At the gelcoat stage - help needed!!!

[morebass 17]

Re: At the gelcoat stage - help needed!!!

Water was mentioned because most house paints are latex based and water is used for clean up, water will only create problems if used with other types of paint.

The areas where you sanded back down to raw glass will need to be pre-coated before spraying the gel coat. Raw glass will have small pin holes and other small imperfections that may not be covered easily and create defects in the finished surface. The squeegee mathod works well to pre-coat these spots.

Thanks Ondarvr for explaining that for me.
I was planning on repeating the squeegee step , but certainly not with the brushing gelcoat I originally used. I will wait untill I purchase the sprayable gel and possibly even thin it slightly, ( all depending on the original viscosity ) and hopefully it wont add to the high spots like it did on my first attempt. Hopefully be at this stage by next week.

 

[morebass 17]

Re: At the gelcoat stage - help needed!!!

looking good

Thanks lonnie t.

 

[Yacht Dr.]

Re: At the gelcoat stage - help needed!!!

Your setup if just fine ..

Work with it until you know what to do.. dump 2 quarts in 10 mins and you will not have the gel Kick off in your gun. thats why you put reducers in there..POT Life and for your gun.

If your scared about kickin off in the gun as suggested..then yea.. fine.. flush the whole system out after 2 quarts.

Dump guns are for small parts for a small shop program. They Cannot Spray Horiontal .. only top down LOL..

Big boats use an Airless gun that mixes the MEKP with the gel AT THE TIP !! Not dump guns.. They are Pumpers.. you dont have that nor can you afford that kind of gel gun .. again LOL. They dont spray boats with Dump guns .. trust me..

This is how you do a Full Gel Spray.. I again would ask Anyone here to suggest a better way to do it. Dont keep telling me that It should not be done..or its not Advisable..or etc.. Tell me HOW to do a Full Gel Spray ( I allready know and have posted on HOW ) ..

Anyone out there That has done a full gel ? Ive never had them fail personally.. tell me how Its done then..

Regards YD..

 

[morebass 17]

Re: At the gelcoat stage - help needed!!!

Dump guns are for small parts for a small shop program. They Cannot Spray Horiontal .. only top down LOL..

After watching the video clips of these guns in use, I was thinking how you can spray horizontal with this gun, I'm glad you answered this cause i was about to ask a silly question.

Work with it until you know what to do.. dump 2 quarts in 10 mins and you will not have the gel Kick off in your gun. thats why you put reducers in there..POT Life and for your gun.

If your scared about kickin off in the gun as suggested..then yea.. fine.. flush the whole system out after 2 quarts.

I think I will start with 1 quart to make sure I am able to dump 2 quarts in 10 mins. As this is my first spray job I may not be that fast at first.
I think I will flush the system after each batch, just to make sure, It may be over cautious but I am scared of it kicking on me and wrecking my chances of doing the full respray in 1 weekend.

Although there is so many different methods on the best way to do a full diy respray, (which all of them may work for the individual) I think I can safely say YD's method seems to be the best for me. Please keep posting your personal views though as this is what forums are all about, and its always good to have a little debate on the best way to do things, there is never just one way that works.

 

[erikgreen]

Re: At the gelcoat stage - help needed!!!

After watching the video clips of these guns in use, I was thinking how you can spray horizontal with this gun, I'm glad you answered this cause i was about to ask a silly question.

For someone who seems to be fairly negative about the cheaper dump guns, YD doesn't seem to have used one.

To spray horizontally I just do the radical thing and turn the gun sideways. To make it spray you just have to ensure that gravity moves the gel to the nozzle. You can't spray straight up, but I can accept that from a cheap gun.

Morebass, you're right that most DIY types shouldn't spray the two part paints. Fortunately the manufacturers know this and have either reformulated the paints or brought out new ones that work about equally well with what's called the "roll and tip" method. Here's a video link:

http://www.youtube.com/watch?v=Gjyzc4c9JnE&feature=related

You get the same control of the finish as with gelcoat, you just do the sanding before you apply it. What most folks do on a new or patched hull is start by fairing, then apply a high build primer and start the sanding process. Once you think you're close to the finish you want, you wet the surface down with water or solvent to "simulate" the polished finish. When the surface is ready to go, you roll and tip the paint on. No sanding required after that unless you get drips or runs. The result is usually indistinguishable from a sprayed paint job.

Erik

 

[morebass 17]

Re: At the gelcoat stage - help needed!!!

