Time for an overhaul of my 1.9 '98 BMW Z3 Individual

[Matt Barnes]

So my impression is it’s not a totally ridiculous idea to flux core thin metal. In which case, I’m quite tempted to have a punt on my sills

absolutely mate.... it is temperamental and messy compared to MIG, but totally doable... er hello ?.. newbie welder here !?

one word of warning.... it gets bloody addictive... the number of times I said to myself to stop... then it's …. "ooo let me try this little corner".... an hour later and you'll be finding random things in the garage to weld together !

 

[Matt Barnes]

My pair of sills cost £245, so yeah!
Thinner metal is easier to warp, but it’s also going to take less heat to melt and it’s easier to planish, basically smack it with a hammer to stretch it. Welding it causes the tacks to shrink, if the fitment is really tight it’s immediately obvious when it shrinks. The edges will buckle or lift. At that point, stop, grind the tacks flush, smack them with a hammer and dolly ideally, but a hammer and chunk of metal works. Keep going until the edges are level again. Tack and repeat.
You can speed up the process by cooling the tacks with compressed air, even a damp rag.

My test piece was starting to buckle so I took it out of my workmate, put it on the floor and whacked it flat with a hammer. The only reason I was trying NOT to take it out of the workmate was because I wanted to practice as if it was the car, i.e. upright. Added benefit of doing the actual car is the sill is a massive heat sink so in theory MIGHT be a bit more forgiving

 

[IainP]

More wire cools the arc, too high a wire speed and you feel the torch tap, tap, tapping as the excess tries to force the torch away. It can also cause a “birds nest” of wire at the rollers as they try to force wire through the torch. I don’t think bird nesting is quite as prevalent as on migs though, flux core is thicker and stiffer. Migs will also bird nest when the wire speed is too low, burns back and fuses to the tip.
Not there just as a means of producing the arc, it’s also the filler.

 

[Matt Barnes]

More wire cools the arc, too high a wire speed and you feel the torch tap, tap, tapping as the excess tries to force the torch away. It can also cause a “birds nest” of wire at the rollers as they try to force wire through the torch. I don’t think bird nesting is quite as prevalent as on migs though, flux core is thicker and stiffer. Migs will also bird nest when the wire speed is too low, burns back and fuses to the tip.
Not there just as a means of producing the arc, it’s also the filler.

well I never !.... have to add that to my welding cheat sheet

 

[IainP]

So my impression is it’s not a totally ridiculous idea to flux core thin metal. In which case, I’m quite tempted to have a punt on my sills

If they already have holes the worst you can do is make the holes bigger.
The first sill I ever repaired was with an arc welder with only two settings. High was like a plasma cutter. The small patch panel became a much bigger patch .

 

[DrWong]

It’s only the ends that have gone and you can’t really see those bits, which is kinda why I’m willing to take a punt. The main parts of the sills you can see look fine.

The man-maths and man-logic is strong here haha

 

[Matt Barnes]

It’s only the ends that have gone and you can’t really see those bits, which is kinda why I’m willing to take a punt. The main parts of the sills you can see look fine.

The man-maths and man-logic is strong here haha

same with me mate...each and the jacking points are the areas worse for wear....and as for the sills ..

 

[DrWong]

This is the sill in last stages of cleaning using Bilt Hamber - circled bit is what I’d be repairing/welding in, it’s only the edges that have gone.

Starting condition for comparison. Left one was after I’d poly-wheeled the loose stuff off, but still deeply pitted

 

[Matt Barnes]

This is the sill in last stages of cleaning using Bilt Hamber - circled bit is what I’d be repairing/welding in, it’s only the edges that have gone.
View attachment 292087
Starting condition for comparison. Left one was after I’d poly-wheeled the loose stuff off, but still deeply pitted
View attachment 292089

my offside sill is similar...need to replace about a 6 inch piece on the bottom section, given that you'll be covering it with anti gravel paint, definitely give it a crack...

 

[Matt Barnes]

Ok not strictly Z3 related but .... I managed to solve a long running saga with my Peugeot ABS.... replaced the controller, no difference....ABS light still on.... I decided to buy this...... and it's a game changer...

Not only did it identify all the faults with the ABS, it pointed out which sensor had a permanent fault... so I replaced the sensor... then went through a complete pump and solenoid check which it steps you through... and all faults went away and brakes feel much better as a result...

 

[IainP]

My local Lidl had this today, plus other sizes,

I have tips for the 0.6 and 1.0mm sizes, none for the 0.9 and they don’t have a 0.8mm.
If I run some test pieces I can compare better to Mig and maybe give you folks better advice.
I’ll need to make an adapter to fit my welder first, these are teeny.

