Kirk Frameworks JKS-C, Serotta Nova, Gazelle AB-Frame, Fuji Team Issue, Schwinn Crosscut, All-City Space Horse
a light wetsanding of the primer would be advisable once the primer has dried throughly (see can for directions for curing time). I forget what grit I used when I painted the cuda, but I'm going to say a 600-800 is probably good if you have a light hand. Mostly you want to take out any imperfections in the primer but not smooth the paint to the point where your color won't stick properly. I ended up wet sanding between each coat of primer but that's likely overkill and I ended up sanding through the primer in several areas forcing me to do additional primer work.
Sanding probably is in order, assuming laquer based sandable primer, do not be surprised if spot touch ups are required at the lug edges. 400 or 600 wet, not dry, wash after, prepsol or similar unless you really have dry hands, typical hand oils will often start a fish eye, or poor adhesion.
50 degrees... gloss black, probably rattle can.... not good for a smooth finish, most cans will state a preferred temp range, 70 degrees F is usually the min. I would only attempt it iff the frame had been normalized to a warmer temp, near the heater in the house, keep the paint there too, even warm it up by immersion in hot (not boiling) water, will help the "flow" I would test on the fork first, if you botch it, much easier to redo.
The good Dr. may correct me, I have only painted cars, not bikes, but I concur with the replys, wet sand 400 then 600. All paint orange peels and sanding is the only way to remove the bumps. Who ever invents non-orange peel paint will be very rich. If you don't sand, gloss black will highlight the imperfections, flat white will hide them the best.
A good trick for sanding primer is to overspray black onto the primer. This is done by lightly spraying black at 2-3 feet from the frame. You do NOT want a good coverage, you just want some black to get into the crevices of the orange peel. This lets you know when to stop sanding when the black disappears.
First apply Bondo to really pitted or gouged spots. Also check for, and Bondo, pinholes, especially at the dropouts.
Then if you like you can spray a "guide coat" of black. Shoot lightly from 3 feet away.
This step is an automotive trick and isn't overly critical on a bike.
Now, using 280-320 "wet or dry" sandpaper, sand the Bondo spots smooth. Then sand all the tricky spots, like the BB shell, the seat cluster, around brake/chainstay bridges, bottle bosses, cable guides and lugs. Doesn't matter if you sand down to the metal, just make it smooth. Don't forget the forks! (dropouts, canti bosses, crown)
When you have all those areas dialed in, you sand the tubes using just the 320.
Next clean. I use PPG DX330 Wax & Grease Remover. I use an old clean toothbrush to apply around the tricky spots first and wipe off quickly. Or blow out with an air hose.
Then I clean all the tubes.
Are you seeing a pattern here? That's good, as it will be key to painting success.
Masking time!! Screw some old clean (DX330 is good cleaner) bolts into h20 bosses, and rack bosses etc.
Seat tube & BB. This will be your holding points for flipping the frame, so do them properly.
Start by using GOOD quality tape (1 1/2" wide Blue 3M painters tape, and NOT the delicate surfaces kind!)
Tear off one piece, about 2-2 1/2" long. Fold it slightly lengthways. Insert it into the seattube almost all the way. With just a bit above the rim of the seat tube, press it firmly to the inside of seat tube. Now do that with a second piece. Now with an old Xacto #11 blade, trim the tape by using a chamfering motion on the inside lip of the seat tube. Apply what should be the last piece of tape and trim.
Do this same application to the BB shell.
Also mask the fork crown race seat and the pivot tips of canti bosses.
Now you're ready for the final primer!!!
Double check that the frame is clean and dry. Do any last minute touch-up NOW!
Clean again if needed.
Have enough primer to spray 2 good coats. I hold frames with a peg that I slide the headtube over. You can clamp a wooden dowel in a workstand or vice to do the same thing. Be sure you can easily get to both sides of the frame.
Before spraying, lightly dust off the frame with a tack cloth. Now you're ready.
I start with the frame upsidedown. Start spraying from one side of the frame, starting at the BB. Use little pritzy blasts around all the little hidden spots. Then go to the rear dropouts, brake bridge, seat cluster, headtube lug area. Now back to the chainstays, far one first, then the near one. On to the seatstays, far one first. Now the back of the seattube and around to the front. Up at the downtube (which is on top right now cause the frames upsidedown) and to the haedtube. Then the headtube, then the top tube.
Now go to the other side of the frame and repeat!
Work as quickly as you can being careful not to miss spots (holidays) or cause a sag (run) in the paint.
When you've done that, stick two fingers in the BB and a middle finger in the seattube. Carefully lift the frame off the peg, flip it over and put it back on the peg.
Resume primering by starting at the seat cluster. Go to the rear dropouts, then to the BB, up the downtube, (which is now on the bottom cuz the frame is right side up now) then the headtube to the top tube (which is now on top).
Over to the other side and repeat.
Done...with one coat..wait an hour and repeat!
How long to dry/set before I paint? Planning on a glossy black.
1-2 hours, or as per can instruction time limit. If the final COLOR is going to be black, then the above "final primer" should be black also.
Now if you got some dusty spots or a little gnat blemish, sand lightly with 600-800 grit "wet or dry" sand paper. If you got a run, wait overnight before trying to sand. Use 360 "wetORdry" and a popsicle stick as an emery board type file, to smooth the run. Be careful not to sand through the "final primer".
So the "final black primer" is all nice and even, you're all set to color.
Start with the frame upside down and do the same thing you did in the primer phase.
Tricky spots with spritzes, then the tubes. Other side, tricky spots, tubes. Flip the frame. Tricky spots, tubes. Other side. Tricky spots, tubes. Done with one coat. Repeat 1 or 2 more times, waiting between coats about an hour, more if it's colder. Check the can.
After 2-3 coats of the black, do the same thing with 2-3 coats of clear.
If its cold where you are spraying, leave the clear till the next morning. If you spray clear at the end of the day and it gets even colder in the evening, you run the risk of getting the evil "solvent popping", and trust me, you DON"T want to get that!
That should be it! All super wet and glossy lookin!
NOW WAIT 2-3 WEEKS!!, before you do anything with the frame.
The warmer the better. When you can't stand it any longer, try pressing your fingernail into the paint. Somewhere like the dropout where the QR is going to clamp.
If you can make an impression, you have to WAIT SOME MORE!
6 good coats of Krylon may take 4-6 weeks to harden all the way, especially if it's colder.
It's dry and cold (50's) here in the Central Valley.
50's is about the lowest of the low end for decent painting. Refer to the note about NOT clearing at the end of the day.
That about cover it, in a nutshell.
Good luck, have fun
and post pictures
when you're done!