Body work welding? Tips n Tricks Please!

[timbosaurus]

I made my own flipper at trade school and still have it now, 14" bastard file, heat up the middle area with an oxy then put 2x 45degree bends to form a handle then grind the handle area flat so that you're not filing your skin off when you use it.

And that's exactly how it should be done I don't know if you can even buy them.

To stretch the metal use a flipper.

There is a LOT to metal finishing, but usually you use the slapper/flipper to shrink metal, not strech it.

Two hard domed surfaces (hammer and dolly) hit with a fair force will obviously strech metal.

But when you use a flat dolly under a small bump and hit it with a slapper/flipper, it actually shrinks it down to a flat surface. The sharp file edges tend to grip the metal on the outside and squeeze it together as you hit it. Thats how you get a rippled panel smooth without stretching and jam-tinning it.

I prefer oxy welding for panels, but that maybe because my TIG skills aren't up there. But I can't see any disadvantage if you use mild steel TIG rods.

MIG is great if you just want to patch a hole and fill it so that your car lasts another 10 years... but if you plan to metal finish the work, then you must use oxy (or I guess TIG) with mild steel rod. You can't planish the really hard beads of MIG weld.

[Alex]

Timbo, you are spot on when it comes to using an oxy for metal finishing, but a flipper can most definatly be used for stretching metal only, it is not used for shrinking at all, the texture of the file spreads and thins the metal like crazy, therefore stretching it, pretty much any hammering or tapping force on sheet metal is always going to stretch it.

There are special shrinking hammers you can buy but they do'nt work all that well, thats why heat shrinking with an oxy is the best way to shrink.

[barned01]

I made my own flipper at trade school and still have it now, 14" bastard file, heat up the middle area with an oxy then put 2x 45degree bends to form a handle then grind the handle area flat so that you're not filing your skin off when you use it.

alex, can you or someone else post a picture? google images is letting me down and constantly showing me dolphins and a lady with extraordinarily large breasts

[Hurricane]

what i do is tac the sheet in all the corners then half way in between those weld , then maybe every 2'' or so along the panel join, then i get a damp cloth and hold it on the back side of the panel, weld in 1'' lengths runs but say at least a foot apart between each one, or keep switching from one end of the panel to the other to stop heating one area up as little as posible.

as for warps i have not tryed it yet, but you can get a grinding disc that is just like a smooth dish, run that over the warped area then stop when it heats up and very quickly blow cold air over it to rapidly cool it and i beleave it will shrink it a little, so you just keep goin till its shrinks enough.

can also use on oxy and water.

i also just use a mig for panel steel as it heats it up the least ive found.

dan.

["Z" UTE]

Sometimes you have to have a good mate handy when doing car repairs. The brass/aluminium block will have to be held in place by hand, and unless you are the rubberman, your arms are just not long enough. Brass is definately non-magnetic.

The real advantage with oxy, is the ability to control the heat into the job. You can also temper an area around a weld, to allow a bit of give before dollying. Quite hard to do that with a TIG.

cheers Chuck.

[Alex]

alex, can you or someone else post a picture? google images is letting me down and constantly showing me dolphins and a lady with extraordinarily large breasts

this is my flipper and dolly

[ReQuieM]

Cheers guys, I have previously only used a 'soft' base for stretcing, shot/sand bag. I grabbed a file to turn into a s/flapper and some .8 wire but ran out of time to try it out today, so it will have to wait till the weekend.

Interesting that you leave the teeth on the s/flapper, the main book I've previously referred to used a polished surface one, so as not to mar the surface. Although he says he uses that s/flapper for smoothing the surface after forming.

[Alex]

If you use a sandbag it's fine but the effect wont be as agressive, which is a good thing if you do'nt have much experience doing this kind of thing, so there is less chance of fudging it up.

The idea behind leaving the file texture intact on the flipper is to stretch the metal, if it was smooth you would be just "planishing" (smoothing out the area).

