Spraying gelcoat

RECESS · Mar 20, 2010

I would think that applying Awlgrip would be easier than spraying gelcoat. I did Perfection and it was not that difficult. You just had to be able to work quickly. My wife tried to help me roll and tip but she could not take moving that quick.

RECESS · Mar 20, 2010

I used to spray generators when I worked for Detroit Diesel. It was one of the tasks I did at the plant and got pretty damn good at. There was a lot of technique that went into spraying many coats to make it have a deep shine. Just like rolling, any mistake shows. If you do not put it on wet enough or have the gun too far away, you will kill the deep shine. Having done both techniques, the rolling and tipping was more forgiving and by the time I did my first coat I had down what I needed to do.

Other's mileage may vary but I found the rolling and tipping an easier learning curve than spraying paint.

Chuck Creel · Mar 20, 2010

The gelcoat was pretty rough looking after being on since 1979 and had some crazying/cracking going on. The yard and i agreed to rremove all teh interlux paint that wife and I applied few years back and start over.

Had them sand off ALL the old paint then re aplply barrier coat, then Awgrip paint.
Expensive to take it down to galss and start over but now i know whats there.

This painter only used 2.5 qts of paint on a 30 ft boat.

Sumner · Mar 20, 2010

Hermit Scott said:
............ Or is buffing and polishing ALWAYS steps to a pro looking gelcoat job? ........

First off I've never painted a boat, but have..........

.....experience with auto-body work and paint is pretty much paint. If you want a factory looking or better paint job you have to very good with a spray gun technique wise and know what you are doing with reducers and such if you expect to lay down a paint job that looks good close up without sanding, and buffing it. I'm not saying you can't do it, but I'm talking about painters that have a lot of hours just spraying. In addition to that you are going to need a $300 to $500 gun and a good 220 volt 2 stage (not 2 cylinder) compressor ($900 minimum), water traps and a place to spray where you aren't going to get dust, dirt, bugs into the paint.

Now there is another way to do it on a car and probably a boat for someone like myself that doesn't paint that often. I use what is called a base/clear system (2 part), but you can do this with some 1 part systems and I would imagine that is what some people do when painting a boat. Here the trick is to get on a generous amount of paint, the clear coat in my case or the urethane single coat if you go that way.

Then you start sanding the orange peel, runs, dry spots and such down flat. You do this with different grades of sand paper starting with about 1000 or 1200 grit and go finer. When you are doing this you are leveling the paint job so that it is flat and also dulling it at the same time. You will think you ruined it.

Then with a 'good' variable speed buffer you use a cutting compound and and take the sand scratches out. Then you will switch to one or two different polishing compounds to bring back the gloss. This is all very time consuming as you can imagine and you have to make sure you don't cut back through your paint job doing it.

I would go with the roll and tip method if I ever painted our boat. It is proven and probably close to what I described above looks wise. One other factor spray painting is that you have to maintain a wet edge while painting and if you are outside in the sun that is going to be hard to do. I might re-stripe our boat with a spray gun, but can bring the boat inside to do that. I wouldn't consider painting the whole boat, water line up or even the whole deck with a gun, but if that is your choice keep researching in and practice with that gun.

Good luck,

Sum

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Joe · Mar 20, 2010

I thought gel coat had to cure without exposure to air. That's why they spray it on the mold first then lay the glass in... the repair kits I've used say to cover the repaired area with plastic film to keep air out... am I mistaken????

Sumner · Mar 20, 2010

Hermit Scott said:
Why is it important to have a 2 stage compressor? ................ Most of the deck is nonskid with frames of smooth areas. So it will be easier than painting the topsides for instance since I won't be as good at keeping a wet edge over a large area.

First, I've been talking paint and not spraying gel coat. I know nothing about that, but have read the same comments as Joe mentioned.

The non-skid is going to be in your favor. I thought you were looking for a flat gloss surface.

Chances are that a single stage compressor is not going to provide enough air to spray continuously like you are going to want to do. A two stage usually does compress air to a higher pressure, but mostly provides more air (volume wise) for a given HP size. Anything that isn't a 2 stage is usually only going to be a 5 or 6 HP and they don't produce a lot of air for what you want to do even though they might look impressive with the two cylinders.

HVLP guns usually even require more air 'HV' is 'high volume' at a 'LP' 'low pressure. They will spray at around 10-12 psi at the nozzle, but still usually require 40-60 psi at the gun itself. Find the gun you are going to use and find out what the CFM requirements are for it at what pressure level at the gun (don't forget you will loose pressure from the compressor to the gun) and see if the compressor will deliver that continuously. Forget how big of a tank is that you are using. You can quickly have a 60 gallon tank drawn down spraying continuously. If you are spraying primer or smaller parts or a car blown apart you can start and stop and get by with a smaller compressor with a larger tank.

You might think about renting a portable compressor or doing all of the prep work and paying someone to just do the actual spraying with their equipment.

Where you are with the high humidity you are for sure going to need good water separator and just running rubber hose from the tank to the gun is the worst situation on top of that.

I'm glad to see you are going to build an enclosure. Take care of yourself and read about what you are painting. Unless you are in a paint booth that can move large quantities of air a face respirator just isn't safe anymore. You are young, don't screw up your future. I have a supplied air (air pump, hose, mast) that I use to paint now. These new paints are great, but they aren't the same stuff your father or grandfather were painting with. Roller/brush isn't near as bad. Spraying even with the HVLP will put a lot of stuff in the air quick in an enclosed space.

One last thing and I'm sure you are aware of this, but the final paint won't cover up any problems under it only highlight them. Prep is the whole/total key to a nice looking paint job.

I'm not trying to discourage you, just letting you know what you are getting into.........

