RomanArmyTalk

Building

Well, so far we've made 7 lath strip scutums; have 4 more cut out, wood shaped ready to glue up; have wood for 7 more; and have plans for an additional 6 over the next couple of months.... we're putting a third press into action...

Until a few months ago we used to say that someday we'll build just one scutum the way they were built. Well, one wasn't enough was it? So, now we say that someday we will build a scutum with wood we've harvested, turned into strips using historic methods and covered with linen that's been hand spun and woven... we have these capabilities, just need to put them into action...

Testing

It has become obvious that we will not be able to properly test the integrity of these shields because the modern wood is generally grown under conditions that cause it to grow fast and thus cause it to be weaker. Slow growth (old growth) wood generally has denser grain and is stronger.

I am sure shield makers selected wood for appropriatenes for scutums. We do not have these luxuries and are forced to use commercially available boards and timbers.. though I do reject most boards, seeking wood with better grain, closer to quarter sawn, and I am not adverse to pawing through stacks and racks of lumber for the best selections.

There are also some tricks and techniques we still need to learn.... such as adding fibers to the glue to strengthen the bonding; gluing the lath strips damp instead of perfectly dry; and maybe using strips that aren't perfectly smooth, the idea being that a coarser face creates more surface area for adhesion...

It is an interesting process to be sure and we hope that the rest of the Roman re-enactment community can learn by our mistakes.... and successes! The photo essay for our webpage is coming along nicely and as soon as it's posted we'll let everyone know.

There are some pictures posted on our yahoo group...
http://groups.yahoo.com/group/TheLegioIXHispanaGroup/

Why bother? Does this laminated method give a stronger shield than using 2 plywood halves?

Otherwise, if it's all covered in linen/leather, and you can't see the construction, what's the point? Especially if the finished product that you see is just as authentic from an aesthetic point of view?

Quote:Why bother? Does this laminated method give a stronger shield than using 2 plywood halves?

Otherwise, if it's all covered in linen/leather, and you can't see the construction, what's the point? Especially if the finished product that you see is just as authentic from an aesthetic point of view?

Magnus/Matt Lanteigne

"Why bother? ..what's the point?"

Because, for us in LEGIO IX HISPANA, its more than how it looks... You can rest assured that the lath strip scutums look and feel different than the plywood versions.

And, yeah... these scutums are stronger than modern plywood but that's not the point. And, I suspect that scutums made from slow growth wood will be even stronger.

Why use plywood when other materials are as easy to use and more durable?..... take aluminum for example.. I've made some aluminum scutums for some SCA guys. Made others than have one layer of luan and one layer of aluminum. When its covered in linen and painted... Heck, might as well glue hide and cloth over 1/3 of a plastic barrel... I've seen some very nice scutums made from those large blue plastic barrels. Couldn't tell it was plastic until you thumped it.

These too are also "just as authentic from an aesthetic point of view..."

By the way.... we feel kinda bad about the scutum we have on display at the Ontario Canada Police Museum.. its "luan!" plywood....

That's cool. I'd like to heft one of the laminated ones to see how it feels vs a regularily constructed modern one.

Quote:

Quote:Why bother? Does this laminated method give a stronger shield than using 2 plywood halves?

Otherwise, if it's all covered in linen/leather, and you can't see the construction, what's the point? Especially if the finished product that you see is just as authentic from an aesthetic point of view?

Magnus/Matt Lanteigne

"Why bother? ..what's the point?"

Because, for us in LEGIO IX HISPANA, its more than how it looks... You can rest assured that the lath strip scutums look and feel different than the plywood versions.

Maximum authenticity is important to a lot of people- like I wrote when you first mentioned that you guys had decided to make scuta this way, I'd already done one a year ago, and have orders for 2 more now plus one for myself.

Quote:Testing

It has become obvious that we will not be able to properly test the integrity of these shields because the modern wood is generally grown under conditions that cause it to grow fast and thus cause it to be weaker. Slow growth (old growth) wood generally has denser grain and is stronger.

For this to be true you'd have to prove that the grain density is sufficiently different to have a significant effect on the shield's performance. Personally, given the fact that it's the construction, i.e. 3-ply alternating direction, that gives the scutum the lion's share of its strength, I would doubt that slightly tighter grain would be a signficant factor.

Quote:I am sure shield makers selected wood for appropriatenes for scutums. We do not have these luxuries and are forced to use commercially available boards and timbers.. though I do reject most boards, seeking wood with better grain, closer to quarter sawn, and I am not adverse to pawing through stacks and racks of lumber for the best selections.

Again, you'd have to prove this- I know of at least three species of wood that were used for shields- sycamore, birch and oak- so clearly the requirements weren't that stringent and again because it's the plywood nature that is the major strength of the design, unless the wood is full of knots or something, I can't see major selection happening.