To spray horizontally I just do the radical thing and turn the gun sideways. To make it spray you just have to ensure that gravity moves the gel to the nozzle. You can't spray straight up, but I can accept that from a cheap gun.

Well that makes sense, Thanks Erik.

Morebass, you're right that most DIY types shouldn't spray the two part paints. Fortunately the manufacturers know this and have either reformulated the paints or brought out new ones that work about equally well with what's called the "roll and tip" method.

I tried the roll and tip method on other parts of the interior, I have to say I got a good finish doing it this way but from 12 inches away from the surface you could see fine brush marks, more than 12 inches away it looks like a spray job, It may have been due to my technique but this was the reason I prefered to use gelcoat as any imperfections could be sanded out.
although paint can still be sanded to eliminate imperfections ie. brush marks, to my understanding gelcoat will go on thicker so more sanding can be done and there is more room for error.

Once you think you're close to the finish you want, you wet the surface down with water or solvent to "simulate" the polished finish.

Wetting the hull is a great tip Erik thanks for that, I used to always rely on sunlight to check my work, but where i'm from we only get sunshine 2 days a year lol, and its usually when i am at work !!

When the surface is ready to go, you roll and tip the paint on. No sanding required after that unless you get drips or runs. The result is usually indistinguishable from a sprayed paint job.

As mentioned above I have already tried the roll & tip method with good but not perfect results, so I didn't want to do a full hull with this method.
I will be applying most of the interior paint using the roll & tip method, and i am sure with a bit more practice I will get a great finish when closer than 12 inch away from the surface.

Thanks again Erik for the advice.

Ian

 

[Yacht Dr.]

Re: At the gelcoat stage - help needed!!!

For someone who seems to be fairly negative about the cheaper dump guns, YD doesn't seem to have used one.

To spray horizontally I just do the radical thing and turn the gun sideways. To make it spray you just have to ensure that gravity moves the gel to the nozzle. You can't spray straight up, but I can accept that from a cheap gun.

I like our spars Erik ..

Yes I have used a dump gun for small parts on the Plug ( small flattish parts ).

I never knew you could turn it sideways to get all the gel out of that disposable quart cup. I had to pull the trigger ( while the gun was facing up ) and then bring it down to the part to dump it..and dont release the trigger untill the gun is facing up again ( also ALOT of air pressure needed ).

While I Have seemed to use a dump gun... Have you ever used a pressure pot for sprays Erik ?\

I have done MANY Full gel sprays with a 2 qt and as well as a 3 gallon pressure pot ( You know..mix 3 gallons of gel and spray it ).

All I was suggesting with the dump gun is that Big boats are not sprayed with a Dump gun..geeesh..

OH..and that YouT vid..from Those guys.. where is the outcome ( final product ) of there roll and tip lol.

Those guys can do a spray with shorts and a t-shirt .. but there wearing a full face and full suits to "roll and tip".

I think there Reading the threads here myself....

Another thing..if you want to do paint correctly as you stated..you have to prep (120ish) ..then Prime..let stand..then sand the Whole thing with 320-400 .. then wipe and tack..wait for just the right day then apply the paint. If you have a few runs/sags..go block them out. Ez right..well have you done many runs/sags in your life ? Erm.. Not that ez without Burning through ( whole different topic there ).

Rant Mode Off...

YD.

 

[ondarvr]

Re: At the gelcoat stage - help needed!!!

One method of spraying gel coat that hasn't been mentioned here yet is using an airless paint sprayer like you use to paint your house, not a cheap unit from the hardware store, but a good one from the rental center. I used to do this a great deal, it was easy and handy, plus very quite, it made field jobs much easier. You need to use a small tip, a 13 or 15 works well, with these tips you don't need to thin it and it will lay down fairly good.

 

[morebass 17]

Re: At the gelcoat stage - help needed!!!

oh..and that yout vid..from those guys.. Where is the outcome ( final product ) of there roll and tip lol.

Those guys can do a spray with shorts and a t-shirt .. But there wearing a full face and full suits to "roll and tip".

lol.

 

[morebass 17]

Re: At the gelcoat stage - help needed!!!

One method of spraying gel coat that hasn't been mentioned here yet is using an airless paint sprayer like you use to paint your house, not a cheap unit from the hardware store, but a good one from the rental center. I used to do this a great deal, it was easy and handy, plus very quite, it made field jobs much easier. You need to use a small tip, a 13 or 15 works well, with these tips you don't need to thin it and it will lay down fairly good.

