Too Much Bondo? First time doing body work (56K= Death)

[Karateboy]

I don't have a welder yet and I can't afford to go to a shop.


If Bondo dries for about 12-24 hours, will it still let water in? I patched up a much smaller hole and didn't cover it up. I think it rained either 12 or 24 hours later. If water is in, how can I tell and what should I do?

Picture of feared water-penetrated spot

If I get the car paint, is the Bondo filler screw me over?

These are just aluminum sheets we fitted inside. I'm worried that this is too much body filler.

If not, are these the next steps (?):

1) Sand the Body Filler

2) Put on some soft putty so fill the the tiny air holes

3) Wet sand the Bondo and the rest of the paint

4) Primer

5) Wet Sand the Primer

 

[piman]

Hello KB,

body filler will let water in, even when set as will primer, and the metal will continue to rust away.
You need to either patch repair or replace the sills for strength, body filler is no use whatsoever, you car has lost a lot of strength with such corrosion.

Alec

 

[Karateboy]

Hello KB,

body filler will let water in, even when set as will primer, and the metal will continue to rust away.
You need to either patch repair or replace the sills for strength, body filler is no use whatsoever, you car has lost a lot of strength with such corrosion.

Alec

Thanks for answering my question. I'm new to this forum

The side skirts give the car rigidity? I thought they were aesthetic.

Maybe I'll try to rent a welder- how do you recommend I do this? If I cut it along the line where the grey paint meets the red paint, will i be able to grind the bead down so the sills look smooth?

 

[piman]

Hello KB,

there are very few cars where the sills don't provide body strength.

You need to gut back to sound steel or it may be better to get replacement sills, it depends on the car and how good a finish you want. If patch repairing don't grind off too much metal as that will weaken the weld, it's better if you can to dress the weld with a hammer and then fill over the top. The main thing is to get the strength.

There is a lot of information on here about car body repairs, have a look at the tutorials.

Alec

 

[bigbadbugga]

For the type of repairs you are doing bondo is not suitable mate. It should really only be used to put a very thin skim over the body panels so you can get a perfect flat paint finish.

After the holes are welded up you can use the bondo to tidy the area up.

there are loads of cheap second hand welders out there, will be cheaper in the long run anyway.

Oh, and books and wood blocks are a very dodgy way to hold a car up, please be carefull.

 

[hotrodder]

Skipping over the structural location of the corrosion and Darwin award axle stands i wouldn't worry too much about the filler absorbing water- it'll fall out in no time anyway as it's not designed to be used like this

 

[rikrobson]

See you can use algebra to fix Cars
Is that a brake balance valve in the wheel arch? Surely that would be better the other side of the inner arch?

 

[Karateboy]

It's just the hand brake line.

What I keep hearing is the Bondo won't last. I'm glad I asked because I was worried it wouldn't. I'm willing to do this right.

I CAN rent a gas welder for $70/day- not bad- but I've never welded before. I don't know how I'd be even how to best approach a project like this.

If I cut the panel in half, horizontally, along the grey line, and welded a clean new piece, would I be able to grind/bondo it smooth?

How difficult would it be to weld this? About as easy as it gets?

 

[zardoz]

bondo will let water in eventually, but a day or two of rain will be ok. Also primer will let through rain eventually, so get it sprayed as soon as possible.

As for the "too much bondo" question, well bondo if put on thick, ie: more than one eigth of an inch may be too much. You should either weld in a new metal piece, ie: not alluminium unlesss the car is made of that, so use steel. Or if its a dent then the dent should be pulled out or knocked back into approximate shape and then bondo used to skim over the last few mill.

If you are heart set on not welding then you should use fibre glass mat and resin (with hardener) for the bigger stuff, as this is designed to broach wider and deeper holes/dents. (some people use alluminium mesh instead of fibre glass)

If you have never welded before then i wouldnt use this to try it, although for $70 a day you might as well get a cheap welder for $200, although i have no idea what make of welders are for sale in your part of the world. Most will be crap for that price but the odd one or two will be ok for beginers. Best ask someone on this site who is from the USA.

ps: thin bodywork is usually not the easiest thing to learn on.

 

[zardoz]

ah lay off the guy, im not too proud to say i did exactly the same when i was a teenager and didnt have any other method to fix car bodywork. Indeed as far as i knew it was the proper thing to do.

 

[jaykay]

bondo

dont put bare ali to bare steel,it creates a chemical reaction, like a battery.it will rot out in a years time.
try to find someone to weld for you.
if you cant weld,you'll dis tort panel badly.

 

[Iky]

Is that an S14 Karateboy ?

 

[Karateboy]

Yea it is.

I was worried that this approach would not work, and all you guys did was confirm it

I'm in the process of finding a welder for myself and trying to do it- it's meant to be a project car.

I've been doing a lot of reading on here and I think I know how to do it.

This is probably thin metal, 0.8mm, so I know I need to be careful.

I read that distortion from the heat is an issues so I would start by tack welding the start and the end of the new panel. Wait a bit, then tack weld every 1''. More waiting so it cools down, then finally finish it off by stitch/pulse welding.

Lastly, I will grind off the weld with a flap disc.

How does that sound? Do you guys recommend I just cut out about an 1'' bigger than the current hole or cut the WHOLE thing in half along the grey line and try to weld a new peice in? I know there is at least surface rust on the inside of whole length of the sill.

