ZEP/Red Max Pro
I have questions specific to my unit construction on using this to restore the finish. I've looked over this post ZEP/Red Max Pro and it appears it does wonders on older fiberglass units. Mine is alum...
Forum Discussion
One of the reasons people like ZEP is that it is a harder finish than any other product you can buy including those products designed for automotive use. Because of the hard finish, it washes off much easier.
I would also suggest that if anything is turning yellow, it is probably the aging of the paint below the surface. The primary ingredient in ZEP is Acrylic. The scientific properties of Acrylic is that it is completely transparent to UV, which means that it can not be affected by sunlight. So, there is no reason for ZEP itself to turn color. Now the other aspect is, since acrylic is 100% transparent to UV, it does not protect the surface below from UV damage.
There are other scientific factors that will affect bond. Acrylic expands and contracts with temperature at a different rate than fiberglass. We know this, because when you install acrylic boat windows, you have to allow for expansion, otherwise the windows will shatter. (I just bought a sailboat with that exact problem). If you read on the boat forums, you also find out that many of the cracks in gelcoat are a result of putting the gel coat on too thick. Where it is too thick, it is not able to stretch with the expansion and contraction of the fiberglass. So translate this into using ZEP, it is a temperature sensitive product. So if you have dark colors and live in a hot climate, the expansion rate of the fiberglass will cause the ZEP to crack.
So one solution is don't put it on so thick. You all get so excited about that deep shine that looks like a million coats of clear, but you are asking for trouble, especially on dark colors, and hot climates. I only have 2 coats on my RV and it does shine pretty well. If I want more shine, I can wax over the ZEP.
I would also suggest that if anything is turning yellow, it is probably the aging of the paint below the surface. The primary ingredient in ZEP is Acrylic. The scientific properties of Acrylic is that it is completely transparent to UV, which means that it can not be affected by sunlight. So, there is no reason for ZEP itself to turn color. Now the other aspect is, since acrylic is 100% transparent to UV, it does not protect the surface below from UV damage.
There are other scientific factors that will affect bond. Acrylic expands and contracts with temperature at a different rate than fiberglass. We know this, because when you install acrylic boat windows, you have to allow for expansion, otherwise the windows will shatter. (I just bought a sailboat with that exact problem). If you read on the boat forums, you also find out that many of the cracks in gelcoat are a result of putting the gel coat on too thick. Where it is too thick, it is not able to stretch with the expansion and contraction of the fiberglass. So translate this into using ZEP, it is a temperature sensitive product. So if you have dark colors and live in a hot climate, the expansion rate of the fiberglass will cause the ZEP to crack.
So one solution is don't put it on so thick. You all get so excited about that deep shine that looks like a million coats of clear, but you are asking for trouble, especially on dark colors, and hot climates. I only have 2 coats on my RV and it does shine pretty well. If I want more shine, I can wax over the ZEP.