Thanks for the info ondarvr, I'm not familiar with this kind of sprayer but i'll look into it, and keep it in mind.

 

[Yacht Dr.]

Re: At the gelcoat stage - help needed!!!

One method of spraying gel coat that hasn't been mentioned here yet is using an airless paint sprayer like you use to paint your house, not a cheap unit from the hardware store, but a good one from the rental center. I used to do this a great deal, it was easy and handy, plus very quite, it made field jobs much easier. You need to use a small tip, a 13 or 15 works well, with these tips you don't need to thin it and it will lay down fairly good.

You have used a Wagner airless spray setup with Gel ? ( basic concept thing ) .

I was wondering if I should try it..but how do you flush the system out ?.. acetone ?

Im thinking at this point that I should relinquish this thread to other Gelcoat applicators out there .. with there own ways of doing a Full gel spray..

But..would you please do a Step-by-Step application Guide that I have done.. please... not just " oh that wont work..use paint and look that this YouT vid..use a dump gun etc. ". Please..DETAIL How Your Method is applied.

You want to Hammer me..fine..dont tell us lagistics on how my way wont work..tell us how You would do it.

I have been asked several times via PM for a "sticky how to guide for application of gel" . I have not done so because of the forum bickering of how and why Gel Should Not Be used..

So lets clear it up.. how would you apply gel ( or are you saying it cannot be done ). Facts..not fiction here.

Remember I have full sprayed gel on 40' plus boats IN THE WATER !

YD.

 

[nymack66]

Re: At the gelcoat stage - help needed!!!

Morebass,
Can you post your plans for this shoot? How many coats? Wet on Wet? and final coat? How many mils thick? Thinning with? etc ..Have a plan in place ...Hopefully you do post it and let the Guys get an idea in regards to what you be doing ...

 

[ondarvr]

Re: At the gelcoat stage - help needed!!!

Not sure what you are asking exactly.

Wagner no, higher end commercial units yes, they work fairly well, you just need to stay a head of the gel time or it becomes pricy very fast.

The short version for a large job.

It?s a 10 step process, probably should be 12, but I?m lazy.

First choice for a large job is an airless gel coat unit with a small tip.

Next would be an electric airless paint sprayer, you need to be very careful though, mistakes cost money, I don't do this much anymore though.

Pressure pot.


1 Clean the surface

2 Sand with 36 to 80 grit depending on the tool being use or hand sanding plus surface profile.

3 Clean the surface again, depending on the size of spray job I may not do a solvent wipe.

4 If possible use a standard high emission gel coat, they cure much better.

5 Use about 5% wax solution or Patchaid, with slow Patchaid I may use more than that.

6 Make sure no part of the surface to be sprayed is in direct sunlight.

7 Catalyze at 1.75 to 2%


8 Pray that the power doesn't go out, the compressor doesn't break, a hose doesn't come loose on the spray gun, I don't fall in the gel coat I just sprayed, it doesn't start raining mid spray job, a cat doesn't walk through the wet gel, a dust storm doesn't kick up, a jet doesn't fly over, someone doesn't complain about the smell and shuts the job down, a swarm of bugs doesn't decide to land, the temporary cover put up doesn't get blown over, I don't get overspray on something valuable, its the correct color, my helper doesn't walk through wet gel coat and then across the customer's patio, I get paid, that its not too hot or too cold out, there's no water in the air supply, I don't suffer from heat stroke, My helper measures the catalyst correctly and then actually adds it to the gel coat, I don't set up the airless paint sprayer I just rented, there is no porosity, its thick enough, there are no thin spots, and more.

Possibly repeat #8

9 Pull the trigger and go for it.

10 Clean up and have something cold to drink.

Sanding is another chapter.

 

[ondarvr]

Re: At the gelcoat stage - help needed!!!

Remember I have full sprayed gel on 40' plus boats IN THE WATER !

YD.

When I was self employed I was doing 3 jobs a week that size, some with gel coat, some with epoxy and some with 2 part PU.

For twenty years when not self employed I was gel coating 2 units a day about that same size, plus assorted other things.

 

[Yacht Dr.]

Re: At the gelcoat stage - help needed!!!

Not sure what you are asking exactly.

Wagner no, higher end commercial units yes, they work fairly well, you just need to stay a head of the gel time or it becomes pricy very fast.

