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View Full Version : Do you sand between coats of gelcoat



BenKeith
09-07-2002, 09:33 PM
Basically, I need spraying gel 101, never sprayed the stuff but fixing to. Spraying clear gel to put shine back on boat.

I've sanded boat with 180 grit color looks good wet

Current plans are to use a Sharpe's Cobalt, HVLP gravity feed 1.4 gun.

Plan to apply two or three coats.

Plan to use Duratec High Gloss additive in final coat mixd 50:50.

Do I sand between each coat or just wait and sand final coat.

If I sand, do I seal each coat to exotherm or just let it cure a little till hard

I need this info fairly quickly, plan to spray it later this week.

Any help/advise (other than using something else) will be greatly appreciated. The boat has clear gel so I'm coating it with clear gel.

Keith

Techno
09-07-2002, 10:16 PM
I've never done it but I think once its cured you would have to sand it so it gets a mechanical grip. If it was in its curing stage you might be able to add to it but I think this is a no no.

Hopefully someone will post with more info. It seemed like tricky stuff to spray. You might also want to do a test panel just to get used to it and what can go wrong. I remember something about pinholes from curing too fast or some odd reason.

BenKeith
09-08-2002, 02:17 AM
Techno,

From what I've read, if you blink at the wrong time the stuff will screw up. It seems to little catalyst, too much catalyst, too thin of a coat, too thick off a coat, spraying on the wrong moon phase and just about anything else can make the stuff screw up. I just can't find out anything about how you add the second/third coat once you've layed the initial coat.

BarryStrawn
09-08-2002, 11:47 AM
Looking at the Duratec application guide it looks like you just spray it all in one session letting it flash off between coats. It doesn't really say but if you let it cure out I would guess you need to resand. Try calling them and see if they will put you in touch with a tech rep to answer your questions. I'd be curious to know how helpful they are since I have some gelcoat repairs to do this fall.

http://www.duratec1.com/ag07.html

BenKeith
09-08-2002, 01:38 PM
Damn Barry,

All this time I've been scrambling trying to find out how I go about applying multi layers and haven't even thought about contacting Duratec. I will let you know what they say.

H2Onut
09-08-2002, 05:18 PM
DURATECH. lay 1 medium coat on, let if flash, floow with FLOW COAT, a heavier coat that first it will flow together. Make sure you are consitent with mix, I used it 50/50.

BenKeith
09-08-2002, 08:05 PM
H2Onut,

The guy at PC Composits, where I ordered the stuff, said to spray on my gel coats and on the last coat, mix the Duratec 50:50 so I only ordered two quarts of Duratec. He said one would probably be enough, but I ordered two just to be sure. I only spraying about 50 square ft total, just the top of the bass boat. I ordered two gallons of gel, two quarts of styrene. Would the two quarts of Duratec make go far enough to apply two coats of it without spraying straight gel first?

What size gun did you use, what needle and nozzle? Did you get a good smooth finish or did you have to sand and buff?

I have several Sharpe guns, but according to Dr Gun at Sharpe, I need to change the tip, needle, cap and use my pressure pot to spay straight gel. Says neither siphon feed or gravity feed work well with gel but I hear people say they will work. I'm concerned the pressure pot gun would be too hard to clean every 10 minutes to keep the stuff from setting up in the gun.

Can you help me out with any of this?

Keith