Author Topic: black dots in gelcoat  (Read 2344 times)

falko

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  • Boat Model: Bavaria 37 cruiser
  • Boat Year: 2006
black dots in gelcoat
« on: July 22 2024, 08:14 »
Hi, I have 2006 Bavaria 37. On deck I have noticed regions of tiny black dots in the gelcoat. They are only seen  from  up close. I’ve tried with 3M Medium (cut+polish) to no avail. Do you have any suggestions how to fix this?

Regards.
Bavaria 37 Cruiser
"Kamari III"

IslandAlchemy

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Re: black dots in gelcoat
« Reply #1 on: July 22 2024, 08:26 »
This is a result of pressure washing the decks. Little holes get blown in the gelcoat, and water and dirt gets into them and go mouldy.

Get some mould & mildew spray. Spray it on and walk away. A day or two later it will be gone.

Ailatan

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  • Boat Model: Bavaria 44
  • Boat Year: 2003
Re: black dots in gelcoat
« Reply #2 on: July 23 2024, 06:21 »
I used bleach with excellent results

falko

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  • Boat Model: Bavaria 37 cruiser
  • Boat Year: 2006
Re: black dots in gelcoat
« Reply #3 on: July 23 2024, 13:20 »
Thank you both. I'm on it.

Regards.
Bavaria 37 Cruiser
"Kamari III"

marioxp

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Re: black dots in gelcoat
« Reply #4 on: July 23 2024, 18:30 »
it's the first time I've heard that pressure wash causes gelcoat damage!  Was it a particularly strong pressure wash?  I wash the deck with pressure wash a couple of times a year, always before polishing, I haven't noticed anything unusual.

tiger79

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  • Boat Year: 2014
Re: black dots in gelcoat
« Reply #5 on: July 23 2024, 19:02 »
it's the first time I've heard that pressure wash causes gelcoat damage!  Was it a particularly strong pressure wash?  I wash the deck with pressure wash a couple of times a year, always before polishing, I haven't noticed anything unusual.

I think it's more likely to be a case of micro bubbles in the gelcoat, which are then broken by pressure washing and form voids in which dirt and mould can loiter.  I had the same problem on some areas of the superstructure on a Hallberg-Rassy I owned.

Yngmar

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Re: black dots in gelcoat
« Reply #6 on: July 23 2024, 20:12 »
I think it's more likely to be a case of micro bubbles in the gelcoat, which are then broken by pressure washing and form voids in which dirt and mould can loiter.  I had the same problem on some areas of the superstructure on a Hallberg-Rassy I owned.

Yup, that's it, plus UV degradation of gelcoat over time contributes too. A Lagoon 38 S2 had it everywhere on deck except where it was shaded by the hardtop + tent.

You definitely want to have a care when pressure washing - a sufficiently strong pressure washer will take the gelcoat right off. Waterjet cutting is used to cut granite slabs :)
(formerly) Sailing Songbird  ⛵️ Bavaria 40 Ocean (2001)

nightowle

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Re: black dots in gelcoat
« Reply #7 on: July 23 2024, 22:48 »
I, too, have the same problem that has plagued our boat.  So, I'll have to try the mould removal method and see if that garners success.
S/V In Deep - 1999 Bavaria 35E
Seattle, WA USA