Complete Gel Coat Resoration Question and Help

opmope

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Hello all. Great site and lots of info. Unfortuately can't find the info I'm wanting here or any other website.
I'm going to re gel lcoat my daughter 14' Sidewinder. Doing the hull first. I'm wanting it to be 80% all white with 20% 3 red stripes like a Hydrostream Venom. I have all my gel coat, styrene, and air dry. Not going to use Duratec because I do not want to go to the expence and I already have way to much gel coat now to have it go to waste. I don't mind the sanding and have all the time in the world. I have a 2.5MM HVLP greavity feed gun and am going to stray first coat one day the second the 2nd day and the final with air dry on the 3rd day.

1.) Once cured, after 3 days, will the tape underneath the gel coat peel off like the tape after painting with automotive paint? Or will it be so hard that now I won't get a clean edge because the Gel will crack when lifting tape? I do not really want to remove the tape in 4 hours and re tape for each coat.

As I said earlier. Would like to do two seperate colors. White being my main boat color and red being the accent color.

2.) How to do the two colors is my next question. I know it is usually done in a mold but how do the professionals spray an already built boat? Say I would like to do the red first. Tape of white area off and over a three day period spray my red last coat with air dry. Hopefully question one gets answered and I can the remove the tape. Then I would like to tape off the red and spray the white same as the red over the next three days. Remove tape. Sand and buff.
Do not really want to spray the whole hull white first and then tape off the white to spray the red because then under the red I will have 6 coats of gel coat and a huge ridge. Plus, when I remove the tape, will I have a clean edge.

The top deck will be as the hull with one exception. the red will be a large candy apple red Metal Flake like the bass boats. There, I will be using the Duratec 1040 Hi Gloss additive to replace my Styrene and will be putting three coats of clear over the whole deck.

3.) For the deck, spray the same as the hull but before spraying the Metal Flake, I will put one coat red base down first. Cover with flake and then 3 coat Clear Gel over entire deck.
Any help would be appreciated.
Dave
 

Woodonglass

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Re: Complete Gel Coat Resoration Question and Help

Welcome to iBoats!
Yacht Dr, OOPS are two of our resident Gelcoat experts. You might try sending them a PM (Private Message) and see if they will give you some advice. I am a Paint guy never shot any gelcoat, only done minor repairs.

WelcomeAboard.JPG
 

opmope

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Re: Complete Gel Coat Resoration Question and Help

hi,,,,,welcome to iboats....

yacht doctor typed it out here

http://forums.iboats.com/showthread.php?t=516156

Thanks oops for the link. So I understand the 2 different color application from reading the post in the link you provided. With the materials I am using as mentioned in my original post and the time period I'm want to shoot over, 3 day period for my 3 coats to be applied with the last coat having the wax in it. Do I need to remove the tape edge from my secondary color and then have to re tape the edge the next day and the next day till my three coats are appied. If yes?? Then how do you ensure a straight edge when re taping?
Question #.3 in original post. I can shoot the primary color on deck having the secondary taped and masked but when it's time to shoot the metalic, the second color, I will have to mask the primary off??? Can't just blow the flake our the primary because you can't sand over the flake. Flake has to be Clear coated before sanding. IMO. So if i'm doing this step incorrectly, can anyone shed some light on how to apply the metal flake stripe?
Dave.
 

oops!

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Re: Complete Gel Coat Resoration Question and Help

i actually have not shot more than 2 colors due to the fact i work alone with one gun.......cleaning the gun is paramount, so time is a factor .

after you shoot, give the gellcoat a little time to kick.....aboout 15 mins....then pull the tape.....dont let the tape hit the boat....
gellcoat is not like paint where you can pull the tape the next day or week..gellcoat is a really hard shell.....and the tape will break before the gell comes off, if you take it off too late.

as far as crisp lines......once the gellcoat has cured......that line is there.....so you can get over spray on that gell,,,,cause you have to sand it any how right?,,,so when you break thru the over spray, the color and line is there.

you can mask off the colors after they cure. it will save a little sanding,


what are you working on? ....is this a centurion?
 

opmope

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Re: Complete Gel Coat Resoration Question and Help

Hello. Really helps. Thank you. I PM'ed Yacht Dr. But his PM box is full. He must be away.
Dave.
 

