[BentHammer]

I'm planning to build a frame (a trike, specifically, but this would affect standard bikes too). I'll be using 4130 cromoly. I've read about a substance that can prevent rust. I suppose that I could just run some paint down the tubes, but there'll be no practical way to keep it from pooling (and this creating a lousy seal to the metal and not giving much protection).

Anyone know what I can use to avoid rust inside the frame?

Thank you.

 

[binary visions]

There are a couple products made specifically for this problem. Probably the most popular one is a product called Framesaver. It's simply an oil that has something mixed into it (some kind of adhesive?) to cause the oil to coat the frame rather than just running off and pooling at the bottom bracket/chainstays.

Your LBS should be able to source some for you. Doesn't seem to be popular at online shops though I did find this place. A similar product is called Boeshield but I've got no indicates as to how well it works - never known someone to use it.

 

[BikeGeek]

A similar product is called Boeshield but I've got no indicates as to how well it works - never known someone to use it.

It was developed by Boeing as an aircraft lubricant, but caught on with boaters as a serious corrosion inhibitor. I was planning on using it in my new frame. I'll report back next January on how well it worked.

 

[BentHammer]

Hmmm... both nice... but both list as aerosols. I want a solution that I can pour in, since I will have limited access to the inside of my frame. I can gin together a spitball to spread things (fuzzy ball 2.5" in diameter [for my two inch tubes] with a wire to drag it through the tubes, spreading whatever goop I decide on evenly over the entire ineteor surface) but a spray is going to be ineffective.

Should I just go with a durable oil-based paint, spread it well and run low-pressure dry air in one end of the tube to assist drying? I'd like to do this once then forget about it forever, ideally.

One monkey wrench in the works is that I plan to cap these tubes during the welding process. I can easily enough tap in an allen screw but it will be of limited size. So I would either need a solution that could be worked in through a .5" or so hole (I might be able to work the spitball through that) or I need a solution that will stand up to the temperatures of TIG welding for a minute or two. Powdercoating? (that'd be a bit pricy for something I will never see!)

 

[binary visions]

Just out of curiosity, why cap the tubes? Isn't that excess work for little or no gain?

Tapping a small hole in the caps should allow you to get the Framesaver junk in there, you'd just use some plastic tubing to direct the flow of the aerosol cans. Might have to use more than is necessary and then pour the excess out.

Don't know what will stand up to welding, though, sorry. I'm not much of a materials guy.

 

[BentHammer]

I want to cap the tubes to seal them, so that they will not be exposed to water, salt, lava, whatever I am riding through. On a trike, at least the main tube is exposed at both ends- that's what I plan to cap.

 

[BikeGeek]

You should be able to use the little red tube that comes with some spray cans (wd40, some bike lubes, etc.) to direct the spray into any tube on your bike. My understanding is both products are liquids that dry to a waxy covering, so you should be able to work it around your tubes before they dry.

 

[BentHammer]

I'm still leaning towards paint. If I could assure myself that my little spitball would spread it well enough to seal the metal (appearance is irrelevant... who'se going to be in my bike's tubing anyway?) I would just call this good. I hope to never have to retreat the frame.

 

[Reactor]

I'd stay away from the paint, especially if you are going to seal the frame, it's not going to have a serious corrosion risk if it's sealed. You could use your small hole to put on a fitting, pressurize it and leak check it. Then spray some framesaver or boeshield in and cap it. Boeshield, if I'm not mistaken is really just a very light weight machine oil mixed with a trace amount of parafin. It should work fine.

 

[Wumpus]

Linseed oil works too.

 

[H8R]

I'm planning to build a frame (a trike, specifically, but this would affect standard bikes too). I'll be using 4130 cromoly. I've read about a substance that can prevent rust. I suppose that I could just run some paint down the tubes, but there'll be no practical way to keep it from pooling (and this creating a lousy seal to the metal and not giving much protection).

Anyone know what I can use to avoid rust inside the frame?

Thank you.

If it's sealed, as in the welds will fully close the tubes, no worries. If it will have drain holes, etc, then yeah Framesaver is great.

Or: a couple times every winter, strip the parts off the frame and spray in some WD40 and swish it around - let it air out for a few hours and re-build. Works well.

 

[H8R]

What are you welding this with anyway?

 

[Wumpus]

Independent Fab uses Weigle's.

Required Maintenance
Each time the frame has been exposed to wet conditions, or at least every 3 months, the following procedure should be followed for IF steel frames:

1)Remove the seat post and leave the bicycle upside down over night so that the seat tube can drain and dry. This is best done in a warm and dry environment. Bikes which are routinely hung by their front wheel for storage have the fewest incidents of rust.
2)Before reinserting the seat post, spray a generous amount of, "J. P. Weigle's FRAME SAVER" or its equivalent into the seat tube. Cover the opening and agitate the frame to insure that the Frame Saver covers all of the inside of the seat tube.
3)Apply a light layer of grease to the seat post before you install it in the frame.
4)Bikes which are routinely hung on a wall hook by the front wheel tend not to have seat tube rust problems as the water has an opportunity to run out while the bike is not being used.

NOTE: Do not use a product such as WD-40 as this will wash away the Frame Saver and make your frame even more vulnerable to rust in the future.

Frame saver is available at most bike shops or may be obtained from IF or directly from J.P. Weigle's Frame Saver at 860-873-1671.

I've use weigle's on all my steel frames. You just spray it in (even the little drain holes on the stays) and tilt the frame around to make sure it coats everything and you are good to go.

 

[H8R]

NOTE: Do not use a product such as WD-40 as this will wash away the Frame Saver and make your frame even more vulnerable to rust in the future.

Hmm. Good to know.


It really does have thousands of uses. Frame Saver Stripper is a new one.

 

[BentHammer]

What are you welding this with anyway?

The full recipe:
4130 cromoly tubing, 1.75" x .035 wall
TIG welding

The rear frame will be a triangle cut out of a mountain bike. The front frame will be a single spine running from the old seat tube to the pedals, and a cross axle bent to around 110 degrees.

I plan to cap the tubing, both for appearance and for protection. Just to allay my psychotic phobia of rust, I plan to drill out the end of one cap and tap it, spray in rust protection of some flavour, then put an allen screw in the tapped hole so that no water gets in.

In some future build I may want to route the cables through the tubing, but that's really just vanity for me and I'm not worrying about it in this build. So the interior surface of the tubing will have limited exposure to the elements, assuming that my brother can run a good tight seam

 

[H8R]

The full recipe:
4130 cromoly tubing, 1.75" x .035 wall
TIG welding

I plan to cap the tubing, both for appearance and for protection. Just to allay my psychotic phobia of rust, I plan to drill out the end of one cap and tap it, spray in rust protection of some flavour, then put an allen screw in the tapped hole so that no water gets in.

As far as I know, if you fully seal the tubes with welds, no rust will occur.

Tapping it would be unnecessary.

 

[Wumpus]

As far as I know, if you fully seal the tubes with welds, no rust will occur.

Exactly. There might be a very light surface rust if for some reason the welding doesn't drive all the moisture out.

 

[Zookster]

Use the frame saver it does the job, I used it on my boys BMX and no rust.

Even though the can is an aerosol, it contains a large amount of liquid. I would just drill your little hole when you’re done, spray the entire can into this hole and just rotate the frame around slowly to coat all the tubes. It will take a while but it will work I think.

 

[Kornphlake]

You could just use a sacrificial annode in the form of a magnesium or zinc plug and that would corrode instead of the steel, you'd just have to remember to replace the plug every couple of years.