Gel coat help

[kirkll]

I’ve got a situation I need some help with. I was buffing out the gelcoat on this old boat and found out somebody hollywooded the dad burn thing ..... there was obviously some serious gouges in the side of it at some time in the past, and someone decided to bondo and paint it to match rather than grinding it down to glass and matching the gelcoat color and put it back right.....

So now I have a mess.... looks like I’m going to have to sand quite a bit of this side of the boat down to original gelcoat , and sand all this paint off. I can’t believe someone would do this.

I was prepared to do some scratch and ding repair and have a color match gelcoat kit and a pint of gelcoat. But now I’m looking at possibly doing the whole side, if not both sides, and will need to spray this rather than just touching up.

my questions are this: what type of spray gun do I need for shooting Gelcoat, tip size, and how much do I reduce it to get it through the gun? I’m familiar with spraying auto clear coat , epoxy clear coats, and lacquer. So I’m no stranger to a spray gun. But I’m using HVLP guns and not spraying large surfaces.

any help pointing me in the right direction would help. My polishing job just turned into a much larger project which seems to be atypical of working on these old boats..... thanks Kirk

 

[sphelps]

Its not unusual for someone to paint a boat ... Gell coat is a heck of a lot more work ...
Its just a matter of how much time and money ya want to spend ..
Most use a cheap hvlp spray gun with the biggest tip they can find to spray gell . That or a dump gun ..
There is an additive that alot of folks are using to cut down on the sanding .. I cant remember the name ..
dura tech or something like that ...
Hopefully some of the guys that have more experience will chime in .
Welcome aboard !

 

[chevymaher]

There is a thinner for Gel Coat no more than 10%. A primer gun from harbor freight works. They got nice guns with replaceable paper cups that are best to use.

My brother and I both painted cars all out lives. We both got boats and did gel coat for the first time recently. It is easier to get results with than paint "IF" you actually knew how to paint in the first place. It is more labor intensive but alot easier to get perfect results.

We both used automotive paint tools and supplies and got the same results. Paint sand buff wax.

2 choices get really fast and good at cleaning the gun or just use it and throw it. Or 3 actually get the right gun for it.

 

[Scott Danforth]

for spraying gel coat

you need the fairly cheap Vapor brand HVLP gun. Northern Tool and Amazon have them. get the 2.3 tip

the harbor freight gun has too small a tip and the Vapor brand is what they sell at most fiberglass places (just at 2.5 times the price) you can use the cups from the HF guns in the vapor gun

dont thin.......you then need to mix duratec 904 gloss additive to the gel. this allows you to spray the gel like paint with minimal orange peel. the mix ratio is about 1:1 with only 1.5% MEKP. need to do a test spray on the day you are spraying to verify the ratio

have the whole area sanded, prepped and taped off

have all your gel and 904 pre-poured in plastic measuring cups sitting in a cooler on ice the cups hold about 20 ounces max, so pre-measure accordingly

have your MEKP in a quick dispensing container, pre-figure out your 1.5%

have a large bucket with acetone in it and a lid. have two small containers of acetone with lids on as well

have a friend standing by to mix and hand you 20 ounces at a time

start spraying, move as fast as you can

when your cup is half full, yell for another mix

pour and shoot....

pour and shoot.....

repeat as needed

then when you are done, grab one of the small containers of acetone and run it thru the gun, spraying into a rag, well away from your boat

then quickly pull the gun apart and soak the parts in the bucket of acetone

then pull your taping quickly, or you may need to cut it off with a razor.

drink beer

the next day you can wet-sand and buff

 

[Scott Danforth]

this one https://www.amazon.com/Vaper-HVLP-Spray-Gun-Plastic/dp/B000BTJALA

or this one https://www.northerntool.com/shop/tools/product_200319459_200319459

or you can get the same gun with a slightly larger cup at most fiberglass places for about $120

 

[kirkll]

Its not unusual for someone to paint a boat ... Gell coat is a heck of a lot more work ...
Its just a matter of how much time and money ya want to spend ..
Most use a cheap hvlp spray gun with the biggest tip they can find to spray gell . That or a dump gun ..
There is an additive that alot of folks are using to cut down on the sanding .. I cant remember the name ..
dura tech or something like that ...
Hopefully some of the guys that have more experience will chime in .
Welcome aboard !

Well I could see using a high grade auto grade paint as a more cost effective solution to do a repair, and who ever did it , did a great color match on paint, but they didn’t do the job right at all. There wasn’t even a decent clear coat applied.