Yacht Dr.

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Re: Complete Gel Coat Resoration Question and Help

Hello. Really helps. Thank you. I PM'ed Yacht Dr. But his PM box is full. He must be away.
Dave.

I am kinda away :) .. but your PM did not register.

You need to pull the Fine line tape away ..then spray your second "inlay" color. ... wetsand your overspray and find that fineline. .. sand and buff it out and it will be .... factory ..

YD.

PS. pull the tape as soon as it gels out .. try not to flap it on your product or your boned. ..you will know when to pull when you pull your tape. If its Crispy then its too late.
 

opmope

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Re: Complete Gel Coat Resoration Question and Help

Thank you Yacht Dr. For the reply. I'm using a HVLP gravity feed gun with a 2.5 mm tip and 1l pot. What should my pressure be set at?
 

oops!

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Re: Complete Gel Coat Resoration Question and Help

i run 5 in the pot......but if i remember correctly......yd runs 8. (dont want to speak for him....but i think remember reading he shot at 8)
 

opmope

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Re: Complete Gel Coat Resoration Question and Help

i run 5 in the pot......but if i remember correctly......yd runs 8. (dont want to speak for him....but i think remember reading he shot at 8)

5 - 8 what, Bars or PSI? The posts I have read for a HVLP gravity gun all say 30 to 40 PSI or 4.5-6.0 bars. What is bars?
 

opmope

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Re: Complete Gel Coat Resoration Question and Help

Next question I have is primer over fiberglass repairs that have been done. The Sidewinder boat is a metalic orange brown combination. I have repaired the hull in areas. When changing the color to white gel, should I prime the whole hull first or just the repaired area or not needed to prime at all. In my readings I found a few post stating to prime to avoid pin holes in the final product.
Sorry for all the questions. Just can't seem to fing the questions I want answered on the net.
 

ondarvr

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Re: Complete Gel Coat Resoration Question and Help

Primers are used for paint, not gel coat...but.

If you have sanded through the gel coat and into the glass there will be small pin holes that can be a bugger to cover when spraying gel coat. The easiest way to solve this is mix a small amount of gel coat and use a squeegee (small bondo spreader) to spread it on the bare glass surface, use pressure so it removes 95% of what you put down. This will force gel coat into the small pits and not leave a build up on the surface itself.
 

Yacht Dr.

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Re: Complete Gel Coat Resoration Question and Help

Next question I have is primer over fiberglass repairs that have been done. The Sidewinder boat is a metalic orange brown combination. I have repaired the hull in areas. When changing the color to white gel, should I prime the whole hull first or just the repaired area or not needed to prime at all. In my readings I found a few post stating to prime to avoid pin holes in the final product.
Sorry for all the questions. Just can't seem to fing the questions I want answered on the net.

No need to prime with Gel.

You do however need to fill up pinholes that are dominate in glass or prefair.

If you can see it before you gel .. then its going to be a hardship on the spray.

Spray is spray .. you should have All of your filling done before spraying gel or paint ( paint Must be Primed ).

Gel over gel IMO is best with 80-120g surface grit prep ..

YD.
 

opmope

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Re: Complete Gel Coat Resoration Question and Help

ondarvr and yacht dr thank you. Just with the air pressure at the compressor and then at the HVLP gravity fed 2.5 MM tip gun. What should they be? I see some say 6-8 but they never say Psi. Then some say 5-6 Bar? Then some say 30 - 40 psi. Yes that's what they say for my type of gun. Thanks and hopefully all my questions are answered.
Dave.
 

ondarvr

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Re: Complete Gel Coat Resoration Question and Help

On a gravity feed gun its all about volume, not so much pressure. You need to have a small valve in the air line right at the gun to adjust the volume for the best pattern. Too little volume and it splatters in large dropplets, too much volume and it will blow the gel coat around on the surface resulting in a wavy surface.

