Painting rims... part of the rims that is?

[xray]

I'm still working on my 62 Typhoon rat, that I'm making into an 8 speed. I'm hoping it will be ready for some pix next week.

I got the Nexus 8 speed coaster brake laced into a new rim, and got the rear triangles spread apart to accommodate it. I cold set the frame using the wooden clamps trick I found in an old thread here on this board. I eased the rear dropouts apart using a couple of Harbor Freight clamps, gradually, spreading them easing them apart and then checking the spacing. I got them out to about 136 mm and then bent the dropouts back in to make them roughly parallel.

So, here's my next task - I bought plain aluminum rims, I did not want fully painted rims and didn't really want any stock color either, but I would like to add a touch of color to them. This is going to be strictly a coaster brake bike - no rim brakes.

The profile of these rims has flat side walls, then a flat bevel, then a roughly flat center portion where the spokes attach.

I'm thinking I'd like to paint just the sidewalls or just the bevels, leaving the rest of the rims aluminum silver. The bike is black, but I'm using some red and burgundy accents. I'd probably do the rims in a burgundy metallic.

So - never having been much good at painting stuff, I have a couple of questions:

1 - Does anyone have recommendations for painting aluminum? Type of primer and paint? Should I sand the aluminum a little for better grip?

2 - The REAL question: How about tips on masking a rim for this kind of job? (Assuming I'll use a spray can.) Would you try to mask the entire rim and then cut away the portion I want to paint? Should I be real anal about masking and try to get real clean lines, or should I mask it rough and then rely on cleaning paint off of the adjoining flats? (For example - if I paint the sidewall only, and get a little wobble in the line at the bevel, I could sand the edge of the bevel clean?)

Is there an argument that for this kind of job I might be better off applying paint with a brush? I can see maybe hand brushing the bevels and then cleaning the edges with chemicals and/or real fine sandpaper.

Is there maybe a somewhat transparent paint that would go on kinda like fingernail polish, without primer, giving the colored stripe a little depth?

 

[horsefarmer]

IDK about the best paint or surface prep, but masking would be tricky especially between the bevels. I think if it was "off" much it would pretty bad.
Maybe just paint the entire center area and leave the sidewalls natural? that way less masking and less chance that road debris or tire changing will scratch the paint.

 

[xray]

So, I understand you to say you think I should paint all but the sidewalls? If so, how does one mask the spokes?

If I was not clear - this wheel is already built.

And, yeah... I am thinking that I have a pretty difficult task here, to get right, and I am definitely considering NOT doing it.

 

[Junk Man]

To get paint to last good on bare aluminum you should use an etching primer first, but what about having someone who does hand pinstriping lay some line down instead? That could be done with the wheels assembled

 

[xray]

Junkman: Thanks for that suggestion. I had started thinking that way myself, a little bit, and a little encouragement is probably all I need.

Afterall, the original rims were white with a black pinstripe, so pinstripes are true to that original look. I'm only looking to add a little color - highlights or accents rather than going with the entire rim being painted.

I also was looking over new materials, at least new to me, and came across a couple of intriguing things:

1 - Plasti Dip... interesting stuff for doing a kind of translucent finish over metal

2 - hydrographic films! Wow - I never heard of the stuff until last night, but you can do some crazy stuff with it. Pre-printed designs that you float on top of a water bath, and then dip your pieces into so that it adheres. Then you clear coat it.

I might leave the rims and film coat the fenders with flames or skulls.

 

[Junk Man]

I've watched a bunch of YouTube videos on hydrographics.... That's some fascinating stuff!

 

[xray]

Yeah, I am surprised we have not seen more bikes done with hydrographic films here on this forum. I'm sure it is trickier to get good results than it looks in some of these videos - takes some practice - but such cool results in some cases.

 

[horsefarmer]

Wow! Really something.

 

[Duchess]

The rims are most likely coated with a clear anodize or clear coat. You'll have to get through that first, then acid etch primer. Masking shouldn't be too hard. I painted built V-rims and masked off the brake surface with 1" frog masking tape—just take it slow and steady, guiding it around the curve. It stretches pretty well, though you might not be able to do it in one piece of tape. The added bonus I found was that the tape folded over the lip of the rim as I stretched it around the curvature of the sidewalls. To mask the spokes, cut and roll a piece of tape for each of them or use a combination of tape and plastic straws.

 

[Bicycle808]

So, I understand you to say you think I should paint all but the sidewalls? If so, how does one mask the spokes?

If I was not clear - this wheel is already built.

And, yeah... I am thinking that I have a pretty difficult task here, to get right, and I am definitely considering NOT doing it.

I wouldn't even try. Painting rims presents some problems before the wheelbuild; painting the rims alone on a built wheel is a fool's errand. Why didn't you paint before you re-laced?

.........bent the dropouts back in to make them roughly parallel...

Just a thought--if you end up have shifting problems with the Nexus 8, this would be the second thing i'd re-check, after cable tension.

 

[xray]

Thanks - I decided not to paint or color the rims. The bike is nearly finished, and shown in the Builds forum as 62 Typhoon Nearly Complete.

I apparently got the rear drop outs right - the hub shifts great.

 

[Bicycle808]

Thanks - I decided not to paint or color the rims. The bike is nearly finished, and shown in the Builds forum as 62 Typhoon Nearly Complete.

I apparently got the rear drop outs right - the hub shifts great.

That's awesome!

 

[xray]

Thanks, man. I am obviously now using the bike as my avatar. I am really enjoying the 8 speed coaster brake.

 

[seangee]

You could use something like vaseline on the surfaces you don't want painted and then spray your paint. When it dries just wash the vaseline off, and with it, the overspray

Sent from my LGLS990 using Tapatalk

 

[LukeTheJoker]

If so, how does one mask the spokes?

Get drinking straws and split them down the sides, they then collapse in on them selves a bit making them a tight fit over the spoke nipples, just slide the straw on using the split over the spoke.

 

[5speed]

i use colord electrical tape comes in an arat of colors and widths,same thickness as paint,clead the surface,put it on,trim with a razor blade,less tha $2.50 a roll,try and get 3m,try it,if you dont like it,takes about 20 min per wheel,try it and let me know,ust did the side walls on some felt aluminum,ill try and do pics as i have them inside

 

[Pop.Cycle]

#takesnotes

I too am in a similiar predicament as I am mismatch in a set on my current build! Plastic dip peels off as big chucks if you scar it tho as I hear.....I am relacing mine with white nipples on one and building the rear from scratch for I don't have a masking issue but AM worried about tire changes as I am doing a whole color swap.....

 

[us56456712]

I have painted built rims. You have to tape EVERYTHING that you don't want to be sprayed, including the hub. Old rims that are already painted pose no real problem. I use etching primer. For built up chrome rims I have used etching primer, then adhesion promotor, then the color and finally 2 part clear coat. This is the best I have found for chrome but it still tends to flake off fairly easily and requires frequent touch up. If you don't use the 2 part clear you have to touch up your chrome after each use. Not recommended unless you have a clear vision of what you want and it is not otherwise available and you are OK with frequent touch up. I have also used Gorilla clear epoxy over painted chrome. It works but it is not very smooth, kinda lumpy. I have used the epoxy as a top coat on old chrome handlebars that I pained black. The bike was a faux old bike so it looked good. I would not do this on a bike that I wanted a smooth shinny finish on.