cheap gelcoat spraying

Thread starter #1
I am getting yeady to gelcoat the deck of my sunfish. Does anyone know of any relatively cheap methods of spraying gelcoat? I have seen aerosol cans that you can use to spray stuff with, which can be loaded with most liquids. has anyone tried anything like this, or have any ideas on how to spray the gelcoat? I don't want to pay a shop to do it, and don't want to buy an expensive gun, and if I can't figure anything else out, I guess I'll just roll and brush it on, and do quite a bit of wetsanding and buffing. I'd appreciate any ideas or suggestions. Thanks,
-Nick
 
#2
If you have a compressor Harbor Freight has some guns that are all most throw away cheap.
86-6VGA
Central Pneumatic TOUCH-UP SPRAY GUN $9.99
Central Pneumatic Professional 20 OZ. GRAVITY FEED SPRAY GUN $14.99
The touch up is a little small but works real nice for smaller repairs. I'd stay away from rolling or brushing gelcoat at all costs.
 
Thread starter #3
thanks jsdeimel,
I do have a compressor. I get loads of cheap stuff from harbor freight, I can't believe I didn't think of them. The more people I talk to, the more bad things I hear about rolling and brushing it on. I am definitely going to spray it.
 
#5
What is the name of the site where i can find the spray can type arosol for the deck? Im in the same boat " no punn intended" as you are. What did you get in response for you thread you posted?

Jonathon
 
Thread starter #6
John, I don't think that you can buy an aerosol can of paint to use on the deck. I ended up spraying my deck with white brightside polyurethane, using an automotive type spray gun and a compressor.
you can find cheap guns at harborfreight.com - search "spray gun" You'll also need a decent sized compressor, plus paint and paint supplies. If you don't already have the equipment, it will be especially time and $ consuming.
hope that helps,
-Nick
 

congressman

opinionated but not bossy
#10
I'm confused. You want to use 24 spray cans? Let's do the math.

When I buy 5 gallons of gel, the bucket weighs 53 to 55 pounds depending on the color. We'll use the lighter color.

5 gallons liquid = 53 pounds
1 gallon liquid = 10.6 pounds

24 spray cans x 16 liquid ounces = 384 liquid ounces
128 ounces to the gallon
384 liquid ounces is 3 gallons

3 gallons of liquid gel weighs 31.8 pounds

Last boat I painted I used a little less than 2 quarts of white on the deck and a little over an ounce of blue on the stripes. Been too busy to paint the cockpit, maybe this winter.
 
#11
I quite agree, 20 square feet per quart is the rule so around 2 qts (4 spray cans) should do it. But, I was thinking with an aerosol spray you’d have propellant, sanding between coats, and overspray to compensate for. How much of those aerosols do you think is propellant?

So, you are saying you’ve used this spray can method. Can you get the same thickness you can with cup-gun application? I was envisioning much thinner coats with sanding loss between coats since this appears to come as only finish resin.

I guesstimated at 2 mils per coat like paint so to achieve 10 mils (assuming about half of the old gelcoat would remain after preparation sanding) I gave it 6 passes (12 mils) minus sanding loss and curing shrinkage to reach the original thickness.
 

congressman

opinionated but not bossy
#12
Dan
You're probably right about the 4 cans, I've never used the stuff myself, I was really just trying to point Nick to a supplier. The big assumption here is that there is 16 ounces of sprayable material in the can - I doubt there is that much.

I have equipment that ranges from preval sprayers to big guns that pump straight from the 55 gallon drum.

Explain to me your spraying process if you would. Are you spraying thin coats, letting them cure, sanding and then spraying another coat and repeating the process?

I've always be of the impression that a factory fish paint job was about 20 mils. Enough to give a smooth buff-out but never quite enough for a decent patch.

Jeff
 
#13
Jeff – I was reading through the spray can instructions they post and I get the impression it’s intended for covering small patches. Reminds me of the boat equivalent to those touchup paints you see in the car parts store. That’s sort of where I was going wondering about the coverage not necessarily economical for a complete recoat.

I get to “borrow” a shop after hours. 20 mils give or take is about what I’ve measured on inspection port cutouts. My mentor mixes the catalyst and little if any patch booster for the buildup layers so I get 24 hours between coats. I think when he does a small boat job there’s only a few hours in between coats so he’s done in one day. So far I’m getting good results in 3 or 4 coats. The pro who’s guiding me does this size boat in two. With access to a boat yard I am able to use tooling resin and no sanding or buffing until the finish layer where we add patch booster and surfacing wax. I gather you do big hulls like he does 20’ – 60’ or better. Much thicker coats than these dinghies get.

I was thinking thinner coats for the spray cans because they say it kicks in 3 hours and in a DIY setup if one section started to kick before you were done overlapping you’d get blisters. What’s your thought for a backyard application?
 
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