I wanted to take a minute to write about priming as it’s something a lot of modelers do before painting a kit. Though generally a good idea, it’s not always needed.

You should use primer when……

• You have a rough or uneven surface – Primer does a good job of evening out surfaces. If you have a kit that has heavy sanding marks, paint may not do a good enough job leveling them out. Typically, you should work the pieces with a lighter grain of sandpaper  before priming. If the surface has pot marks or other defects, priming can help identify them prior to paint and provide a good working surface for sanding and filling. If this is your main concern, consider using something from Mr. Surfacer.
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• You’re going to a lighter colour than the surface plastic – This is the most common reason for priming. Any time you want to go to a lighter colour, the plastic should prime before hand to provide a lighter andThis is especially important for vibrant and bright colours. The look of many paints will be dependent on the tone below and bright colours will pop considerably more if the underlying colour is also bright. Darker colours won’t be impacted nearly as much and subsequent coats will help close the gap.Here are some examples of how basic colours look depending on the base coat below them. If I’m painting a like colour to the plastic underneath, I generally don’t prime as the effect is generally negligible.

• You’re going to paint on a multi-toned/coloured surface – As paints will often appear differently depending the surface colour they’re applied on top of, having a base surface with different colours can result in tone differences amongst pieces. Sometimes this is results in a desired effect (i.e. pre-shading) but when unintended it can make a kit look awkward.
• Your paint has difficulty adhering to the plastic – Paints will sometimes have difficulty adhering to plastic. A good coat of primer creates a nice consistent coat for paint to stick to. Most modern kits don’t have this issue and many older ones just need a wash before painting. Resin, on the other hand, needs both a wash and prime for best results.

Note that covering with white primer is going to be time consuming and require a lot of a lot of coats. Whether it’s the lightness of the white, or a thinner mix that’s used, you’re going to spend more time applying coats than simply going with a darker colour. Because of this, it’s important to make sure all your pieces are coated to the same extent. If not, you may assemble and find that two concurrent pieces, having not received the same coats, feature different tones. It’s also worth noting that in my experience, shades of red are generally the hardest colour to completely white out. read more