body work for a newbie

[cantankrs]

Hi Michael,

Anybody wants to learn about forming and welding coachwork I recommend Ron Fournier's series of sheetmetal handbooks.

I highly recommend the Metalshapers Association website. Heaps of pictures and advice to learn from.

I bought a MIG and then had to learn how to use it which for some reason was hard for me and after that knowledge, it improved my oxy and stick welding - go figure.

You can't weld rust despite what some jokers will tell you. Some steel rusts such that the whole thickness is a hard rust that looks like its solid - it kinda is and it's hard to sand and grind but it's brittle and touch the mig to it and it just melts and falls out. All that has to be replaced if you encounter it.

You need good replacement steel same thickness as the old. I've used zinc anneal sheet with success. I'd be interested to know what anyone else thinks about that.

I use 0.6mm MIG wire on body panels.

Don't hold a bit of 16 gauge on the edge of a lump of channel and tip the edge with a hammer - clamp it down or use some sort of weighted bag (sand bag or lead shot filled leather bag) and rest your hand on the bag to support it - my wrists didn't take to the shocks from holding it down.

The most important tools are the eye, ear, face, nose and throat protection. You only get one pair of eyes, you want to protect your good looks (face), and you want to be able to breathe without rasping when you're old.

The most often used tool tools for me are a 4" angle grinder (can get 1mm cutting discs here now), a Black and Decker PowerFile. One hammer - I'd pick one with a round, slightly convex face and maybe with a pick on the other end but not needed. You want some clamps - G clamps, vice grips, whatever you can scrounge. You want something solid to clamp things to that has a straight edge and can handle being hammered - a bit of I-beam might do the trick and the grinder with grinding disk can dress it up how you want.
A magic marker and a pencil and a ruler and some scissors and cardboard to make templates and mark out. Also some snips are handy - I prefer Wiss left and right cut pair of aviation tin snips.

Try and make your patches an exact replacement shape.

The powerfile is quick and easy to clean the edges around the hole you intend to patch. Can't mig weld paint, grease, or sealant. (use scraper and or degreaser on grease).

You aim to shape and fit your replacement steel patches with no more than about a 1mm gap all around. You turn the mig up a bit and tack the piece FLUSH all around and with a minimum number of spot tacks i.e. 4. Stop and check the position and flushness with the surrounding metal. Cut the spots and make corrections until its perfect. Then tack half way between using same small hot tacks. Don't let the metal get too hot. Once you have nice low build tacks with 100% penetration every one inch, then I tend to do 1cm (just under half inch) welds at opposite areas and keep the panel cool. I use a wet rag from a bucket to cool the panel if I think it needs it.

I'll think about what I've forgotten to mention

Regards

Alex

[Richard Coutts-Smith]

Another top tip is using a Copper backing plate. Piece of old electrical Buss Bar is perfect. Clamp behind and across the patch to be welded. As the weld will not stick to this Copper plate, it makes filling the join a lot easier, as well as sucking a lot of the heat out of the job.
Most Scrappies have drums of this stuff, and at pay per weight it is worth every penny.
As mentioned above, the extra thin cutting discs are a must, they are magnificent. The better fit a patch, the less welding, less heat, less clean up. Speaking of clean up, standard grinding discs tend to leave a pretty nasty finish. I use a softer compound polishing disc (they're white and I can't rember the brand, usually used for stainless steel work) after removing the worst of the weld.
Take your time, amazing what a mess that extra 1/2 second of welding can do.
Good Luck.
Rich.

[Speedy]

Originally Posted by Richard Coutts-Smith

Another top tip is using a Copper backing plate. Piece of old electrical Buss Bar is perfect. Clamp behind and across the patch to be welded. As the weld will not stick to this Copper plate, it makes filling the join a lot easier, as well as sucking a lot of the heat out of the job.
Most Scrappies have drums of this stuff, and at pay per weight it is worth every penny.
As mentioned above, the extra thin cutting discs are a must, they are magnificent. The better fit a patch, the less welding, less heat, less clean up. Speaking of clean up, standard grinding discs tend to leave a pretty nasty finish. I use a softer compound polishing disc (they're white and I can't rember the brand, usually used for stainless steel work) after removing the worst of the weld.
Take your time, amazing what a mess that extra 1/2 second of welding can do.
Good Luck.
Rich.

oo I like that tip! would the copper mostly help so you dont blow thru?

one of my neighbors told me about putting clay or something around the weld area to pull in heat also, not sure if I understood it right.

