Richard Sachs is a foremost practitioner of the high art of building steel frames.  We asked him to show us how it is done.

Tacking a frame in the jig allow me to take a frame design from paper and make it into a three-dimensional pattern. You have to be careful to tack it and not braze it. When I tack a joint, only ten percent of the area is covered in brazing material. By not fully brazing the joints, you can check the alignment and make changes if you have to. I'll tack the seat and headtube lugs on the jig, but I'll tack the bottom bracket on the alignment table, because then I can make sure that the bottom bracket is in alignment with the rest of the frame.

After it's tacked, I'll check the alignment and make any changes. This allows you to remove any stresses from the frame that would be built in later if you just went ahead and brazed the frame up without checking it. I like to say that my frames are born straight rather than built and straightened later, like production frames. I think that if I build my frames straight, they will stay straight. If they're built and then straightened, the frame will want to return to where it was, because steel has a memory.

I use silver brazing in the main triangle, and brass brazing in the dropouts. The difference between the two is that with silver, you're bringing the joint up to a temperature that's not visible to the eye. With brass, everything has to be much hotter, like red hot, so you have to get in there quickly, do the job, and get out, because you're concentrating a lot of heat in a small area and you can't do it for long. Silver you can take more time with.

Using silver is like repairing jewelry, whereas brass brazing is more like what you'd see at a Midas muffler shop. One's no better than the other; I've just gotten used to silver. It makes the joints easier to repair if the bike's been crashed, and it heats the tubes up less, so theoretically the tubes retain more strength than with brass, but some of the best builders in the world have been brass-brazing for years and their bikes don't fall apart, so . . . .

The thing about silver is you'd never use it on dropouts or in places where you need to fill gaps because it doesn't fill spaces; it's just for close-fitting joints. Brass you can use to build up a joint like on the rear dropout, where there are gaps to fill.

I'll dab the joint with silver rod until it fills, but without letting it overflow, because that makes the joint harder to clean later. It's something you have to learn from experience.
 

Richard Sachs is a craftsman framebuilder who has been refining his skills for over a quarter-century.For more information, please contact: