Can someone tell me what the different stages are for painting the bodies of car models. I keep reading things like wet sanding and buffing with a compound. Can someone explain those processes for me?

Thanks in advance
Hisham

ha, well, seeing as how I just spent most of the day doing this, I'll see if I can't shed a little light on the topic for you. Here are the steps I followed.

1) get the initial shine off the plastic. use something like a 1000 grit just to scuff it up. be sure and do the WHOLE body

2) Lay a coat of primer. I don't recommend using automotive primer because the pigment is too large. Tamiya primer is probably your best bet, or Mr. Surfacer 1200.

3) Check for imperfections and remove or fill respectively. I also smoothed the primer again with 1000 grit, but I'm not necessarily sure you have to. just make sure when you're done with body work you have the WHOLE car covered in primer.

4) From there, lay your color coat. Depending on the color you will have to lay different numbers of coats. Lighter colors will probably require more than 2. Start with a light coat, let it sit for a minute or two, then spray wet coats where the paint is visibly "wet". Just be careful not to get too much paint on to the point where it starts to run.

5) At this point, let the paint dry. Some people will say a week and some will say a few hours. I just experiment and see how long works for me.

6) Now you're ready for a clear coat. I do a clear the same way I do a base coat. spray a light misting, let it sit to get sticky for a minute, then spray a few wet coats. I would definitely go over it a couple if not a few times. It'll pay off a little later.

7) The clear coat is the one you definitely want to let dry for 24 hours. it needs to be hard before you can continue.

8) Here comes the laborous parts. You need to start by smoothing out the clear coat. this is done with fine sandpaper. You can use just a 2000 grit, but i work up from 1000 to 2000. do the whole body. You want to sand until you don't see the little bumps in the clear. it needs to all be one uniform flat tone.

9) This is where the polishing comes in. I use tamiya polishing compounds, but I think you can find others, and you can use turtle wax buffing and polishing compounds. start with the coarsest and work your way up to fine. when you're done with the fine, it should be smooth as glass if you did everything right. when you're done with the polish, some even like to use real car wax to give it that extra glisten.

note* make sure when sanding and polising to be careful around edges and seams. It's much easier to burn through the paint in those places.

Hope this helps!

Hi Eric.

Thanks for taking the time to jot down your process - don't suppose you'd be interested in putting together a build feature sometime with pics? Would be tremendously helpful particularly to us occassional Auto builders

Just a quick question: in step 1 you rub now the plastic body prior to priming in step 2. Why is this? Is this something you for all model genres to help the primer bind? Or is there another reason specific to auto modelling?

Thanks mate!

Rudi

Rudi, that would be for removal of seems and imperfections on the body. Some folks like to lay an initial color coat, then wet sand to look for low spots{or high ones} and then coat again to blend these areas together. Color changing paints love to show high and low spots off on a seemingly flat quarter panel....or cycle tank.

Good questions and answers.
What are some of your clear coat brands and methods?

Thanks Bob! I guess this technique would also be employed with some other genres where one has fairly large body panels (like ships?), but even more so by you auto guys with all those funky colours which, as you say, highlight flaws in the panels really easily.

Thanks for the great tips. 2009 is my year to build a car!

To expand on some of the tips that Eric posted:

Tamiya primer is definitely worth the added cost. For years I used automotive primer, thinned and sprayed through my airbrush. It was plentiful and cheap, but it also meant a lot of sanding, since the pigment grains are large. Getting a nice smooth surface took some elbow grease, some time over the kitchen sink and more than a bit of patience. The Tamiya primer has much finer pigment, and it results in a primer coat that is pretty much ready for color, right out of the can. It's a time-saver, and well worth the additional expense, IMHO.

I let my color coats dry a lot longer than I think is neccessary. Then again, I paint a lot with enamels, which take forever to dry. Lacquers are usually good to go in a few hours.

If you have any dust or runs in your color coats, it's best to wet send these out before you clear coat. If you clear over a speck of dust in your paint job, you're going to have to sand through the clearcoat to remove it. And speaking of sanding through clearcoats...don't do it! It's been my experience that clearcoats are hard to touch up, and you can usually see the "repair" afterwards, unless you're really good, or very lucky.

On a related note, not everyone uses a clearcoat. I have a few modeling buddies that skip the clear and polish out the paint directly. This works especially well with lacquers, but I've seen it done on both enamel and acrylic paint jobs too.

For polishing, I've used the Micro Mesh system for years, with very good results. Detail Master carries an assortment of MM polishing kits and supplies.

Just my two shekels. HTH.

-YL

Thanks for all the input, guys... and thanks, Eric, for taking the time to write that detailed explanation.

Just a couple of more questions:

* How is wet sanding done? Do you wet the whole body and sand, or do you wet the sand paper itself? (Sorry if my questions sound really stupid, I've just never done this before)

* Is there a special material(cloth) that you use for buffing with the various compounds?

Finally, when I was a kid my older brother used to make me wax his car on the weekend and I remember he made me do it in a circular motion... Is that necessary while buffing with the compounds, or do you just use a normal left to right motion?

