Paint question

[RickH]

I decided to test out paint colours on my boat before getting coach enamel mixed . I used normal Dulux interior paint in test pots for colour . I found the colour I wanted and sent it to be matched in coach enamel , got a test pot of that and did a test on the side of the boat . Now its raining and what is interesting is that the coach enamel has beading whereas the Dulux seems to be dry . My question is what is the advantage of using coach enamel over regular exterior paint ?

 

Thanks

[Ex- Member]

I decided to test out paint colours on my boat before getting coach enamel mixed . I used normal Dulux interior paint in test pots for colour . I found the colour I wanted and sent it to be matched in coach enamel , got a test pot of that and did a test on the side of the boat . Now its raining and what is interesting is that the coach enamel has beading whereas the Dulux seems to be dry . My question is what is the advantage of using coach enamel over regular exterior paint ?

 

Thanks

 

Hi rick

 

I think generally the standard exterior paints are usually applied to wood so the paints tend to be softer more flexible.

 

Of course flexibility is required with paints on steel but to a much lesser degree. Other than that though there is probably very little difference. I painted our Bow in B&Q Black 10 year gloss about 4 years ago, It's been over painted now, but there was basically nothing wrong with it, having said that we were on dry land and it probably wouldn't have fared as well battling with locks boats and overgrowth.

 

So I think general hardness and durability of the enamels is the main difference.

[Higgs]

I decided to test out paint colours on my boat before getting coach enamel mixed . I used normal Dulux interior paint in test pots for colour . I found the colour I wanted and sent it to be matched in coach enamel , got a test pot of that and did a test on the side of the boat . Now its raining and what is interesting is that the coach enamel has beading whereas the Dulux seems to be dry . My question is what is the advantage of using coach enamel over regular exterior paint ?

 

Thanks

 

I was once asked, by the firm I worked for, to paint a boat that needed the snow removing from it before the work could be done. I had no answer to that problem using enamel. I brush painted the job with cellulose paint, as fast as I could.

 

There's no doubt, enamels don't dry very quick; the fact they don't is an advantage. It allows for brush strokes to relax. If you are painting in conditions that don't allow for a slow dry, it is a problem. You can buy additives to accelerate the drying.

 

Hi rick

 

I think generally the standard exterior paints are usually applied to wood so the paints tend to be softer more flexible.

 

 

 

I can tell you, from the results of the build-up of paint in roller trays, your average enamel boat paint is very flexible, and stretchy. It's very strong and resists impact, but it also has to be thick enough.

Edited October 13, 2013 by Higgs

[frangar]

Be warned....some "enamels" are now water based.....and I dont care what anyone says water based paint is cr*p for use outside.....I used to love dulux weathershield for things like tunnel bands...it was quackish to dry and only needed one coat....then used some of the water based wethershield on a house front door based on how good to old stuff was only to find it looked horrid every time it got wet and then just fell off....not impressed!

 

cheers

 

Gareth

[Ex- Member]

 

I was once asked, by the firm I worked for, to paint a boat that needed the snow removing from it before the work could be done. I had no answer to that problem using enamel. I brush painted the job with cellulose paint, as fast as I could.

 

There's no doubt, enamels don't dry very quick; the fact they don't is an advantage. It allows for brush strokes to relax. If you are painting in conditions that don't allow for a slow dry, it is a problem. You can buy additives to accelerate the drying.

 

I can tell you, from the results of the build-up of paint in roller trays, your average enamel boat paint is very flexible, and stretch

Of course flexibility is required with paints on steel but to a much lesser degree.

[Higgs]

Of course flexibility is required with paints on steel but to a much lesser degree.

 

I don't know to what degree, it's just very flexible. You'd be hard pressed to pull twenty layers of paint apart tugging. It would be easier to tear it.

[Ex- Member]

 

I don't know to what degree, it's just very flexible. You'd be hard pressed to pull twenty layers of paint apart tugging. It would be easier to tear it.

 

Paint in the bottom of a paint tray hasn't been baked on to steel in sunlight, the fact it's thicker in the bottom of a roller tray will keep moisture within so it will not harden properly and of course be flexible. Applied coat by coat with each consecutive coat drying properly before next application the paint applied to steel will be significantly harder than paint left in the bottom of a roller tray. You are trying to compare 2 completely different things/situations.

