In article , Primrose wrote:
On 25/09/2019 10:35, Chris Hogg wrote:
On Wed, 25 Sep 2019 10:29:13 +0100, Primrose wrote:

We painted some of our fence panels last year, today I noticed that
there are rusty coloured growths on the painted panels which are
slightly raised.

Does anyone know what this is please?

Sounds like a fungal growth.

Put up a picture on an image-hosting web site, and you'll get an
informed response.

What did you paint the panels with? Did it contain a wood preserver of
some sort, or was it just a fence and shed paint, unspecified?

Thanks for your reply.

I used Cuprinol Garden Shades.

Just took a snap of it.

https://www.dropbox.com/home?preview=fence_panel_1.jpg

That's not a public site. Try imgur.

However, the most likely cause is that you have painted over knots,
and they have oozed resin. While you can use knotting or other
specialised sealers (before painting, unfortunately), they only
reduce that a little. I suggest ignoring it.


Regards,
Nick Maclaren.