 

[Matt Barnes]

My local Lidl had this today, plus other sizes,
View attachment 292627
I have tips for the 0.6 and 1.0mm sizes, none for the 0.9 and they don’t have a 0.8mm.
If I run some test pieces I can compare better to Mig and maybe give you folks better advice.
I’ll need to make an adapter to fit my welder first, these are teeny.

thank you mate....I was in my Lidl today and saw this, and welding magnets!.. you can tell it's Spring as they stock up on DIY stuff..which is heaven for me!... I bought reels of masking tape this time round for when I do the sills again.!

 

[IainP]

I need to check one of the Lidl in Glasgow, it’s right in the student area, so the diy stock level stays high, not really a student activity

 

[Matt Barnes]

I'm conscious I haven't posted any updates recently....so..... I'm still practicing my welding which is getting mildly better, but the Z3 is still covered up and my next target is to remove the big undertray, firstly to see how much of the brake and fuel lines I need to replace, and then bite the bullet and start welding up the sills. I have however, used my recent learnings onto my other cars. I also have a Peugeot 206SW and a Mk2 Skoda Octavia VRS... last weekend on the Peugeot I replaced the discs, pads and ground down and painted the front calipers... again.. I know it's not Z3... but it's exactly how I did my Z3 calipers and they came up amazing... this is purely elbow grease and Hammerite silver paint.....new pads, discs

Just goes to show you can do it on a budget.... it's just Hammerite brush on paint......

I've also invested in a full Zinc plating kit from Gateros UK...I opted for the variable power supply as well.... so when I get that set up I'll walk you through a couple of example pieces

Last July I told my wife the Z3 will be back on the road by Spring..... it's now Spring..... oops !

 

[t-tony]

You didn't say which Spring!

Tony.

 

[Matt Barnes]

You didn't say which Spring!

Tony.

exactly mate....... I do seriously want to get it back on the road soon.....because the car has been on jacks now for so long... this is the offside front suspension..... now I know, this is just surface rust as I can brush it off.. but it proves it doesn't take long for the elements to kick in

 

[Matt Barnes]

ok I told you I was going to be doing some zinc plating and explaining the process used (I can also add this as a separate thread if needed).

So this is the setup.... got it from Gateros UK, and I'll include their link here. https://www.gaterosplating.co.uk/

I ended up ordering the Ultimate kit as it includes everything apart from the deionised water (I bought 50 litres !) but includes a variable power supply which makes the plating process a hell of a lot easier !

So this is what's in the kit (it comes with one fish tank heater and I bought another two off Ebay)

bought 50 litres of deionised water.... but the buckets come in the kit

you then mix up the pre measured amount to mix with 10 litres of water

and the Zinc mixer

this then makes up the plating bath

Fish tank heater instructions

warm up the plating solution to 25 deg C, and that's ready to go

you do the same for the Alkaline degreaser and the Dry Acid pickle etch

No your eyes don't deceive you.... it's blue chemicals, but it's YELLOW passivate....

If i get time tomorrow I'll run through a test piece......

 

[DrWong]

I've always been interested in this but have always ended up buying new bolts from BMW just for convenience. Saved all the old ones though, so maybe some time in the future.

How much was the kit, out of interest.?

 

[Matt Barnes]

I've always been interested in this but have always ended up buying new bolts from BMW just for convenience. Saved all the old ones though, so maybe some time in the future.

How much was the kit, out of interest.?

the kit was about 165 quid mate.... I'm paying in PayPal instalments !...... the 50 litres of Deionised water was 35 quid, the two extra heaters were 25 quid...but you can use the kit again and again forever, and you only need to top up the chemicals every now and then.

you can do what I originally did and make a homebrew using white vinegar, Epsom salts and some zinc strips. Then use Hydrochloric acid for cleaning the parts and just buy a passivate. I used a 200mA mobile phone charger as a power source.

The most important thing in the whole process is cleanliness. All rust off, and all grease and contaminants off.

 

[Matt Barnes]

right so I had a little go and..... quite please with results..... one thing you have to bear in mind is, unless the surface is smooth, plating won't cover it up.. so if it goes in rough... it comes out rough

I started with the handbrake support on the rear trailing arm... looks rough so I wire wheeled it from this..

Alkaline degreaser to get rid of any oils, great, rust debris.... then the Acid Pickle etch the surface....

So in there there's the Zinc solution, a fish tank aerator and a heater to warm the water to about 25 degrees.... the parts are hanging off a copper bar as the cathode... the zinc plates are the Anode

You vary the current depending on the size of the part... a bolt might be 0.2 A whereas a bracket might be 1.2A

you can see from this, that if the part is heavily pitted, then it will affect the adhesion of zinc

After another acid etch, it was into the yellow passivate and the results where quire good for a first run