- Thread starter Dcal
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Hi Dcal,
I'm just about to undertake the same bulkhead repair around the centre vent that has rotted away. I was wondering if you could remember the thickness of the steel required for the bulkhead, also, did you use a thinner gauge for the vent shroud?
Dcal
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Hi @Hudders
Welcome to the forum.
Good to hear of another 75 getting some TLC, I hope you are going to start a thread on your repair.
The steel I used was 1mm for the bulkhead and 0.8 for the rest as that matched what was there.
The steel that formed the air intake vent might have been even thinner but I stuck with 0.8.
I still have the bits that I cut out, so will measure later and confirm.
The bulkhead repair is easy, but the shroud and the vent are really awkward to get to fit nicely to the bulkhead.
How bad is yours?
I took the whole shroud off because I had to fix the bonnet hinge areas.
If you can, just cut enough of the central section out to give access.
Good luck and as I still haven't finished mine, I can get any dimensions you might need.
Welcome to the forum.
Good to hear of another 75 getting some TLC, I hope you are going to start a thread on your repair.
The steel I used was 1mm for the bulkhead and 0.8 for the rest as that matched what was there.
The steel that formed the air intake vent might have been even thinner but I stuck with 0.8.
I still have the bits that I cut out, so will measure later and confirm.
The bulkhead repair is easy, but the shroud and the vent are really awkward to get to fit nicely to the bulkhead.
How bad is yours?
I took the whole shroud off because I had to fix the bonnet hinge areas.
If you can, just cut enough of the central section out to give access.
Good luck and as I still haven't finished mine, I can get any dimensions you might need.
Thanks Dcal, that's very helpful info, and yes, I probably will start a thread on the 75 as I'm very much a beginner in welding so you can all have a laugh.
I've been doing my research, both in the 75 which landed me on an Australian Alfa forum with a rebuild that you were also following, that brought me here which is a happy coincidence as its just the place to help me with the bodywork, I've been taking notes of what paint to use and the how-to weld sections.
My bulkhead is quite bad looking at it from the engine bay, the shroud turned to dust and even the vent cutout is bad, that part that the drain tube held onto had dissolved some time ago. so it looks bad but the wing ends around the hinge from the outside at least look ok, I'll know for sure when I get the dash out. I intend to do the cut to the scuttle to give me access but I don't want to go as far as you went, taking the screen out and the whole shroud is getting in deeper than I'm comfortable with, I'm even hoping to keep the engine in but I do wonder how painful it will be trying to weld whilst lying on the engine.
Dimensions would be super helpful if it's not to much trouble, I don't suppose you have the template you made for that cover do you?
Anyhow here's a couple of pictures of my 75, I bought it in January as I've always wanted one, it's been stripped into a kind of track day car so that put people off keeping the price down a bit, I do intend to track day it as well as take it on Alfa runs. It does have an MOT and I want to have it as a running project but I'm not doing anything till the bulkhead has been fixed, how that didn't get spotted on the last mot ill never know.
I've been doing my research, both in the 75 which landed me on an Australian Alfa forum with a rebuild that you were also following, that brought me here which is a happy coincidence as its just the place to help me with the bodywork, I've been taking notes of what paint to use and the how-to weld sections.
My bulkhead is quite bad looking at it from the engine bay, the shroud turned to dust and even the vent cutout is bad, that part that the drain tube held onto had dissolved some time ago. so it looks bad but the wing ends around the hinge from the outside at least look ok, I'll know for sure when I get the dash out. I intend to do the cut to the scuttle to give me access but I don't want to go as far as you went, taking the screen out and the whole shroud is getting in deeper than I'm comfortable with, I'm even hoping to keep the engine in but I do wonder how painful it will be trying to weld whilst lying on the engine.
Dimensions would be super helpful if it's not to much trouble, I don't suppose you have the template you made for that cover do you?
Anyhow here's a couple of pictures of my 75, I bought it in January as I've always wanted one, it's been stripped into a kind of track day car so that put people off keeping the price down a bit, I do intend to track day it as well as take it on Alfa runs. It does have an MOT and I want to have it as a running project but I'm not doing anything till the bulkhead has been fixed, how that didn't get spotted on the last mot ill never know.
slim_boy_fat
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Nice Turbo coupe poking its nose out there 
, yours too?
, yours too?Not mine but the guy that sold me the 75, he did have it for sale at the time on fleebay.Nice Turbo coupe poking its nose out there
But I did have an Alfa GTV 916 which I think was based on the same platform.
Dcal
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Dimensions would be super helpful if it's not to much trouble, I don't suppose you have the template you made for that cover do you?