[timbosaurus]

The best thing about metal finishing is that there are so many ways to work it. The down side is like this, where two people get different results from using the same tools and trying to explaining the difference

Anyways, the way it works for me Alex, is holding the dolly under a small low... like a small hail dent (of which a rough panel is just a large collection of). An easy way to find theses in addition to using your hand is to coat the panel in prussian (sp?) blue or toolmakers die. It wears off the high spots quickly, and makes the low spots obvious. When you move the dolly under the low spot and tap it gently with the slapper, the file edges 'grips' the two surfaces either side of the low spot, and the dolly brings the low up flat, effectively shrinking it. Try it one day, it works surprisingly well I've never had to heatshrink a panel planished this way, but when I use to use a hammer i'd occasionally have to.

All i'm saying is that everyone has their different techniques, and the slapper most certainly can shrink metal when used as above.

The only time I use a shotbag is using it to stretch metal. Hard blows with a mallet into the bag make nicely crowned surfaces ready for planishing.

Really good hearing other people techniques Alex... thanks for posting them!

Cheers,
Timbo

[Alex]

When you move the dolly under the low spot and tap it gently with the slapper, the file edges 'grips' the two surfaces either side of the low spot, and the dolly brings the low up flat, effectively shrinking it. Try it one day, it works surprisingly well I've never had to heatshrink a panel planished this way, but when I use to use a hammer i'd occasionally have to.

All i'm saying is that everyone has their different techniques, and the slapper most certainly can shrink metal when used as above.


Cheers,
Timbo

The technique you are talking about is'nt actually shrinking the metal at all, the flipper simply does not shrink, that technique is a way of moving the lows up level with the highs, so all you are doing is adjusting the metals shape, i've done this many times, it is just the same as useing a hammer but by using the flippers width and holding it nice and flat you can get a more even result by covering more of the "high" area and what the dolly is actually doing is pushing the dent out.

I'm not trying to be a smart arse with you, but i am a qualified Panel Beater with years of experiance and i agree with you that there are many different techniques that people use and i am always open to learn new techniques, i must admit that shrinking and stretching is one of the things most people struggle to get there head around.

[o_man_ra23]

Anyone got a vid of a flipper/slapper in use??

This is some good reading.

[timbosaurus]

I know you're not trying to be a smartarse Alex, don't worry about that. I hope you realise that I'm not trying to be either, but my experience has definately been using a slapper to shrink metal, and while looking around the net to try and find some footage for Oman, I see that many people actuallycall slappers/flippers "shrinking files", and the hammers with a file face are called shrinking hammers.

I guess we'll just have to happily disagree on this one

What I expect is:

You start with a flat 20cm long sheet of tin fixed at both ends. You put in a few dings that makes the surface wavey. The length of this piece of metal from one end to the other is still 20cm, but if you measure it through all the ups and downs it might be, say, 20.5cm.

If you then simply 'smooth' this out with a hammer and dolly you will be left with either a slight convex or concave shape that will need heatshrinking.

But, if you hold a dolly under the low spots and gently slap, it cold shrinks the metal and will make it smooth and back to 20cm long.

Regardless, ReQuieM, try it one way, and try it the other. What works for some, doesn't work for others, so the best way you learn is through experience.

[Alex]

I'm glad you're not taking me the wrong way and not taking you the wrong way either, i can most definatly see where you are coming from with your argument, but we must do things differently.

I am happy to disagree too

[o_man_ra23]

Don't lie Timbo... your just using my post as an excuse to go 'inadvertantly' looking for dirty movies shot at a dolphin sanctuary

Seriously though, thanks for looking, let me know if you find any. If I found one, I wouldn't be sure if the technique used was right or not, as I just don't have the experience there to tell. Being able to cold shrink metal could save me a LOT of heartache!!

[ian]

hi guys
if you look in the classic car magazines ,they quite often have books and dvds on this subject for sale
ian