[Higgs]

 

Paint in the bottom of a paint tray hasn't been baked on to steel in sunlight, the fact it's thicker in the bottom of a roller tray will keep moisture within so it will not harden properly and of course be flexible. Applied coat by coat with each consecutive coat drying properly before next application the paint applied to steel will be significantly harder than paint left in the bottom of a roller tray. You are trying to compare 2 completely different things/situations.

 

The paint in the bottom of the roller try had as much chance to cure as that on the boat. If it hadn't cured enough I wouldn't have been able to pour fresh paint on top without it disintegrating into the liquid paint. You don't actually need a coat of paint to be thouroughly hardened before you apply the next coat. In fact, unless you leave the previous coat for weeks before apply a fresh coat, your previous layer is not going to be fully cured.

 

There are two forms of creating a good bond, that I know of; one is the mechanical bond that keying up provides. The other is a chemical bound - it relies on the new paint effecting the previous coat, softening and knitting to the previous coat.

 

Two packs are different, in that this softening is not going to be happen to the same extent and keying up plays a bigger part.

Edited October 13, 2013 by Higgs

[Ex- Member]

Dear me LOL

 

The paint left in the bottom of a roller tray will be thick so will not dry the same as paint applied to a steel boat. Unless of course you try to get a non sagging finish in the bottom of your roller tray and put that roller tray in a similar position to what you've just painted.

 

The paint on the boat will dry out much quicker in it's recommended time prior to next coat especially if the steel is warm on application due to sunlight or ambient heat. Each successive layer left in the tray will again be thicker so preventing the first layer to further dry out.

 

Enamel paints are well known generally for being harder for the reasons I stated. Comparing the density of dregs in a roller tray to what's applied on a boat is bonkers.

[Higgs]

Dear me LOL

 

The paint left in the bottom of a roller tray will be thick so will not dry the same as paint applied to a steel boat. Unless of course you try to get a non sagging finish in the bottom of your roller tray and put that roller tray in a similar position to what you've just painted.

 

The paint on the boat will dry out much quicker in it's recommended time prior to next coat especially if the steel is warm on application due to sunlight or ambient heat. Each successive layer left in the tray will again be thicker so preventing the first layer to further dry out.

 

Enamel paints are well known generally for being harder for the reasons I stated. Comparing the density of dregs in a roller tray to what's applied on a boat is bonkers.

 

 

As I've previously explained, and I know when paint is dry enough to take another coat - the paint in the roller tray was cured enough.

 

Do you think having liquid paint sitting on dried paint, in the bottom of a roller tray, that the liquid paint would be unabe to effectively desolve any paint not cured enough. As you suggest, the paint in the roller tray was uncured and soft - no, my experience tells me when paint is too soft.

 

I must explain that I had several roller trays in rotation, and one roller tray would not be used the following day. Call me lazy or worked off my feet, but I didn't have time to wash trays every day.

Edited October 13, 2013 by Higgs

[Ex- Member]

 

 

As I've previously explained, and I know when paint is dry enough to take another coat - the paint in the roller tray was cured enough.

 

 

 

You clearly have little understanding of paint. Paint requires a second coat in line with the manufactures instructions. You seem to be confusing curing with drying. Worrying when you claim to be a boat painter.

 

Do you think having liquid paint sitting on dried paint, in the bottom of a roller tray, that the liquid paint would be unabe to effectively desolve any paint not cured enough. As you suggest, the paint in the roller tray was uncured and soft - no, my experience tells me when paint is too soft.

 

 

 

Again further lack of understanding. The paint in the roller tray doesn't have to be cured to reuse just dry, furthermore it should be cleaned out before if left to dry. You clearly need more experience.

 

I must explain that I had several roller trays in rotation, and one roller tray would not be used the following day. Call me lazy or worked off my feet, but I didn't have time to wash trays every day.

 

Well that's a very strange method of painting, why not continue with the same tray . you don't get to clean them every day!!! surely it's quicker to clean them when wet No wonder you're so busy, you methods are highly questionable IMO

[Higgs]

 

Well that's a very strange method of painting, why not continue with the same tray . you don't get to clean them every day!!! surely it's quicker to clean them when wet No wonder you're so busy, you methods are highly questionable IMO

 

Well, I guess, over eleven years of painting non-stop I got some things right. What's your record of boat painting.

