Shot peening titanium has 4 major benefits:

• Fatigue life is enhanced significantly increasing the useful life of the frame
• The frame is stress relieved so that all of the component parts work together
• Surface hardness is enhanced, increasing resistance to scratches
• An aesthetically pleasing finish

Shot peening is a cold working process in which the frame is bombarded with small spherical metal balls called “shot” at a precise angle. Shot act like tiny ball peen hammers and create a uniform dimpled texture on the surface of the frame. This compacts the outer layer of the material.

The processes of butting and welding titanium tubes to make a bike frame are known to create tensile stresses in the frame material. Tensile stresses make the area in question want to pull itself apart. This is a bad property to impart to a bicycle frame as any minor notch or micro crack in the frame will want to propagate and further compromise the material. The induced tensile stresses are most concentrated in the heat affected zone — the area of the welds. Thus, strength is compromised precisely where you would like it to be greatest.

Shot peening a welded titanium joint substantially increases both fatigue strength and fatigue life. Shot peening imparts what is called residual compressive stress which counteracts the residual tensile stress, which is created in the process of cutting, grinding and welding. Typically, fatigue strength of a welded titanium joint after shot peening is double that without shot peening. Fatigue life is enhanced by shot peening to an even greater degree.

By shot peening the frame after it is welded, we are able to relieve the stresses in the material providing compressive qualities, which are known to reduce micro cracking and enhance fatigue life. Without stress relieving, each of the tubes will retain tensile stresses which tend to conflict with one another. Stress relieving allows the component tubes of the frame to work together as designed, acting as a unified structure rather than a collection of competing parts.

The shot peening process work hardens the surface of the tube, while giving it a finely textured surface. These two properties together create an attractive finish that is highly resistant to scratches. If scratched, the scratch is harder to see because the surface is textured. The textured surface glitters in the sun in a manner similar to that of a pearl paint job.

Some people may confuse shot peening with sand blasting or bead blasting. At IF, we use sand blasting on our steel frames to remove contaminants. We also use it to put a microscopic tooth to the surface of the metal to provide a mechanical bond with the paint. Bead blasting is used for cosmetic purposes to provide a uniform finish to the surface of the metal. Neither sand blasting nor bead blasting improve the mechanical properties of the metal.

Shot peening is used precisely because it improves the performance characteristics of the finished parts. It is used in the aerospace industry, in high performance cars and motorcycles, and in light weight bicycle stems and bars where light weight and high strength are performance imperatives.

We collaborate with Metal Improvement Company in Wakefield, MA, which specializes in shot peening high performance parts for the aerospace industry. At Metal Improvement our frames are peened along side of parts for the space shuttle and F14 jet engine rotors.

See www.metalimprovement.com for more info.

To shot peen properly requires the use of very large, sophisticated, and expensive computer-controlled equipment, and trained personel. Shot Peening really is high-tech stuff, and it’s tough to get right. We decided to leave it to the specialists. In addition, we are confident in the established leadership, reputation, and quality of Metal Improvement.

No.

The shot peening flow at less than 85 degrees is known as overspray. This neither helps nor hurts the frame surface. It does nothing to a previously unimpacted surface and it does not detract from a previously impacted surface.

Your bike is painted with the same high quality PPG paint that is usedin the painting of most show quality custom hotrods, sports cars and motorcycles. But, unlike cars, bicycles take a lot of abuse from being leaned up against parking meters and, in the case of mountain and cyclocross bikes, running into rocks, stumps and brush. Even after the curing process is fully completed (about 6 weeks) scratches and/or chips in the paint can happen, road debris, roof rack transport, wild animals, clumsy friends, etc.. can all have a negative impact on your frame’s painted surface, it is not bulletproof either but, after the six week curing period is over, you can do your best to protect the frame’s finish with the application of a liquid or paste wax.

If does not sell touch up paint. If you do damage the paint, you can obtain touch up paint from any auto supply store (call IF for thePPG reference number). Alternatively, you can use Testors model paint(available in most hobby shops) or nail polish (available at most drugand department stores). Before applying any touch up paint, be sure to clean the affected area with denatured alcohol to remove any oil or wax so that the touch up paint will adhere properly, do not use nail polish remover or acetone at any time, this WILL damage your paint. Light scratches can often be removed by the use of a light grade of automobile rubbing compound available in all auto parts stores. Use it sparingly as you will be rubbing a portion of thepainted surface away. Once the scratch is removed, you can restore the polish by the application of liquid or paste wax.

Because of the increased strength of the new steel alloys we have been able to reduce the wall thickness of our tubing substantially, saving you more weight than ever on our current line up of custom steel frames. But, due to this reduction in wall thickness of the tubing, we must be alert to the possibility of corrosion. To battle rust on the inside of the tubes we actually fabricate the frame to be completely sealed from the elements, with the exception of the seat tube. Although we ream the seat tube to exacting tolerances water can still find its way into the seat tube, either through the top of the seat post or (via capillary action) between the seat post and the seat tube. To protect the internal surface of the seat tube we treat it with 3M Rustfighter 1 Internal Panel Coating prior to shipping the frame to you. Although this is the best product available for this application IT IS NOT A PERMANENT METHOD OF CORROSION PREVENTION AND SHOULD BE RENEWED PERIODICALLY.

WARNING: Seat tubes that have a serious rust problem due to lack of proper maintenance will not be covered under our warranty. Remember: your frame is made of steel, steel rusts, protect it if you want it to last.

Each time your steel frame has been exposed to wet conditions, or at least every 3 months, the following procedure should be:

• Remove the seat post and leave the bicycle upside down overnight so that the seat tube can drain and dry. This is best done in a warm and dry environment not a cold damp basement. We recommend hanging your bike from the front wheel when not in use, just for safety’s sake.

• Before reinserting the seat post make sure that the interior is dry and spray an even coating of, J.P. Weigle’s Frame Saver or its equivalent into the seat tube. Make sure to cover the entire inner surface of the seat tube.

• Apply a light layer of grease to the seat post before you re-install it into your frame.