97 Challenger 1800 - Paint over Gelcoat questions...

[funvee]

I'm sure this MUST have been covered here but I honestly can't find the answers I need with my searches. If it exists, please point me in the correct direction.

On my 97 Challenger 1800, we want to get rid of the green gelcoat look and paint over it but after experimenting, I sanded the gelcoat to scuff it, then put an epoxy primer and then paint and clear coat but the paint still can peel off really easy (obviously not bonding properly).

If someone can tell me what my options are for painting and what paints and primer I have to use it would be hugely appreciated.

Thanks

 

[Dr Honda]

I never tried to paint a seadoo hull... but I've painted other gel coated boats, and PWC. (should be the same) In those cases... I just sanded the gel... and shot it with regular automotive paints. The best is the old Imron paints... but they aren't the same anymore. It would bond great, and was 100% chem proof once cured.

 

[funvee]

Did you use a specific primer or did you shoot the color straight onto the sanded gel coat? I'm not sure why mine is so easy to peel when tested.

Thanks

 

[Dr Honda]

Shot it right on the gel. No primer.

Are you sure you have sanded into the gel good enough? The gel has pores, and can hold wax. After you give it a good sanding... wipe it down with a good Pre-Sol, or MEK.

 

[funvee]

I thought I sanded it pretty good... I used 80 grit on a power sander but how deep I was supposed to go. The local boat shop said something about an Interlux epoxy primer that I should've used but she didn't know what it's called (I think she was the weekend staff and not necessarily the most experienced).

 

[Dr Honda]

80 grit???? That will leave gouges, that you will see though the paint.

If you are going to use a primmer... ONLY use the primer recommended by the paint manufacture !! Back in the day... it was easy. Either acrylic or lacquer. But, today... there are SO many compounds, that paints and primers aren't always compatible.


But... as I was saying before... you shouldn't have to "Primer" the entire boat/ski. Once clean... the paint should stick. AND... since paint is expensive these days... call the help line for the paint you want to ues, and ask the company if there is any special prep to use their product on gel.


Finally... this is VERY open and generic since you haven't told us what paint you are trying to use.

 

[funvee]

I used 80 grit to get the whole boat scuffed really well, then did 200 to get it smooth for paint.
The paint I shot was Dupli-color performance red using an hvlp gun. Did 3 coats to be sure I had covered the old green. Then 5 coats of clear.
The paint 'looked' great but when I put the number decals on the bow, I noticed a raised edge... When I pulled it, there was nothing holding it to the gel coat under.

I'll try calling the tech line for dupli-color, that's a good idea.

 

[CaptSteve]

Why not just use one of the marine urethane paints made for top coats. Awlgrip, Imron, Interlux, Petit all make a very good topside paint. These are the paints used on the Megayachts I work on. They are specially made for fiberglass and have a high UV blocker added to them. They come as either a one part or two part urethane. The two part part paints are the best.

Here are the steps the boat yards do after all patching and fairing is done.

1. Wash the boat with dish washing liquid ie. dawn etc. to remove all wax. Sanding alone will not remove all wax.
2. Lightly sand the hull with 220 grit sandpaper
3. Wash again with dish washing liquid.
4. Wipe hull down with acetone, mek or recommended thinner. Change rags frequently. One wipe, turn rag over, another wipe, turn rag, etc. change rags.
5. Spray on primer based on manufacturer recommendation.
6. Lightly sand primer with 220 grit. This gives you the smoothest finish.
7. Wipe hull down with recommended thinner.
8. Spray on two or three coats of urethane paint.
done.
No clear coat is required, but some places do put on a clear coat made by the same manufacturer as the paint they use. The boat I work on did not have a clear coat added and it looks great. It is also easier to buff any scratches out or touch-up.

Some of the paints can be put on with a roller and tipped out. Interlux Perfection and Interlux Brightsides are one of these. Most Awlgrip and Imron paints are spray only.

 

[funvee]

Hey Steve, I was just about to post my results from "tech support"... Basically he said what you said. He said gelcoat is a very tight molecular structure and normal paints / primers only stick temporarily at best. He had me take a kitchen fork to an in conspicuous spot on the paint and run it on the new paint. He said if anything comes off with light pressure, the paint isn't sticking. Mine took moderate pressure to peel the paint so I'm going to leave it on for now and might make a winter project out of stripping and shooting Interlux.

Thanks for the replies!