Originally Posted by Janb313
I understand that the PoliGlow is designed for outdoor use - on boats - and has something in it for UV protection that Zep doesn't. But again - the Zep on the bottom half of the trailer still looks very good - no chipping , no flaking. I'm guessing that the sun and wind erode the top edges and it wears down from there.
It is pretty common on older trailers for the bottom half of the trailer to look much better than the upper half. I know when I purchased my old scamp
it that had sat out in the Idaho sun for 15 years required a good deal of buffing with a 3M compound to get the upper half of it close to the shine that was still on the bottom half.
Most probable due to being impacted by the sun.
As to why the PoliGlow may have failed faster than you expected I wonder if perhaps you actually did not get all the Zep off of the trailer prior to applying. I know that there are a lot of folks who will not use the Zep as they are concerned with the contamination of the trailers finish - i.e. not getting it all off without having to use a heavy duty compound and in doing so taking off more gelcoat than they would like. I actually know a couple of people who decided not to purchase trailers they were interested in buying due to the previous owner having used Zep on the trailer they were selling for that reason. The previous use of Zep on a trailer is also a real concern to anyone who might be considering repainting a trailer they are wanting to purchase.
Before you put another application of Poliglow on it you are probable going to need to really scrub it with a compound of some sort - you could as suggested use Bar Keepers friend but it may not be enough to remove the old Zep, why not use a compound that is designed for use on fibreglass and simple give it a good waxing after? At the end of the day once you have it all clean and shining again putting a coat of wax on it once a year is going to be easier than having to strip off the whole trailer of Poliglow or Zep every few years and reapplying a number of coats.