Prime in patches?

[pmx_super]

I'm repainting my wooden window frames. Mostly it'll just be a matter of sanding existing paintwork then undercoating and topcoating, but in some places the existing paint is flaking so I'll end up going back to bare wood. Do I need to use primer on these small bare patches, on the whole lot, or not at all?

Thanks
James

 

[TheDec]

You will need to prime the bare areas, if you are using a primer undercoat you can use this to both prime and undercoat if you are using a specific wood primer then you should only spot prime and you must not use it as undercoat.

Dec

 

[pmx_super]

Which approach would you recommend? Primer on the patches followed by undercoat all over, or one coat of combined primer & undercoat on the whole lot? Or rather is the latter sufficiently inferior to the former to be worth another day of drying time?

 

[dcdec]

Its worth spot priming even if its with a primer/undercoat as there will be some sinkage into the bare timber. So the best way to do it really is prime with an acryllic wood primer then undercoat as the primer will dry fast and allow the undercoat to go on fairly quickly afterwards.

 

[TheDec]

The bare areas should be spot primed then just a light sand back before undercoat is applied, when you prime bare wood it raises the grain of the timber so sanding the areas is important.

Dec

 

[pmx_super]

when you prime bare wood it raises the grain of the timber so sanding the areas is important.

Even 70 year old timber that's been primed before? (purely out of interest now, I'll heed the sanding advise regardless)

 

[pmx_super]

Its worth spot priming

If there's an official term for it it must be worth doing!