Goatskin parchment application??

[Andrew Collins]

Hi all, this is my first post so hopefully you can be of help.
I'm doing a cabinet making college project i intend to wrap the cabinet in real goatskin parchment. The effect i intend to achieve is a check pattern made out of squares or 'tiles' cut from the parchment.
The problem is finding information regarding the application of parchment to (in my case MDF 18mm) ie: weather the parchment can be glued down while dry or does it have to soaked first? And in either case what type of glue should i use. Hige glue? Fish glue?
I'd greatly appreciate help with this matter as its almost impossible to find information regarding this.

Regards Andrew

[John Vernier]

I have handled parchment, but I have yet to try to glue it down to anything. It has been glued to wood for many applications over centuries (medieval shields, small caskets, travelling trunks, etc), and hide glue would have been the glue they used - after all it is what holds the parchment together in the first place. Fish glue would probably work just as well. I would do a small test piece. Parchment goes limp pretty quickly when it gets wet, and I suspect it will soften from the water in any animal glue. Soaking it thoroughly may make it too limp, slimy and stretchy to be manageable, but if the glue doesn't soften it enough I would try just lightly wiping it with a damp sponge, a couple of minutes before glueing it down.

[Ralph Okonieski]

Andrew, I'm sorry I am unable to offer any advice regarding the glue, but your project sounds really interesting. I hope you will share pictures of it when it is complete.

[Ryan Mooney]

So I haven't worked with parchment, but have used rawhide and leather a fair bit but in different contexts so take this for what its worth (wrapping a saddle tree in rawhide isn't quite the same thing as you're using the contraction of the drying hide to stiffen the structure in that case - in your case a similar approach would just pull itself off of the wood).

I wouldn't wet the parchment. If you do it will stretch and then shrink as it dries and either (best case) leave a lot of gaps or (worst case) pull free. Ongoing the moisture changes may be a bit of a problem so using something like shellac to top seal it would I think also be a good idea (wood and leather have different expansion rates so if you can slow down the movement of both they are more likely to survive the event). For this reason I'd also look at it some and try to figure out which side was likely the flesh side and put that towards the wood (sometimes its hard to figure if the hair side has been sanded a lot, if not the hair side is the smoother side).

I'd probably consider trying to use some sort of sizing (rabbit maybe? although fish or even just plain gelatin would probably work fine as a base) on the underside of the parchment. It looks like book binders doing parchment over wood add a paper backing with a sizing between the paper and the parchment (and then press it until its dry and flat). Apparently the paper acts as a buffer for movement so the parchment is somewhat less likely to tear free. Once the parchment is sized and dry I expect it'll also be easier to cut the squares you want out of it.

For sticking it down a glue with some small amount of flex is likely the best bet so it survives humidity changes. For that Rabbit is probably better than some of the other hide glues as its a bit less brittle/stiff, some of the book binders us starch glues (wheat, rice, corn starch + water) or PVA.

If you search for "book binding parchment glue" and "leather bellows glue" there are some interesting sources (some of the book binding restoration articles in particular talk about some of the wood-parchment bonding issues).

Do a few test runs and maybe stress them a little by putting in a humid spot and then a dry spot for a few cycles out to see how they hold.

And yes please do follow up with how you end up doing this and pictures - interesting project :D

[Sam Puhalovich]

Andrew ... If I were to be doing the project ... I would first stop-off at the local shoe repair shop and ask for their advice.

[David Barnett]

Andrew ... If I were to be doing the project ... I would first stop-off at the local shoe repair shop and ask for their advice.

Well-intended, I'm sure, but woefully misguided. Parchment does not equate to tanned leather in mounting praxis. From Parchment Over Boards, Peter Geraty, copyright © 2010:

Parchment is completely different. Several things have happened in the skin to bring about these differences. Even though it is bated, the ground substance is not completely removed. In addition to that the elastin fibers are still tightly wrapped around the collagen. The string has not been cut and movement of the “flexible rods” is restricted. Being dried under tension has created the most important changes. The fibers have chemically bonded with each other further limiting their movement. The stretching has also caused the fibers to lie over at a low angle, aligned nearly parallel to the surface of the skin. This is quite unlike the more vertical nature of the fibers in leather.

The result of these changes within the skin is the characteristic rattle of parchment, its opacity, great tensile strength and ability to withstand tearing. The strength and tear resistance are what make it such a wonderful material for binding. Keep these aspects in mind when working with parchment. Disruption of the structure changes the nature of the skin. Unlike leather, parchment can revert back to a raw state and therefore, is also more susceptible to biological attack.

When working with parchment it is best to avoid using much water, as it can disrupt the structure. If you wish to gently soften parchment, the use of a 50/50 mixture of either water and isopropyl alcohol or water and ethanol will achieve this with less disruption to the structure.

I would add that any moistening is best accomplished through a well-wrung and nearly dry sponge in a patting motion or sparingly sprayed with a fine atomizer. Both should be immediately blotted of excess moisture, again, in a patting motion. Rubbing or sweeping motions may stretch and distort the skin. For the OP's application, there should be sufficient moisture in the HHG alone (which should be applied cooler than the 140° F used for wood veneer as exposure to 140° F and above for any but the shortest duration will harm parchment and vellum).

For anyone attempting to mount parchment over MDF who has not before done so, it's generally best to first affix the parchment to handmade paper (machine moulded papers have pronounced grain direction whereas handmade paper does not), slowly dried flat under even, light pressure with the minimum adhesive to get the job done and to retain maximum opacity, and this skin-paper assembly then mounted to the substrate. If mouldmade or other machine made paper is used, test for best grain orientation.

Shoe repair shop? Maybe not. :)