I'm a rookie metal shaper and I'm going to shape a rear fender. I shaped one some time back but I did a lousy job on rolling the fender lip. So for this one I am going to make a simple buck out of 3/16'' round bar and some bondo. I'm making the buck just so I can use it for a hammer form for the fender lip and flanges. This is way overkill for a one off fender but if it works it will be well worth the three hours it took to make it. Started off by forming the wire to the inside of the fender. It does not have to be perfect. You actually want up an 1/8'' from the fender so the bondo will be able to flow underneath the round bar. Make sure you will be able to get the wire form out from the fender. I actually recorded a flange and then cut it out so I did not have to make this a two piece wire form. Next I remove the wire form. While it was removed I waxed the inside of the fender heavily, the wax will act as a release agent for the bondo. Then apply the bondo and let it set up. Then I tapped it with a rubber mallet and it released from the fender. Next I will be taking a flexible shape pattern from the fender. Some might be able to shape this fender with a simple paper pattern but for me information is the key, so the more information I have the better off I will be.