Sill repair Honda Jazz. Top coating?

[carl0s]

My runabout (Jazz) failed MOT on both sills, at the rear.

I am going to patch weld. I know the requirements for a continuous weld, and the technique of joining spots to minimise warpage. I'll do some practice butt welds on sheet metal first.

Question is really about painting it.
I think I'm happy to just go with matt black, although I'm also happy enough to try any other colour - I was going to do the wing mirrors and bonnet anyway, and not necessarily in the proper colour. This car was a freebie from my sister, but I like using it because my other car is a big boat with a silly engine.

I was going to apply stone chip shield, then overcoat with 2k clear over basecoat, since I have some of that stuff in various colours, and thinners including fadeout thinners etc.

But I'm kind of unsure where to fade out to, or if to just stop at that horizontal line where the factory stone chip shield stops. I realise clearcoat can't be blended, and will peel at the edge eventually, but I don't really have much choice, do I? The sill and quarter panel are finished as one.
So I am thinking I might paint up to that stonechip-line that you can see.

What do you think?

The car was free, it's my "ideal car-body welding project" car, so don't tell me to take it to a pro please!

 

[Edward Teach]

I think I have an old tin of light blue or white, house hold gloss, for painting welding repairs,
No point going overboard too much, it will rust on the inside anyway,
It will be good enough till next year.

 

[carl0s]

Fair enough.
Why will it rust on the inside anyway and only last a year though? I'm hoping to clean up all the bad metal, and will be cutting and patching the lower inside arch as well.

 

[carl0s]

I know it will oxidise from air.. I suppose best I can do is weld thru primer maybe? Or fill with cavity wax?

 

[marlinspike]

I'd probably just weld in repair patches, use a decent primer, then stonechip up to the original stonechip line. I don't think I'd bother with top coat and 2k on a car that was free and isn't worth much.

Silverhook Bitumastic Underseal

Ideal for use under vehicle chassis, wheel arches, door sills, fuel tanks and other high impact areas giving a tough, flexible, anti-chip, anti-corrosive coating. Provides a durable high impact protective coating against corrosion, water, stones and salt. It also finds many uses in a wide range...

www.toolstation.com

 

[Edward Teach]

Fair enough.
Why will it rust on the inside anyway and only last a year though? I'm hoping to clean up all the bad metal, and will be cutting and patching the lower inside arch as well.

I am assuming the end of the sill is double skinned, with the lower wheel arch, unless you treat the inside somehow, it will rust.
The area further along will quite possibly need attention next year.

 

[carl0s]

OK, good advice, cheers.
I have a few tins of hammerite stone chip guard, which I think might be pretty much the same as that stuff above.

 

[charlysays]

Fair enough.
Why will it rust on the inside anyway and only last a year though? I'm hoping to clean up all the bad metal, and will be cutting and patching the lower inside arch as well.

Needle gun the whole area including behind the sill till you turn the rust into an island. Chop out the thin metal, weld in zintec repair sections, 0.8-0.9mm probably be fine using weldthrough primer (Upol do one and bilt hamber etch weld) on any overlaps, scuff with 80grit, epoxy prime, seam seal, more epoxy primer then some kind of stone chip and any old top coat. Spray anti corrosive wax on the inside. Will probably outlast the rest of the car. Probably overkill though depending how long you want the car to last.

 

[carl0s]

Damn. Those needle guns are impressive.

Here's what I am faced with though. I'm kind of wondering when the 'good metal to weld to' is going to appear.
Also, any special things for getting the thick gloops of seam sealer off?

 

[Ruffian]

Big bits of sealer, go at it with a stanley knife first,
Cut off the most then either blowtorch or hot air gun scrape of the burnt bits.
Then clean up through the primer.