defender tub replacement and galvanised bulkhead

[Bigmark]

Hi all, i have been away from this forum for a while due to illness but im back to share (somewhat belated photos) of a few stages where i replaced damaged tub with a new one. Then i bought a secondhand bulkhead , had it sandblasted and now at the galvanisers ( hope it comes back straight enough to fit), photos to come shortly. I have heard of some horror stories with warping but its worth a shot as my current bulkhead was badly rusted in the A pillar and i could have pushed my foot thru the floor..

Anyway sort of thought of taking photos too late in the project but wanted to put up something incase it helps others considering doing the same.

[uninformed]

Good work BigMark,

lets us know how the bulkhead goes with the HDG.

[jboot51]

Yes keep us updated on the bulkhead.

[mark2]

I have galvanised a couple of Series 2a firewalls with reasonable results. Some rippling of the flat sections but no major warping.

I chickened out on doing my 110 firewall and had it sprayed in zinc primer after sandblasting. I think a 110 firewall has less inherent stiffness than a 2A firewall. Not to say it wouldnt be ok, but I decided against it at the time.

It was later suggested to me that a simple jig consisting of a piece of 50mm RHS with tabs welded to it and then drilled to fit the lower firewall bolts would hold it in straight during galvanising. Silicone can be used to stop the zinc locking the bolts in place.

Anyway, hope it works out. A galvanised firewall is a great thing.

[Mettalique]

In terms of warping, it may not be such a problem unless heat has been involved in welding new sections into the firewall. In such a case, the heating of the galvanising process will release the energy built up and may warp it. Generally it won't warp if the item is just pressed metal. I used to do a lot of forge work and stopped galvanising (hot dipped) as the tension release would warp it so instead I'd use hot metal spray in zinc. Same goes for big welded jobs. The only problem with hot metal spray is that it won't get into areas the hot dip will.
On another note, I just love the way these things are like a big mechano set. Great work!

[Bigmark]

Ok i got the Bulkhead back and i have to say i was surprised how good it turned out. It fit straight back into place with only a slight warpy look to top flat section of footwell (passenger side only) and a few little ripples elsewhere , but nothing worth talking about.

First i have to say that it was hot dipped and (on request) not quenched afterward- this may have helped- it was also placed down on flat surface to cool to help keep straight. amazingly the chassis bolts lined up but i had to drill out slag from holes.

Now there is a problem- i was told by the galvanisers to thread tape bolts and wind them into threaded holes. Well most snapped and other turned the capture nuts inside. so i have to now drill them out and tap them. next time i would probably leave them and tap them all out. the main problem ones are the 3 that hold the door closers and the 2 large ones that hold steering column plate- i will have to drill thru to inside to use nuts and bolts as the captive nuts tore out while i tried to turn the bolt.

[red_tj]

looks good mate. can I be so bold to ask about how much it cost to do?

[Bigmark]

well I paid $750 for the bulkhead so I could get it galvanised
before I took the defender apart. I will sell the original bulkhead as is or repaired. anyway only $80 to sandblast, little bit of welding by myself- then $165 for hot dip galvanising. quite reasonable I thought. this was done in perth, prices may vary around the country.

[red_tj]

cheers. thanks for that, the prices seem reasonable.

[uninformed]

Hi BigMark, good work so far mate.

Apart from sandblasting, was there anything else the Galvanizers had you do? I was thinking there may be some sealer inbetween seams that may not be great when dipped? did you have to remove any sealer etc or just blast and good to go?

[Bigmark]

the sandblasted got 99% of the seam sealer, I used an air disc grinder to get rid of the rest.
overall the whole project was much much easier than I expected.

[isuzurover]

Nice work. Which galvaniser if you don't mind me asking?

[Bigmark]

it's Hartways in canningvale, off bannister rd. they also have another workshop in naval base

[isuzurover]

Thanks.


...they also have another workshop in naval base

Well, they have a block of land at least...

No Cookies | Perth Now (http://www.perthnow.com.au/news/western-australia/m-fire-destroys-naval-base-galvanising-factory/story-fnhocxo3-1226687324917)

[uninformed]

Having started to look at the possibility of doing this as well, I have noticed that there is double skin in the footwell, and the ribbing on the engine bay side creates cavitys. Did you drill holes for these to be coated and drain?

Some here have mentioned welding will cause problems. Well as a budget is always a problem, finding a bulkhead with NO rust repair needed is hard or expensive. What methods can be used to help control warping etc? Is there anyway of stress reliveing the welds prior to HDG?

