bubbles in gelcoat (topsides)

[Bladerunner]

Looked over a Kingfisher 26 this morning and noticed there were a lot of bubbles in the gelcoat covering on the topsides.

There doesn't appear to be any sort of pattern in their formation but they are from bow to stern.

They measure from <1mm to about 6mm in diameter and go right through to the matting.

There is no smell when they are opened but the gelcoat appears to be very brittle.
I have asked a number of people in my club about this problem but nobody has any idea what might have caused it.

A number of people (including myself) think air might have been trapped under the gelcoat when the boat was laid up but it's 30 years old and seems to be a fairly recent problem. (last 12-18 months)

If anybody can solve this mystery I would be eternally grateful.

Many thanks in advance

Vince Ed.

<hr width=100% size=1> Bladerunner - Hung like Einstein. Brains like a donkey

 

[oldsaltoz]

G'day Vince,

Sounds to me like you are describing a common fault in older boats where the gel-coat has voids (not blisters) in it; in many cases this is caused by too much heat during construction, causing the gel-coat to boil.

When new no problems are visible, however with years of cleaning and in particular polishing, the voids will break open.

Most common along the edge of the deck, or edges of the cabin top close to bends and the cockpit topline, or high wear areas, almost always first seen on corners or right-angled bends.

The cure is painful, you have to locate all the voids and break them open, clean and fill them with 'Q' Cells and epoxy resin and finish with a good quality paint.

I hope this helps

Avagoodweekend.



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[branko]

Can be also that wrong Hardener ( too fast )is used during production. ...Or too high ambient temperature.
Can also be that wrong diluent was used !
Who knows - but everything is going on that way!

<hr width=100% size=1>skipp