Roll not spray :/

I see everyone rolling their paint on on most boat build forums, why not spray? Isnt a spray application more controlled and faster?

I sprayed my whole car with the primer and top coat. Seemed a breeze and top notch finish. Did the 'flying esky' styrofoam core/fabric skin canoe with auto white too and went on beautifully and is lasting great

Why isnt auto paint used for boats? Cars get soaked without any paint damage and auto paints seem to wear very well

A litre of Easycote auto white is $25FJD and clear is same. Custom colors are twice the price but still very cheap

 

Saqa, if you have the gear & can drive it....... I shoot 2K auto paints onto boats, not as durable as Awlgrip style paints but I believe Awlcraft paint is a cousin of the type. I use Protec.. from South Aus but coloured/batched by a local firm.
Jeff.

 

I like to roll (or roll and tip) two part linear polyurethanes. I use Interlux Perfection and I believe that Awlgrip is a similar product.

The reason I roll is primarily toxicity. I understand that when isocyanates, which are a primary reason why two part boat paints perform so well in the marine environment (aliphatic isocyanates), are sprayed they become quite toxic. Paint manufacturers recommend that an approved protective suit be worn to prevent skin contact and that a respiration system provide fresh outside air to the applicator while he or she sprays the paint.

Since I don't wish to invest in the respiration system I simply roll the product. I wear gloves, old clothes and a organic vapor 1/2 mask when I paint and get out of the area quickly when I'm done. Rolling gives you very nice results, quite close to a sprayed application. This is especially true once the applicator gets the hang of the thinning process which is related to the temperature and humidity present when the paint is applied. I cannot speak for the Awlgrip but the Perfection needs little to no reducing.

In short, you don't want to breathe an aerosol that contains isocyanates. Rolling keeps the isocyanates on the surface thereby lowering the toxicity greatly.

 

Missinginaction is correct. The Isocyanate is present in the 2k hardener only, it is a known carcinogen and can cause other respitory problems. In Europe the spraying of any 2k is highly controlled, extractor, water bath, air fed masks etc.
Rolling is a good way of getting a good job. I often use it with one packs as well, but hardly use the alkyds anymore.

The 2010 VOC EU legislation also deprived us of effective paint strippers.... so no more dichloromethane based ones. Almost none of the replacements work, certainly not as well. 2k is a pig to remove off a whole interior now.

Car paint is very similar to marine ie an acrylic/polyurethane in 2k form. However depending on the material you are spraying you will need to add a certain ammount of plasticiser to allow for more flex. This is added to auto paints applied to plastic parts like bumpers (fenders). On small dinghies I have successfully used car paint 2k but the substrate has nearly always been epoxy coated marine ply, or laminated, glassed and sheathed foils.

 

two part auto paints are used on boats. Only they are sold as marine coatings and sell for 3X the price.

the big name lpu polyester polyurethane vendor sells its stuff for about $400 or so per gallon buy the stuff I sell is under $200 for 1.5 gal units. It is proably impossible to make a paint where the product and manufacturing costs are more than maybe $80 a gallon.

Marine vendors expect a profit of 400% or more. Industrial vendors are very happy with 25-70% profits.


Paul Oman - MS. MBA
A.K.A. “Professor E. Poxy”
www.epoxyfacts.com
epoxies since 1994
Member: NACE (National Assoc. of Corrosion Engineers) -- SSPC (Soc. of Protective Coatings)

 

I didnt know about the danger of spraying boat paints

What about regular 1 pack auto paints? Does it have a place on boats?

 

People paint boats with everything from latex house paint to the expensive two part LPU's that we've been discussing here. I suppose it all depends on how much money you want to spend and how durable the finish needs to be. The only comment I can make regarding auto paints is that while it's true that most cars live outside, it's also true that except for parking lot dings and accidents car paint doesn't get abraded much. What impressed me about the two part LPU boat paints was how hard they are once cured. People walk on painted boat decks, fenders rub against topsides and these two part LPU's hold up very well under that type of abuse. They are pricy. However, I don't think I'll need to repaint decks for years and vertical surfaces look like they will last damn near forever.