[Richard Coutts-Smith]

Very difficult to blow through with a copper back plate, but too keen an effort will still make a mess....
Rich

[Ken Hughes]

Hi speedy, some good advice here so far,practice on some old unwanted metal of the same thickness for a start(so yo do not bugger up the good stuff first)till you get the hang of it.
Also be care- full not to grind too much out of the weld when cleaning up the weld as it will crack and you have to do it all again.
Check out metalmeet dot com as well.
Do not hesitate to ask questions as there are a lot of talented people on this site .

[colin jones]

Hi Mike, lots of great advise here if you already have the basics of mig welding. Set your gas at 15-20 make sure the material is clean from paint and oil and if its thin body work keep your amps low and spot rather than trying to do long runs as apart from heat distortion you may run the risk of thinking it all looks good then 'plop'! you've got a big hole. If you are a novice then it will be a bit of trial and error. If you are welding a truck cab then I would use .6 wire. This will reduce the amount of heat generated while welding. Wire speed to amps is very critical and you will need to do some test pieces to familiarise yourself to the machine. Even a experienced welder would do a couple of small runs to set the machine. Lots of little spots can achieve great things. I also use 1mm cutting discs for cutting and flap discs for grinding.
Regards and good luck!
Colin.

[Speedy]

WOW!
thank you lots Scotty and Alex!
I feel much more confident about my first try.

going to keep your responses handy as I will be referring back to them some more and the links provided.

Alex. I dont understand this part "Don't hold a bit of 16 gauge on the edge of a lump of channel and tip the edge with a hammer - clamp it down or use some sort of weighted bag (sand bag or lead shot filled leather bag) and rest your hand on the bag to support it - my wrists didn't take to the shocks from holding it down."

also, willys used 18guage steel?
and should I expect to be using any body filler?

seems I need to pay a visit to my uncle for some tools (vice grips for body work)

thanks again

[cantankrs]

Hi Michael, I was in a hurry when I typed it. I was just writing that you should protect your wrists from undue shocks when trying to bend heavy guage steel sheet by holding the metal with one hand and trying to belt it around something solid to form a shape with a hammer in the other hand.

Also when I say 1mm gap then that's about what I suggest you aim for. I agree with the Scotty where he wrote

but you will need some gap

The edges expand together when heated and then will shrink a bit afterward but if no gap at all then the panel has to grow outward which isn't desirable. I've not really used the copper backing idea - sometimes you can't always get a backer in situ so it's best to learn so you don't have to rely on it. When I said turn the Mig up for tack welds, it's so you get 100% penetration from the momentary pull on the trigger. When you've finished tacking back the voltage and wirefeed off. You'll find the build up is high and penetration low as you start laying down a bead, and by the time you've finished your run the build is low and the penetration is high. Tricky to juggle this balance over short runs. And like Ken says don't grind off too much - or only grind off one side depending on how your welding shapes up. Everyone here is saying practice on same guage. I think 18 gauge is about 1.2mm so a nice gauge to work with.

You ask about body filler. Everyone has different ideas. Some fillers work better on bare steel and others over primer. Same for stop putty's. some people declare any filler is bad. On American Hotrod they cover the car in filler and then shape it down. You can lay tins of the stuff on ($$$) and end up with 99% of it on the floor as dust. They used to use a Lead/tin alloy for filler but its hazardous to health but then plastics got better. I try and get the steel work as close as poss and then as little body filler as I can get away with. I think filler and primer are hygroscopic? they absorb moisture so consider that. A faint overspray of a dark colour is sometimes used as a 'guide coat' before sanding so once you get stuck into sanding you can see the high and low spots in the primer or filler. Always have a layer of primer over filler before colour coats. Understand that I'm mainly discussing the single pack acrylic paints here. I've never touched 2-packs and single pack enamels generally need fewer coats than the old acrylic because enamel is thicker. But the basics are the same.

