Best way to apply UV soldermask paint?

[Fusion916]

I bought a few of these off ebay:

http://i01.i.aliimg.com/photo/v2/301532553/pcb_ink_UV_curable_solder_mask.jpg

And I'm wondering if anybody knows a good way to apply this paint? I tried using paint rollers but I still needed to use my finger to flatten it properly (still not a great result).

Any suggestions?

 

[Ian Finch]

Is it solvent or water based?

 

[JMFahey]

It can't be too different to this:
Apply a Solder-Resist Mask to PCBs (Printed Circuit Boards) - YouTube

I find the paint roller application very crude and uneven.

I silkscreen my own PCBs so *if* I need a soldermask (usually don't care much about it) , I use the strong 2 component epoxy type and it means 1 extra screen pass, no big deal and *much* faster if doing a production run, even is small scale.
It's 20 seconds per PCB plus letting it cure , or putting them in an oven, while I do something else.
When I see these guys using 2 or more hours to apply it to a single PCB, it gives me shivers.

Personal opinion, I don't think they are needed in prototypes (just solder slow and carefully); later when you order a production run, let the fabricators apply it.