I'll check later and if I don't still have the template I'll make you one and can post it or could scan and email you a PDF.
Do you have the plastic grill for the air intake? It's a good place to start.
Keeping the screen and engine in place shouldn't be a problem.
I took the screen out to repair some rot to the screen surround and I repaired the bulkhead with the engine in place (Took the engine out later of course)
Dcal
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There's a fair chance that grill is not an OE part.
Found the bits I cut out but not the template.
The bulk head is 1mm the shroud 0.7 and the air intake 0.65
I can't get at the bulk head easily at the moment (it on the lift and there's a bloody tractor underneath) but I will be able to get you templates if / when you need them.
Mine is stalled.
I have it in primer and I need to get it painted when the weather picks up.
I bought it to do wee bit and get it on the road, didn't work out that way
Need to get back to it or I'll be dead before it's finished.
Found the bits I cut out but not the template.
The bulk head is 1mm the shroud 0.7 and the air intake 0.65
I can't get at the bulk head easily at the moment (it on the lift and there's a bloody tractor underneath) but I will be able to get you templates if / when you need them.
Mine is stalled.
I have it in primer and I need to get it painted when the weather picks up.
I bought it to do wee bit and get it on the road, didn't work out that way
Need to get back to it or I'll be dead before it's finished.
Your right there, that grill is propper home made, the plastic one you have is how it should be, I guess this was made after the grill fell inside the car
Don't suppose there is a part number printed on that plastic cover?
Thanks again for the measurements, it's so helpful, means I can get the steel in advance and practice with that gauge.
Don't suppose there is a part number printed on that plastic cover?
Thanks again for the measurements, it's so helpful, means I can get the steel in advance and practice with that gauge.
Dcal
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Decided to try and get back to the Alfa and see if I can get it on the road for the spring.
It's been almost a year and a half since I did anything on it and it's been blocking my lift since then.
The bonnet needed work as the lacquer was lifting in a few spots, started scraping it off and noticed a bit of rot on the leading edge of the bonnet.
I do have a spare bonnet but thought I'd fix this one.
Nasty spot to do a repair but I gave it a run with my surface prep tool to clean it up.
As always, that made it worse so only option was to cut it out.
Cleaned it up and gave it a coat of galvafroid.
I don't much like galvafroid, but for a double or triple skin repair I use it as it's mostly zinc and I recon some of the zinc must remain after the welding is finished.
The galvafroid and the zinc steel certainly doesn't help the welding but everything’s a compromise.
I made a patch out of electro galv steel the right thickness and tacked it in.
Because I need to weld the folded return lip to the edge of the bonnet I turned the bonnet so I could weld vertical down and let gravity help.
Then cut a strip to replace the folded return. Then tracked and welded the return of the bonnet skin.
There has been a bit of chat on grinding welds so I thought I show what I did here.
Most of the grinding was with a "thick" cutting disc, 3mm thick to be precise, in a 4.5 inch grinder.
I mostly used the edge of the cutting disc.
I then finished it off with a 120 grade Wurth flap disc.
There was a couple of dings left with the patch was cut out, so I used a slide hammer to get the worst of it out.
I used the flat of the cutting disc to shape the edge and finished it off with a body file.
I'm sorry if this is a bit long winded for a small repair, but they do take time.
It's been almost a year and a half since I did anything on it and it's been blocking my lift since then.
The bonnet needed work as the lacquer was lifting in a few spots, started scraping it off and noticed a bit of rot on the leading edge of the bonnet.
I do have a spare bonnet but thought I'd fix this one.
Nasty spot to do a repair but I gave it a run with my surface prep tool to clean it up.
As always, that made it worse so only option was to cut it out.
Cleaned it up and gave it a coat of galvafroid.
I don't much like galvafroid, but for a double or triple skin repair I use it as it's mostly zinc and I recon some of the zinc must remain after the welding is finished.
The galvafroid and the zinc steel certainly doesn't help the welding but everything’s a compromise.
I made a patch out of electro galv steel the right thickness and tacked it in.
Because I need to weld the folded return lip to the edge of the bonnet I turned the bonnet so I could weld vertical down and let gravity help.
Then cut a strip to replace the folded return. Then tracked and welded the return of the bonnet skin.
There has been a bit of chat on grinding welds so I thought I show what I did here.
Most of the grinding was with a "thick" cutting disc, 3mm thick to be precise, in a 4.5 inch grinder.
I mostly used the edge of the cutting disc.
I then finished it off with a 120 grade Wurth flap disc.