Oh and flap discs and sanding discs are good. Pick your grit size carefully (clogging vs damaging older paint layers). And rough your bare steel before applying filler if that's how you're doing it - to provide a key for the filler.

You might also consider a bare metal prep/etch but not sure that many people really know how to use it properly - me included.

Regards

Alex

[Geoff Winnington-Ball (RIP)]

Just a small point, but one alluded to earlier in this thread. When I was MIG welding a long time ago, I used both argon and CO2 and I found that the argon worked a lot better. It's more expensive, but gives smoother welds with less splatter. Welding sheet metal is tough enough at the best of times, so I concur with the advice to practice, practice, practice first! When you're confident you can do it well, then go for the real thing.

Let us know how it works out!

[Phil Waterman]

All of the tips points given are what most experienced welders would tell somebody starting out. The most important tip of all for the new vehicle restorer though is Ken's practice.

It can not be over stated DO NOT start on the part you want to use.

Start with scrap bits and keep practicing until you can produce the kind of weld on junk that you want.

Cheers Phil

[Keith Orpin]

Two of the best tips so far mentioned are the use of Argon as opposed to Co2, as Argon is not as "cold" as Co2 when welding ( if you are feeling really flush try Aztec 25, which is a mixture of Methane/Argon). The other one is the use of copper as a backing plate, I've use this technique for many years now, and even the largest hole can be welded up. Once you get good at welding with MIG, you will be amazed at what you can acheive, believe me you will not be needing much in the way of filler !. Interestingly enough, steel from the 40's welds exceptionally well, much better than today's steels, far too many impurities these days.
Regards
Keith

[ozm29c]

Speedy,
Further to the constructive comments by other forum members. Here are some other thoughts to consider.
1. Always check what lies behind the proposed patch panel ie will it burn!!!!! Is there a fuel line or electrical wiring looms.
2. Prepare the joints to ensure that you are welding clean metal, Any contaminants in the weld pool will either weaken the join or blow out while you are welding like a mini volcano!
3. Keep the joint width between 0.5 to 1mm
4. Use 0.6/0.8mm dia wire with your smaller Mig welders. Having said that my thoughts on MIG welders are the bigger the better. Small MIG welders are fine but the bigger welders have more OOMPH!
5. If possible try to avoid using flux cored wire.
6. With patch panels don't try to weld in continuous seams, spot here then move away and place a spot there. Continue staggering your spotting until the join is filled-This takes more time but will help dissipate the heat and minimise your patch panel and parent metal from heat distortion. Remember HEAT is your enemy. A good cup of Tea or Coffee can be enjoyed many times
7. Use heavier gauge metal ie 1.2mm or at a pinch 1.6mm (than your parent metal)to make your patch from. This will help you to start your weld without blowing a hole in the joint. Looks no different on the outside.
8. Use sunscreen on exposed parts of your skin as MIG welders have a tendency to burn your skin with excellent results. Better still, try to cover all exposed parts of your body.
9. I know it is hard but try to weld with elbow length gauntlets (Leather gloves). I am sure experienced welders at some time in the past have grabbed a hot bit of metal with their bare hands by mistake. OUCH!
10. If you can borrow an auto darkening helmet, do so. Good for tak welding.
11. Buy yourself a cheap Chinese angle grinder but always use good quality cutting and grinding discs. Use the very thin section cutting discs and always use PPE (Eye protection and hearing defenders)
12. When grinding off the finished welds try not to use excessive force to speed up the removal of excess weld. All you will do is create heat with the end result being metal distortion. Once you have leveled the ground surface, get hold of a flapper disc to further smooth the surface.
13. Paint/prime the exposed metal as soon as possible to prevent corrosion.
14. The point of a screw driver is a very good tool for probing around the affected area to try and determine the extent of rust damage. Once you have cut the rust out of a particular area, then and only then is when you will know where to start your repairs.
Anyway I hope this will give you something to work with.
Don't rush the job
Good luck
Cheers
John Wilson
Reply With Quote