[R-390] Dent removal

[John Lawson]

On Sun, 3 Jul 2005, Dan Arney wrote:

> Tim, you are peeing upwind into a hurricane to try and get the panels 
> straight. If you heat it like some one suggested you will remove all of the 
> alodine.

   Alodining kits are available from several sources - and they're in the 
same average toxicity range as PC-board etch stuff, etc.  I have managed 
to re-alodine several pieces of mine, and we do it to very large items 
where I work, re-furbing military aircraft ground support gear.


> Heating aluminum with a torch is asking for blowing a hole in it in a blink 
> of the eye due to the low flow point of aluminum.

   For heavier guage aluminum and soft steels - we use an oxy-acetyline 
torch fitted with a 'rosebud' to spread a lot of heat over a large area. 
For the lighter, thinner stock we, and I, have straightened out panels 
that were bent, crumpled, and had holes knocked in them, using a plumber's 
MAPP-gas torch.

   Of course if you don't keep the flame moving, and don't practise any on 
similar scrap pieces until you get the hang of it, then what you describe 
is bound to occur.

   HOWEVER - when pounding the dents out of thin sheet metal, some form of 
annealing and re-tempering of the affected area is needed to maintain the 
dimensions of the affected piece, and it is common practice in all shops 
doing any kind of sheet-metal work, to use a torch to heat the work.

   Besides, in the few hurricanes I've had the dubious 'honor' of being out 
in - the continuous sheets of 90-mph horizontal rainfall would tend to 
obfuscate the fact that one was micturating therein....  ;}


   Have a great 4th y'all - let's pause in between the food and the TV to 
reflect a minute on what this Monday stands for - and all those who have 
given up their lives so I can hang out in my back yard with a burger in 
one hand and a brew in the other...


    Cheers

John  KB6SCO