learn from others mistakes/experience... painting

[DiscoStu]

Well, being as painting is one of the two things that will take me the most time on a bike (the other being welding when I start my next project), I figured I'd share a couple things I learned/ran into on my first bike and maybe some of you other cats can lend an idea or two to get your paint to come out looking smooooooth.

So I was just using rattle cans (do you guys get carded for buying spray paint?, MN requires ID now and you have to be 18 to purchase?! WTH? now it's not just beer and cigs anymore, but paint too!) to do my bike and here are my observations:

1. Painting wheels without removing the spokes and relacing. I used the 3" painters masking tape to flag the spokes, only being concerned about getting it tight to the rim at the bottom of the spoke. What I didn't think about was the bottom of the tape effectively being painted to the rim. So a little test proved that after flagging the spokes, use scisors to cut the tape at an angle up away from the rim so you don't leave little ridges of paint.

2. Make sure that the flags of tape on the spokes are long enough to tuck behind the neighboring spoke for when you paint the other side of the rim. I had a couple that were too short and had to extend them to keep them off the painted side of the rim.

3. Prep work on your frame/fork: I kind of went crazy with the wire brush attachment for my drill to remove some surface rust and other areas where the paint was a bit much to smooth out with hand sanding. However, I did not account for the grooves into the metal nor the layers of paint at some points on the bike. So if you to wire brush or take the paint down to the metal, spend extra time fairing out these rough areas with sand paper, steel wool or a finer bristle wire brush.

4. Multiple coats:This is where it would be helpful for someone with more paint experience to chime in. After applying a coat of paint, I let it set up for about 30 min. Basically it was just a bit tacky when I touched it, but no paint came off on my finger. This is the basic technique I used when doing epoxy for glassing wood (save for epoxy taking much longer to set up). The reason for this is with epoxy, when it is still tacky to the touch, applying the next layer will give you a "chemical bond" as opposed to a "mechanical bond", thus being a stronger adhesion to the layer below. In the end my paint came out looking pretty good, but I don't know if this is the best painting method as doing it this way precludes any sanding between coats.

5. Painting blast zone: I didn't really think much about this but noticed there was a very fine film of paint on the ground and on the walls and my tools that were on the other side of my painting area. Since it was to cold to paint out in the garage, I ventillated a room in my basement, however, didn't account for the paint particles being heavy and falling on things while the pressurizing gasses were vented out the window. So I had to spend some time cleaning up the room. When I moved onto painting my wheels, I put a tarp down on the floor and painted facing one direction rather than blasting in all directions.

Hope this is helpful to someone and feel free to pile on the tips.

 

[Anonymous]

4. Multiple coats:This is where it would be helpful for someone with more paint experience to chime in. After applying a coat of paint, I let it set up for about 30 min. Basically it was just a bit tacky when I touched it, but no paint came off on my finger. This is the basic technique I used when doing epoxy for glassing wood (save for epoxy taking much longer to set up). The reason for this is with epoxy, when it is still tacky to the touch, applying the next layer will give you a "chemical bond" as opposed to a "mechanical bond", thus being a stronger adhesion to the layer below. In the end my paint came out looking pretty good, but I don't know if this is the best painting method as doing it this way precludes any sanding between coats.

after you sand you should prime. then you have something to sand smooth and it keeps the metal from rusting under paint.

light first coat see through(tac coat allows next coat to bond better) wait about 10-15 mins then spray second medium coat wait till paint is tacky before you spray third. slick out to finish you want. the times between coats will vary depending on temp,humidity and how much you spray on the parts

as far as the spokes tinfoil works best for me. comes off easy because solvents will make tape glue harden to part.

 

[ratina]

TINFOIL! what a great idea! I used tape last time and it sucked taking it all off, not much residue just a pain. I will definetly use that next time!

 

[66olds98]

From my experience working in a Pro. Bicycle Painting shop(gForsebikes.com)
1: Frame Prep is the most important thing. If your prep is crap, Your paint job will be crap! I recommend getting your frame sandblasted, much less hastle than what I hear everyone else going through with wire brushes and all that.
After S.B. sand it down with like 180 grit. this is the time to fix any cosmetic stuff.

2: At gForse, sometimes we treated frames with metal cleaner. We also used self-etching primer (Imron). 3 coats and like White Trash said, first coat is a lite coat, wait 15min or until the primer goes dull. Repeat until you have 3 good coats. We had an oven to dry things in, so we only had to wait until the next day.This is where it becomes a labor of love, Wet Sanding with 400 grit. For prob. about an hour? Sand everywhere!!! Until its nice and smooth 8) Especially where its hard to get to, because its also hard for paint to get in there, so you want to be sure your paint has something to grip onto. As long as everything cosmeticaly is ok and you havent sanded thru anywhere, your good.

3: Before we laid down color, we laid down a coat of sealer.
Then we laid down a couple coats of Basecoat color, We mostly used some H.O.C. Let it dry over night. Check it in the morning and sand any blemishes.

4: Then it was time for Clearcoat! I believe we were using Imron also, very good stuff for small things you might not be able to buff, it drys smooth, no "orange peel"
Before clearcoat though, we used adhesion promoter. We usaually did 3-4 coats of clear. If we were doing decals, we would spray a couple coats and wait overnight to sand it down a little bit so that the final coat was level. leaving no "ridges"
Finally after you've done all yer coats of clear, we check for blemishes, sand if need be and spray more clear or just buff if it was in the top coat of clear.

There are alot of other steps we took...
After we primed, we would mask off the drop-outs right where your nuts/quick release will tighten, so that you dont just chip the paint and cause it to chip more. Mask off inside head tubes, B.B.'s etc.
Lots of Clear coat will give your paint job real depth. In a prof. setting it is very nice, not nearly as many variables, just as long as you mix your paint, hardeners, reducers and make sure to keep out the moisture that an Air Compressor can spit out with desecant(sp?)

This is prob. the longest post i have seen on here, but, Painting bikes is more of an art that takes a while to learn, practice will help!!! I dont claim to know it all, this is just what I have come to learn.
Painting Bicycles is harder than alot of people think, with all the bends and joints and corners and round tubes. Much Harder than some big, flat, hood of a car!!! If you have any specific Q's PM me.