Quote:There are also some tricks and techniques we still need to learn.... such as adding fibers to the glue to strengthen the bonding; gluing the lath strips damp instead of perfectly dry; and maybe using strips that aren't perfectly smooth, the idea being that a coarser face creates more surface area for adhesion...

The addition of sinew fibers and the rough face for increased gluing area I understand, but why would you want to glue the strips wet?

Wouldn't demand and situation also dictate what type of wood is used? If the "best" choice wasn't available, I'd be interested to see what was used in a pinch.

And if you're going to give all this information here on the RAT, why don't you post a few pictures too instead of making anyone who'd like to see them join your Yahoo group- it's a whole lot easier

Quote:Wouldn't demand and situation also dictate what type of wood is used? If the "best" choice wasn't available, I'd be interested to see what was used in a pinch.

Exactly. Species of tree are region-dependent, wood supplies surely weren't consistent in antiquity, and necessity is always a driving factor in the production of anything. If a scutarius had to produce some hundreds of scuta, would he really have the luxury of selecting only the best wood? It actually seems to me that the plywood construction would make up for deficiencies in the wood used...

Oooohhhhh...that's an interesting point matt. In fact, I'd wonder if the inner layer of plywood wasn't some different type of wood, and the outer pieces something else. Kind of like how the japanese sandwhich highcarbon steel around a lower carbon steel core in their swords. Gives'em good flexibility but retains a lot of strength.

If not, be interesting to see if they used maybe a lower grade wood in the center, sandwhich'd between 2 good pieces of supplies were running low. Cool stuff!

Quote:For this to be true you'd have to prove that the grain density is sufficiently different to have a significant effect on the shield's performance. Personally, given the fact that it's the construction, i.e. 3-ply alternating direction, that gives the scutum the lion's share of its strength, I would doubt that slightly tighter grain would be a signficant factor.

Lion's share of strength... I disagree.
All factors are crucial, not equally crucial: glue type, glue quality, presence or absence of fibers, materials used to skin the scutum, its chord, its laminations as "plywood", varieties of woods.. some may be a greater part of that lion's share than others.

Tighter grain is harder to compress.. the lateral strips if they were denser ( old growth or slow growth) would be harder to crush or cut through than wood grown using modern growing techniques. Modern growers often select fast growth rates or hybrids of tree species that grow fast.. means that a tree gets to market sooner.

Quote:Again, you'd have to prove this- I know of at least three species of wood that were used for shields- sycamore, birch and oak- so clearly the requirements weren't that stringent and again because it's the plywood nature that is the major strength of the design, unless the wood is full of knots or something, I can't see major selection happening.

First, I do not believe that there were requirements. It seems quite clear by the evidence that scutum makers knew that a stronger less flexible vertical core laminated between two layers of more flexible more compressable species was the best way to make a scutum.

Thus, I can see selection happening especially if selection is possible. Why not? It's practicle.

I can see trees grown specifically for use in making scutums. Growing wood for specific purposes is something that's been done throughout history. Why not something as important as a military item?

A good wood worker always picks the best parts of a tree for his needs if he can. I use clear ash for pilum shafts, but if after milling into usable lengths and widths the grain does not run right or if a knot is in just the wrong place I reject it. When I select 2x4's at the lumber yard they dread me. I pick the best pieces. I often bring a tool to snap the metal band around a stack of lumber so I can have access to more choices... not all 2x4's a are created equal!

Quote:The addition of sinew fibers and the rough face for increased gluing area I understand, but why would you want to glue the strips wet?

That's easy... first I did not state wet wood I said damp. When wood is damp it absorbs glue better. When wood dries water is drawn out, but when you're gluing you want the glue to penetrate into the wood for better adhesion. As the dampened wood draws the water in it also draws the glue.

Quote:Wouldn't demand and situation also dictate what type of wood is used? If the "best" choice wasn't available, I'd be interested to see what was used in a pinch.

I was referring to the woodworker's desire to pick the best sections of a tree but I agree that in a pinch other choices might have to be made.

Quote:... In fact, I'd wonder if the inner layer of plywood wasn't some different type of wood, and the outer pieces something else. Kind of like how the japanese sandwhich highcarbon steel around a lower carbon steel core in their swords. Gives'em good flexibility but retains a lot of strength.
If not, be interesting to see if they used maybe a lower grade wood in the center, ...

Stronger less flexible wood for the verticals.. ash or oak.

Quote:And if you're going to give all this information here on the RAT, why don't you post a few pictures too instead of making anyone who'd like to see them join your Yahoo group- it's a whole lot easier

No one has to join our yahoo group. Some photos are posted on Roman Army Group as well. The photo essay will appear on the Legio IX Hispana web page in due course.

pictures

Quote:Lion's share of strength... I disagree.
All factors are crucial, not equally crucial: glue type, glue quality, presence or absence of fibers, materials used to skin the scutum, its chord, its laminations as "plywood", varieties of woods.. some may be a greater part of that lion's share than others.

