Cost of painting the hull

[Idylles15.5]

Originally Posted by Pelagic

I'm interested in what you have seen happening with ALEXSEAL?
Have been using Awlgrip successfully for years (roll & brushing) but tried Alexseal last year as stock was available in the Philippines.

The same painters who have done both, thought Alexseal was a little more forgiving on the roller.....
Depth of gloss appeared the same... but time will tell on gloss retention in the tropics.

What have you heard or seen?

Sorry I didn't respond until now, just got home from work. We just repainted a Wilber, which is a very fine custom boat built in Maine. They built Billy Joel's Fishing boat Alexa Ray years ago. Anyway it was painted with Alexseal in their Forest Green color. The boat is about 6 years old, the green was starting to get that fade on it, like the Gelcoat colors do in red blue and black. The sheen was gone. The boat was just repainted with Alwgrip Forest Green. As far as Imron is concerned, yes it is very durable, but it is very hard to blend color back over a repair, even with their blending agent. The paint dries so hard that its tough to bleed the new paint back into the original. Especially with Black an dark blues.

[Pelagic]

Thanks for the explanation.... As I well know running Super yachts, well meaning crew can wash a paint job to death over 5 - 6 years, over soaping in the tropics and getting too aggressive with trying to remove the soap film.

Time will tell as with my own boat, I wash rarely and just rinse when needed

[svGenesis]

It appears i will be re-painting our topsides soon, Can someone explain what is the difference is between interlux and Awlgrip? and one part, and two part? What about kiwigrip for decks?

[bstreep]

We painted our decks a couple of years ago, with Interlux Perfection. Search and you can find our step by step process. I can say that the light gray nonskid is way WAY hotter on the feet than white.


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[UNCIVILIZED]

Guys,
Part A) Read Jim Cate's post
Part B) If there's any question on colors, go walk around on (light grey) Concrete or (tan) Beach Sand on a hot day. And carry shoes with you, otherwise you may burn those delicate bits that you walk upon.

[Scout 30]

Originally Posted by Jim Cate

So, here in this thread we have folks who say the colour makes no difference in temperature, and those that say it does indeed make a difference.

May I suggest before making a rather expensive decision that you do what we did: get samples of the colours in question and apply them to identical small bits of timber or other practical substrates. Set them out in the sun, and after a while, use an IR thermometer to actually measure the temperature.

No more folk wisdom or opinion... real data that applies to the specific colours that you are considering. We were surprised at the difference between a nominal white and the pale grey that was our alternative choice.

Jim

To be even more accurate hold the piece vertically & check the temp on the opposite side that the sun hits. We're not talking about a horizontal surface & only one side gets the sun at any time & then only gets hit directly early in the morning or late in the afternoon when things are cooling down.

[darylat8750]

Thread drift warning. Mention was made of awnings in the tropics. Awnings made so that you can continue ventilation during down pours is really BIG imho.

[Jim Cate]

Originally Posted by Scout 30

To be even more accurate hold the piece vertically & check the temp on the opposite side that the sun hits. We're not talking about a horizontal surface & only one side gets the sun at any time & then only gets hit directly early in the morning or late in the afternoon when things are cooling down.

We are talking about evaluating the difference in heat absorbtion between different colours. IMO, it is not necessary to muck about with the added complexity that you suggest. As long as each sample is exposed to the same sunlight and in the same attitude, the data will be adequate to see which colours are cooler.

And BTW, these same discussions pop up frequently with regards to deck colours... nice horizontal surfaces!

Jim

[Scout 30]

Originally Posted by Jim Cate

We are talking about evaluating the difference in heat absorbtion between different colours. IMO, it is not necessary to muck about with the added complexity that you suggest. As long as each sample is exposed to the same sunlight and in the same attitude, the data will be adequate to see which colours are cooler.

And BTW, these same discussions pop up frequently with regards to deck colours... nice horizontal surfaces!

Jim

My mistake. I thought the question was how much hotter the interior of a boat is when the top sides are painted a dark color. Clearly it doesn't take a rocket scientist to know black absorbs more heat than white. We all learn that as children when we step on asphalt without shoes on. The question of this thread is does painting the vertical topsides of a boat have a dramatic effect on the temperature inside the boat & I say it doesn't. That conclusion is based not on supposition, as I think most opinions are here, but on actually painting our white hulled boat black, in Florida.

