Making an Authentic Viking Shield, part 3: Attaching a hide facing

Hi guys, so welcome back. I'm now going to prepare the hide glue for attaching the parchment to the shield board. And as you can see I have already prepared the hide glue here. Hide glue itself is a glue that has been used for millennia and is still very common in woodworking and restoration. It has a number of properties that divide it from modern glues. One of them is that it doesn't really hold up very well against humidity and it is also sensitive to heat. Now these could be considered disadvantages but at the same time it's also an advantage which is for instance used by builders of musical instruments. If for maintenance purposes you have to disassemble say an old violin these instruments were usually glued together with hide glue. Now because hide glue is sensitive to heat you can easily heat up the joints and without any damage to the original material, namely the wood in that case, you can disassemble the instrument. Another advantage of hide glue is that it sticks to itself. So other than a lot of modern glues you can put on hot liquid hide glue onto hide glue and it will create a bond. Okay so if you look at the hide glue here. Hide glue is produced from, as the name says, hide. So scraps of hide are slowly boiled up and the gel that ultimately is created is then dried and cut to either sheets or like in this case to these granules. And this can be kept on the shelf forever as long as you keep the material dry. Once it is wet it may be destroyed by microorganisms so if you are left with hide glue either keep it in a freezer or make sure that you dry it out again before it starts to rot. Once it's rotten it is destroyed and cannot be used again. So the granules that you see here they are completely dry and I put some into water for a couple of hours and what happens then is they're going to absorb the water and swell up. So that also means that as hide glue dries it will shrink. So here you see the watered gel-like material. So this is what these granules look like if you put them in water. They swell up to probably four times the size and this stuff I kept in a jar and this jar I put into a water bath and this pot I put onto a heater and now I'm going to heat it up to some 60 degrees centigrade. You should not heat it up any hotter than say 70 degrees centigrade or more because then the proteins within the glue will be destroyed and it will lose all its adhesive power. While the glue is becoming hotter so I can work it a few words on the board. A couple of people asked about the kind of wood that was used to create that shield board. That shield board by the way was made by Kim Wichglasen who is a woodworker and an expert for reconstructing medieval replica furniture. So he's making really nice replicas and he's a friend of mine and I asked him to make this board from split planks. He used hide glue to join the planks which are simply butted to each other to that purpose. Of course he had to use clamps to keep the boards in place and only after that they were thinned down. As you have in one of the previous videos you know that I thinned down the board myself too. After I have attached the hide all the planks will neatly be clamped together by the hide which means I can thin it down even further which I will do. This is poplar wood also known as linewood and it's a local wood that grows a lot around here. It is confirmed by finds from various Germanic bog finds like Illerup and Torsberg and these finds also contain a lot of shields which were made from elderwood. Poplar or linewood has some really nice properties. First of all it's very resilient so it's not so easy to cut into that material. At the same time it is very light so that renders it a very good wood for making shields. So as you can see the glue is already molten. It has a nice temperature of exactly 60 degrees centigrade which I measured with this device which I nicked from the kitchen a long time ago and now it lives in the workshop for this purpose. So with the board and hide being firmly kept in place by this plank and the anvil I can now fold back the hide and proceed with gluing. So this is what the board looks like the next morning. The hide is firmly attached but you can see there are a lot of wrinkles here and some bubbles and I'm wondering if because the glue is sensitive to heat if I could simply iron these wrinkles down. Now here are a few places where there are air bubbles and if I compress them a little bit I can see that it actually would stick if the glue was still open which it is not anymore. But yeah I'm going to see if this idea works out. There are some serious bubbles here and even here and so I'm going to give this a try first. Seems to work. So what's critical is you have to make sure that it doesn't get too hot because then the glue will lose all its adhesive power and strength because the protein molecules would be destroyed if it was too hot. But as you can see I still have fine wrinkles here but overall these fat bubbles they have all gone and it seems like the hide is sticking nicely to the surface. Very cool. I like it. So I'm very impressed with this method. This part here I have already ironed down and it's all smooth. I mean there I can still see some of the really big wrinkles and bubbles. No I don't see any bubbles but I see some of the wrinkles. But what works really nicely is heating it up and then afterwards when I have heated it up with the iron I use a smooth wooden handle to compress the parts which need to be pressed down and this is just super cool. I mean what a great system. You can just work the glue again by heating it up. I have of course no idea if this was ever done in historical times. Arthur von Eschen correctly pointed out that this method could also be used namely using heat and moisture. It could also be used to make repairs. So if say you need to disassemble your shield you can do that by using heat and maybe some steam to loosen up the glue. What I'm doing here is I loosen up the glue and make it open again because I want it to stick again. So with my hand I can feel which parts are hot and then I'm going to use now I'm going to basically polish these parts pressing the height onto the board and polishing out any wrinkles. And you can see they simply disappear. Okay three hours of smoothening the surface and here it is. No more wrinkles at all. I put the boss into the center so you have some sense of proportion and here's our nice even height facing. No more wrinkles at all.