Gel coat touch up, would that be....

[Marcq]

Good enough to spray gelcoat ?
http://cgi.ebay.com/ebaymotors/GRAVITY- ... 237519740&

I have a lot of small touch up to do on the transom (removed my trim tabs) 21 holes that I made bigger to fill them up with fiberglass and want for now, finish it with gelcoat

Marc..

[ANTIBLING]

harbour freight has those for 7.99!

[Marcq]

But are they good ?

Marc..

[slippery73]

This might be the problem with people thinking that gel coat is a pain in the but to spray because it orange peels. It doesn't if you use the proper equipment. Quick lesson for you as it doesn't seem like you don't have much knowledge with spray equipment. The first thing you want to look at when buying a gun is what kind of material you are going to spray. The more viscous the material the larger tip you need for it to flow well and not orange peel or spatter out of the gun. The tips are rated in mm, the tip that comes in the gun shown is a .5mm. A standard auto basecoat clear coat tip would be 1.3mm-1.5mm. Primers = 1.8mm-2.0mm. High build primers, thinned gel coats = 2.2mm-2.5mm. Straight gel coats and extremely viscous resins would be 3.0mm-4.50mm.

So, trying to spray gelcoat through a .5mm tip would be near impossible. I ended up buying a nice devilbiss gun with a multitip setup for redoing my boat. I've sprayed my gel with a 2.2mm tip thinned 50/50 with duratec high gloss clear and it flows really well, no orange peel, etc. Minimal sanding and buffing to get a mirror shine. If you are shooting straight gel you would need at minimum a 3.0mm tip to get decent results, anything less you may as well brush it on with a high quality brush and just take more time to wet sand and buff it smooth. Problem with the larger tip guns is they are harder to find over 2.5mm and generally cost more. Compare that to what a shop would charge and its not nearly as painful to buy the tools.

Here's the setup I got for my boat, the little extra for a decent gun pays for itself over and over when your sanding your butt off later.

http://cgi.ebay.com/DeVILBISS-FinishLin ... dZViewItem


Here's a link to a gun thats specifically for gelcoats.

http://cgi.ebay.com/Gelcoat-Spray-Gun-G ... 18Q2el1247

[RickK]

Nice explanation slippery73.
Can you copy your post and paste it in a new post under the "Resources" forum so we can find this data later please?

[Marcq]

Yup, that was well explained slippery73

Now, with right spray gun and tip would it be easier to to spray it 50/50 or with just gelcoat with wax and catalyst ?

Marc..

[slippery73]

Definately easier with the duratec mixed 50/50. There's a fine line with the waxed gelcoat as to its curing ability, I think thats another reason people get scared away from it. Gelcoat isn't made to air cure, so anytime its done outside of a mold you need to protect it from air to get it to cure, you can used waxed gel and the wax comes through to the surface to form a barrier, or you can spray pva over it to form a barrier so it will cure. But it seems like you have many more problems getting the gel to cure properly with these two methods.

The duratec is very thin in viscosity compared to the gelcoat so when you mix it up it really thins the whole mix out nicely and it sprays more like a high build primer than a gelcoat. You would want the duratec 904-001 polyester high gloss clear. Mix it 50/50 and catalyze with 2% MEKP. I would use anywhere from a 1.8mm tip to a 2.2mm with this mix. Im using a 2.2mm tip with that same mix and its flowing well.

Make sure you have acetone at the ready, 15 mins max pot life once mixed, its not fun if it gels in your gun.

[slippery73]

RickK: I might just get some photos together and do a step by step tutorial on regelcoating next time I spray some stuff. That way a lot of peoples questions get answered as to the process and then they can see the results.

Heres the link for the duratec:

http://www.duratec1.com/dp07.html

[Marcq]

Thanks slippery73

One last question , what is MEKP ?

Marc..

[slippery73]

Methyl Ether Ketone Peroxide, its the catalyst that you mix in to activate your resins. You can buy it in small quantities, I get it by the quart.

www.fgci.com

[Marcq]

HA, wasn't sure,  seemed like they were two different product

Thanks, Marc..

[RickK]

RickK: I might just get some photos together and do a step by step tutorial on regelcoating next time I spray some stuff. That way a lot of peoples questions get answered as to the process and then they can see the results.

Heres the link for the duratec:

http://www.duratec1.com/dp07.html

Sounds like a plan.  8)