail outlets you don't really know what you are getting. There are only a few companies that make gel coat. They sell it to other companies that repackage it into smaller sizes and put other labels on it, many of these companies switch suppliers frequently looking for a lower price. Also gel coat has a shelf life, 3 to 4 months is normal, the older it gets, the more chance you have of it not curing correctly, sometimes the stuff on the store shelf has been there for a year or more.