Painting Questions

[Pull-doo]

My first wooden boat is almost done. If it didn't rain so much on the weekends it would have been done a long time ago. The boat is glassed, epoxied and ready to paint. This is a duck boat and will get hard use. For my outer coat I want to use Parker Duck Boat Paint. Is there any reason why I should first put down a primer with the Parker on top of that? If so why, and what kind of Primer would be best? Like everything else on my first boat this is new territory for me. I want to do it right.
Also, thanks to all those that helped me with my epoxy questions a few months back. I have discovered the wonders of epoxy and I will never be the same.
God I love building wooden boats, I don't care what my wife has to say about it.

[On Vacation]

FYI, here is a real duck boat. ;)
http://www.imagestation.com/picture/sraid15/pb49aa9c98ba432b10d666a567602d984/fde67c2c.jpg
This is my .02 worth. Seal your fiberglass with 2 part high build primer by Awlquip paints. This will give you a large margin of protection under the topcoat. Depending on the finish you are attempting to achieve, either roll it with a short nap roller or spray the 545 regular primer on it. The high build will need to be thinned a little for thinner application for sanding later on, but you can put multiple coats on as soon as it skins over.

We use Pettit Dead grass green on the hulls over the primer. The primer is not cheap but tough for what you are doing. Normally your topcoats are not thick enough to fill and cover for a good protection of the underlayment which is the glass.

[ 10-21-2002, 04:02 PM: Message edited by: oyster ]

[JimD]

Most paint sticks well to epoxy with or without primer, but primer never hurts so I would prime. Aside from that just do the usual prep ie wash well to remove any blush and give the surface a bit of a light sand to help the paint grip. WB mag a couple issues back had a very comprehensive article on painting.
jimd

[JimJ]

Jim

What issue # had the article on painting?

At $16.00/17.00 a copy I tend to buy only the ones of specific interest.

[Wild Wassa]

Originally posted by Pull-doo:
God I love building wooden boats, I don't care what my wife has to say about it.Pull-doo, he, he, he. You should.

One thing that I will say is, try not to mix the products from the different manufacturers if at all possible. The manufacturer makes an allowence for their materials to be compatible.

This is chemical.

Warren.

[ 10-23-2002, 03:20 AM: Message edited by: Wild Wassa ]

[Wild Wassa]

Originally posted by Pull-doo:
Is there any reason why I should first put down a primer with the Parker on top of that? If so why, and what kind of Primer would be best? Generally we use primers on unpainted surfaces. It's recommended that the type of primer that's selected suits both the underlying material, for example, wood-stone-steel and also the porosity of that material.

Primers are available for the various media. For oil based or latex based paints and others.

The reasons for priming are, to gain maximum adhesion of the paint, to gain a uniformity of the finished appearance and to stop staining or discolouration of the top layers by the underlying layer.

Uniformity of the surface is not just paint thickness, it also refers to, uniform opacity or transparency, and the development of the gloss or sheen.

There are two types of adhesion, physical and chemical.

The physical is gained through 'tooth'. This can be the scratch pattern, the depth of the scratch, the uniformity of the scratch and the sharpness of the scratch. I prefer my scratch to be circular, uniform and not too deep or sharp. I generally achieve this with 320 grit or 400. Above 400 I generally wouldn't recommend. Too fine a pattern, results in lack of adhesion (for some).

Chemical adhesion, I refer to as, surface softening. Each coat swells (not visible with the naked eye)after the next coat has been applied and chemically fuses. This is catered for by the manufacturer and is generally consistent throughout their range of advised products. Changing between the different manufacturer's materials can negate this procedure and impact adversely.

I agree generally that over epoxy a primer isn't needed, using a primer can only give a 'finer' and more uniform result.

Check with Parker's as to the paint base type. I'm guessing oil based. Then you will be able to select your primer. Following Oyster's advice is what I'd do. Oyster calls it .02 cents worth, I'd call it 2 decades worth of experience.

If your painting is to be a highlight of your duckboat. I would also select a tinted undercoat, this could save on having to apply extra topcoats.

The camouflaged duck boats look very smart. Spraying is the fastest technique and the soft edge of the spray coverage is so appropriate and can only enhance, the low visibility image.

Using a roller to develop the shades and scatters, I'd find more enjoyable. I like things more, if they're difficult.

Good luck

Warren.

[ 10-23-2002, 04:51 AM: Message edited by: Wild Wassa ]

[On Vacation]

Posted by Warren:
One thing that I will say is, try not to mix the products from the different manufacturers if at all possible. The manufacturer makes an allowence for their materials to be compatible."

This is the only real case of a mixmatch of products that I will advocate in the instance of chemical mixture just because of sealing fiberglass and protecting fiberglass from heavy abrasion.

One more issue on this, many will redo at a later date sometimes to turn their ducking pleasures into a pleasure craft. You will have a good base coat to work with at that time.

In duck boat application we ding a lot and redo it almost every year. Poly paints for topcoats are throwing away your funds for the next project.

I don't know much, but what little I do, shines. This is just an example of a converstion.
http://www.imagestation.com/picture/sraid36/pa10619f469768d6ac99a2fa8074d3ecb/fd21fc95.jpg

[ 10-23-2002, 07:30 AM: Message edited by: oyster ]

[thechemist]

Originally posted by Wild Wassa:

<snip>
Chemical adhesion, I refer to as, surface softening. Each coat swells (not visible with the naked eye)after the next coat has been applied and chemically fuses. This is catered for by the manufacturer and is generally consistent throughout their range of advised products. Changing between the different manufacturer's materials can negate this procedure and impact adversely.
<snip>Someone gave you some false data, Warren.

Actually, if solvents or resins of one coat soften another, the bond one may obtain with one polymer a bit mechanically interlocked into a somewhat degraded, somewhat recovered polymer.....that bond is only mechanical.

The definition of a chemical bond requires that electrons be shared between different atoms.

A chemical bond is the result of a chemical reaction, and one functional group establishes new [chemical bonds] with some functional group of another polymer.

Chemical bonds do not require surface softening or degradation of any sort.

A chemical bond between two molecules creates a biger molecule.

Bonds may be by chemcal bonding or by the polar attraction of negatively-charged regions of one molecule for the positively-charged regions of another molecule. This, also, does not require "tooth", but only a clean surface and suitable molecular structures. This bond is sort-of-in-between the chemical bond and the mechanical bond.

Cured epoxy resin systems have many polar groups and thus stick by this mechanism to many surfaces where they do not form true chemical bonds.

Many plastics such as polyethylene or teflon have neither reactive nor polar groups on the surface, thus adhesives tend not to stick to them.

[Wild Wassa]

Thankyou Chemist, I'm still learning. I appreciate every bit of advice.

The way you described chemical bonding, is the way I thought chemical bonding worked. I just couldn't describe it in such detail.

Warren.