[Ex- Member]

 

Well, I guess, over eleven years of painting non-stop I got some things right. What's your record of boat painting.

 

I've done about the same including 5 years as a paint sprayer over the past 30+ years. I will concede though I've known many painters better than me who didn't go to college or undergo training and if you have happy punters over that time then happy days.

 

We've gone slightly off topic though LOL

Edited October 13, 2013 by Julynian

[Higgs]

 

I've done about the same including 5 years as a paint sprayer. I will concede though I've known many painters better than me who didn't go to college or undergo training and if you have happy punters over that time then happy days.

 

We've gone slightly off topic though LOL

 

 

My approach is - my way isn't the only way, but the approach I take is, I've practiced and my standards have always been high. There isn't much point in getting out of bed to do rubbish.

[bizzard]

I don't think oil paint ever dries absolutely completely if it is to remain flexible. When it does eventually dry out completely its life is expired and begins to craze, break down and go chalky or flake because it can't flex with the substrate anymore. The life span of the paint I suppose depends on its quality. Erm LOL.

[Ex- Member]

I don't think oil paint ever dries absolutely completely if it is to remain flexible. When it does eventually dry out completely its life is expired and begins to craze, break down and go chalky or flake because it can't flex with the substrate anymore. The life span of the paint I suppose depends on its quality. Erm LOL.

 

That's true, when I was a paint sprayer the full curing time for a bake on paint we used was estimated 7 years. Similar to plastics is many ways, they all contain moisture in the form of oils , when it disappears the plastic will shatter like glass. I believe with enamel paints it's the surface that hardens more than the remaining paint but not to the point of being brittle of course, hence it's better performance and durability.

 

This pretty sums up enamel paint for me and is pretty much as I was taught.

 

http://www.housepaintingguide.org/what-is-enamel-paint/

[Neil2]

I don't have any practical experience but I've worked with lots of painters, and many of the old stagers would talk about the good old days of lead based paints that would retain their flexibility much longer than today's alkyd based paints which break down much quicker - or is this just rosy tinted glasses stuff?

 

It seems that in the wood and grp boat world water based acrylic paints are becoming increasingly popular - do these offerings have any merit on steel boats?

[PaulD]

Be warned....some "enamels" are now water based.....and I dont care what anyone says water based paint is cr*p for use outside.....I used to love dulux weathershield for things like tunnel bands...it was quackish to dry and only needed one coat....then used some of the water based wethershield on a house front door based on how good to old stuff was only to find it looked horrid every time it got wet and then just fell off....not impressed!

 

cheers

 

Gareth

Gareth,

 

In between the rain and after finishing the boat touch ups I am now trying to paint the house. The Dulux weathershield undercoat is water based but the gloss is definitely solvent based. Certainly requires lots of white spirit to clean the brushes. Still very nice paint to work with.

 

Paul

[Swallowman]

I don't have any practical experience but I've worked with lots of painters, and many of the old stagers would talk about the good old days of lead based paints that would retain their flexibility much longer than today's alkyd based paints which break down much quicker - or is this just rosy tinted glasses stuff?

 

It seems that in the wood and grp boat world water based acrylic paints are becoming increasingly popular - do these offerings have any merit on steel boats?

 

Sorry, Neil2 is barking up the wrong tree a bit:

"Lead-based paints" Contain lead carbonate as part of the white pigmentation. Now only allowed under VERY strictly controlled licencing for paints used to restore old buildings and the like. These days, titanium dioxide and other fillers are used as pigments.

Lead salt complexes were also used as driers for the alkyd resins before being banned in favour of other heavy metal complexes; these are also now coming under review and before long, all metal complex driers are likely to be banned by the good ol' EU with no thought as to what will replace them.

"Alkyd based paints" Alkyds are the long chain fatty acid oil based resins used to bind the pigments to the substrate. Alkyds have been around for donkeys' years and before then, the unmodified oils were used on their own. These days, urethane and acrylic modified alkyds are used because they yellow over time much less than unmodified types.