Well i finally got around to working on that new plaster pulp mix today that i mentioned in my earlier post. I will have to be careful here i might get a liking for being punctual & frequent whats this for today post three lol. I actually started working on this new mix yesterday but today was the mix i wanted to make properly. Hmm!, better explain this a little better i think.
After some discussion(s) as mentioned in a previous post a suggestion by Jonni Good 'for' using linseed oil & some research of my own i purchased some online a few days back, two 500ml bottles to be exact. I didn't buy it for the extra hardening properties alone however, no. The outer hardness of my own plaster pulp experimental mixes was not the issue i was having. It was the bonding of the heavier paper pulp i was using to the plaster in my plaster pulp mix. I am hoping the softer thinner toilet roll tissue pulp i have now used will absorb some of the linseed oil & then harden with it being there. Then hopefully it might bond to the plaster a little better in the 'core' of the mix. The linseed oil only arrived today however. Yesterday i thought I'd mix up a batch (many small batches as per requirements during use to be precise) as a comparison to today's mix containing linseed oil.
The new batch is a slight variation on Jonni Goods variation of one of my original plaster pulp experimental mixes. This could get very confusing i think if i am not careful lol. Anyway i am using raw linseed oil unboiled. In my original mixes i carefully measured out specific amounts of all the ingredients. The original mixes were larger batches of what i made today of around 4 ounces. This time however i am working to smaller molds so i have been making them at around 1 ounce or so batches measuring the ingredients by the 'spoonful' basically. My current experimental plaster pulp goes as follows:
1: 4/5 desert spoons (depending on mold size) of very wet toilet tissue pulp (as from the blender very water logged wet).
2: 1 cap full of raw linseed oil unboiled mixed directly into the wet tissue pulp.
3: additional water as required just prior to adding the plaster.
4: approx 1 to 1 & a 1/2 ounces of sculpting grade plaster mixed together to form a runny porridge like paste.
5: This i then mixed until it began to thicken (go off) at this point i split the mix between two or four molds depending on the size of the molds in use at the time using a small flat bristled paint brush to apply in the molds. I have not used any supportive mesh cloth at this point. Primarily as i simply don't have any to hand. Its not something i can't seem to find easily locally.
6: If required some molds were 'patched up' were the mix had slid from the rim or edges of some of the molds because of having to work quickly.
7: The molds were then left to air dry for the next couple of days.
At this point i am 50/50 both hopeful & sceptical that this particular mix is yet right. Some of the mini batches dried hard to the touch minutes after going into the molds even if i applied the mix when still very runny. Some remained very wet more than 2 hours later. I feel this was simply due to sometimes each spoonful of tissue pulp came with more water on the spoon than others. Also sometimes a little more plaster than other times went into the mix. I think i might have to drain the tissue pulp next time & measure both it & the plaster a little more accurately for a more consistent & better working mix to prevent these dry & wet irregularities in the same mix. Not the best scientific method of experimenting using the rule of the thumb, but then it has been a bit of a crazy day for me.
I don't know why at this point but my original working times 'after' mixing has been radically reduced from 8/15 minutes to worst case scenario literally 1/2 minutes after mixing. Could be the change from heavier paper to tissue paper, or the slight irregularity in the plaster amounts i am adding. Hmm!, more than likely the latter i think.
So to draw this post to an end for now. I have made a host of castings up: mini skull trophy/candle sconces, new slightly bigger realistic skulls to the first casts of my ouroboros project. I will let you all know how these batches went once they are all fully dried & de-molded in a few days.