[neilpride]

Originally Posted by svGenesis

It appears i will be re-painting our topsides soon, Can someone explain what is the difference is between interlux and Awlgrip? and one part, and two part? What about kiwigrip for decks?

Just for the record , I sand blast a aluminium deck 6 years ago and prep the deck with interlux stuff plus perfection 2 part poly, the boat come to me last year for few work in the rigging and I have the chance to inspect the paint deck job and honestly I can say the deck looks fantastic with just a couple of bad spots where running rigging wear the paint...

For topsides work I put my money in awlgrip....

[minaret]

Originally Posted by Scout 30

My mistake. I thought the question was how much hotter the interior of a boat is when the top sides are painted a dark color. Clearly it doesn't take a rocket scientist to know black absorbs more heat than white. We all learn that as children when we step on asphalt without shoes on. The question of this thread is does painting the vertical topsides of a boat have a dramatic effect on the temperature inside the boat & I say it doesn't. That conclusion is based not on supposition, as I think most opinions are here, but on actually painting our white hulled boat black, in Florida.

Obviously depends on the boat. Cored hulls not such a big deal. Solid=more heat transfer. Alloy=effective heat sink due to heat exchange below the waterline. This does not negate the fact that dark colors are bad for fiberglass hulls, as they promote rapid print through. They also absorb more UV damage and as a result last a fraction as long. Herreschoff himself said "there's only two colors to paint a boat, white or black; and only an idiot paints a boat black".

[maxingout]

I know an economical boatyard in Sudan where you can get the job done at a very reasonable price.

[Scout 30]

Originally Posted by minaret

Obviously depends on the boat. Cored hulls not such a big deal. Solid=more heat transfer. Alloy=effective heat sink due to heat exchange below the waterline. This does not negate the fact that dark colors are bad for fiberglass hulls, as they promote rapid print through. They also absorb more UV damage and as a result last a fraction as long. Herreschoff himself said "there's only two colors to paint a boat, white or black; and only an idiot paints a boat black".

So you're saying that the UV rays go through the paint & then the gelcoat & then hurts the fiberglass. I'd love to see some proof of that. Heat might get through the paint but UV rays will not & if you see print through after painting your boat black it was already there. Hinckley has been building their boats with black or dark blue topsides for decades & they're holding up pretty well. IMHO the quickest way to improve a boat's looks is to paint the topsides a dark color. It would be a dreary world where every boat was white.

[neilpride]

Where and when Minaret say the UV go through the paint film......

[minaret]

Originally Posted by Scout 30

So you're saying that the UV rays go through the paint & then the gelcoat & then hurts the fiberglass. I'd love to see some proof of that. Heat might get through the paint but UV rays will not & if you see print through after painting your boat black it was already there. Hinckley has been building their boats with black or dark blue topsides for decades & they're holding up pretty well. IMHO the quickest way to improve a boat's looks is to paint the topsides a dark color. It would be a dreary world where every boat was white.

I don't need to try to convince you. Anyone can easily convince themselves of this effect by walking through a marina and looking carefully at boats with white hulls but dark stripes. After a while you will conclude that there is much more print through in the dark stripe than there is in the white hull in almost every case. Explain that away!

And while I'm glad some people are willing to go the colored hull route, as a pro painter I could certainly never recommend it. Certainly stripe away if you must, then the more frequent recoat times aren't a big deal. But painting the whole hull a dark color will ensure it needs to be repainted in something more like 10 years than twenty, for Awlgrip. At the same time, it requires a higher level of fairing and finish for these flaws not to show in a dark color. This work is then defeated by print through caused by the high temps reached by the dark color, and at recoat time it must be faired again to get rid of the print through. This leads to use of high build primers, which results in even more print through. It's a vicious cycle which can cause one to spend serious $$ over time. But it certainly is nice when done right, I'll give you that.


In short, it is indeed high temps which create print through. It is increased UV absorption which causes accelerated degradation of the paint surface.