Sean, your suggestion was that the grain of the wood was the most significant factor- since you believe that the wood you can get presently is so much less tight-grained than that which was available in antiquity, you can't consider any tests you do accurate with respect to how original scuta performed. I suggested it was the fact that the scutum was a plywood piece- thin strips glued together alternating grain directions- is far more significant a factor. OF COURSE the strength of the glue, and the additional elements made a difference, but that's irrelevant to your statement and mine. You have to PROVE that the wood from which real scuta was made was significantly different from ours for your suggestion to be considered valid.

Quote:First, I do not believe that there were requirements.

Well what would you call your suggested "selected wood for appropriatenes for scutums" (sic)? Sounds like you mean there were requirements they tried to meet for grain, etc. I agree- suggesting that there were stringent requirements is unlikely and would most definitely have to be proven.

Quote:It seems quite clear by the evidence that scutum makers knew that a stronger less flexible vertical core laminated between two layers of more flexible more compressable species was the best way to make a scutum.

And what evidence is that? Does James mention mixed wood scutum artifacts in his book or is there some other mention of that?

It makes no sense anyway- you wouldn't want one layer to be stronger than the other because otherwise the scutum is weaker in one direction than the other. In fact, the fact that the outer layers are horizontal suggests that impacts that would flex the shield laterally were the most common or necessary to protect against.

Quote:Thus, I can see selection happening especially if selection is possible. Why not? It's practicle.

If possible- yes, but you wrote it as if it was a universal fact Sean. Sure if he could a scutarius would choose good wood- but, again, if the requirement were for hundreds or thousands of scuta, any significant selection would be impractical. Not only that but you're not taking into account the fact that for an army in the field for years, materials would be what was at hand- yes? If replacement scuta were needed, they had to be constructed as best as possible- meaning no excessive selection, if that was ever done in the first place. Once again, if you're going to state that you think it was done, you have to have evidence of it. A proper theory is generated FROM observations- to explain them. Unless some scutum artifacts show extremely tight grain, or other features suggesting they're select woods, your suggestion is completely unfounded.

Quote:I can see trees grown specifically for use in making scutums. Growing wood for specific purposes is something that's been done throughout history. Why not something as important as a military item?

hock: Evidence? Is there even a hint of this written, described, etc. anywhere?

Quote:A good wood worker always picks the best parts of a tree for his needs if he can. I use clear ash for pilum shafts, but if after milling into usable lengths and widths the grain does not run right or if a knot is in just the wrong place I reject it. When I select 2x4's at the lumber yard they dread me. I pick the best pieces. I often bring a tool to snap the metal band around a stack of lumber so I can have access to more choices... not all 2x4's a are created equal!

This is exactly why a great deal of excess selectivity isn't practical- if there's only so much useful wood in each tree and there's no industrial supply like there is today, it makes no sense at all to expect the kind of selection that goes into fine furniture for a purly funcitonal item that needs to work not to just look nice.

Quote:The addition of sinew fibers and the rough face for increased gluing area I understand, but why would you want to glue the strips wet?

That's easy... first I did not state wet wood I said damp. When wood is damp it absorbs glue better. When wood dries water is drawn out, but when you're gluing you want the glue to penetrate into the wood for better adhesion. As the dampened wood draws the water in it also draws the glue.[/quote] Fine- semantics. But do you actually mean that the dry wood absorbs the water from the glue causing it to gel faster and thus preventing it from penetrating as much? Because if dry, wood absorbs water readily, but when damp it does less so because there's already water there- basic diffusion dynamics. Well that does make some sense, but have you actually proved this or is it just a theory? I seem to recall trying it myself last September and finding it not as strong a joint as with the wood being dry...

Quote:No one has to join our yahoo group. Some photos are posted on Roman Army Group as well. The photo essay will appear on the Legio IX Hispana web page in due course.

Twice at least now you've made announcements with a suggestion that pictures can be seen on the Yahoo Groups page Sean- and you can't see those without joining the group. Thanks for posting them properly here to go with the threads :wink:

Quote:

Quote:I can see trees grown specifically for use in making scutums. Growing wood for specific purposes is something that's been done throughout history. Why not something as important as a military item?

hock: Evidence? Is there even a hint of this written, described, etc. anywhere?

Well, I've read that coppiced ash groves were commonly maintained and harvested for spear and javelin shafts, but like so much else in my brain I can't quote a source for that!

While I agree that the ancients had good ideas about the best materials to use, I don't think they always busted themselves to find them. We can't be sure that only old growth trees were used for shields, for instance. I don't even think we've proven that shields were faced with rawhide rather than leather, though I'm certainly happy with either one. It just seems like a little bit of a stretch to me to be constantly pushing for the absolute strongest and toughest shield--I have a feeling that all too many of the real ones were simply "good enough". Concentrate on getting pretty much the right wood and making it the right thickness, and yeah, I think tests on a shield like that will be much more instructive than whacking anything made of modern plywood.

Keep at it!

Matthew