Re paint or Re gelcoat

[AtlanticAl]

I have been stripping the paint off the hull of my boat. It had bad paint job, on top of a good one, but i decieded to stirip the lot down to the gel coat. I was going to attemtp to re polish the original gel coat, but i think that is just way too much work, and i dont have the patience for it. So i decided that i would paint it, using awlgrip expoxy primer, and an awlgrip expoxy top coat, (sprayed) but i have discovered that gel coat will go through a spray gun, i didnt know this, and i am wondering if it would be possible to re gelcoat it. It seems doing that would be cheaper, as i dont need the primer, and the gel coat is cheaper per gallon. What i understood though about gel coat, was it never dries smooth and shinny, and has to be sanded after application, then polished, then waxed, which would be just as much work as bringing up a shine on the original gel coat.

Anyone know anything about this, because i found, i can get coloured gelcoat, that goes through a paint gun.

 

[sailormanbigd]

you are correct

You are correct in that gelcoat can be sprayed on. It has to be thinned enough to flow properly, you have to add sanding aid (wax) into it or spray over it with mold release wax for it to cure. The prep is the same as for paint, clean then sand/scuff, then clean again. Then you spray either product, prime and paint, or thinned gelcoat. You can build up thickness of gelcoat without sanding between simply dont add the wax inbetween coats. The gelcoat will be sticky and uncurred, then add wax for final coat. The finish will be dull and not smooth like paint-it doesn't level off or layout like paint does. If you want a new boat look with shiny gelcoat you have to sand till smooth, then wet sand to #400, #600, #800, at least, then buff, buff, buff. The finish probably won't shine as well as paint, gelcoat is pourus with tiny holes or grain. So, if your gellcoat after stripping is intact and thick enough for sanding and buffing you could just leave original gell and clean it up. BUt if you want that new shiny boat then epoxy prime and paint would end up to be an easier task in my opinion. The difference is that gelcoat is tough and chemical resistant more so than paint. spraying gelcoat is doable but alot of work to get it to flow thru a gun properly, you might even look into an airless sprayer to apply it, no easy fix and trade offs for each approach. My 2 cents

 

[Bill Roosa]

the wax release is not what hardens the gelcoat. There is an alcohol product that is sold right next to the gelcoat for that purpose. It is commonly incorporated into the wax release product so that is where the confusion is. But you don't need the wax if you are spraying it on and not using a mold.
As far as getting gelcoat shinny, sand and buff is the ONLY way I know of.

 

[Maine Sail]

the wax release is not what hardens the gelcoat. There is an alcohol product that is sold right next to the gelcoat for that purpose. It is commonly incorporated into the wax release product so that is where the confusion is. But you don't need the wax if you are spraying it on and not using a mold.
As far as getting gelcoat shinny, sand and buff is the ONLY way I know of.

Bill,

The wax is not what makes it cure chemically it is what makes it cure by sealing the surface from air. Gelcoat is an air inhibited cure. The "wax" migrates to the surface and seals the gelcoat from oxygen so it can cure just as if it was in a mold, even though it is not. A "mold release" paste wax is different, and only used so the finished product peels easily from the mold it has been laminated in. The mold itself creates the air inhibition, the mold release wax is there so the part comes out..

A PVA mold release agent can be used in the same manner as a mold release wax but can also be top applied. It serves the same purpose as Wax-Sol or liquid wax but is better to be sprayed on after the gel has been applied, rather than mixed into the gelcoat. The purpose is the same for PVA and a liquid "mixed-in" wax, seal the curing gelcoat from air..

Wax for non-mold gelcoat work is commonly sold as "Wax Sol". If ordering gelcoat you can simply order it waxed or un-waxed just like polyester resin. When you purchase resin you buy laminating (un-waxed) or finishing (waxed)....

Personally I like to buy un-waxed gelcoat so that I can build the DFT and then the final coat has Wax Sol added..

Painting would be easier if the OP is already adverse to buffing... Even the best guy I know who blew gelcoat still wound up with orange peel and he had some seriously top secret ingredients and processes he used. Still won't tell me all of them... He's now stopped blowing gelcoat as it cost his customers about 1.5 to 2X the cost of doing AwlGrip, Alexseal or Imron by the time you have a good looking finish...

 

[MrUnix]

What Maine Sail said

Just want to add.. while you can certainly spray gelcoat, it is nothing like paint! Paint is designed to flow and self-level which is why you can get such a nice smooth shine right out of the gun (or can or brush). Gelcoat on the other hand is thixotropic, which allows it to be applied thicker to places that paint would normally run and sag (vertical and inverted surfaces). It does not flow very well so you will not get a smooth surface with gelcoat, and it will require lots of sanding and buffing to get it that way.

