Bicycle Mechanics - MTB frame: Aluminum or Steel?

My apologies if this belongs somewhere else....

I have an older roadmaster bike, and it's extremely light. I'm planning on repainting it, but I need to know if it's aluminum or steel. My logic tells me that if it's as light as it is, it's probably aluminum.

As far as repainting is concerned, does it make a difference with regard to procedures if the frame is aluminum or steel?

Can anyone provide any insight to these questions?

Also, should I remove the cranks before painting or just tape them off?

Thanks!

does a magnet stick to it? If so, it is steel.

does a magnet stick to it? If so, it is steel.

LOL! I feel like an idiot. Such a simple way to find out and I didn't think of that!

I'm still curious about the repainting question.....

This is the first time I've heard the terms roadmaster and extremely light used congruently. As far as repainting, I would remove all the componentry before painting, and then face the BB shell and headtube before reassembling.

As far as repainting is concerned, does it make a difference with regard to procedures if the frame is aluminum or steel?

Depends on how thorough you want to be, and what results you're after. An all-out paintjob require disassembling all components and then stripping the frame down to bare metal. Media blasting gives a great result, but you've gotta use softer blasting media for Al than for steel. Al is a bit tricky to paint, and best results are achieved if you use an etching primer. Steel isn't as finicky.
But maybe you're only looking for a rattle can paint job on top of the current paint? In that case what's below the paint doesn't matter. Scuff, degrease and paint as your heart desires.


should I remove the cranks before painting or just tape them off?
Once again a question about your expectations for the finished results. Taping will just about always leave a border with messed up paint. If you're OK with that then taping off is certainly faster than disassembly.

Basically, I'd like to make it look good...I don't want it to look like I haphazardly took a can, sprayed over it a few times and let it dry...but I don't necessarily need to go for that "brand new out of the shop" look. I will be using a spray can...I've been looking at possibly doing a "chameleon" paint job...I've seen a few spray cans that do that. I may just use a single metallic color...

At the very least, you might be able to pull the cranks off the bottom bracket spindle. If it is an older bike, it would not be a bad time to repack the bottom bracket while you are painting.

Best results will be had from stripping, but if you are rattle canning it, you can probably get by with just going over the frame with sand paper to rough up the paint and give the new paint something to adhere to better.

This is the first time I've heard the terms roadmaster and extremely light used congruently. As far as repainting, I would remove all the componentry before painting, and then face the BB shell and headtube before reassembling.

Roadmaster and extremely light in the same sentence........ Maybe its a Carbon frame :):):):):)

I don't want to be "that guy" in this thread, but seems like someone has to do it.

A Roadmaster???? As far as I know, years ago they built 3 speeds that were practically made of cast iron. They were solid and reliable in their way, but not even remotely light. Probably around 36-7 pounds. And in the last few decades, they have been selling mountain bikey-like things at the Xmarts. Often with front and rear "suspension". These latter incarnations are extremely heavy and do not even have the virtuous simplicity of the earlier bikes that made them tough and reliable.

I think few people here on BF would call me a bike snob. I have a penchant for old, unloved old bikes. I am not a weight weenie. I love the idea of repurposing an old bike and giving it new life. But unless Roadmaster made something else that I am not aware of, I fear that every penny you put into this thing will end up being a disappointment for you. If I am wrong, and it is the right bike for you, I will gladly apologize and admit that I am a snob.

jim

If it were aluminum, wherever you got down to bare aluminum, you need to use an aluminum/galvanized primer. Regular primer comes right off. Using a spray can, you need to spray a clear coat over the top. Every little scratch shows up otherwise.

jgedwa, I kind of agree, except that he wants to paint his bike, and there's not much to lose. It's not like learning to paint on a better frame would make more sense. This way, he gets to learn how to do it, including the mechanical parts that will be necessary.

Joshman, painting metal, particularly metal that's going to get a fair amount of wear and tear, is no mean feat. If you're going to rattlecan it, you'll really benefit from stripping all the parts off. Mask the brake bosses and anything else you can't get off.

Absolutely, without a doubt, remove:

Wheels
Chain
Bars
Stem
Cranks and chainwheel
Derailleurs
Brakes
Seatpost
Cables

You can mask the headset and bottom bracket, but I'd remove them, myself.

Then go over it with very light coats of spray paint, leaving at least a day between coats to dry in a warm, dry area. If you don't live in a part of the world that is currently warm and dry, do it in a few months.

I should be clear: it's kind of a big job to do yourself. You'll need to get bike tools to do the dismantling if you don't have them, and Roadmasters aren't made to be dismantled; they're made to be used and thrown away, so stuff may wind up breaking as you take it apart.

I painted a frame (A Trek 7300 aluminum frame) a year and a half ago. It's got some chips, but it still looks OK. It's a long way from the factory-like finish my Cannondale has from the $75 powder coat I got on it.

(As far as I know, the only difference between painting an aluminum or steel frame is that you have to look out for the steel rusting quickly once you get the paint off. Don't leave it around overnight in a damp place or anything. Strip it and paint.)

Well, there are just a few more things to remove now...here's the pic: :D
http://img.photobucket.com/albums/v488/joshy380/021409_15271.jpg

sweet, what engine is that? I fly RC airplanes as another hobby of mine and I have a few gasoline engines 62cc made by Zenoah. But your engine looks like maybe a little larger than that.

Looks like the fork has a slight bend in it from a collision?

Looks like the fork has a slight bend in it from a collision?

I was thinking the same thing about the fork.

sweet, what engine is that? I fly RC airplanes as another hobby of mine and I have a few gasoline engines 62cc made by Zenoah. But your engine looks like maybe a little larger than that.

This is a Raw motorsports "80" cc engine. It's actually something more like 66cc's but it does the trick. It supposedly can go up to 35mph, but I'm still in the break in period and can't quite go full throttle with it yet. I'm a little scared to go that fast to be honest....

I can tell you one thing though, I need to look into getting some fenders for this bike as I'm noticing a lot of water (from the recent rains here in the OC) being kicked up from the tires. Got to work with a wet butt this morning, but it's worth it.

As far as the bend in the fork, it doesn't seem to be from a collision, as the stock paint isn't cracked or showing any signs of a collision ever occuring, and the bends are equal on both sides of the fork.

I was thinking the same thing about the fork.

Me, three.