I've only used an old cup sprayer Binks 7 - all metal. I would suppose that a HVLP would work - that is a good question. With thinning, tip, and pressure adjustment it should work because the Gel coat is reduce to about same as paint for spraying. Perhaps Jake or somebody else can help that has used a HVLP gun.
I keep on thinking about getting a new gun but I just rebuild my Binks each time. I have a “mini” HVLP for tight spaces and touch up but I not used it for anything but paint. A long time ago when I first started messing with cars a friend of mine who did show corvettes tutored me in shooting lacquer paint and a show car finish. But we all know that paint is only 20% of the job – prep is 80%. He helped me in the technique but always seemed to do better paint job it took me awhile to figure out why – it was all in the gun. I was using a cheap gun at the time. For Gel Coat you can get away with a cheap gun. I have shot gel coat that came out pretty smooth with the Binks and it did not need to be sanded.
The last few boats I’ve used paint – auto paint on one for a custom job and Alwgrip on the other.
Gel Coat is cheaper the durability falls in between Auto paint and Alwgrip but the effort for Gel Coat is much more then both.
Pepin Cohiba Robustos - mmmmm from Havana?
Last edited by TheManShed; 06/27/1110:39 AM.
Mike Shappell www.themanshed.com TMS-20 Builder G-Cat 5.7 - Current Boat NACRA 5.2 - early 70's
you can use an HVLP gun for gelcoat. I do frequently. Just be sure your tip size is 2.3mm or larger. Northern Tool has a decent $30 gun with the larger tip (the green gun). There's no point in spending a ton of money on the gun...it's going to end up a little lumpy anyway.
I just bought a cup gun that has a 6mm tip (good lawd). I haven't had a chance to use it yet but am hoping to make a cradle mold with it in the next couple of weeks. The cup gun spits out unthinned gelcoat but is, in my opinion, probably not good for finish work (perhaps if you have a finer tip). It is great, however, for interior mold gelcoat prior to lamination and looks to be super easy to clean up.
I got one of the little Preval sprayers. It will do about a square foot at a time. You can thin the gel coat in the glass spray bottle, then clean the sprayer and then spray with PVA.
Thinning of Gel coat, Someone said they used Lacquer thinner for gel coat. I never had, but I tried it. I have used mek solvent,styrene, Duratec, and Duratec thinner. I think the lacquer thinner worked the best. I have had no clogging of the sand paper when using lacquer thinner. Duratec is good but it adds a lot to the cost and I haven't seen the abilty of the gel coat to resist stain or loss of gloss improved by using it. Their thinner works great but is expensive. I haven't tried the the clearcoat they make but I will at some point.
Have Fun
Re: TMS-20 update 6/17
[Re: catman]
#234144 06/28/1109:18 AM06/28/1109:18 AM
Some of the dings will need filling. I was thinking of making my own bog by thickening gelcoat with cab o sil. The rationale: easy sanding, relatively water proof, the color will be easier to cover.
Thoughts?
Pete Pollard Blade 702
'When you have a lot of things to do, it's best to get your nap out of the way first.
Re: TMS-20 update 6/17
[Re: pgp]
#234146 06/28/1109:49 AM06/28/1109:49 AM
Some of the dings will need filling. I was thinking of making my own bog by thickening gelcoat with cab o sil. The rationale: easy sanding, relatively water proof, the color will be easier to cover.
Thoughts?
cabosil (fumed silica) does not sand easily! use microballoons (preferably phenolic but glass microballoons will work).
Or...easier...use premium bondo (black/gold can with blue hardener...I think the can says "professional" or "premium"). I use bondo with good results under gelcoat. It has a polyester resin base.
Jake Kohl
Re: TMS-20 update 6/17
[Re: Jake]
#234147 06/28/1109:58 AM06/28/1109:58 AM
I want to get away from any contrasting substrate colors. Additionally, I use such small amounts another can of anything will just clutter up my work bench while it's going bad.
Last edited by pgp; 06/28/1109:59 AM.
Pete Pollard Blade 702
'When you have a lot of things to do, it's best to get your nap out of the way first.
Re: TMS-20 update 6/17
[Re: pgp]
#234148 06/28/1109:58 AM06/28/1109:58 AM
the different colors can actually work to your advantage in they help you see how the fairing is going. I would suggest a light color rather than a vivid one so it won't show through on the final product.
It's very hard to hide darker colors under a white top coat. At a distance they will show up as shadows.
It's simpler to tint the substrate the same shade as the top coat. Fairing is accomplished by dusting a light coat of black lacquer on the substrate and working until it is gone. It's like looking at a topographical map.
Pete Pollard Blade 702
'When you have a lot of things to do, it's best to get your nap out of the way first.