Airbrushing flowcoat

[pandos]

Has anyone tried to airbrush flowcoat for covering very small repairs on a hull,

I have quiet a few small scratched and dings to repair including some old badly done repairs.

I have managed to mix a colour that is practically a perfect match but am concerned that the gelcoat will have been sanded to within a hairs thickness near the old repairs.

I thought that perhaps spray on a few thin coats that can be built up and would only need to be fine sanded or perhaps only buffed would be a solution.

This poped up as a possible device....http://www.halfords.ie/motoring-tra...paration/spray-craft-easy-to-use-airbrush-kit

Tony.

 

[William_H]

You would need to thin the flowcoat down a lot because it is a thick consistency designed to go over rough inside GRP.
You might be better considering using a polyurethane paint, easy to brush on and much more durable (sticks better ) than flow coat. You still need to get the right colour or repaint the whole hull. Which is often the final solution. good luck olewill

 

[ShinyShoe]

I think the commercial producers may use an air gun to apply gel coat to the mould but we aren't talking small & subtle kit here and I doubt it would be any better than manual in your situation.

I doubt it will be any use thinned down.

Instead mask well and use a filling knife to apply / finish the surface before sanding with 800+ grades of wet and dry, very wet and polishing.

Flow coat should stick fine to other gel / CSM + resin if the surface has been properly prepared - that may mean making your scratch bigger!

 

[pandos]

Thanks for the replies But....

Perhaps my post may need some clarification....

I have already done almost invisible repairs in areas where holes had been drilled and star cracking occurred near stanchions, these are so good that I moved on to dings and chips that had not been repaired, now I am considering addressing old repairs.

Anything done will be with flowcoat, it can be thinned with styrene, it can be sprayed, the question is about airbrushing, kits like those in Halfords in particular

Making the scratch bigger is one of my fears and not doing so is one of the objectives....

Tony.

 

[Rum Run]

You certainly can spray flowcoat, also gelcoat, and I have done both professionally. However, you need a piece of kit such as the G100 gun: http://www.ecfibreglasssupplies.co.uk/c-863-g100-spray-gun.aspx Not too expensive at the price, and designed for the job. Needs a fairly good compressor though.

Probably an airbrush will work if you use enough styrene. Getting a bigger paint nozzle and holding the airbrush upside down (like a gravity gun) will help too. At that price what can go wrong?

 

[contessaman]

why don't you just roll or brush it on, wet n dry through the grades and finally machine polish?

 

[pandos]

why don't you just roll or brush it on, wet n dry through the grades and finally machine polish?

Because if I thin it enough to get it smooth with a brush it runs, the repairs i want to do are really small and I find that sanding the repair and blending it to the surrounding area without sanding some of this surrounding area is impossible and it seems that some of these areas surrounding badly done repairs are already too thinly coated.

What I really want is to build up thin coats that are smooth from the outset and require only minimal sanding/blending.

I just watched a youtube clip where they did a repair and sprayed gelcoat on it using a " Preval " http://www.mcdonnellpaints.ie/decor/paints/preval/

so that may be worth exploring.

Tony.

 

[contessaman]

Because if I thin it enough to get it smooth with a brush it runs, the repairs i want to do are really small and I find that sanding the repair and blending it to the surrounding area without sanding some of this surrounding area is impossible and it seems that some of these areas surrounding badly done repairs are already too thinly coated.

What I really want is to build up thin coats that are smooth from the outset and require only minimal sanding/blending.

I just watched a youtube clip where they did a repair and sprayed gelcoat on it using a " Preval " http://www.mcdonnellpaints.ie/decor/paints/preval/

so that may be worth exploring.

Tony.

I did a large area once, my whole stem and about 3 feet back either side and used a longboard to get it smooth and faired in... Basically a plank of wood with some sandpaper stretched over it and handles nailed in place.

I'm very interested in your spraying success or otherwise though. The infamous blue stripe on my rassy is faded scratched and worn through to the white in places. Common sense and forum knowledge suggests 2 pack paint but as a rule I despise paint above the waterline on boats. Funnily enough, the best finish for grp is... Gelcoat. And as you are finding out with your scratches, it's not hard to touch in and repair little dings to a good standard.

Please take plenty of photos and videos if you do some spraying buddy.

 

[contessaman]

Interesting link Tony. Has got me thinking.. What about using a scuba cylinder? My twinset holds 5000 litres of air at 3000 psi. Even a single 12 is 2500 litres. A cheap old scubapro mk 2 first stage will give you an intermediate pressure of about 9 bar. Plus you could breath from a demand valve in one of the other lp ports so you don't destroy your health.

That would surely take care of the air source? Who makes a suitable spray gun for something with the thixotropy of flow coat and how much does it cost?

 

[greeny]

I tried it a few years ago with a cheap airbrush off ebay. It worked fine at first until the styrene I'd used to thin with, attacked the plastic bits and seals on the airbrush and it packed up on me. The plastic went "sticky" and the o ring seals failed. It did get the job done though, and then I threw it away. Since then I've just brushed or rollered it on and cut it back with wet and dry. Easier for small repairs. Less prep work and less time cleaning thing up afterwards.