"Moving" dents around during body work?

[AKcharger]

I've heard that on flat surfaces like hoods dents can "move" around durnig repair. That doesn't make sense to me, can someone explain that if it's true. I did all the work on my two Chargers and never experienced anything like that.

AK

[Silver R/T]

Im not sure who told you that, its not true. What might happen is when you stretch metal you will have "tin can" body panel that will be able to pop in and out of shape in a spot. thats when you need to shrink it to make panel sturdy again.

[AKcharger]

a Pal told me tht happened to him on a hood he was working and read it again in Hot Rod®

[tan top]

What might happen is when you stretch metal you will have "tin can" body panel that will be able to pop in and out of shape in a spot. thats when you need to shrink it to make panel sturdy again.

 
yeah  if the metal has become stretched or worked too much with out shrinking , this is an example of a really bad case (witch would need  hot or cold shrinking) if there is a dent in a large flat panel  the edge around the dent has become slightly high and the metal in the dent has become stretched . if you can get behind the dent and tap it out with out using a shrinking method it may become really stretched & if you press the area it will oil drum( plink plink) pop in and out then if you were to bondo over this a high spot would show through the bondo when rubbed down . so then you would tap it down an another high or a low  would almost certainly appear close by because the metal has been stretched , & then you could end up with bondo- ing  most of the panel

[AKcharger]

OK, I see. so what is the remedy, heating up the area and hammer/dolly it?

[tan top]

you can cold shrink with a slapper file , shrinking   hammer / dolly , an air power grinder with a coarse fiber disc on it , moving it in a continues  circular  motion getting  smaller to the centre . that  can tighten the metal up ,   then run a body file over it to finish . or if you have access to a body shop use a carbon tip attachment on a single sided spotwelder . this will glow red hot  use it the same as air powered grinder or what ever you think is best for the given  panel ,and then wipe it with a damp sponge . or you can use a acetylene torch to do this ,( but unless you are experienced doing this , you may make it alot worse)  then finish with a hammer & dolly , body file ,   or what ever the repair needs.

[AKcharger]

Hmmmm well I may need some schooling on that when I get there. I'm planning on bringing the '70 down for another major overhaul in 2008 and the '72 is scheduled for 2010 provided I have a house to work in, until then I'm just enjoying driving them!

Thanks

AK