using salt to make rust

[mjderstine]

i know i have read the thread or idea in here somewhere. searched for a while, and couldnt find the one i was thinking of.

can someone post up for to use salt to paint over and make it look like your body has been rusting?

[heartless]

i believe that thread was in the "Scale Accessories" area...ah yes...here ya go...

nick's adventures in styrene

Scroll down on page one for the write up on using the salt.

[2WheelFlyer]

You don't neccessarily need to use salt. The technique I use and won 3 awards (best diorama, participant's choice and people's choice) with it on a "junkyard" diorama at the same IPMS event is with baking soda. The finer grain of the baking soda allows you to make very realistic effects, rather than using a bigger grain material like sand or coarse salt. Fine salt might be ok but try first to see if it dissolves with the paint if you will use the technique below.

-prep your base material shape with all the wrinkles, jagged edges, etc. Whatever it is that you are making. Your base material can be styrene, wood, thin aluminum sheetmetal, cardboard, etc.

-Use a spray can with red oxide color to paint your part and while it is wet, take a small spoon and sprinkle the area with baking soda. This may take several steps (just spray more red oxide and repeat the application) depending on how "rusted" you want to make the part look. You can also use a brush to apply fresh paint and create "streaks" where water might have dripped and created rust. Apply more red primer paint on top when you are finished to seal the baking soda to the part.

-Use an airbrush and paint the rest of the part (the non-rusted sections). I use matte modeler's paint or airbrush specific paint in matte colors as well. You can custom mix colors too to achieve the look or tone you want. An airbrush will give you more control and fading where the painted area meets the rust and will look more natural. Talking about paint, to make it more realistic; whatever color is it that you use for the rest of the part, mix a little white to it and spray the top areas of the part to make the paint look sun faded as well. You can add a deeper shade or a little dark gray to the part color to make it darker and spray the bottom areas to make an "artificial shade" and make it more realistic. You don't want something to look with nice fresh uniform paint color and a rust spot, that is not realistic, everything has to look weathered.

-Use a dry brush technique on the rust spot, with 2 or 3 different colors to highlight the rust and make it blend with the color painted areas. Use a tan color to show older rust, Use a darker orange for rust that has formed more recently and last use a brighter yellowish orange to highlight the areas of "fresh rust" and areas where water drips down and leaves marks and stains on the part. These combined with the red primer gives a lot of variations and gives a natural look to the rusted area.

-Seal everything with matte clear, a couple thin coats with an airbrush sprayed at more distance works well.

-Depending on how "detailed" you want the model to look, I like to spray the whole model with a dusting of matte tan with the airbrush, like a mist sprayed from above to make the whole thing look uniformly "dusty". That ties the whole model and even the ground together, including clear windows, rubber parts, galvanized metal looking sections, wood pieces, etc. Of course each of these materials had to be weathered on its own previously, the dusting is just to harmonize them all together.

Practice on a scrap piece to see the different looks you can achieve with this technique, hope it helps!

[mjderstine]

heartless:
that isnt the one i was thinking of, but that will def work.

2WheelFlyer:
thanks for that write up. very detailed. i actually have an airbrush setup with a nice little AC. but i couldn't get it working right, but i think i was using the wrong paint or something. i couldn't it to come out.

i have never tried anything like this before, so i think i need to practice on some scrap styrene before i go painting on my brand new D90 body.

[mjderstine]

i also googled this and got lots of great examples!

[heartless]

what kind of airbrush do you have? & what size needle? paint needs to be very thin for most - milk consistency.

also, most "craft" grade paints do not do well in an airbush - the pigment particles are too large & wont flow worth a darn causing all kinds of problems.

most "model" grade paints will do ok, if properly thinned.

Correct air pressure is also important - and will vary some depending on the type & consistency of the paint.
A good starting point is around 25-30 psi on an empty brush, trigger fully depressed - then adjust up or down as needed from there. for very fine, detail work, you will probably want lower for more control, for spraying larger areas, a little higher.

[2WheelFlyer]

Well MJ, if you're thinking of using it for an actual crawler body, I would probably use only an airbrush and dry brush technique in layers, because anything you stick on a body will probably be ripped and scuffed off when you hit a rock or roll over the first time. The paint will probably be scratched but with more drybrushing it can be spot repaired without problems. As Heartless said, you need to thin the paint properly, and make sure your airbrush is perfectly clean before starting any paint job. You need to disassemble it completly and make sure all pieces are clean, not just run thinner through it while spraying, that is OK if you're in the middle of a job just changing colors, but before and after a full clean up is needed. Don't go higher than 35 psi on the airbrush or you can blow something up.

Your're going to paint a D90 rusty? D90 don't rust, they are aluminum! only the bulkhead is steel. You can dent it and weather it though.

[mjderstine]

thanks guys, both give great points. oh and i thought it was aluminum... that is gonna be a kinda different process. right now i just sprayed the whole truck with some automotive primer. need to wet sand the whole thing, and then i can try painting. will do a base of aluminum color, and then work on the corrosion for the alum. won't be much since alum holds up pretty well. but maybe i will start painting this weekend.

i have this AC and a badger gun.
acdc977d-3e1f-40c3-8947-9ad9364a8fb4_zps9835c5df.jpg Photo by mjderstine | Photobucket

[crawlhog]

i found using my wifes makeup makes it look wheathered , after i get the look i want i spray it with flat clear coat

[T I N Y]

I used sea salt and baking soda on mine.