First Major(ish) Project Advice

[Dunny]

Hi chaps,

I have done 2-3 small welding projects so far (motorbike seat base repsir, and motorbike frame repair. They turned out just about OK.

Now moving on to doing some sills on a fiesta and looking for general advice or any specific advice if you have any. I doubt I will replace the whole sill as it comes up in the body colour and I don't want to ruin this. Should I just patch wherever I find the holes or should I look at replacing the complete lower half of the sill section?

The latter would require a seam weld the length of the sill and this may not be a great idea?

Thanks

D

 

[the snooper]

Hi chaps,

I have done 2-3 small welding projects so far (motorbike seat base repsir, and motorbike frame repair. They turned out just about OK.

Now moving on to doing some sills on a fiesta and looking for general advice or any specific advice if you have any. I doubt I will replace the whole sill as it comes up in the body colour and I don't want to ruin this. Should I just patch wherever I find the holes or should I look at replacing the complete lower half of the sill section?

The latter would require a seam weld the length of the sill and this may not be a great idea?

Thanks

D

any weld you do on the sill needs to be a seam weld or it will fail mot, you can plug weld the lower seam

 

[Dunny]

any weld you do on the sill needs to be a seam weld or it will fail mot, you can plug weld the lower seam

Yes, that's as I understood it. If I patched it though it would be so,e rectangular seam welded patches as,opposed to a seame weld the length of the sill. Not sure whatbis better / easier?

D

 

[cumbriasteve]

It depends how many patches you will require to repair it, there comes a point where it's easier just to put a full length in rather than mess about with several smaller sections.

 

[optima21]

once you start cutting metal out you will normally find that things get worse. if you're replacing the lower part of the sill you might find that the metal that it is spot welded to is rotten so you also need to cut that out and replace it. as a worse case scenario, you may end up cutting out the edge of the floorpan too.....

here's one I did earlier

I ended up replacing the bottom of the inner sill, then replaced the edge of the floorpan, and then finally replaced the lower section of the outer sill. if you do replace the outer sill only, tack it along its length, but do this from both ends or else the panel will move and the alignment will move if you just work from one end

also beware of fire as cavity wax burns easily, so have someone with you if you can to look out for this. for small fires in the past I've extinguished them with compressed air (but I have a 5 litre plant sprayer filled with water and fire extinguishers handy).

 

[addjunkie]

If you can get replacments, i would, much easier......cut out old, weld in new.

 

[Dunny]

once you start cutting metal out you will normally find that things get worse. if you're replacing the lower part of the sill you might find that the metal that it is spot welded to is rotten so you also need to cut that out and replace it. as a worse case scenario, you may end up cutting out the edge of the floorpan too.....

here's one I did earlier

View attachment 81712

I ended up replacing the bottom of the inner sill, then replaced the edge of the floorpan, and then finally replaced the lower section of the outer sill. if you do replace the outer sill only, tack it along its length, but do this from both ends or else the panel will move and the alignment will move if you just work from one end

also beware of fire as cavity wax burns easily, so have someone with you if you can to look out for this. for small fires in the past I've extinguished them with compressed air (but I have a 5 litre plant sprayer filled with water and fire extinguishers handy).

I have seen this scenario quite a few times but I have never actually tackled anything like this myself.....might chicken out an patch!!

D

 

[cliff366]

Agree with above until you dig about you don't know what's there had a job for a neighbour on a mazda 6 failed on a small hole (size of a 10p) on the sill
Then the trim came off and there was no sill under it ended up with 2 6"plates front and back corners plus making a new wheel arch lip
So a 1h job turned in to a days work as ended up stripping all interior out and having to fold the metal etc would have been quicker to put a sill back but run out off mot and needed the car yesterday as usual

 

[cliff366]

also beware of fire as cavity wax burns easily, so have someone with you if you can to look out for this. for small fires in the past I've extinguished them with compressed air (but I have a 5 litre plant sprayer filled with water and fire extinguishers handy).

it's a ford prob already had newspaper jammed in the sills and fibreglass and stone chip over the top

 

[Dunny]

it's a ford prob already had newspaper jammed in the sills and fibreglass and stone chip over the top

This one is genuine 40k miles and never been welded. Rest of the car is mint and is well worth saving so it's worth doing well but can't bring myself to make it such a major mission with my level of welding experience!

D

 

[Dunny]

Supplementary question.....what's the best strategy for cutting the rot back? I know when I did the bike frame I didn't cut enough and ended up blowing holes. On the flip side I don't want to cut too much. How can I best tell where to stop?

Sorry if I am over thinking this!

D

 

[marlinspike]

Poke with a screwdriver till you find the hole. Use something like a Black and Decker power file to remove the paint around it until you get to solid metal. As others have said, there is usually more rust than is initially visible. If it's extensive and Fiesta sills are cheap, I would buy one and cut it down to make the repair. You don't have to fit the whole sill of it's not needed, though as others noted it can be easier than patching.
I would cut back to clean shiny metal, where there is no pitting.

Put some photos up when you have established the extent of the rot and the guys on here will tell you how to proceed.

 

[Dunny]

A couple of photos if what I have found so far. Not formulated a plan yet, just cutting out at the moment.

D

 

[Dunny]

What gauge steel is best for this repair? Thanks.

D

 

[optima21]

normally the same thickness as the original metal or slightly thicker

 

[Dunny]

Another daft question.....if welding 2mm steel to 1mm steel which setting should the welder be on?

The 2mm recommended setting or the 1mm?

Thanks

D

 

[addjunkie]

Logically the 1.5mm setting.

Try it on a couple of bits of scrap. On thin stuff feel and your speed of travel is critical, too slow equals holes too fast no penetration.

 

[Kent]

Oh heck I never look at such things as recomend settings especially with so little difference.
Run a few tests and go as high as you can manage. If you start having to peel through parent metal to separate stuff and you ain't blowing holes and such - that's bang on!

 

[Dunny]

Need some new gas for this project - is Argon + 5 OK?

Thanks

D

 

[Kent]

Yes