Car paints are generally base coat / clear coat combinations. They look great but I do not believe they are nearly as hard or durable as the LPU's.

 

Agreed, the two part finishes are very durable. I think I can live with the car paint though on this build. I reckon I can get good millage out of it and if I get scuffs and stuff then touching them up would be much easier too with the auto paint. I am also keen to explore vinyl wrapping on the sides to get the bright nuclear green I want over a white hull

 

Vinyl wraps work, but don't last long and they need to be put on dead nuts fair surfaces. The gloss isn't as good as paint either.

 

The vinyl wrap is popular. It works. On a small boat it will be troublesome. The film is rather soft...it wont tolerate scratches and bangs and is not particularly durable underwater...near the waterline. If its just graphics over a paint job ...go for it.

You can spray if you want...not in your living room, big mess ...overspray on your TV and all your food will begin to taste like awlgrip reducer.


And dont kill yourself, that stuff is toxic. This is why most small boat guys roll and brush.

 

Lol boat is heading out as soon as all wood surfaces get at least one smear of epoxy on them, am thinking the next few days sometime. Then its lotsa the fun stuff like sanding before she heads off to the spray booth aka the mango tree under which the my mechanic drinks kava

 

Most topcoat paints will not stand immersion. Dont topcoat below the waterline.

Manytimes its best to launch the boat...fully load the boat with gear...then carefully mark the waterline...then haul out and paint the boat.


By fully loaded i mean everything...even beer


subir imagenes gratis

 

One coat of epoxy doesn't protect or water proof wood. 2 coats will just barely get it done, though there will be areas where absorption is probable. 3 coats is the recommendation from every formulator. Paint isn't water proof (not even close), so . . .

A good quality LPU will tolerate immersion occasionally, on the bottom of a boat, but it can't stay in the water for extended periods and must be applied on a stable substrate (if wood, fully encapsulated). As a rule, top coats don't stay stuck if used on bottoms, but it will last a weekend, if permitted to dry after. If you do this often enough (let is soak for 48 hours), it'll lift, but it will tolerate blasting around for an afternoon, then riding home on the trailer, for several years.

The automotive industry (at least in the USA) is not using the same LPU paint as the marine industry (this is changing). They are using an acrylic (aliphatic) polyurethane, while the marine industry is still using the polyester version of this molecule (they're both polyurethanes). This is an important distinction and it's generally accepted that the polyester versions (LPU) is superior. These types of paint don't stick all that well, so a good quality epoxy primer is necessary, to provide a "tie" coat. The aliphatic versions are a little easier to apply and slightly cheaper then the polyester LPU's, but again aren't quite as tough, so know what you're working with, before purchase.

 

I meant a coat of epoxy so I can take it outside on the undercover balcony to do the rest of the sanding and fairing

Am I safe with the epxoy encapsulated 450gsm double bias covered with a layer of epoxy slightly thickened with microfibres followed by epoxy thickened with talc all while previous layer just starting to gell followed by 80 grit then sprayed 'one shot ' primer followed by wet sanding and more primer and auto paint followed by auto clear on a boat that will be used for about 4hrs per day about 3 days a week and kept on a trailer :/

 

Sounds about right. The epoxy waterproofs the wood. The primer is the base for topcoat.

Normally you prime...sand flat...look for small imperfections..fill..sand..prime again...sand flat..then topcoat.

Primer is easy to sand. It is little more than fine filler and it gives a uniform base colour.

If you use a dark topcoat, use a dark primer...normally gray. White primer for light colour topcoats.

A typical paint schedule might be four coats of primer, three coats of top coat

The correct term would be film thickness not coat..but you get the idea.

Plenty of primer to allow you to fill, sand the surface imperfections. Topcoat for shine