The difficult part can be in getting enough gel coat to flow through a gravity gun to do a large area, they tend to be a little slow, so you end up running out of time and the gel coat begins to gel. Pressure pots are needed for doing a large area.
 

opmope

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Re: Complete Gel Coat Resoration Question and Help

So again my question is: What should in, psi, my pressure be at the compressor and then the , psi, be set at on the valve on the gun?? Roughly, give me a starting point.
I'm only shooting a 14' Sidewinder. Doing the hull first then the deck at a later point. Wanting to see how I make out on the hull first prior to doing deck. Thanks again for piping in.
Dave
 

Yacht Dr.

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Re: Complete Gel Coat Resoration Question and Help

Ok opmope .. here is the deal with gelcoat in simple understanding ..

Think of your boat as a hard boiled egg ( no shell ).

Gelcoat application is like putting on a hard shell.

Paint application is like putting on the colors after the shell is made.

I have never full gelled with a HVLP or a gravity gun. I think using these guns would not be efficient in the gel application.

With gel you have to apply all coatings at ONE time. You cannot wait another day and put on other coats without prepping the surface.

Gravity guns are not recommended for Full gel sprays.

There is no " special " PSI that Anyone can say for sure with Gel ( again gel is NOT Paint ! ).

I would set your compressor up to max PSI. You can control how much air is at the nozzle with your spray gun.
You Cannot however change the pressure at the fluid end because you are using a Gravity Feed system.

Yes .. I use about 8-12 PSI on the Regulator to my Pressure Pot. .. Your gun supplies Fluid and Air to your mix. (know your gun)

You can Not use this method if your using a gravity feed.

I cannot help you with pressures and such when your using this system. I would recommend you buy a gallon of some cheap latex ( water based ) paint and spray with a good Thick layer. Clean the gun with water then Acetone before you spray your GelCoat. This will give you some Idea of what Viscosity your going to be working with.

Not All Gelcoats are the same .. so get used to a Base Viscosity of your spray Before you add the M.E.K.P. ....

When you Cat it .. its Now or Never .....

Hope this helps.

YD.
 

ondarvr

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Re: Complete Gel Coat Resoration Question and Help

Like YD said, pressure is almost irrelevant, its all about volume, you meter that with the air valve you install in the air line at the gun.

Put some uncatalyzed gel coat in the gun and see how it sprays, after doing that if you think you can spray everything you plan to, go for it. If not, you may need a different plan or gun. Remember, you may only have about 10 minutes to empty the gun before it starts to gel.

If this was just a stripe you probably wouldn't have much of a problem, but doing a complete re-spray may be very difficult with gravity feed gun.
 

Yacht Dr.

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Re: Complete Gel Coat Resoration Question and Help

Put some uncatalyzed gel coat in the gun and see how it sprays, after doing that if you think you can spray everything you plan to, go for it.

Yea..but at a hundred dollars a Quart that might be an expensive Test. .. thats why I suggested Water based latex paint to get the Feel of the viscosity of what your gun can handle.

Remember .. Gel is NOT paint .. it needs to be applied thicker then normal paints ( it will not run like Imron or auto paints ).

YD.
 

ondarvr

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Re: Complete Gel Coat Resoration Question and Help

While spraying some latex house paint will let you get used to how the gun works and what the adjustments do, it doesn't give you any experience with the actual gel coat you're going to use, which can be significantly different. It takes from 2 to 4 oz to dial in a gravity feed gun, this needs to be done instead of catalyzing larger amounts and spraying that much or more while trying to dial it in under the stress of it being your first attempt at a job like this and the clock rapidly ticking until gel time. Whatever gel coat you don't use in the test spray can used as normal. If that first test spray with gel coat turns out terrible it gives you time to ask questions and get it right without wasting a full pot and/or screwing up the job.
 
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