Custom/Hybrid Can gelcoat be sprayed, and look decent without sanding and polishing?

[luker]

I thought epoxy and polyester gel coat were a bad mix .

my thoughts where that epoxy can bond with ester resins, and ester resins cant bond with epoxy

 

[WFO Speedracer]

Regardless of what you spray the gelcoat on, if its after the composite is cured you will only get a mechanical bond, this mechanical bond is achieved by roughly sanding the surface so the gelcoat has some tooth, I suggest 80 grit for this, if you spray gelcoat into a mold and then do a layup with Poly or vinyl ester resin while the gelcoat is still tacky you achieve a chemical bond.

 

[jeastes1]

Here's where I'm at currently, chemically stripped the bottom. Two paint jobs, plus primer on here, probably won't strip the top though. I just didn't want all this extra material on the bottom. I ordered some gel coat and some microballoons, and some black tint for the resin, that way it will be black all the way through.

 

[KTM434]

Damn get some gelcoat on that thing! It's sad to see a Superfreak look so old and beat up. On a sidenote definitely thin it out and mix quickly and thoroughly cuz gelcoat is nothing like paint... It dries stupid fast and is very frustrating to learn with if you've never used it and haven't received good instructions. These posts are pretty informative. I would definitely use a cheap gun since you may be surprised how quickly it hardens and it may solidify in the gun (I know from experience). My worst advice was to mix the gelcoat, thinner, and pigment for at least 10 minutes... WRONG. I'm not sure what's recommended but 10 minutes of mixing literally gives you less than 2 minutes spray time. I thinned mine out but didn't mix with clear. That sounds like a great idea

 

[jeastes1]

Geez thanks, this hull is only two years old, its not beat up just needs paint! Anyway thanks for the pointers!

 

[WFO Speedracer]

You can most certainly coat the whole bottom with Microballons -epoxy, sand down to 80 grit then shoot gelcoat on top of that, its how most all of the repair we did on SKI NAUTIQUES were done, it did not come off ever !

 

[bobob729]

so you spray epoxy microballons..

 

[jeastes1]

No I will fill with microballoons and epoxy tinted with black toner, then sand and spray black gel coat.

 

[WFO Speedracer]

so you spray epoxy microballons..

No microballoons basically are mixed with epoxy to form a fairing compound , much like Bondo, but epoxy based, tinting it black will work wonders for coverage , it will make it harder to eyeball high and low spots though.

 

[bobob729]

yes but my question is do you run epoxy and i know of microballons. helps to sand also. first and then spray gelcoat as that becomes tacky.

 

[WFO Speedracer]

No, think bondo, let it completely dry, sand it , then gelcoat it.

 

[bobob729]

alright now it makes since just wanted to make sure. been thinking about spraying the bottom of my ski

 

[KTM434]

Why microbaloons and not cabosil?
P.S. I wasn't saying your Freak was beat but with the paint stripper showing multiple colors it LOOKS beat.

 

[WFO Speedracer]

You ever tried to sand cabosil-epoxy ?

 

[KTM434]

You ever tried to sand cabosil-epoxy ?

Nope, I just know cabosil and microballoons are fillers/thickeners and wasn't sure the difference other than cabosil is more structural so that makes sense to me that you'd use microballoons for filling/shaping and cabosil for filling/strengthening...

 

[WFO Speedracer]

Cabosil is definatly structural and it dries hard as a brick bat, you can add small amounts of cabosil in with microballoons to stiffen it up if you like, the more you add the harder it will be to sand

 

[jeastes1]

Why microbaloons and not cabosil?
P.S. I wasn't saying your Freak was beat but with the paint stripper showing multiple colors it LOOKS beat.

Yea they definately get really ugly, before looking good when doing stuff like this. It drives me nuts filling and priming with normal automotive putty and primer just to take it to the lake once, and scratch the paint on the bottom and reveal what is under! Thats why I decided to strip it and do it this way. All that is getting filled is just a few spots where the black primer is missing in the middle and you can see the composite. And just some little scratches from scraping a boat load of paint off! I don't think they make that stripper like they used to!

 

[tom21]

if you sand the microballoons you will have a crapload of pinholes to deal with.

 

[WFO Speedracer]

if you sand the microballoons you will have a crapload of pinholes to deal with.

If you are shooting with gelcoat what does it matter , gelcoat fills pinholes nicely.

 

[jeastes1]

Thanks everyone for all the info, It's nice to here everyones input! Like I said the important thing to me is the bottom is black all the way through, spraying gel on it for durability, its the bottom of a ski, not a show car!