Learn How To Work Metal with Ron Covell
No clever tools here, just a straight edge rocked across it to check for evenness and the reflections of a strip light to check for non-conformities in the curve.
Words and Pictures: Mike Pye
Last year we were fortunate to be offered the opportunity to attend one of Ron Covell’s metalworking courses, organised by Kris ‘Pop’ Brown and hosted by Fintan H Ellis at his premises in Odiham, Hampshire. When, at the end of that weekend session, Ron asked the assembled visitors if they’d like to do another course, almost all those present put their hands up, so it was no surprise to see a similar group of people assembled for this year’s course. The subject matter this year was aluminium, more specifically working aluminium, from annealing through shaping to welding and metal finishing – in this case a ’34 Ford rear fender and the tail section of a Midget Sprint Car. The course took the same format – Ron up the front explaining, doing the demonstrations and answering questions from the floor. As such, it’s not exactly a hands-on experience, though everyone I’m sure came away with some helpful tips and ideas for how to improve their own metalworking skills. Once again though, watching someone with Ron’s skills and experience at work made me realise how much I have to learn and, as good as any workshop or lesson is, the bottom line is you just have to get out there and practice.
“From annealing through shaping to welding and metal finishing”
Section 1: Annealing
For all those who, like me, end up using whatever scrap of metal they’ve got lying around, a brief discussion on the different types of ali to use for forming work was enlightening. 1100 grade is pure aluminium, but Ron prefers to work with so-called 3003 ali – an alloy with 3/10 of 1% manganese added. In the UK, the nearest to that we get is 3101. The manganese element gives it a little more strength and makes it easier to weld.
An H14 designation means it’s in the half hard condition, and this is what you want to buy. However, annealing changes it into the full soft condition, which is preferable for working. To do this, the metal must be heated to 800°F (450°C). The trouble is, unlike most metals, aluminium doesn’t change colour when heated, and if you go too far it turns to cast metal and soon after jelly. The trick then is to coat the metal first, either with soot from an oxy-acetylene torch or – and here’s another neat trick – with permanent marker ink, then you heat that area until the marking disappears. It’s not time dependent, so you don’t need to rush, but the metal will start to work harden as you hammer / work it, so you may find it helps to re-anneal a piece as you progress. And only anneal the bit you’re going to work, not necessarily the whole piece. Be careful though, over anneal it i.e. get it too hot and it’s scrap.
Section 2: Wheeling
A wheeling machine (or English wheelif you prefer to use the US parlance) is one of those tools most people have heard of but few will ever get to use. It’s one of the hardest metalworking tools to master but what was useful was a discussion on how different tracking patterns can be used to produce different results and how raising the pressure between the two wheels increases the curvature introduced.
Here you can see the regular paths taken across a panel to produce an equal curve in both directions, while the illustration shows a ‘staggered stop’ technique, which Ron suggests for helping blend edges into a dome in the centre of a panel. The key thing I learnt, however, is that a wheeling machine will only bring metal up. If you go too far, you can’t turn the piece over and work it down again, the only way to reduce an introduced contour is to bring the edges up around the raised area. And that’s very difficult to do.
Apologies for the out of focus picture but, for an old guy, Ron doesn’t half move around! As we’ve said before, sometimes the simplest tricks are the best. What we’re showing here is Ron ‘sighting’ the curve he’s introduced into a panel.
Section 3: Hammer and dolly work
A great deal of Ron’s shaping work was done with nothing more complicated than a hammer and dolly. The trick is to use a former with the right curvature for the job, not just the same one for everything and blind hope. Hand held dollies are fine for some work, but a post dolly like this, held firm in a vice is much more controllable and here Ron’s using one to put a gentle curve into the top of the main panel where it will meet the second, more complex panel.
The metal you’re working over it can be either hit direct or with glancing blows. What I noticed was that Ron did all his shaping like this with a slap hammer (indicated), rather than a normal body hammer – his reasoning being that it spreads the force out over a larger area.
Section 4: Shrinking / stretching
Last month, we mentioned some of the tools used to make different types of panels and parts. Here’s a shrinker / stretcher in action – in this case shrinking the return lip to form a curve into it.
These tools work by having serrated jaws that grip the metal and physically pull it closer together – keep running it through and the curve will tighten further, until the metal actually wants to overlap. Though they’re not cheap, you can buy something similar to this for home use that has interchangeable jaws and will do both functions. You’d be amazed what you can do with it with very little practice.
Section 5: Complex shaping
We’ve shown you basic mallet and sand bag shaping before, so here’s a complex panel further down the line that was started on a sand bag, further shaped with a hammer on a steel work bench then rolled through the wheeling machine to smooth out the hammer marks.
The tricky bit was putting the second reverse curve in, and to do that Ron used nothing more clever than a dolly and slap hammer. What was interesting was that he used one of the curved wheels from the wheeling machine as his former, obviously taking great care not to damage it in the process. Note: this is not the kind of panel you’re likely to be producing in your first week of metal shaping...
Section 6: Hammer Welding
Put all the above together and you could end up with something like this. Yeah, right. What is interesting though is that this one panel, or two to be accurate, cover most of the techniques you’re ever likely to use in metalworking.
Once accurately positioned, mark the panels with a reference, or witness, mark so they can be removed and accurately re-positioned. A permanent marker line or scribe line will do just fine. When trimmed (always rough cut first ¼-inch outside the final cut line, then trim down) and happy with the fit you’re ready to weld – no ugly overlapping welds here, neat butt welds are the order of the day. Here Ron chose to tack the two pieces together with a TIG welder, then planish the welds for a neat, strong join. Planishing is the act of making smooth either by hammering or wheeling. Ron opted to hammer the welds smooth over a post dolly. Note, this hammer welding technique does not work with MIG welding, so if you want a perfect finish, you’ll have to get the grinder and flap wheel out.
Section 7: Metal Finishing
No matter how neat your panel looks, there will be some imperfections that need to be worked out. A body file (seen here in the background) may seem a harsh thing to attack such a beautifully shaped aluminium panel with but it does the trick, knocking off the high spots and showing up the low spots in your work. These can then be picked up either by hammering on dolly or, as here, with a bullseye pick, which has a pointed end that taps them up from underneath. Once you’re happy, you can go as far as you like with the final finishing, but remember that every process removes some metal and you don’t want to end up with a wafer thin panel. A car like the track-nose roadster we featured last month had been taken to the limit and finished all the way to a Scotchbrite pad but, as Ron put it, “the trick is knowing when to stop.”
Oh, and in case you wanted to see the ’34 fender we mentioned at the beginning, here’s what Ron made on the Saturday. It’s only tack welded and still needs the return flange adding, but that’s not bad for a few hours work, eh?
Read this article in the November 2009 issue of Custom Car magazine(p16-17).