Over the last couple of weeks transatlantic communication lines between Henri and myself have been busy the principal topic of conversation being resin/gum.
Henri uses a pine resin based gum and offered to get some to me here in the UK from New Hampshire. Sadly UPS and USPS shipping rules along with UK import regulations thwarted that plan so we were looking for a Plan B or C. The gum was used where the bark had been stitched, gores cut in the sides and at the stems. In his building process Henri tapes and seals the joints both on the inside (between the bark and the sheathing) and the outside. A disadvantage of traditional gums is that during hot weather they soften and run off and when cold can go brittle. Some have moved away from traditional gum to more modern tars, caulks and sealants which are far more durable with greater longevity.
So I thought I would go down both routes. Firstly, using a syringe usually used to administer childs medicine, I applied a fine 2mm bead of highly flexible and waterproof roofing shingle adhesive along the gore cuts which were visible. this was pushed into the gap to fill and bridge it. It is a material which both stretches but also compresses. Using a flat blade fitted to my solering iron I found that I could soften the original gum, manipulate it and smooth it back into place. I tidied up the stems and then eased the traditional gum back into place over a gores and the bead which was now dry. I have only done one so far as wished to experiment with the process.
This is the flat blade on the soldering iron
This is the gum on the stems which I have flattened out with the warm iron. Note it is lighter in colour.
This is a gore cut to which a bead was applied and the original resin heated and eased over. Note that it is all much darker i colour.
In some areas on the gores there has been a greater loss of the original gum which I will need to supplement. I found some pitch pine glue for sale on a bushcrafting site here in the UK so ordered a sample; it arrived in hard ,very dark blocks. I have also found online some pine resin which I have ordered. Henri has confirmed that it is just like what he used.
Whilst the pitch pine is already mixed and tempered and just needs to be reactivated by heat, the pine resin will need to be mixed with some fat and tempered. Henri has said that he will let me have his mixture ratio. I suspect I will end up using a bit of both. On the stems and where applied thinly, the original gum is a mid to dark brown whilst whre it is thicker on the gores it is closer to black.
Below is the pine resin which I have ordered.
All of the work which I am proposing is a "bolt and braces" exercise. It will not only add to the watertightness of these details but will also keep the aesthetics correct.
It's now just a waiting game for the resin to arrive and the weather and garage to warm up a bit!
Nick