[isuzurover]

Having started to look at the possibility of doing this as well, I have noticed that there is double skin in the footwell, and the ribbing on the engine bay side creates cavitys. Did you drill holes for these to be coated and drain?

Some here have mentioned welding will cause problems. Well as a budget is always a problem, finding a bulkhead with NO rust repair needed is hard or expensive. What methods can be used to help control warping etc? Is there anyway of stress reliveing the welds prior to HDG?

Serg, Weld repairs are not a problem. The welds will just rise up a bit when galvanised. I can take some pics if you want. Even series bulkheads have some double skinned areas. The gal just coats and seals the area, and you won't have any problems,

[uninformed]

Pics are always good :)

What if rust/corrosion has started in between the skins and is not visible from the outside etc, I thought it might get trapped and continue with condensation etc?

[isuzurover]

Pics are always good :)

What if rust/corrosion has started in between the skins and is not visible from the outside etc, I thought it might get trapped and continue with condensation etc?

Zinc is a sacrificial coating, so no need to worry about that.

[isuzurover]

Pics are always good :)

What if rust/corrosion has started in between the skins and is not visible from the outside etc, I thought it might get trapped and continue with condensation etc?

I will take some firewall pics and profile pics, but this is what I have to hand at present.

Bullbar welded, welds ground flush, then (steel) shot blasted.
http://i124.photobucket.com/albums/p29/isuzurover/LR_PICS/County_parts051.jpg
http://i124.photobucket.com/albums/p29/isuzurover/LR_PICS/County_parts051.jpg

After galvanising
http://i124.photobucket.com/albums/p29/isuzurover/LR_PICS/Misc_June_2010022.jpg
http://i124.photobucket.com/albums/p29/isuzurover/LR_PICS/Misc_June_2010022.jpg
The shot blasting would have stress relieved the welds, but did not stop them rising up (or reduce it).


These welds were also ground flush before galvanising
http://i124.photobucket.com/albums/p29/isuzurover/LR_PICS/Misc_June_2010019.jpg
http://i124.photobucket.com/albums/p29/isuzurover/LR_PICS/Misc_June_2010019.jpg


EDIT: This article suggests it is not the welds rising up, but rather a thicker coating of zinc induced by higher silicon content in the weld area (due to welding rods or grinding discs). http://www.zinkpower.com/media/files/arbeitsblaetter_englisch/2_9.pdf

All my welding was done with a MIG, and I did plenty of cutting and grinding on non weld areas - without the same thickening... So it sounds dubious. I will need to check the Si content of my mig wire.

[isuzurover]

A few more:

Weld repair on bulkhead corner before galvanising - also ground back flush.
http://i124.photobucket.com/albums/p29/isuzurover/20140108_084151_zpscc2fb021.jpg
http://i124.photobucket.com/albums/p29/isuzurover/20140108_084151_zpscc2fb021.jpg

Repair section plated over footwell - you can just make out section on the LHS of the image with a horizontal and vertical line of spot welds
http://i124.photobucket.com/albums/p29/isuzurover/20140108_084240_zps5f2a4a4e.jpg
http://i124.photobucket.com/albums/p29/isuzurover/20140108_084240_zps5f2a4a4e.jpg
This panel was spot welded in place deliberately so the gal could get under it more easily. The bulkhead was galvanised in 1994... No problems yet.

[Dervish]

Bullbar welded, welds ground flush, then (steel) shot blasted.

...

After galvanising

I have a very scruffy looking LR bullbar exactly the same as yours and would've got it dipped with a recent batch I put through, but I thought they'd never touch something like that! Did you have to drill the hoops?

[isuzurover]

I have a very scruffy looking LR bullbar exactly the same as yours and would've got it dipped with a recent batch I put through, but I thought they'd never touch something like that! Did you have to drill the hoops?

I drilled small (~4-5 mm ) holes at each end of every pipe section in the vertical plane. This does not weaken the bar.

I did not drill the lower c-channel. They lifted it out of the bath on a slight angle so I have a huge sacrificial anode (about 1-2 kg) in the LH "dumb iron" of the bar. :D

[lokka]

When gal dipping stuff with threaded holes and nut serts and the like its best to fill them with silicone then wipe it into the threads with wire

The silicone wont burn out and its stops the gal sticking in the threads a quick poke with some wire after gal dip removes most of the gal and a quick run through with a tap of the right size and good as new

We use to do this with gear for underground rigs mainly manifolds and other exhaust stuff as it was all gal'd so it would last longer as it all had coolant running through them