Volvo Amazon 1965 (Volvo 13134)

[MrCrankyface]

More tiny steps towards a completed firewall.
-Welded in a 2mm plate in the previously shown "problem area". I didn't cut the old thin sheet out, instead I slathered on a special weld-thru primer meant for areas where you'd have several layers of sheet and then just stretched the 2mm plate over the area.
-Welded the new panel together with the bottom piece and blended it somewhat.
-Welded the now joined panel tot he footwell and above panels.
I'm aware these updates are miniscule, but it keeps me motivated to continue and doing small steps makes it feel less like an insurmountable task overall. Not to mention how hard is it to make progress when you're so tired of the metal dust that grinding brings with it, if only the car fit in my milling machine ...


Initially I considered having the tunnel removeable(for reasons I dont remember) but I took it out and primed the surfaces underneath so I can weld that in next.
This might make it easier to fill in the left side of the firewall..

 

[MrCrankyface]

Havent had much time or energy to work on it but got some done today.
Very quick and rough shaping on these pieces.
The right piece needs a bit more shape on the stickout to the left, I want it to bend forwards to make it easier to meet up with the existing sheet.
After that it should be 1-2 small plates and the firewall is basically done.

 

[MrCrankyface]

Tiny bit of shaping and lots welding.
Doing the welds is starting to become my least favorite part because it always requires so much prep...
Had to take all panels off just to grind the "subsurface" flat-ish, clean it with acetone and apply weld-through primer etc.
I also started welding the tunnel to the car. I don't think I will need to take it out again anyway.

 

[MrCrankyface]

Tiny bit of an update.
Economy and general health being what it is, progress is rare and slow.

Upgraded the english wheel again, more in this thread: HM Thread
Night and day difference to before, lower wheel now tracks perfectly and the tension/force is extremely repeatable.


Took a lot less effort to get these two plates done compared to how it used to be.
It doesn't look like it due to the fisheye lens but there's quite a lot of stretch/compound in both pieces.
The upper part I stretched from center out and over the lower edge, the lower piece I stretched a lot around the radius to make it move away from the motor and create more space.
Just need to close this final little hole now and the firewall is pretty much done shapewise, unfortunately ran out of material so we'll see if I can use something else or sort that out somehow.


Edit: The upper edge of the lower piece is quite rough, I bent that over using hammer and dolly once the part was welded in. Will finish the shape once the motor is out again and I can reach both sides.

 

[MrCrankyface]

Now this is a good day!
Took me three tries to even get started because wow this last filler piece was annoying to make.
But now I finally have a complete firewall and I guess also some floor, which is a big milestone.


Just as a reminder what I started with roughly a year ago.

 

[MrCrankyface]

I want to try making some real thick and deep beads in some of the remaining floor pieces and figured this could be a good application for testing stamping/pressing.
Flattened some suitable scrap, 10mm top piece, 17mm middle and 10mm "floor".


Bolted them together and started milling a pocket for where I want the sheet to stretch down into.
The top and middle piece are milled completely through whilst the bottom is left alone.


And assembled with a piece of sheet just for test.
From top to bottom it's:
1. Piece of cast iron to distribute pressure(not an optimal choice, brittle)
2. Parallels to further distribute pressure
3. 3D-printed die out of PLA(99% infill)
4. 1.25mm steel sheet
Since this pressmold will be attached to a bigger plate I wanted to use as few holes as possible.
Whilst I could probably have calculated the pressure excerted by these 6x M5 screws I choose to just test it instead..
My initial idea is to clamp the sheet so hard that all deformation will happen inside the pocket rather than letting the sheet flow in from the sides.


Above ~5 tons of force I could tell it was being pulled in from the sides by the wrinkling on the exterior but decided to keep going.
At ~15 tons of force the cast iron piece snapped in half, causing the plastic die to also snap in half. This increased the pressure locally causing the middle to almost form fully whilst the outer edges are more shallow.
Not success but definitely learning a lot.


After some very rough adjustment of the sheet it does seem rather promising.
Will print a new die and am currently making a much stronger top piece for distributing the pressure, out of steel this time.
I will also use all available bolt holes on my next try to see if that is enough to hold the sheet metal in place.
If that still doesn't work out I will have to resort to flowforming it with my pneumatic hammer.

 

[mattthemuppet2]

if you restrain the metal being formed you'll turn it into a large punch press die, which will probably fail as the top/ pushing part is made out of plastic and the tonnage needed will probably exceed what your press can deliver. The typical approach to this kind of stamping is to let the sheet move then trim off excess afterwards. You will also need clearance between the upper and lower dies to accommodate the material plus some, as well as a few (2 - 5?) degrees of draft on the bottom die and some judicious rounding of the lower die edges to prevent tearing. This is not a trivial endeavour though props for trying

 

[brino]

Not success but definitely learning a lot.

This is not a trivial endeavour though props for trying

I dunno, but this:


looks a lot like success to me!

Brian

 

[MrCrankyface]

Thanks!

There's a massive amount of space around the top die so no worries there. I did end up doing a fillet along the lower die to smooth the transition, figured it might help it flow in.


Optimally this entire form would be a lot thicker and use even bigger hardware but I'm working with whatever scrap I have laying around.
The reason for wanting it to stretch rather than flow in is that I need to make multiple of these in a larger sheet and I suspect it will be a big pain to fix distortion afterwards if it flows around too much.


Took a few hours to clean up and weld together that green junk piece, should distribute the pressure a lot better..


Went ahead more carefully this time, at around 10 metric tons I could see that the clamping force was not enough and the metal started moving in so I let off and replaced all screws with M6 of a higher grade.


At 10 tons and M5 screws this is the amount of shape I managed to make, still very flat and uniform thanks to the new spreader piece.


Same sheet reinstalled with M6 hardware.
Another positive is that these thread right into the bottom die so I don't need a nut on the bottom and spacers to lift the bottom die up..


That managed 15 metric tons with no problems at all, the metal moved a tiny bit more but this is still in the region where I think I can smooth it back out and it shouldn't be a problem making several of these in the same plate either.
I think I can go slightly above 20 tons but it seems to fully form at 15.
It's much more uniform than the last try, just as deep but looks wider due to the fillet.
I considered pre-stretching the area with the english wheel but then the whole process just becomes way too annoying when you need to make several so it's not something I want to rely on.
I would like to try this a third time but hammerform it instead and see how that ends up.

 

[MrCrankyface]

Alright so gave the pneumatic hammer a try. Took some testing to get the anvil right, had to be quite "sharp" to actually shape the steel.


I pretty much bottomed the anvil all around the perimeter resulting in a quite deep shape.


And compared to the 2 other tests.
The walls are almost vertical due to how the lower die is shaped and that I pushed the anvil as far as possible.
Most important takeaway here, for me, is that this produced no warp at all in the rest of the sheet so this should be quite risk free in a larger sheet.
Also only used 6 bolts here(7th hole was a dud) which leaves a lot less welding to do afterwards compared to 18 holes per stamping..