Master the basics of this cheap but powerful metal-shaping tool
Set up your shrinker/stretcher.
There are myriad ways of shrinking and stretching sheet steel using all sorts of tools. A bench- or stand-mounted shrinker/stretcher is one of the quickest, easiest, most predictable and quietest methods. Most shrinker/stretchers originate in the Far East, with prices staring at around £120. They wear many different badges – but they’re pretty much the same under the paint. Though a separate shrinker and stretcher is jolly handy, buying one tool body and two sets of jaws will be cheaper. A floor stand that allows foot operation is very handy, as it frees up both your hands. They can be bought cheaply – or you can make one yourself (PC, December 2015).
This type of small shrinker/stretcher is ideal for making all sorts of repair patches, as we’ll demonstrate. Many of these would be fairly time-consuming to make simply with hammers, dollies and a shrinking-fork. The shrinker/stretcher doesn’t mimic these hand-tools, but instead takes a swift and rather brutal approach to its job. It has serrated jaws that grab hold of the metal. The jaws forcibly squish it into itself to shrink it, or pull it apart to stretch it. It’s very effective indeed and once you’ve started using one, you’ll wonder how you ever managed without it.
The results are usually pretty good, though the finished piece may benefit from a little light correction with some brief hammer and dolly work. The marks left by the serrated jaws will need to be linished before refinishing, too.
This guide will show you how the shrinker and stretcher works and how to tune it up so it functions at its best. It’ll also help you to appreciate the interaction between the metal that’s shrunk or stretched and the metal that hasn’t been worked.
You will need Smoothly does it… Check it yourself Wire brush, grease, shrinker/stretcher. Don’t take it for granted that the shrinker/ stretcher was set up correctly at the factory. Check it as detailed on the opposite page. The best results are gained from uniformity. Move the metal through the jaws by the same amount for each ‘bite’ and exert uniform pressure each time. Always think of how the differential between shrunk/stretched metal will interact to create the shape you want. Plan your moves