Your
project looks really awesome!
Take this into consideration: I AM NO EXPERT PLASTERER! I have worked with lime and done small projects and done lots of reading on the subject.
My advice is to wait at the
bare minimum two months before applying a lime plaster otherwise you may run the risk of the plaster cracking heavily because your wattle cob is still drying.
Even in the hot dry climate of Yemen I believe they wait a year to lime plaster after the last brick is laid. These walls are substantially thicker than yours but it also looks like you're in a decently humid area?
ONCE PROPER DRYING of you walls has taken place here are
the steps I would take to plaster your walls.
1. Make sure your lime has been slaked for a proper amount of time per the type of lime you use. I've only used type S lime that you get from big home improvement (oxy moron?) stores, and while the longer it slakes the better it is, after 24 hours it is sufficient for use.
2. Make a key on your cob walls no more than a 1/4" deep on your walls. This can be done with anything that will gauge into the wall to that depth.
3. Make a lime wash primer about 12 parts water to 1 part lime. Paint this mix onto your cob walls applying 3 coats waiting 24 hours in between each and misting with clean water before each application. This will provide a stronger substrate to plaster onto.
4. Now you can start plastering your walls with lime. Mist your walls down with water the night before you plan to plaster, and mist right before applying plaster and mist anything that starts to look "dry" before applying plaster to it.
5. I would do 2-3 layers of plaster. The first would be 3 parts sand to 1 part lime, the second 2.5 parts sand to 1 part lime if you do a third I would make this the weakest at 1.5-2 parts sand to one part lime.
Now after the first coat is leather hard, meaning it is hard to press finger into but can scratch with finger nail I would key the whole plaster to a depth of 1/8". Cover the wall with berlap sacks and keep them moist or cover with plastic and
keep the wall moist for at least 4 days. Then apply your second layer in the same process omitting the key after it is leather hard. Make sure to keep your final layer moist for the prescribed 4 day minimum. I would apply a lime wash at any time after the four days or do a fresco the day after your final plaster layer is applied. The asthetics of your plaster will depend on the trowel and technique you use which would probably take up a whole thread on its own. And this post barely gleans the surface of lime plaster mixes, techniques, types of lime, curing time, application, troweling ect, ect, ect......... ect ect ect...... ect.
With that being said, IF YOU HAVE 0 PLASTERING EXPEIRIENCE
DO LOTS OF TEST PANELS! Practice, practice, practice.
Also make sure that while your plaster is curing, to keep sun, wind and rain from contacting the curing plaster.
And practice more.
And post more vids/pics.
Thank you!