thinwater
Well-Known Member
Firstly apologies everyone for the short delay in the test - my partner and daughter invaded my project space and replaced it with a giant Christmas tree! The cheek!
Hope to have the panels completed this week and set them free to the big outdoors.
Thinwater, that sounds an interesting test, do you have a link to the work or a blog perhaps? I would be interested in following you on that.
Just a few thought on it:
Vinyl and gel coat are two completely different animals and I understand your issues and the potential problems with testing various products on such a material.
"uncoated samples will fog in the rain if the product does not block water"
Yes, and for this reason alone it governs the approach on what products will work at protecting and what will degrade the material faster.
If one was to sandwich the vinyl between two sheets of glass and seal the edges, I doubt moisture would be an issue. This is in effect what we are attempting to do with an application product, though vinyl and gel coat are chalk and cheese.
With vinyl, the degradation (IMHO) comes from the application of products where the main active ingredient has been broken down with petroleum distillates in order for it to be applied.
These petroleum distillates are accepted easily into the material as indeed the water and moisture are and will accelerate the breakdown of the vinyl much faster than an the un-treated.
So we would assume from this that your un-treated control would fair better than the treated.
If however you had a product that was capable of sealing off to oxygen / moisture but didn't contain breakdown ingredients, then you would have a superior protection product for vinyl.
Gel coat does accept water and moisture, although this is usually whilst up against water for long periods, the membrane is much tighter and osmosis will take some time compared to vinyl.
The relevance of gloss and beading:
Gloss is simple a measure of what is going on at the surface level, we needn't wait until the entire depth of a material is compromised, we just look at the surface.
The beading gives us a visual aid to coverage on that invisible layer of glass we applied to seal off from oxygen / inhibit UV.
Beading or surface tension has far more important qualities and roles to play than this, but the ability to see when the protection has been exhausted is a good visual aid.
Would be interested to know what products you are using in the test?
Tony
Mostly, I was just commiserating with your project. You have a lot of hard work ahead of you, and I know first hand just how much! Thank you.
Yes, there are certainly differences. No, unfortunately I cannot blog too freely on this as it is for publication (Practical Sailor Magazine). However, I do put cut down versions of stuff on my blog from time to time:
http://sail-delmarva.blogspot.com/
a. Very few of the products contain petroleum. That would disqualify them from consideration for the reasons you stated. In fact, at 3 years no product I have tested had any negative effects. Some have accumulated micro scratches; no mater how careful you are, after years of regular cleaning the occasional bit of grit is rubbed about and vinyl is soft. But none of this can be blamed on the products, only on me. Just as an occasional buff keeps gelcoat looking fresh, hands off seems to be better for vinyl, since it is very scratch prone.
b. Fogging is only a factor on un-coated vinyl. Coated premium products (O'Sea, Strataglass) are not affected. They have a thin polyurethane film, which can be removed by excessive buffing (compounding), which may product a smooth finish, but will then be prone to fogging.
c. The relative durability of the coated vs. uncoated vinyl is a good question. It seems the coating may at least double the life of the vinyl, making the price premium much less painful than years of waxing. Additionally, a coated product that is NOT cleaned an buffed will not be at risk of scratching, further increasing life.
d. I'm not sure I agree that beading correlates to oxygen exclusion or UV protection. Beading has to do with hydrophobic surface energy, while the other 2 are not at all related to that. Second, beading does not closely related to vapor transmission; consider durable water repellent finishes that are applied to garments, which bead waster but do not stop vapor. Yes, the surface topography is much different, but we have not proven causality, and in fact, the finishes that bead water best are NOT the best at preventing vinyl fogging. In brief, without other evidence, there is no reason to believe that either gloss or beading correlate well to water, oxygen, or UV exclusion. They might, but mostly it would be coincidence, in my opinion. As for manufacturer claims, I don't believe much.
e. Now that I think about it, the best test for UV would probably be on a paint that we knew faded quickly in the sun. Perhaps a red urethane alkyd. Try that! Gel coat is simply too durable. The other thing you might try is upping the UV exposure with 24/7 lamps. I have been using heated UV chambers for some of my testing; 10:1 time compression is practical.