There was a couple of dings left with the patch was cut out, so I used a slide hammer to get the worst of it out.
I used the flat of the cutting disc to shape the edge and finished it off with a body file.
I'm sorry if this is a bit long winded for a small repair, but they do take time.
Exuptoy
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Don’t apologise re-good info mate. Anyone needing a guide will find this invaluable and we all love pics.
Glad to see you’re back on it. Not done anything on my mini as I have been isolating following getting Covid and I am supposed to be back offshore this week but following them having a fair number of cases on board we may not be allowed to go until they have isolated the place and had a deep clean.
If we don’t get out I’m getting back on the Mini this week.
Glad to see you’re back on it. Not done anything on my mini as I have been isolating following getting Covid and I am supposed to be back offshore this week but following them having a fair number of cases on board we may not be allowed to go until they have isolated the place and had a deep clean.
If we don’t get out I’m getting back on the Mini this week.
Dcal
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Thanks @Exuptoy you are putting me to shame with the progress you are making on your Mini.
I must try and get some epoxy and seam-sealer on the inside of the bonnet over the next few days, then I'm away for work.
This working lark does get in the way of our projects.
@fizzy is yours a twin spark?
Is it in one piece?
I might need a photo or two for bits where I've forgot how they go back together.
I'll happily return the favour when you get into the guts of yours.
It doesn’t help that I've another Italian car from the same era that’s been in bits for far longer than this wee quick project.
It even has the same body and trim colours but it's from a different manufacturer.
I must try and get some epoxy and seam-sealer on the inside of the bonnet over the next few days, then I'm away for work.
This working lark does get in the way of our projects.
@fizzy is yours a twin spark?
Is it in one piece?
I might need a photo or two for bits where I've forgot how they go back together.
I'll happily return the favour when you get into the guts of yours.
It doesn’t help that I've another Italian car from the same era that’s been in bits for far longer than this wee quick project.
It even has the same body and trim colours but it's from a different manufacturer.
Thanks @Exuptoy you are putting me to shame with the progress you are making on your Mini.
I must try and get some epoxy and seam-sealer on the inside of the bonnet over the next few days, then I'm away for work.
This working lark does get in the way of our projects.
@fizzy is yours a twin spark?
Is it in one piece?
I might need a photo or two for bits where I've forgot how they go back together.
I'll happily return the favour when you get into the guts of yours.
It doesn’t help that I've another Italian car from the same era that’s been in bits for far longer than this wee quick project.
It even has the same body and trim colours but it's from a different manufacturer.
Yes mine is a 2L twinspark Veloce totally original and not fiddled with yet.
175,000 miles on the clock on the original clutch
Yes mine is a 2L twinspark Veloce totally original and not fiddled with yet.
175,000 miles on the clock on the original clutch
You'll enjoy changing it . . . especially if the de-dion front fixing won't come undone . . .
stevieturbo
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For most metal removal or grinding...flap wheels are awesome. They remove metal better than grinding in most cases, plus leave a smoother finish.
There are some "ceramic" flap discs...they definitely remove metal better and last a little longer than regular ones. I'd rarely ever use an actual grinding disc these days
There are some "ceramic" flap discs...they definitely remove metal better and last a little longer than regular ones. I'd rarely ever use an actual grinding disc these days
Dcal
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I also agree with @Exuptoy
Flap wheels are great for removing stock and leave a nice smooth finish which is their greatest strength.
However this can become a weakness when you only have 0.8mm of stock to play with it's very easy to remove too much and not even know it.
It is also very easy to overheat the metal and cause more distortion than you had from your careful slow, tack here, cool, tack there welding process.
If you use a grinding disc you can see the scars appearing in the parent metal before you go too far.
A quick run with a flap disc is then all that’s required.
The cutting edge of a disc will get into spots that a flap wheel cannot, so sometimes it's horses for courses.
I think it's better to leave a few pits than thin everything down for that invisible repair, but it's hard to leave well alone.
Flap wheels are great for removing stock and leave a nice smooth finish which is their greatest strength.
However this can become a weakness when you only have 0.8mm of stock to play with it's very easy to remove too much and not even know it.
It is also very easy to overheat the metal and cause more distortion than you had from your careful slow, tack here, cool, tack there welding process.
If you use a grinding disc you can see the scars appearing in the parent metal before you go too far.
A quick run with a flap disc is then all that’s required.
The cutting edge of a disc will get into spots that a flap wheel cannot, so sometimes it's horses for courses.
I think it's better to leave a few pits than thin everything down for that invisible repair, but it's hard to leave well alone.
