I am interested in feedback regarding if you guys use a wax or a polish and maybe any learned lessons as you were determining what worked best in your situation.
I have a 1995 Carver 355 and the gelcoat in places hit by the sun is a little chalky. I have used Mequires one step wax applied with a Turtle Wax palm random orbital waxer. It last for about 4 weeks before it is time to wax again. Have heard good things about Mequires Flagship wax as well as NuFinish polish.
Wow... loaded question & answers may be as mixed & controversial as anchors... but here's my $0.02
It sounds to me like you are beyond what the one step cleaner/waxes are meant to do if the shine only lasts 4 weeks. So you probably need something more aggressive. All the major manufacturers have a variety of products to remove varying degrees of gelcoat oxidation. My opinion is any major manufacturer's product will work and while they claim theirs is "best" I'm not sure there is all that much difference in the prep products (oxidation removal). Whether you can do it by hand, will need some mechanical assist or need a professional depends on the degree of oxidation and you ability / energy.
Lots of info on the Web re fiberglass care & restoration... Here's one summary that may help
Restoring the Shine to Fiberglass By Don Casey
The best advice if you are doing it yourself...
Consult w/ someone knowledgeable that can assess your gelcoat condition & recommend product(s) / steps or read product descriptions & do trials
starting w/ the least aggressive products moving to more aggressive only as req'd.
Rotational buffers are the most effective but dangerous in the hands of amateurs - I use & would recommend casual users stick to random orbit RO or dual action DA machines when using mechanical equipment. I have tried several buffers and have invested in a Flex DA unit - caution they also make a straight rotational buffer - again recommend staying away from those. I believe Flex is the only unit that drives both actions vs the "giggle polishers" that are not as effective.
What pad to use w/ each product is a study in itself - I'm just getting into that now that I have the Flex polisher.
Once you have removed the oxidized gelcoat material you can then wax to keep it looking that way - choose a wax you like or look through the many test / comparisons online - there are lots of these - just be sure to only consider ones that are neutral / impartial not "mfg comparisons"
I have seen earlier reports from Practical Sailor / Power Boat Reports that indicate Collonite paste wax lasted better than others they compared it to. I have used their paste wax and it seems to stand up very well - but it is hard to apply / remove - you MUST follow directions, stay w/ small areas and avoid working in sun or warm surfaces or it's nearly impossible to get off. So I use it when conditions are right and in the areas where I'm looking for the most protection. I also have used & like the Collinite cleaner but is has little / abrasives and is not meant for oxidation removal - it does do a nice job of cleaning / preping the surface & removing old wax.
Funny you mention NuFinish - I have also seen reports re: NuFinish being long lasting compared to other products. It is a sealer / polish not a wax and does little / nothing to remove any oxidation. Big advantage is it can be used in direct sunlight without major problems. So I use it when conditions don't permit applying other waxes and on areas where areas are not the most exposed / or don't need the "ultimate" protection longevity... it's easy to use not a pain to put another coat on a little sooner. The admiral usually helps w/ spring prep and on my previous Carver has done the lower hull up to rail w/ NuFinish - lasts a season & looks great w/ water beading all season - in all fairness the lower hull gets the least direct sunlight vs fwd deck, etc.
I see - but have never touched - the "one step" products that claim to restore shine back to oxidized gelcoat - these are the "coatings" that in my mind at least, cover the problem up so until I'm convinced otherwise I've chosen to avoid them - just my opinion and as yet I haven't heard from anyone that I value / trust that has used / endorses them... just saying!