what is a slapping file, and How to use.
Is this something for high spots? How is it used?
Last edited by Reamer; 07-21-2006 at 09:54 PM.
A slapping file is an old time body tool used in place of a hammer that worked/works a lot better on the older thicker softer sheet metal of the cars 50+ years ago than it does on the newer high tensile strength thinner steel bodies we work on today. With the coarser teeth on the file it can work a little as a shrinking tool also. It looks like a regular large file with coarse teeth and a bent tang (handle). It was never one of my favorite tools. If you would like to see a picture of what they look like I can take a picture of one of my slapping files and post it here.
It is a bit more complicated than that.
People that understand metal and moving it can use a slapping file to shrink metal. That starts to be closer to advanced metal work.
You have to understand the cause of the high spot you are trying to fix. More often they are caused by shrunk areas or creases. The true fix could be across the panel and not obvious to all but the most experienced metalworkers.
You could try beating the dent down, but that might just cause another else where. You could try shrinking it with heat and end up with two more else where. Keep in mind you can ruin a panel faster with one heat shrink then you might ever believe possible.
A tool related to the slapping file is the smooth faced slapper. These can be made from a portion of a spring. They are used to planish the surface of the metal. Planishing done right can anneal the metal (make it softer) and get it level. Planishing is done after you have rough shaped the metal with a hammer and you need to get the hammer marks out.
Do some searches on metal shaping on the web to learn more. There are a lot of resources out there, but you have look around a lot.
You can also learn from older autobody text books used at votechs and by watching some the of the videos on metal working. You will also need to do many many hours of practice.
Phil, Please do I'd like to see if my memory is working right . If it's what I think it is I have not seen one in 30+ years . Thanks.
Originally Posted by Phil V
They work great for sorting out car roof's that have been sat on, pushed in & have creases. I use mine all the time when doing bodywork. Look here:
Gee, I have one that I haven't used in 20 years.
My understanding is that planishing does not anneal the metal. Annealing takes place by carefully heating metal to a specific temperature then cooling it down at a certain rate. Planishing makes lumps or ripples in the metal smooth. It will do little to remove hammer marks. Best not to get them in the first place by dressing the hammer face and edge. A slapping file is a cross between one of the most useful and one of the least useful tools in metal finishing; a slapper and a shrinking hammer. Skip the part that marks the metal and go straight to a smooth slapper. After smoothing, even something as simple as a clogged sanding disc mounted to a polisher or sander will do a better job of shrinking than a slapping file or shrinking hammer... without marring the surface.
John, I was hoping you would post in this thread. I think we can all agree that you are the top resident metal smith. I've worked with a lot of professional bodymen and it is very rare that they have honed their metal smithing skills to an art form. I'm relatively skilled at working sheet metal but never had the need or the desire to develop that skill to the level of an art form.
I agree that the more your work metal the harder and more brittle that metal gets - hence the old saying - work hardened metal. One of the main reasons a slapping spoon or a slapping file is not used much anymore is that the metal on the cars for the last close to 50 years is a thinner higher tensile strength steel and not the older thicker softer metal of the older cars. The only more modern vehicle that I've worked on that still had the thicker softer metal was the venerable VW Beetle. I was amazed at how the metal could be worked on those cars compared to their American counterparts. Slapping spoons and slapping files don't lend themselves well to working high tensile strength thin steel.
I don't work on anything built with that stuff
Originally Posted by Phil V
I agree it sounds wrong that planishing anneals the metal, but I have run across references to this in a couple of places.
I believe one place I found it was in a discussion of air planishing hammers. It sticks in my mind because the idea of planishing the metal to anneal was way contrary to intuition. The author made it clear the metal was easier to work after planishing. I have found at least two references to this in my reading of books and on the net. Of course, the problem is finding the reference. I will email you if I run across it again.
This discussion on a metal working forum probably sums it up:
I do remember the references I had read were not very wordy, but they did talk about annealing. I believe annealing was wrong term that the writers had used. The removing of wrinkles will make the metal easier to work.
Hi Phil V,
My expertise/interests are pretty narrow in scope...too narrow to call myself a true metalsmith, but thanks!
Hi Lost in NJ,
I remember that thread. A pretty good example of lots of good information getting a little tied up in terminology...I still wonder if a shrinking disc actually anneals steel. It sure seems to, but nobody has answered the question authoritatively.
I do not know if one could really say the shinking disk anneals the metal.
For background we would have to keep in mind how we anneal. To anneal steel we need to bring it up to a certain tempurature and let it cool slowly. I have been taught you need to get to a uniform dull red to anneal, which is pretty hot. I would have to look up what is considered the correct temp for steel (I am too lazy to wander over to anvilfire at this moment). Then let it air cool.
I think you need to have the metal analyzed by an expert to know for sure.
Clearly it heats the metal so it does something with the crystal structure. To say it anneals might be a far reach. Certainly, if you are not letting the metal cool by air you are not helping it anneal.
I have done several experiments with a shrinking disc. One was stretching a bulge in a fender and shrinking it about 50 heat and quench cycles over a period of hours until it was all the way back down to its original contours. No signs of the metal work hardening. Actual results matter more than terms which is why I hesitate to use the term anneal. It usually devolves into a theoretical discussion. I care more about the work than the terminology. Here is the album showing the test:
This proves to be the most gradual and gentle way to do a drastic change in shape with heat shrinking... and no ill effects. The temperatures achieved are lower (not red hot or even blue) which may be part of why the metal stays workable.
This is comparable to the opposite effect of an english wheel which does very gentle stretching and smoothing for major changes in surface area without noticeable work hardening.
sorta got lost here, back to original ?
So how is the slapping file used?
Originally Posted by Reamer