scutum covering again

[Matt Lukes]

Now since the issue is one of bonding between the rawhide I have and the PVA glue, I'm not going to bother doing any further testing with it- if someone with different, non-dog chew toy, material wants to try on glue-soaked linen, please by all means proceed. In fact, I think it'd be useful to know whether it's just the rawhide I was using or if indeed PVA glue doesn't work with rawhide well in general.

[Marcus Mummius]

If there is no paint under the metal pieces this could sugest that they were applied before painting, perhaps to keep the covering on...

Not necessarily. Maybe the whole frontage of the scutum was a big, brash, red. Decoration and all. Umbo as well.

It would make a striking frontage - a complete wall of red which looks thoroughly complete and linked together. We just do not know.

Hence the qualifier 'could suggest'- indeed no paint under the metal pieces could suggest they were applied before painting- if there's paint elsewhere, just not directly under the metal. Of course there are a kabillion other things this fact could suggest too

Indeed could sugest wink:

I'll have my hands on a few untanned cowskins that I intend to use on scuta. I will try white glue on a scrap piece and see what happens. If it doesn't work I'll have to use hideglue...

Vale,

[Robert Vermaat]

Well okay, but that part of my statement was the extra little addition, not the primary reason for my doubting mechanical fasteners were necessary or even advantageous. From a purely emperical standpoint, I just don't see mechanical fasteners being necessary or even advantageous. A total glue bond is vital to the efficacy of the extra layer, so nothing else would be needed.

So maybe the fasteners were needed because wet rawhide, being stretched while drying out, was impossible to glue down at the same time?
Mind you, my experience is with oval shields only, and rawwhide can be perfectly stretched. Even rims are perfectly held in place with stiching only - not need for any glue in my opinion.
But I can see that glue could give a better bonding and hence structural integrity.
Can you tell me how rawhide can be glued down when wet?

[Matt Lukes]

Well if the rawhide is just there to protect the wood from impact, everyday use and to help keep the planks together, the way simple edging is, being sewn in place is fine- but that makes the rawhide just a protective layer, not anything that will add significant strength to the structure the way bone and sinew on the back and belly of a composite bow do, for example. For that it has to be a bonded part of the shield. It won't impart nearly so much of its resistence to stretching just attached at the edges or even at a number of points as it would if it were glued down.

I would think it fairly easy to stretch wet rawhide- just attaching a few weights around the hide's permimeter and laying it on a scutum form, curve up, raised up from the floor so the weights could hang free would do an excellent job whether it's just drying or if it's gluing. Once it's dry, trim the edge and voila! Or just use a curved piece of wood and clamp it to the form all around the edges and put some weight on top (sandbags or whatever).

To glue wet rawhide, and I'll remind you my test pieces didn't do particularly well, I just dabbed the wet hide with a towel to get the surface water off, applied a good layer of glue to both the hide and the wood, pressed the two together, and placed some plastic and antoher piece of wood on top before clamping for a couple of hours. After that, I removed the clamps and plastic/wood to allow it to dry. Now it just occurs that since rawhide contracts as it dries, removing the clamps might have allowed it to pull away from the glue that had bonded to the wood- and this might account for the poor hide-glue bond. Perhaps keeping them clamped until mostly dry would have been better.

[Tarbicus]

but that makes the rawhide just a protective layer, not anything that will add significant strength to the structure the way bone and sinew on the back and belly of a composite bow do, for example.

What about the linen (and/or felt) that's glued to the three layers of wood on both sides? It's already a pretty strong construction without the rawhide. The rawhide not being surface bonded might allow for better shock absorption and distribution without so much energy penetratiing through. A bit of bounce? After a certain amount of use all you need replace is the top rawhide layer and umbo, which would be much easier if not glued down.

[Dan Diffendale]

Just a note on rawhide vs. leather here...

This is Cassius Dio, Roman History 48.18.2,
"Rufus managed to repel Sextus from Italy, and when Sextus retired to Sicily, undertook to manufacture boats of leather, similar to those used on the ocean. He made a framework of light rods for the interior and stretched over them an uncured ox-hide after the manner of a circular shield."

But I believe this is referring to cavalry shields.

[Matt Lukes]

When was this written? Certainly I think there's little doubt that rawhide is a very important component of plank shields- that's been empirically demonstrated...

[Hibernicus]

We've had excellent success gluing damp rawhide onto the the lath strip scutums

Soak rawhide sheet in warm water to soften it (we prefer goat rather than cow, but cowhide works too)
Stretch it over a scutum blank
Let it nearly dry
Redampen and let it sit in a sack for a few days to allow the moiture to evenly distribute
Apply glue to dampened scutum
Drape rawhide sheet across the scutum
Hold in place with sand bags
Clamp edges..

It can take several days to dry but slower is better.

[Gaius_Calvus]

Matt,

Cassius Dio was born about mid-2nd century AD and died sometime after 229 AD.

The quote is from his Roman History, which spans the period from the arrival of Aeneas in Italy through ca 229 AD.

The specific quote above describes events during the Roman Civil War after the assasination of Caesar, when Sextus Pompey (son of Pompey the Not-so-Great) took over Sicily as the base for his fleet, from whence he could control a good bit of the Roman grain supply.

So, he's a later author describing much earlier events.

Calvus

[Matt Lukes]

Interesting- if Dio was writing in the late 2nd century/ early 3rd century AD, the plywood scutum and clipeus were still in use. But had plank shields shown-up yet? He might have been writing about the civil war, but his metaphor, I think, would have been more likely contemporary so readers would understand better- unless he mentions the ox-hide covering of a round shield at an earlier point and is just referring to that.

I still go back to the Dura finds- there's only one with any kind of rawhide on it (yes?) and that has the skin on both sides, not just the front, and it's parchment thin- which I can't see adding a whole lot of strength. I actually wonder if the parchment is simply there as a painting surface...

[Hibernicus]

Parchment thin...

That's why we prefer using goatskin, also seems a bit more stretchy than cowhide... and it is much nicier to paint than cloth!

[Tarbicus]

Was it 'parchment thin'? Could 'parchment' be interpreted as just another way of saying 'rawhide', and IIRC that is the term the original excavators used, but I may be wrong.

[Gaius Julius Caesar]

Hibernicus wrote

"(we prefer goat rather than cow, but cowhide works too)"

I am sure I read somewhere that the romans used goatskin on scuta as well :?

[LUCIUS ALFENUS AVITIANUS]

Parchment was one material used in antiquity to write. It's a very thin hide of goats or sheeps. It's more rigid than a common leather, probably because a particular tanning, or probably it's only dried or salted. In spanish it's called pergamino.

[Tarbicus]

I know about parchment for writing, but the description by the original excavators may be their polite way of just describing rawhide. I'll take a look at James later.