'91 Honda Concerto MIG Welding

[tommullin]

Hi All,

Following an MOT fail, had to do some emergency repairs on a friends Honda Concerto.

How i found it:

How I cut it:

What i made for it:

And what i used to cut the sheet steel:

And finally what it looked like finished:

Sorry about the picture quality. And i only took the photos after i gave it a skim of filler.

This was my first attempt at actually welding anything that matters (like a friends car) so i decided to make as much of the replacement panel as possible on the bench so i could transfer it and have less chance to make a mess of the car. However, everyone else i have spoen to would have just tacked on a series of patches, hit it with a hammer and then fully welded it. Would this have been a more sensible approach? I also had quite a bit of difficulty not making holes in the car. The new steel was fine, but the mertal on the car was so thin it was making life very difficult - it was clean, but probably rusted from the back quite significantly.

Also, as this was the only part of the car that needed attention, i didnt want to take too much paint off. This meant that i didnt have a place to clamp the earth. Instead i clamped the earth lead to the replacement panel and tacked it in. Is there any problem with doing this?

Thanks for your help / advice / comments.

Cheers,

Tom

 

[daveypower]

nice one tom, ive a patch to do on my 94 JDM Honda prelude in the next couple of days, it only failed on that patch of rust. its up for the retest soon, and it will be my first time doing a job like this, ive been praticing on an old wing and im happy enough to go at it, but id say i will run into the same problems as yourself with rust on the other side and a thin panel.

any tips lol

 

[zx9]

Nice one, we scrapped MRS. ZX9's 214 Rover for the same reason, well that and the head gasket needed changing, at least the Honda had a decent engine.

 

[nodeward]

you need to cut all the way back to decent metal(although it looks like you did) and make the patch out of the same thickness to ensure you dont start blowing holes in either the patch or the origional.

looks like a good job though, i try and do the same as you and make bits on the bench first but it really depends on how good you want it to look, i have made up patches underneath the car that i have just 'banged into shape' but then they are just covered in underseal anyway.

 

[Oldbanger]

looks like a tidy job!!! what did you use to cut out the rust ??? I find it difficult to get a clean cut like that.

 

[tommullin]

Hi All,

Thanks for the replies and comments. All seems quite positive and its just come back from the test station with a shiney new MOT certificate.

In answer to your questions / response to your comments:

@OldBanger - I used a cheapo dremel tool to cut the car, it was a bit more forgiving than the 4 1/2" grinder and much easier to steer.

@nodeward - I did try and cut back past the rust but it all seemed to be quite thin, and i didnt fancy replacing half the car. i think i used 20gauge zintec for the repair, but it did seem to be a good bit thicker than the existing material. I dont think i would have been able to make the patch so close to the original by bashing metal on the car - but wondered if theres a better way or a reason why people prefer a series of small patches tacked up in situe?

@ZX9 - Sure is a good engine - 1600 Twin Carb!!

@daveypower - practice filling holes. I used 0.8mm wire, but perhaps could have used 0.6mm for a bit more control. also watch out for spatter inside your shoes. those are the two things ill take away.

I did have some copper blocks that i was tempted to use, but it seemed a bit fiddly trying to get them behind each bit before welding so i didnt bother. possibly a solution if your metal is thin and behind is accessible?

Also does anyone know of any good reason for not earthing the repair panel? everyone i have seen earths the car, but as i didnt want to take or more paint than necassary and the rapair was clean metal, i though id get away with it.

Cheers,

Tom

 

[Justme]

No reason not to earth it that way. Often I will use the door locking post as they give a good earth too.

 

[daveypower]

heres what i have tom

nowhere near finished preping but that rectangle is cut back to nice strong clean steel, have to do the same below, then ill be cuting a patch of my other prelude and welding it in, so the shape shouldnt be a problem

 

[tommullin]

Thanks again for the replies.

@justme - Thanks for confirming that and ill have to remember about the door post, be handy for small patches that dont lend themselves to having a clamp in the way!

@daveypower - That looks nice and rusty! I bet its handy having a donor car to pinch bits from, although probably wouldnt be too difficult to recreate that from scratch if you mess it up. If you do end up using sheet steel, i found that my zintec sheet didnt weld too well and i had to give it a scrub round the outside where it was to be welded. I had previously thought that it was ok to just clean the oil from zintec and leave the zinc because its so thin, unlike galvanised stuff where it needs cleaning properly. Apparently not. Good luck!

Cheers,

Tom