Radiator painting question.

[solo]

I have a radiator that has previously been painted with solvent based radiator enamel.
I've sanded it down and want to repaint it using a water based satin radiator paint.
Was just wondering if I should apply some sort of undercoat first?
I have some Zinnser Bullseye 123, would this be suitable or should I use something else?
TIA

 

[opps]

Undercoat shouldn't be necessary.

 

[solo]

Shouldn't???
Not "isn't" or "won't"?
Can always change the rad if it goes pear-shaped.
Cheers.

 

[foxhole]

I always spray rads with enamel , look like new and no brush marks.

 

[solo]

Foxhole. Been done in the past. Going water-based throughout the house now. Can't be doing with all the fumes and long drying times anymore.
Cheers though.

 

[opps]

Shouldn't???
Not "isn't" or "won't"?
Can always change the rad if it goes pear-shaped.
Cheers.

Yesterday I painted a cream coloured radiator with a yellow waterbased eggshell. I didn't use undercoat.

If I were painting the same radiator with white waterbased eggshell, I would have used undercoat first. Why? White waterbased eggshell isn't very good at obliterating stronger pre-existing colours.