Bodywork and Paint tips...
http://purplesagetradingpost.com/sumner/macgregor/macgregor-links-1.html

HVLP Spray Gun Setup ....

Sum

zeehag · Mar 20, 2010

after repairing the gelcoat, place wax paper on and squeegie it to th egelcoat repair..let dry and is good
will be perfect--yacht builder gave me that one..lol

rardiH36 · Mar 20, 2010

What About Gelcoat Only For the Non-Skid?

Maybe not completely in touch with this thread, but has anybody used gelcoat for the non-skid portion of the deck? I've not yet come across anything describing this in the marine DIY manuals. Gelcoat certainly would be durable and look good for a lot longer than other non-skid paints. How do manufacturers do non-skid for new boats? I really don't know much about gelcoating (so treat any following "statements" as what-if questions), but it would seem to me that because the non-skid areas are rough and stippled, applying gelcoat would on this type of surface would be greatly simplified for the DIY'er. Use a thickner to give it a little more body? Is there a flattening agent for gelcoat? Could it be applied with a natural bristle throw-away brushes? Might have to apply in a few batches because fiberglass stuff doesn't have much working time. Tap-Plastics, a speciality chain on the West Coast, sells a surface curing agent they say can be applied over the gelcoat to allow the surface to cure in open air without covering.

Can it be done?

sailingdog · Mar 20, 2010

They do sell finishing gelcoat, which has wax dissolved in it. The wax rises to the surface when it is applied and seals the gelcoat resin from the air and allows it to cure.

I would point out that painting, via rolling and tipping, the topsides or cabintop, would be much easier and probably faster and simpler than re-gelcoating large areas of the cabintop.

Joe said:
I thought gel coat had to cure without exposure to air. That's why they spray it on the mold first then lay the glass in... the repair kits I've used say to cover the repaired area with plastic film to keep air out... am I mistaken????

RECESS · Mar 20, 2010

Hermit Scott said:
So it seems I need to make up my mind now as to what I am going to do later. I filled in all the ports and I will need to paint those soon. It is just too much obvious ugly, uglying up the whole marina. I need to be kind to my neighbors and at least get those large areas painted soon, but with something that will be compatible with what I am going to paint it with later.

I am not trying to steer you away from spraying paint, I just know from doing both of them to get a really deep paint shine it takes really good mixing, more reducer as you go from one coat to the next. That means you also have to move the sprayer faster as you apply. The generators we made were huge power plant units that started around $2 million and that was 15 years ago. We had to have a million dollar paint job on them or the customer would be pissed. Getting really good at spraying takes a bit of time. If you do decide to spray, I would suggest doing a few projects before spraying your boat. Perhaps a few repair areas that you will need to sand later to do the entire area.

The two part roll on paint would allow you to make repairs now, prime and paint and then wet sand to open up the finish and paint over again when you do the rest. It is also very forgiving in your mixing ratios. I measured everything with a gram scale but the real big difference was in how fast it set up. If you do go with a two part mix, make sure you allow the paint the full time it needs to set up before applying. I found if I waited 1/2 hour after mixing, I had very few tiny bubbles to tip out. By my third coat I did very little tipping after rolling. There is a guy at my club that used Awlgrip and he refrigerated his paint after mixing for 1 hour and said he never had to rush to apply it.

Good luck with whatever you decide. If I was closer to you, I would come give you a hand with whatever way you chose to go.

sailingdog · Mar 20, 2010

I would recommend going with a two-part paint, but spraying a two-part paint requires some serious safety gear, as most two-part paints have an isocyanate component in them.

Rolling and tipping will waste less paint, require less equipment, and be easier to do. It will work a lot better if you have someone mixing the paint, and another tipping the paint, so that you can keep working while the paint's edge is still wet. This will reduce obvious paint edges.

Hermit Scott said:
I know you painted your bridgedeck instead of gelcoat. What did you use on that? I am thinking of putting a compressor in the back berth and painting the deck in sections, starting in the cockpit. What would be the best paint to use if I were going to spray it in sections. I know there are going to be some lines where the paint meets. I am ok with that if it can't be avoided.

Sumner · Mar 20, 2010

Hermit Scott said:
.........I guess that leaves me with painting. What I don't want to have to do is wet sand and polish the paint after shooting it on. But I don't think I want something that CAN"T be sanded and polished if I really screw something up...........

If you end up doing this it isn't all that bad if you have one of these....

http://www.amazon.com/Makita-9227C-7-Inch-Electronic-Polisher/dp/B0000223IZ

...and I would recommend getting one of those if you need one. I know it isn't cheap, but it will hold the speed regardless of load. You will use it again later for other projects. With hook and loop sand paper and the foam polishing/cutting pads and buffer bonnets the job goes pretty fast. By hand it is a chore.

Have you checked to see if you can spray paint in the boat yard if that is where you are going to do it or even at home.

Sounds like you are reaching some conclusions. Keep researching this. As I said before the cost on a paint job on a car is all of the prep. You can often get someone to do the final spraying pretty cheap if that is all they have to do as it goes quick. If you need to use a primer under the final top coats you could get by with the smaller compressor for the priming as it is sanded prior to putting on the top coat. Your bond will then be a mechanical one. If you are fixing problems I would think you would use a high build primer (epoxy/waterproof) under the final top coat. If that is the case you will be sanding it flat to get things perfect. Use a guide coat while sanding to see what you are doing.

As I said before I'm talking from an auto background, so take what I say with a grain of salt,

Sum

seadaddler · Mar 20, 2010

Rolling tipping

I saw my next door slip neighbor roll and tipp his hull and deck in the water next to me and it looked fantastic just like a new boat some kind two part mix and he worked fast before it dried,but he does it for a living on other boats, it really really looked good.
Nick

Spraying gelcoat

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