Which Primer?

[StevenG]

Hi

I have a customer that's been coming to us for years and whilst I don't really offer the service I've agreed to paint an existing frame of theirs. It's a fairly chunky polcore product (55x45). I reckon that any paint I use would just come off with the slightest contact from anything. Is there a specific primer that I should use first to help the paint adhere to the moulding?

Cheers
Steven

[prospero]

Rub it down with sandpaper to give it a 'key' and then give it a coat of Shellac (French Polish). You don't have to
remove all traces of the old finish, just rough it up as much as possible.

When dry rub it down with fairly fine grit to degloss it - the spongy sanding pads are great for this.
This should then take water based paints. Water based undercoat is as good as anything an a couple of coats will
give you a good base that can be sanded smooth and overpainted.

Shellac is organic and unlike synthetic varnishes it is porous. It forms a barrier coat. It will stick to most things
and most things will stick to it.

The way to check it is the 'fingernail' test. When the coats are dry try scratching it off with a fingernail. You'll soon
find out if it hasn't stuck...

I've done this successfully on poly mouldings a few times.

[StevenG]

Excellent advice! Thanks for the detailed guide too

So there's no issue painting over the Shellac ? Sounds to be quite a versatile product actually!
Thanks again

[StevenG]

Also, would be advisable to add some sort of 'protective' coat over the paint?

[prospero]

Also, would be advisable to add some sort of 'protective' coat over the paint?

After the primer I go in with Artist's Acrylic for the top coats. That's fairly bulletproof.
On some finishes I wax the surface and buff it up.

[StevenG]

Perfect!! Thanks again