You say patina, I say rat-ina. Rat-ina, patina.
I have been watching Youtube for the past week, checking out some new rusting and weathering techniques. Following is the combined stuff I put together for my approach to achieve the rustification I desired on the MIG-RaT. I have my own weird Rat-ionalizations for how I did it.
#1. Pick a nice dry day with a light wind in the mid 60's, and a semi sun / semi shade area.
#2. Use a Park Tool stand from 1988 that doesn't have all it's parts anymore, to hold your bike for the process.
#3. Apply a medium coat of Orange Peel texture to the bike, heavier in the spots where you want the rust to appear to have gathered / bubbled.
#4. Spray the whole frame with a Rust Primer. It is very strong and will hold on to even the places where the paint is missing on your frame. I don't even sand the old paint when I use this, it sticks this well. Designed to keep rust away. I use it to attract rust.
#5. Spot rust over the areas where you want the most rust to show through the paint. This is one of my favorite colors, Cinnamon, which gives an orangish hue to the rust job. This is applied with a heavy scrubbie by shooting it with paint, and then dabbing it on where you want it.
#6. Colonel Mustard did it with a sponge in the BACK40.
Apply some mustard to the car wash sponge, and dab it on the frame where you want the rust to show through. After you apply the mustard, spray your top coat right away, so the mustard doesn't dry hard. Then wait a few minutes, till the top coat looks like it is getting tacky, and then hose off the frame. Where the mustard was, the top coat (my French Blue) will release, and reveal the rust coating underneath. I used my garden hose with the nozzle turned way down to a fine, strong, misting stream for good control.
Let the frame sit out in the perfect weather and dry. Sit back and crack a beer. Or in my case, shower and head to work so you can make money to support your rat rod bike habit....