Any advice on how to shape the metal if I cut the whole thing in half?

 

[zardoz]

cut out where the yellow lines are, you will have to drill out the spot welds at the bottom of the sill. Just drill in far enough to pry off the top sill layer not the one underneath. Later on you can use the plug weld method to re attach it here.


I dont know if this is going to be understandable, but i'll have a go. This is how i would do it. If anyone knows an easier way please shout out. (pleeese!)

You should make a piece of steel (same thickness as the old stuff) half an inch bigger on the 3 sides i have indicated. the its best to use a "joggler" or "joddler" to put a 'step' in the metal where it will meet the original sill. This gives a better fit. Use sill clamps, mole grips or similar to hold it. This is a bit difficult to explain, but you have to put a bend at the bottom at such an angle that you can hold the bottom tight whilst the other 3 sides are reasonably tight against ther inside of the old metal, then put some good tacks in. Then you can bend down the bottom bit to the correct angle. Do a few tacks here but dont plug weld yet. first see if you can make a go of welding the piece in, if it goes ok then do the plugs.

Metal can be shaped by bending over a pipe or similar, a pipe in a vice is often used to get a pretty acurate curve. Any similar cylinder shaped thing will do, if you dont have this, but remember itseasier if you can clamp one end somehow.(unless you have access to a bending machine and do it the easy way?)

You can minimize distortion to some extent by giving small taps with a hammer on the top of welds straight away. Obviously this only works on short welds 1 inch or less, otherwise it has cooled already too much at the begining(forget why this works)

 

[malcolm]

A complete outer sill (rocker) panel might be easier. Ought to be possible to find an aftermarket one. With that much corrosion in the sill you might expect the structure behind to need a bit of repair too, and removing the outer sill would give you access.

Depends how far you want to go with the car. If you only wanted to patch the sill then I'd buy metal of the same thickness (it'll be 18 gauge probably) and follow Zardoz's advice. I'd cut the hole back to clean metal and overlap the repair piece on top. If you grind down the welds afterwards you'll only have 1mm to lose behind some filler. Otherwise the sides of the hole might be persuaded a bit lower with a hammer.

If you buy a welder practice on scrap metal first. Makes it much easier to get the hang of it before tackling the car.

 

[zardoz]

As Malcom says a piece of complete rocker panel# might be eaiser if you can get hold of it. So that way you could put in an entire section and plug weld top and bottom and seam weld the sides.

#(I recalled that in the USA what we in the UK call 'sills' and called "rocker panels" there only because i remember seeing it in the movie 'The French connection' Where that are taking the car to pieces looking for the smuggled heroin. The mechanic says "we have takin it all to bits apart from the rocker panels" Gene Hackman looks at him and asks what they are? When we are told it does seem blidingly obvious that it was one of the first places that they should have looked. DOH!)

 

[Karateboy]

cut out where the yellow lines are, you will have to drill out the spot welds at the bottom of the sill. Just drill in far enough to pry off the top sill layer not the one underneath. Later on you can use the plug weld method to re attach it here.


I dont know if this is going to be understandable, but i'll have a go. This is how i would do it. If anyone knows an easier way please shout out. (pleeese!)

You should make a piece of steel (same thickness as the old stuff) half an inch bigger on the 3 sides i have indicated. the its best to use a "joggler" or "joddler" to put a 'step' in the metal where it will meet the original sill. This gives a better fit. Use sill clamps, mole grips or similar to hold it. This is a bit difficult to explain, but you have to put a bend at the bottom at such an angle that you can hold the bottom tight whilst the other 3 sides are reasonably tight against ther inside of the old metal, then put some good tacks in. Then you can bend down the bottom bit to the correct angle. Do a few tacks here but dont plug weld yet. first see if you can make a go of welding the piece in, if it goes ok then do the plugs.

Metal can be shaped by bending over a pipe or similar, a pipe in a vice is often used to get a pretty acurate curve. Any similar cylinder shaped thing will do, if you dont have this, but remember itseasier if you can clamp one end somehow.(unless you have access to a bending machine and do it the easy way?)

You can minimize distortion to some extent by giving small taps with a hammer on the top of welds straight away. Obviously this only works on short welds 1 inch or less, otherwise it has cooled already too much at the begining(forget why this works)

I think I understand. I need to give it that step and clamp it down.

Here is where I am a little confused: Do I bend the curve into the metal before I clamp it down or while its clamped down?

I think I may need to replace the whole panel, if I can't find replacement parts would I use a similar process?

 

[zardoz]

put the curve in before its clamped down. Unless you can get hold of a section of rocker panel as that will be already the correct curve. Or even better a complete replacement new rocker.

 

[Karateboy]

put the curve in before its clamped down. Unless you can get hold of a section of rocker panel as that will be already the correct curve. Or even better a complete replacement new rocker.

I'm having the hardest time finding replacement rocker panels.

I live in Chicago and I found some for $500+ shipping in Florida- that's almost more than what I paid for the car.

 

[zardoz]

Whaat!! i was thinking maybe $40 or something ? Thats all i paid in the uk for a set for my ancient rover. Best get your fabricating head on i think, and give making a piece to fit. You have nothing to lose.