Couldn't really pick where this should go.
What is the best means of attachment of applique armour, weld, bolt or ?

I guess it depends

On the AAV, the armor plates are bolted to brackets which are in turn bolted to welded lugs on the hull to make them removable :



H.P.

Applique armour simply welded or bolted directly on to the original armour only increases the thickness.
If it is mounted on holders so that there is an empty space (see image posted by H.P. above) there is also the chance of messing with the timing/effect of a missile/projectile.

The standoff plate must be solid enough to set off the detonator in the missile/projectile. Shaped charge warheads which create a jet of white hot metal to melt/burn its way through the armour. With stand-off plates the designers hope to reduce the effectiveness of this metal jet.

Then it also depends on what you are trying to show. Is it a factory produced applique distributed as a kit? Was it added already in the factory or during a factory rebuild.
Something cobbled together by the troops (Super Pershing up-armoured by welding/bolting on pieces of a cut up Panther or Tiger)?
German Pz IVs had both bolt on kits added in the factory and stand-off plates like Schürzen or the stuff added around the turrets.

Figure out a plausible history, think about the facilities/resources available when adding the applique and decide on a mounting system. If it is too elaborate it will be difficult to scratch build ....

A village welder can work with steel but aluminium will be trickier ......
/ Robin

I'm thinking steel and factory fit. Heavy enough to take/disrupt typical late WW2 APC rounds.

https://upload.wikimedia.org/wikipedia/commons/2/22/M10_Tank_Destroyer_%281%29.jpg LARGE image



The "warts" on the sides are mounting points for planned extra armour.

I am not 100% certain about the Cromwell, you may try Googling for more/better facts.
This Cromwell tank also has applique armour and I think the "warts" are the bolts holding the armour in position

https://upload.wikimedia.org/wikipedia/commons/5/58/Cromwell_in_the_Kubinka_Museum.jpg

The Pz.Kpfw. IV Ausf. E had 30 mm of extra armour bolted (hex heads) directly to the outside of the original armour. Later versions had the extra metal included from start.


Some other panzers (some pz III's I think) had stand off armour plates in some areas.


The difference in turret shape between these two A13's (different marks) is due to add-on armour




/ Robin

A observation from WWII British tank crews, "Nothing keeps out an 88."

If you are thinking 1945 or later I believe welding would be the preferred method. Lower set up costs, no extra steps like boring drill holes for bolts etc.

ERA type of armor neede to be replaceable. There are times it needs to be removed. It is an explosive and does not need to always to be attached. Add on steel plate is another story. It can be welded, bolted or riveted on. It will probably not be removed. Steel plate is probably best welded on.

Bolted armour had a habit of send bolts flying out as shrapnel making it lethal to anyone near by and was favoured by the British. A hit on bolted armour often resulted in the loss of the additional plate. Welded armour was superior in this regard and did not come off so easily.

So for simple sakes, an I beam or the like welded to the base armour for standoff, then the applique over that. Practical?

Easy to do, and would allow for any lumps or bumps on the main armor. How practical depends on what you are adding armor to.

Large flat surfaces

Andy I believe he is asking what vehicle not where on a vehicle.

A Tiger 2 the next step on from July45 but not an E-75 yet. Horrendously overloaded. I'm debating just extra plate straight on the hull and turret sides, or a anti heat packages with an appearance similar to a Merkava 2. The hull sides are difficult to fit without putting a big stand off in or vertical them ala panzer 4 skirts. I don't want to put just a big hunk of mesh either.

Sorry Robin
I see no evidence of that Cromwell having appliqué armour, which was fitted to the front of some welded hull versions (not this one though). The turret of all Cromwells is made from an inner welded steel shell to which the thicker outer armour was bolted. This avoided the flying rivets issue which could arise if a rivetted component was hit by a projectile and reflected the DTD’s doubts as to the concept of welding armour directly.

Thus while the turret faces consisted of two plates, it was not appliqué as such as it had always been designed that way.

Thanks Robert!

I think I now understand what you are trying to do. In this case I believe the plates would be attached directly to the turret and hull sides. If you want to follow the trend that German industry used in WWII, then the added armor can be welded, or use those large cone shaped rivets like on the Elephants. The rivets would look nicer than welds, and be simpler to do, both in a what if 1945/46 scenario and on your bench. Cut the add on plates a little smaller than the plate they are being attached to, rough up all the edges, add some big rivets/bolts and you will have a easily done and visually appealing applique.

Here is what I am doing on a what it 1945/46 Panther (waiting for me to get off my duff and finish it).

is that a dragon or amusing panther? conical bolts it is.

This is the Dragon Panther F with Dragon Panther II and a little of everything I had lying around. Meng makes some nice rivet sets. That's what I used.