Question about primer - purpose, color of and final shade

Jim,

If you lightly sand the primer aren't you defeating the purpose of the primer being slightly rough to allow the paint to bite into it?
Or are you using a sand paper that is not that smooth?

Dodge wrote:

The final color will be gloss white with a Cherry red nose "V". The interior walls (inside doors, ceiling, etc...) will be gloss white as well. I've been reading a bit on here and have learned that a "primer" coat is an important element of the finished product ... but what is the actual purpose of this coat?

As mentioned previously, a primer coat helps highlight any flaws that might exsist in the body or body work before a final coat is sprayed. It also gives a better surface for the final color coat to adhere to.

Since my final spray will be gloss white should I use a flat white primer? Or the standard gray? As you can see I'm a bit confused as to how the choice of color is made in regards to the primer coat. I would imagine that white is a bit of a special case - and the undercoat could influence the final shade - is that a good guess?

A flat white primer would be the first and best options of choice.
You could use a "light" grey primer but then you will have to spray a few more coats of the final colors - both white and cherry red (assuming the cherry red is of the transparent type of paint, in which case the red will end up a darker shade).

Tom is kind of correct in stating that you could get away without a primer coat when spraying enamels, but... only under certain circumstances.
Some things to consider for a non-primer paintjob:

• The model kit is molded in white plastic.
• No body work was done; i.e. - no spot putty was used.
• Carefully wet sand the plastic with #320 - #600 and wipe clean with alchohol.
• Spraying a somewhat dark opaque color.

I work exclusively with enamels for my modeling and find it a must to primer before spraying any translucent paints or after using spot putty. It's helpful at times to primer when spraying light colors too such as white, yellow, light blue, competition orange, camel, cream, etc... Using flat white or different shades of primer can alter the shade of the final color. But it works best in helping the paint stick evenly during the mist coat and reduces the blotchy shadows in the final coat.

Don't forget to lightly wet sand the primer coat.

Thanks! :)

Dodge

Dodge - if you are using enamels or lacquers you probably don't need a primer coat... for acrylics thoguht it helps.  and correct.. for a white overcoat you want a white primer... otherwise it would take a long time to cover..  I use plain old Krylon white for light color overcoats with good results...

 

Good luck!!!

welcome to the forums,i'll try to answer the basics and other help will soon arrive

the primer coat serves several purposes,first it gives the finish coats something good to adhere to

it will also help you to spot any flaws in the model (seams,scratches,etc..) before you finish coat it

i would go with the flat white primer coat because of the white topcoat(be very sure you get a full even coverage by looking at an angle)  and it will also help the red be more vibrant,,,,,your on the right track here