(Review/Cautionary tale) Tamiya fine surface primer

[Evil Eye]

This is probably common knowledge at this point but I just thought I would mention it because it tripped me up and I want to avoid it happening to anyone else!

 

So I recently got some Tamiya fine white surface primer spray cans, in the quest for a white primer that doesn't suck. Most white primers are extremely difficult to use, often giving a chalky finish ranging from mild orange peel to a look that gives the impression the model was dunked in Dulux, so I was eager to see if this was any better. And it is!... Sort of.

 

The coverage is fantastic and it self-levels extremely well. I tried both from the can and transferred to an airbrush and both applied excellently. The final results were a gloriously smooth consistent white coat.

 

But.

 

The finish I got was, as it turns out, microscopically smooth. Normally this would be fine as it is meant for use with solvent based paints like Tamiya's own line, which chemically etch into the surface they're applied to and stick firm and fast. For aqueous acrylics however, which take longer to cure and effectively form a shell over the top of the primer, held in place by the incredibly fine texture of the underlying layers, this is very bad. Because Tamiya primer is SO smooth it's actually hydrophobic! There is no "tooth" for the paint to grip to, so water-based paint will simply bead up or run off the surface.

 

As a TLDR, the primer is too smooth for aqueous paint to stick.

 

There are solutions to this; either spray a matte layer of a solvent based paint over the top (Tamiya flat clear is a good bet) or very lightly sand the primer with fine grit sanding sponges, not so rough to take the paint off but not so fine you polish it smoother either; just enough that the surface gets that invisible layer of texture for paint to cling to.

 

So I recommend Tamiya primer, as it is a good product, but please do bear that in mind and don't use water-based paint straight over it!

[Codex Grey]

 

2 hours ago, Evil Eye said:

Because Tamiya primer is SO smooth it's actually hydrophobic! There is no "tooth" for the paint to grip to, so water-based paint will simply bead up or run off the surface.

 

Interesting. To clarify, what do you mean by bead up? And by running off the surface, does it settle in the recesses?

My wishful thinking: Use Tamiya primer as an alternative primer for when I want to apply an all over wash that runs mostly into the recesses, to achieve a quick white with recess shading and little to no staining on the white surfaces. Would this be viable, or is am I missing something?

 

Edited 3 hours ago by Codex Grey