Sanding before Priming?

[strangelove]

Is it best to lightly sand the entire surface of a styrene model before priming?

If yes, what grade of sandpaper is best for this?

Here is the model in question.

Thank you,

[Joseph Osborn]

Depends-- have you washed it with any detergent to remove oils from the manufacturing process (and your fingers)? Usually just washing the bare plastic will get it ready for primer. A good primer for styrene would be lacquer-based, so it'll etch itself into the surface and provide good "tooth" for the finish coats. Nothing says you can't sand the plastic before priming but I'd suggest you use a very fine grade or even fine steel wool. You wouldn't want the sandpaper to show any scratches, just abrasive enough to knock the shine off the plastic.

Hope this helps

[mech]

I have sanded models prior to painting, especially resin, but on occassion, styrene. Pre priming, 600 grit works well, after priming, 600 to 1000 works to smooth out the primer. ymmv

hth

[strangelove]

Depends-- have you washed it with any detergent to remove oils from the manufacturing process (and your fingers)? Usually just washing the bare plastic will get it ready for primer. A good primer for styrene would be lacquer-based, so it'll etch itself into the surface and provide good "tooth" for the finish coats. Nothing says you can't sand the plastic before priming but I'd suggest you use a very fine grade or even fine steel wool. You wouldn't want the sandpaper to show any scratches, just abrasive enough to knock the shine off the plastic.

Hope this helps

Very helpful -- thank you. A few more concerns...

Yes, I have washed it and will wash it again before priming.

Is White Putty, once dry, water proof?

Although perhaps not strickly necessary, I'll be priming the AMT TOS 18 inch enterprise, propapbly in a light grey, to highlight and then fix any scratches and surfaces errors.

I have read of at least six different approaches (in the Finishing thread and on other forums), from gesso, to enammel, to automotive products, to lacquer.

I assume that I am safe to prime with enammel (rattle can). Correct?

I have yet to come across a detailed and step by step set of instructions for painting the TOS 18 inch, or for Aztecting.

Where is the best set of instructions for azteching a starship?

I am not clear on what type of tape to use.

I see many images of patterns cut out of paper, but how is this paper affixed to the model in such fine detail and still keep the paint from feathering underneath?

Thank you for your time,

[Lt. Z0mBe]

I'll do my best, Doc.

Is White Putty, once dry, water proof?

If you're speaking of the Squadron white, yes it generally is. But, it may temporarily swell just a bit. Squadron white, just like the green and Bondo in a tube are basically lacquers with a lot of fillers in them and chemicals to hold the fillers together. The fillers may swell when wet, and definitely shrink wduring their normal drying process (when first applied).

I have read of at least six different approaches (in the Finishing thread and on other forums), from gesso, to enammel, to automotive products, to lacquer.

I assume that I am safe to prime with enammel (rattle can). Correct?

Absolutely! I recommend the Krylon grey from Wallyworld or a hardware store. You can even decant the stuff into an airbrush bottle if you want. The Duplicolor filling primers are really nice too, although all have worked well for me. The only hitch is to READ THE INSTRUCTIONS. Do not spray the model from more than six or eight inches away, or you'll have a dusty coat. You can fix it with a gentle wet sanding and some mopping with a cotton swab soaked in isopropyl alcohol. But, avoid the hassle in the first place.

I have yet to come across a detailed and step by step set of instructions for painting the TOS 18 inch, or for Aztecting.

Where is the best set of instructions for azteching a starship?

Can't help you on that one. I'm not a Trek guy. But, I would be willing to bet the guys in our Star Trek forum could answer you. There are some impressive Trek guys there

I am not clear on what type of tape to use.

Tamiya masking tape. It is the tape that binds the universe together. The main site has some.

I see many images of patterns cut out of paper, but how is this paper affixed to the model in such fine detail and still keep the paint from feathering underneath?

I have seen this done two ways with complicated schemes like aztec, where masks are placed directly on the model. The first is with frisket film, which is really a transparent to translucent, low tack film on a paper backing. The second method is an old fashoned way whereby blank newspaper or heavy, WHITE tissue is cut with a sharp knife and placed wet on the model. Once dry, it grips like a geometric spitball. The downside is it doesn't seal all that well and small shapes are hard to cut. If I had to guess, I would say the paper you refer to has a backing of some type or has some type of clear fixative applied later. Or, it could be very, very-patiently cut Tamiya tape. It's happened before.

I hope this helps you, or at least gets you in the ballpark.

Kenny