Next would be an electric airless paint sprayer, you need to be very careful though, mistakes cost money, I don't do this much anymore though.

What "higher end commercial units" are you refering to ?

Big production sprays are done with Airless guns..but there all pnumatic..they dont Mix the gel before the spray.

Those production guns are with a 55 gal drum..and a gal of MEK seperate of each other and have 3 hoses going to the Gel gun ( 1 air .. 2 gel and third is MEKP ) .

Ive used high end Graco for houses..and also Airless 3 feed gel guns for parts.

I dont know what your talking about..Airless driven spray guns ?? you next would be electric..but I have never used an Airless without spending Thousands for equiptment.

Im getting tired and going to bed..sorry if I missed something

YD.

PS. your step-by-step is staggering..im gonna have to make some notes.. Peace.

 

[morebass 17]

Re: At the gelcoat stage - help needed!!!

Morebass,
Can you post your plans for this shoot? How many coats? Wet on Wet? and final coat? How many mils thick? Thinning with? etc ..Have a plan in place ...Hopefully you do post it and let the Guys get an idea in regards to what you be doing ...

I am still working on an exact plan of action, I am going to reread this thread from start to finish a few times before I finalize the plan, but the following is a rough plan.

1. Obviously finish sanding old gel and fair the hull to the best of my ability.
2. Prep the hull to 60 grit, including the topsides. (complete hull)
3. Final check on the fairing work with a trained eye or telescope or similar.
4. Clean the hull thoroughly with acetone.
5. Vaccum my garage numerous times over a 3 day period.
6. Clean hull again with acetone.
7. Spray 1st coat with no additives, just acetone for thinning, amount of thinning will vary depending on the viscosity. I plan on a 10 mil thickness with each coat, and overall thickness of about 30 - 35 mil before any sanding.
8. Folowing day, spray another coat exactly the same as the last, with no additives.
9. Folowing day, spray my final coat with a wax additive that will be recomended by my resin supplier. Exact ratio still uncertain but in the region of about 10%.
10. allow a 48 hour cure, then clean hull thoroughly with acetone again to remove most of the wax, now the fun part begins.
11. start the sanding process with 320 - 400 and work my way up to 1200 - 1500. making sure I have removed all scratches from the previous grit.
12. cutting/buffing stage. More research needed on this, but I will probably be using products from the 3M range.

Overall there will be 3 coats each aprox 10 mil, applied wet on dry with an overall thickness of about 30 - 35mil. At the moment I am thinking of using acetone for thinning but I may well change my mind.

As i said this is not a final plan, it is subject to change after rereading this thread a few times, as every step thats needed has been included in this thread, I just have to put it all together .

 

[ondarvr]

Re: At the gelcoat stage - help needed!!!

Airless gel coat unit 8-$10,000 Magnum type unit, air operated, large fluid pump, catalyst slave pump, and air assist.
http://www.mvpind.com/products/gelcoaters/

Airless paint sprayer, Graco type, electric, simple suction tube stuck in a pail. Catalyze whatever amount you think you can spray in about 10 minutes and pray you are right.
http://www.graco.com/Internet/T_PDB.nsf/ProdGroups/ContractorPaint#subsection23

 

[proshadetree]

Re: At the gelcoat stage - help needed!!!

Remember I have full sprayed gel on 40' plus boats IN THE WATER !

Good lord and I am worried to death about spraying on land. :facepalm:

 

[ondarvr]

Re: At the gelcoat stage - help needed!!!

7. Spray 1st coat with no additives, just acetone for thinning, amount of thinning will vary depending on the viscosity. I plan on a 10 mil thickness with each coat, and overall thickness of about 30 - 35 mil before any sanding.
8. Folowing day, spray another coat exactly the same as the last, with no additives.
9. Folowing day, spray my final coat with a wax additive that will be recomended by my resin supplier. Exact ratio still uncertain but in the region of about 10%.


All of these can be done in the same day back to back.

Gel coat needs to be sprayed about 18Mils or so for it to cure well, so two slightly thicker layers will be fine if you do them separately.

By the time you spray 18mils and clean the gun it will have gelled enough for you spray more over it without sagging, so you can do it all at one time if you want.

 

[ondarvr]

Re: At the gelcoat stage - help needed!!!

On my list at #8......I forgot, I recently sprayed a hull and after a bout two minutes of spraying the regulator on the pressure pot failed and sort of blew appart. I had to plug the leak very fast and then pinch the air hose to regulate the air to finish that batch.