Hull Paint: Alexseal or Awlgrip

How many gallons of paint did you use? The primer, according to the website, only covers 63' per gallon. Is that right? Seems it should cover more than that. We are using the 302 Superbuild

I drive a 70 foot sailboat repainted 6 years ago with Algrip 3 years ago I started getting small gray spots on the top of the rub rail and transom.
I had a painter look at the transom thinking that it was over spray from nearby work he was conducting After 5 mints with a polisher we confirmed the gray was coming through the top coat and polishing was making the situation worse.
I had the transom repainted at a ship yard in the NE That paint failed in 3 places this year leaving 3 large gray patches that yet again I have had to have repainted.
Upon my return to the USA this spring I am having the Algrip rep come down and look at the issue, unless they come up with some believable answers I yacht will become another yacht no longer using Algrip A sister ship has just had its first paint job in 9 years and although it was showing its age non of these problems where apparent
Andy

There are two elements I think far more important than whether you choose Awlgrip or Alexseal or even another brand. First, is expertise of the person or persons doing the painting. They must know the product they are using and follow the exact instructions for that product. Each product is different and you can't attempt to apply them the same. Second, is care and again I recommend following the manufacturer's recommendations all the way. They've tested the products fully and learned the good and bad, what works and doesn't. Don't cut corners but don't exceed recommendations and do things the manufacturer advises against.

These two rules are true with all products, not just paint. I see people trying all sorts of things on teak, breaking every recommendation, then complaining what a pain it is and how it deteriorates so rapidly. The manufacturers not only have recommendations and products, but they have videos to show exactly how to care for it.

I am only using Arora polish which is applied on a DAMP sponge dries then polish of with a slow electric buffer 3 coats in 4 days nothing else for 6 months Worked fine for years also the top of the rub rail is to small for the buffer so finished by hand
When the yacht was painted they put 3 coats on 1/2 an hour between coats then the 4th coat was 50/50 Clear The hull has held up well but the flat surfaces and angled have developed these spots
As you say BURNT through is this normal? We polished the stern with a buffer to try and remove what we thought was Over spray from a job been use buy just made the matter worse

When your transom was re-sprayed was it just a scratch and shoot or did the applicator spray 545 , sand and then topcoat? Light color or dark color? You say the top coat failed in three places afterward, describe the failures please. Bleed through, fish eye, orange peel or delamination of the top coat from the primer. Also what material is the substrate? GRP, Aluminum , steel ?

Here is the link to the Awlgrip page for maintaining the top coat. I don't know which product you have, but there are a lot of "do not"'s on this page.

http://www.awlgrip.com/support-and-advice/topcoat-maintenance.aspx

There is also a Powerpoint presentation you can open from that page.

And here is the application instruction. http://www.awlgrip.com/support-and-advice/final-priming-and-topcoating.aspx

Notice the emphasis on no clear coat over white.

Arora polish? Awlgrip is not supposed to be waxed at all.

OK The yacht is Fiberglass. the yard sanded out the gray spots in the Dark Blue paint
They then sprayed the whole transom with 545 and then wet sanded to a suitable surface for top coat then sprayed with topcoat I am attaching a couple of photo's Hull not clean but the grey area's are very apparent as well as other spots coming through.

Yes But since Aurora Marine is a liquid polymer rather than a wax and applied using a damp sponge then polished of with a dry cloth ( or SLOW Buffer if you have one)
No issues on the hull except top of rub rail and sloping transom

From that somewhat blurry picture those don't look like typical burn throughs from overzealous buffing, more like poor topcoat adhesion or repairs that were improperly done. For your sake I really hope the 545 wasn't "wet sanded" prior to topcoating. That implies a grit profile finer than 320-400 which will not give enough "tooth" for a mechanical bond to hold the topcoat to the primer.

Maybe not wet sanded, but certainly NOT over buffed as done 90% of the time done by hand and those 3 larger grey spots got worser from early November to mid december when they where photographed No polishing was done at that time as we where in New England in the cold and all the other little spots with no pigment left in the paint I feel if i had left them they would have just got larger

And how many coats of topcoat did you spray on redoing the transom?

Have you yet read the information I linked to earlier?

Just to clarify, did those spots progressively get worse without any polishing or buffing being done or did they begin and show more each time it was done? In my experience 3 coats of G or H series "original" AwlGrip topcoat, thinned to yield acceptable levels of orange peel, is barely enough film thickness to cover spot primed areas of a different color. Any buffing at all would likely remove enough material to allow them to show through.

Yes thank you

A good question. but I am sure the yard would have done the usual 3 plus 1 with clear mixed in
When the original paint job was done Algrip where having issues with Fish eyeing and coagulation They sent reps to the yard and did many tests using the yard equipment and bran new guns hoses etc to eliminate the issues. White was not a problem only the darker colours I believe Every can # of there product was recorded and is in the yacht history at the yard

Yes the spots got worse and worse as if the sea water was washing the color out of the paint They looked great for about the first year after the work was done then the areas started to show what i could only describe as rings in the areas that had been ground down and filled then the color started to fade
When we repaired the stern this winter in St Thomas we found All-fair in the repairs under the 545 so the work had been done according to the manufactures specs
I have seen these spots on another dark blue yacht in the transom just like the ones on my yacht They subsequently repainted the whole yacht in Alex seal (that yacht is in NZ at the moment and I will not see it till next year) but I will email the skipper to see how the paint is holding up

I'm still somewhat unsure if the spots developed their issues after being buffed/polished or it happened without being touched. 545 will seal Awl-Fair on small spots but it (Awl-Fair) is very porous and best practice is to seal it first with a high build primer before the 545, much of which will be absorbed into the Awl-Fair when the first few coats are applied.