When you can buff right through it in the first pass with medium rubbing compound, that’s just not right. All I wanted to do was polish the old girl up, repair a few scratches, and get some wax on it. This is a much bigger project than I wanted to tackle with my allotted time and experience level.

I’m doing this work out in my driveway and don’t have a shop big enough to get her inside. Granted... I’m in the country, and have plenty of elbow room.... but this is discouraging. I really want to do this restoration right, but this is a bit overwhelming.

Kirk

 

[Scott Danforth]

single part paints on boats are common. base/clear on a boat is not common

I sprayed a multi-colored gel coat in my yard

 

[kirkll]

for spraying gel coat

you need the fairly cheap Vapor brand HVLP gun. Northern Tool and Amazon have them. get the 2.3 tip

the harbor freight gun has too small a tip and the Vapor brand is what they sell at most fiberglass places (just at 2.5 times the price) you can use the cups from the HF guns in the vapor gun

dont thin.......you then need to mix duratec 904 gloss additive to the gel. this allows you to spray the gel like paint with minimal orange peel. the mix ratio is about 1:1 with only 1.5% MEKP. need to do a test spray on the day you are spraying to verify the ratio

have the whole area sanded, prepped and taped off

have all your gel and 904 pre-poured in plastic measuring cups sitting in a cooler on ice the cups hold about 20 ounces max, so pre-measure accordingly

have your MEKP in a quick dispensing container, pre-figure out your 1.5%

have a large bucket with acetone in it and a lid. have two small containers of acetone with lids on as well

have a friend standing by to mix and hand you 20 ounces at a time

start spraying, move as fast as you can

when your cup is half full, yell for another mix

pour and shoot....

pour and shoot.....

repeat as needed

then when you are done, grab one of the small containers of acetone and run it thru the gun, spraying into a rag, well away from your boat

then quickly pull the gun apart and soak the parts in the bucket of acetone

then pull your taping quickly, or you may need to cut it off with a razor.

drink beer

the next day you can wet-sand and buff

Thanks for the detailed run down on this. I’ve sprayed a bit of lacquer that was pretty hot stuff, but this sounds like it kicks off pretty quick. What type of pot life do you have before the gun starts clogging up? 2.3 is a pretty large tip.

a few more questions:

How much build up can I expect to get on the first coat? Can I recoat and overlap once it’s kicked off? Or do I need to sand between coats? If possible I’d like to be able to color match and feather it out into existing gelcoat rather than do the whole lower section of the hull. Is this feasible?

Once I realized that I had a painted repair in a couple spots, and wasn’t dealing with gelcoat, it kind of pissed me off and I just shut it down for the day. So I don’t really know for sure haw large the painted area is.

I removed all the pin striping on the entire boat. the upper cap and accent colors polished out well, but those pin stripes we baked on pretty good. I caused a bit of damage with a razor blade taking them off I had to sand those out out. There was also a series if pin stripes on the lower section at and below waterline that I removed. These came off much easier.

Now I’m not so sure whether they we original or not. I used acetone to remove the excess glue before I started buffing. The lower section wasn’t as oxidized, so I didn’t feel the need to wet sand. I figured a medium rubbing compound should do the trick alone......

but now I’m spooked..... I know I need to finish rubbing out this side out and see where the paint job ends and goes back into original gel coat. But I’m half afraid to buff the other side at this time. We have a family camping trip coming up at the end of the month, and I need to wrap this up by the end of the week and put it back together or I’m in deep doo doo with the family.

Im half tempted to get another paint match and just Hollywood it again for now, but I hate to do it.... your thoughts? Kirk

 

[kirkll]

single part paints on boats are common. base/clear on a boat is not common

I sprayed a multi-colored gel coat in my yard

with a single part paint on a boat would a medium cut rubbing compound take it off on the first pass? I’m unfamiliar with these products.

 

[Scott Danforth]

going to channel my conversation with Ondarvr from when I sprayed

What type of pot life do you have before the gun starts clogging up?

depends on temperature, however at 93 degrees F, in theory, 20 minutes...... however plan on about 8 minutes if you iced your gel. if it kicks in the gun you will know it, you will get strings coming out of the gun about 30 seconds prior to everything in the cup and gun turning to a sludge. this is where you dump the contents in a scrap bucket and pull the gun apart and soak.

