Changing gelcoat color

This is quite a bit hypothetical - I am not planning to do this.

Imagine you want to change color of gelcoat on your boat - eg add graphic. One option is, of course, just to add a few more layers till the base color stops bleeding through. That adds quite a bit of weight it the area is larger.

Other option is probably to remove a layer old gelcoat and substitute that with the desired color. But how would one do that in practice?

Paint it
If you have a boat and just can’t live with the color the best way is the sand / prep it and have it sprayed at an auto painter who can shoot Imron or Awlgrip or one of the 2-part poly paints they use on boats or trucks. it’s extremely durable but not a do-it -yourself job. You cannot change the gel coat with any practicality. And hopefully you have a white hull that stays.

Never paint it with regular paint because it will scratch off and look terrible unless you have a really beat up old kayak that you just want to make look a little better.

As far as preping it yourself and saving money, you would consult the place that is going to shoot it.

That’s easy.
Get a Foredom variable speed rotary tool with lots of extra motor brushes, an extended warranty and a gross of HSS burrs of various sizes and shapes for it. Also, you’ll need a respirator rated for VOC’s, extra cartridges for such, a box of nitrile gloves, eye protection that can accommodate magnification, a low-power binocular microscope with a zoom feature and fiber-optic light source mounted on a portable boom and, most importantly, a divorce attorney.

Working under good light, with good ventilation, and, say, one square inch at a time, carefully grind away the gelcoat until you get to within 3 or 4 microns of the underlying fabric/resin matrix taking care not to disturb the fibers in the weave. Be sure to clean the surface thoroughly with compressed air and acetone before starting to build your spray booth.

That’s all there is to it! Quite simple, really.

I thought it would be a bit more involved :slight_smile:

Graphics or graphite?
If you meant graphics, just do your design on paper, scan it into a computer, save it as a JPEG, run it down to most any sign shop and they can cut your design in vinyl in any color or combination of colors you choose. They can do the application or you can if you’ve got a very clean boat, a steady hand, and align everything carefully beforehand. Use a stabilo pencil for your alignment marks and wipe off with alcohol after.

If you meant graphite, its a much bigger job as has already been explained.

Yes, this is definitely easier than grinding down gelcoat, and has advantage of being removed and changed.

One note - for anyone contemplating this - picture should be in “scalable vector graphic” format, not just plain old jpeg. JPEG would probably only be sufficient for something small.

Removing and changing…
…are likely to create results you won’t like. Gelcoat fades over time, except where something - like a decal - covers it. You can see exactly what I mean on page 2 of my “Gelcoat Repair & Restoration” album on Webshots at:

you mean the tan lines?
I think that’s pretty neat! I imagine it blends with time and sun exposure.

for small stuff
you can actually grind the gelcoat off. I used a dremel to mark my HID on my boats. I penciled it in, then dremeled the gelcoat off the S glass. Then with a small brush and marine paint, I filled each letter up with paint. When it dried, it was a little above the gelcoat, so I took 1200 grit automotive sandpaper, and wetsanded it down flush with the gelcoat. After that I buffed it to a nice sheen. It looks really cool, my HID number looks like it was inlaid into the hull in a contrasting color (which it has)

Pretty sure
"tan lines" could be minimized, if not eliminated, by an application of Penetrol and a good wiping after. Don’t let your dry rag get saturated.

Any color difference is lost in reflections and gloss.

I’ve only used JPEGs for smaller designs, true. But any JPEG could be saved at the shop into whatever format works best with their cutter to be scaled up as needed.

Just got back from a nice, though short, evening paddle. Must sleep now.