Again, sorry for all the questions.. I just want to try and get it right.

Thanks again
Hisham

I wet sand over my kitchen sink, since it can get messy.

I keep both the sandpaper and the area on the model that I'm sanding wet. It's important to have enough water, since that's what carries the sanding residue away and keeps the paper from clogging. What's more important, though, is to be sure you DRY the area that you are working on frequently to check your progress. You can't see the surface well when it's covered with a thin film of water, since everything looks glossy. It's very easy to overdo the sanding and burn through the clearcoat or color, and go straight to the primer or bare plastic. So go slowly, use lots of water for sanding, stop often to dry the model with a soft towel and check the sanding job. It's better to spend the extra time then it is to cut through your paint job.

A soft piece of flannel cloth is what I use to apply polishes and waxes. I had an old flannel shirt that I cut up, and I have enough rags from that to last me for years! Whatever you use, just make sure it is very soft, and as lint-free as possible.

As for the direction you should use for polishing...well, I've heard it both ways. One camp says "circles only!" and the other says "back and forth only!". Frankly, I've always used whatever worked best in the application, whether it be a circular or linear motion, and it all looks the same to me. Let's face it, there are some panels on a model car body that you can only polish by going back and forth (trying to work some orange peel out of a lower rocker panel, for instance) unless you somehow miniaturized yourself enough to make a circular motion feasible.

One other tip: practice on a spare body or some scrap plastic before you attack your latest and greatest project. It will save you some headaches in the long run. Don't ask how I know.

HTH.

-YL

Thanks a lot, Yoni, for this great explanation.

Luckily, I do have a couple of old car bodies that I'll be able to practice on.

Thanks again
Hisham

I use the basement bathroom sink ...I run a trickle of water over or near the area that I'm wet sanding and squeegee the area with my thumb, away from the water, to see how it's going. If you ever do clog up a sanding stick or sand paper, you can use an old tooth brush{firm} to clean them off. As the sanding pieces wear down in grit, I remark them and use them as finer sanding pieces. One thing I can add is that squadron sanding sticks are nice for wet sanding, but they don't hold up well after a few uses....the sanding surface begins to peel off/unstick. For rounded fenders I like using a sanding block and a piece of wet/dry sanding paper. The block helps straighten waves{work on the straights - not around corners} and the piece of sanding paper will go around or over rounded surfaces without digging in...remember, let the sand paper/stick do the work...not you{don't lay into it...take your time}.

Howdy guys. Sorry it took me so long to get back to you!

RUDI:: I will have to consider doing a how-to. I never really thought about it, but I've gathered my knowledge from a lot of different places, so when I pull out the next car body I'll get some good pictures of the steps.

The reason I sand the body down before primer is because sometimes the primer will run if you apply it to a shiny new body. Plus, I'm just anal about everything being smooth! It is an opportunity to remove imperfections as well.



YONI:: You're right about the drying times. My most recent body was painted with tamiya spray cans, so needless to say it dried relatively quickly.


KOSPRUE:: I have used ModelMaster Clears, Tamiya Clear, and Future, although I've never used future on a car. I try to use them respectively with the type of paint I'm using underneath, but I will admit that Tamiya paint with Tamiya clear is probably my most favored method of any. I never have any issues with tamiya clear. It always seems to lay down how I want it to!


As for wetsanding and Polishing, Yoni's methods would work great. What I do for wet sanding is cut up a piece of automotive wet/dry sandpaper into 1" squares and sit there with a bowl of water, making sure I keep the paper very wet. if I feel the paper getting less effective, then it's on to the next piece.

My polishing rags are cut up sections of my dad's old underwear. yeah, nasty, I know. I promise they've been through lots of bleach. Maybe if I get really picky one day I'll start using microfiber or something.

I use squadron sticks too for the touch to reach places or the spots that are just too inconvenient to try and fold the paper to work right.

Hope this helps, and I'll definitely see if I can't get some kind of feature written up along with my next car. check out my 350Z thread if you wanna see my before and afters of that.

I have another related question. If there are decals to be put on the body.. would I put them after I paint the base color and before I put on the gloss coat? If so, will the gloss coat be enough to protect the decals during the wet sanding and polishing?

Thanks
Hisham

1- Yes, so they're sealed by the clear coat. 2-3 light coats should protect them...figure it this way...if something can scratch or damage the decals after the clear coat, you never had a chance to save them anyway.
2- If you get the base paint smooth enough before the clear coat, you won't have to worry too much about the possibility of uneveness or bad spots with the exception of the decals themselves, and that will be minimal. Remember to trim the decals close to the colors to remove the clear stuff surrounding the decals...some decal sheets are one solid piece and you have to trim close anyway, but you should do this with individual ones too. 2 coats of clear over the decals and "alittle mild wet sanding" {if needed} between each coat would be enough. Lay the decals, clear it all and see what ya got and go from there...some decals are thin and others are thick.........