As for the wax, I'm with Maine on this one and will typically get the non-waxed variety. This allows you to build up layers without any prep in between coats and only the final coat needs the wax added to let it cure.

Cheers,
Brad

 

[Barnacle Bill]

Painting is no easy task either for a good job. I recommend painting rather than gelcoating. Paint is easier to deal with. Awlgrip, is, by the way, a linear polyurethane two part paint (and not epoxy - or however you chose to spell it). It has the best color retention, gloss retention, abrasion resistance - especially over epoxy, which is very water proof, but doesn't hold up to sun degradation like Awlgrip. There are two types of Awlgrip. The original is very hard and not so easy to repair down the road. The later generation is a softer paint which is much more easily repairable should you need to touch it up in the future. You need to check the instructions on how to use the stuff. If you intend to spray it, then you cure it with Awlcat #2. If you are going to roll and tip it, then use Awlcat#3 and each has a different ratio for mixing. Also you need to us the right spraying thinner for the temperature for best results. And, before you spray the Awlgrip top coat you should prep the hull and then use Awlgrip's 545 epoxy primer first, which will help adhere the top coat, cover up old gelcoat perosity and but a barrier between the Awlgrip and any other paint that might still be on the hull. Awlgrip is very aggressive and if it is put over a less noble paint, you will have some lifting problems, but the epoxy primer will prevent this. In closing I should alert you that Awlgrip is very expensive and also is hazardous to use. So, you should buy yourself protective equipment which will include for breathing, not just touching. If you don't want to deal with the details of using Awlgrip, consider some of Interlux' (same company) DIY paint products like Brightside or their two part brushable Urethanes.

 

[monkeybars]

first off gelcoat is just polyester resin with a few additives,most supplier's sell gallon or five gallon buckets unwaxed but ship seperate bottles of wax and mepk included in the price.second gelcoat will not spray thru the same gun you paint with without changing tips,you need at least 3mm even with styrene thinner and you only have about ten minutes work time before you have to stop an tear the gun down to clean completely.they make much more user friendly gelcoat guns with disposable papercups and no o-rings or seals with large tips that shoot unthinned gel for less than 150 bucks.if your going to keep your boat for 20years use gelcoat if only 5-6 years paint it.for a quality job the prep work is the same for either,they also sell gelcoats for final coats that have additives for harder,higher gloss finish for the last coat and the pva mold release thinned with water is much easier to spray on your last coat for your surface cure then using the styrene wax additive.of course these are my opinions and we all know about opinion's.

 

[tommays]

All of the above seems to be more labor than you will be happy with IF buffing the old is to much work

Painting the Cal 29 in Alwgrip was by FAR the hardest part of a hard JOB and the worse the surface the harder it gets

 

[AtlanticAl]

After i posted this, i found another thread, on pretty much the same subject, with pretty much the same answers. I realised, I will never know how hard it is to spray gelcoat, and finish it, unless i do it, paint, i have sprayed loads of that, and used various paint systems, and found the most complicated thing about that is, getting the right temprature, with low humidity, and mixing the paint correctly, and of course, the preperation. What i have decieded to do, is buy coloured gel coat, and spray the blue band that some call a plimsole line, then depending on the results i get, i may just paint the rest of the the hull. Reason i didnt want to paint it, is the trouble i have had removing the paint. It was properly painted the first time, but subsequent coats were awful, and while they came off easily, the original paint job, was extrememly hard to remove. I am going to get a soda blaster, from Harbour Freight Tools to do the deck with.

 

[25yearslater]

Gelcoat unwaxed and 50% Duratec High Gloss Additive and 5% Duratech thinner, 2% MEKP-9 and a Kobalt HVLP gun from Lowes. Wet sand and buff with Aqua Buff and viola. No magic or special recipes or other garbage, just science.

 

[Maine Sail]

Gelcoat unwaxed and 50% Duratec High Gloss Additive and 5% Duratech thinner, 2% MEKP-9 and a Kobalt HVLP gun from Lowes. Wet sand and buff with Aqua Buff and viola. No magic or special recipes or other garbage, just science.

Forgot about the Duratec. I have a friend who's used it, not for boats though, and raves about it. I've only sprayed waxed gell but will give that a try next time... How was the intial "peel"?

 

[25yearslater]

Hi Mainesail. The peel wasn't as bad as I was expecting. I am a rank amatuer and obtained good results with a cheap gun. I suspect a pro with a good gun can save a lot of sanding though. Your sanding and buffing tutorial was an essential part of this, and I followed it to the letter with the exception of the Aqua Buff.