Hello all, I have noticed right before you guys paint you spray primer over your plane. Why? does it help the paint bond better? I only use it to fill seams. thanks
Well I too use it to check that the seams are Ok.But if the color I am painting is white,yellow or red I like to use a primer coat to reduce the number of color coats needed for complete coverage and intensity. ! 
[#ditto] Also it gives an even finish if you are using PE or Resin parts.
Also if you have lots of filled seams before the primer or different colored plastic or resin, it gives the paint a uniform surface to go on so the main color isn’t shaded different colors in the wrong places from different colors of plastic (or resin[swg]) and putty.
[#offtopic]BTW- For anybody watching the NCAA Men’s basketball final tonight, Go Memphis! I’m normally a Purdue fan [:D] but they were out 2nd round. And thank goodness NC and UCLA aren’t playing ( no offense NC or UCLA grads out there) I can’t stand either of them[:-^]
Oops. I guess Summit pretty much already said that. Oh well…
The big reason is for paint bonding, especially if you use acrylics. It’s a must. Acrylics are designed to bond to plastic but can and will pull off when using masking tapes.
Andy
-
Bonding. I’ve had some very nasty orange peel problems on models I didn’t prime. Basically, if the paint isn’t being brushed on, the part gets primed first.
-
Color uniformity. It’s 99% certain that your putty will be a different color than your plastc, and you need to make that uniform. The same applies if you’re using PE or resin.
-
Fewer color coats. Usually primer cuts down on the number of coats you need to lay down to cover the plastic.
-
Seam finding. A primer coat will often show seams and imperfections that won’t stand out on bare plastic. That’s how I found about 800 problems on the CV-118 I’m building. If I hadn’t used primer, those errors would have been showing up under a coat of silver paint instead! Now that I’ve caught them I’m hitting them with Bondo glazing compound and everything will be smooth.
When painting resin or lots of PE, the primer coat will bite into the medium better and provide a base for further painting. Painting right onto resin almost never gives an even coat, and doesn’t last.
For most of my models, however I use no primer as I paint primarily in enamels, and they’re strong enough to bite. Acrylics just don’t do it for me. Also, I preshade mostly, so I’m not concerend with the slight disparity in shades when using filler. It actually adds to the effect. Most of my filler is CA anyway, and it’s clear.
Oh almost forgot…I use Alclad II for my BMFs, and primer is required for all the non-polished shades.
[#ditto] with all above. For this very reason Wulf stated I put a primer undercoat on all my models prior to painting primary colors. Orange peel effect are a hazard but you can control this by buffing the model with a finger nail buffer block. Buffing the surface smooth after each coat also removes dust build up while painting.
I use primer for a simple reason. Washing the kit in warm soapy water to remove oils is farly pointless if you handle it afterwards. Why wash the kit ahead of time if you’re going to be spending the next few weeks manhandling it?
Instead of blowing an entire day doing the wash and dry routine, I simply prime the kit prior to painting. Primer’s ready to go (for paint) in just about an hour (longer or shorter depending on temp and humidity). I usually give it two hours and then give it a light sanding, a quick wipe down and then paint. Never had any issues other than me being terrible at painting [(-D]
-Fred
[#ditto] to everything thats been said. It does give you a nice surface to work with.
Seam checking, color uniformity, and paint adhesion are all good reasons to use primers. I find it’s also a great way to check the surface texture and ensure it’s nice and smooth for subsequent coats. Primer followed by a quick rub, then another coat of primer will pretty much take care of any minor scratches or the pebbly texture seen on some plastics.
Cheers,