2.3 is a pretty large tip.

yes it is, however unlike lacquer which is the consistency of liquor, gel is like spraying pudding. the 2.3 tips are for gel

How much build up can I expect to get on the first coat? Can I recoat and overlap once it’s kicked off? Or do I need to sand between coats?

you spray wet on wet on wet on wet on wet. you want a minimum of 3 wet coats, preferably 5. since the 904 additive thins it, it is a little more see-thru than a typical layer of gel. if you get runs, sags or drips, dont worry, as you will simply sand them out and spend a little more time buffing. this is where your practice shoot comes in play.

Once I realized that I had a painted repair in a couple spots, and wasn’t dealing with gelcoat, it kind of pissed me off and I just shut it down for the day. So I don’t really know for sure haw large the painted area is.

you are on your own for this, we cant see it. old gel changes color at a rate different than new gel. you want to at a minimum do everything from a stripe to the gunwale rub strip and from the bow centerline to the stern. you could blend today and it will stick out like a sore thumb in 6 months.

I removed all the pin striping on the entire boat. the upper cap and accent colors polished out well, but those pin stripes we baked on pretty good. I caused a bit of damage with a razor blade taking them off I had to sand those out out. There was also a series if pin stripes on the lower section at and below waterline that I removed. These came off much easier.

Now I’m not so sure whether they we original or not. I used acetone to remove the excess glue before I started buffing. The lower section wasn’t as oxidized, so I didn’t feel the need to wet sand. I figured a medium rubbing compound should do the trick alone......

but now I’m spooked..... I know I need to finish rubbing out this side out and see where the paint job ends and goes back into original gel coat. But I’m half afraid to buff the other side at this time. We have a family camping trip coming up at the end of the month, and I need to wrap this up by the end of the week and put it back together or I’m in deep doo doo with the family.

with gel, you wet sand to about 800 grit, then hit it with aquabuff and follow up with finesse-it

if youre buffer is too fast you burn it

you burn paint faster than gel, so......... what RPM was your buffer running at. with an 8", you should be around 1700-1800 RPM

Im half tempted to get another paint match and just Hollywood it again for now, but I hate to do it.... your thoughts? Kirk

your boat, up to you. you could always get the boat wrapped today and be done by 5pm.

 

[Scott Danforth]

with a single part paint on a boat would a medium cut rubbing compound take it off on the first pass? I’m unfamiliar with these products.

depends on the paint used

if it was Alalta (Imron), the pigment and polymers go thru the whole paint and you can spot-repair by wetsanding and buffing

if the paint was awlgrip (commonly used because its cheaper than the good stuff), you must scuff n shoot as the pigment and polymers float to the surface during the shoot. those paints are not repairable by wet sanding and buffing

if it was rustoleum or any of the other alkyd enamels, you can buff at a low speed (to not burn)

 

[Mad Props]

The beauty of gelcoat is you can get away with spraying outside in your driveway because the film thickness of gelcoat should be about 20 mils where paint is only a few mils thick... You can sand out your bugs and screw ups with gelcoat, where with paint, your kinda SOL and have to fix any flaws with more paint.

Many many boatyards do their gelcoat repairs outside.

 

[Scott Danforth]

You can sand out your bugs and screw ups with gelcoat,

unless its florida love-bug season and you spray white. after sanding out over 500 of them things.... at that point wait 3 weeks prior to re-spraying. BTDT...

 

[Mad Props]

unless its florida love-bug season and you spray white. after sanding out over 500 of them things.... at that point wait 3 weeks prior to re-spraying. BTDT...

LOL, you're right... most of us are only dealing with gnats n' such...

 

[kirkll]

You guys are great! I appreciate all the info. I’ve been wet sanding the top and accent stripes to 1000 before using the rubbing compound. I’m only turning about 1200-1500 rpms on the buffer. About half throttle on a 3000 rpm buffer....

I think I’m going to just finish up what I got going on the top right now, and get all pin striping and rails put back on. After further inspection in different ligh today(cloud cover) I can see the lower portion of the hull from the accent line down has been painted the same. The transom was still original gel coating, and that is all polished out.

i think I’ll save this bottom as a different project and do it right with gelcoat. That way I can get all my ducks in a row and all my materials on hand ahead of time, then roll up my sleeves and go for it.

thanks a bunch guys.... I’ll let ya know when I get ready to pull the trigger on that. Kirk


btw.... here are some photos of what I got.

https://photos.app.goo.gl/635Vakqi3yPpdRGJA