And yes agree with the reproofing advice; Go with Grangers or Nikwax, and follow the instructions.
If doing in a machine, it's recommended to run a service wash first. This thoroughly cleans out detergent residue, which contain water softners & surfactants, designed to improve water/soap ingress into the fabric/fibres, and optimise cleaning effect. If your garment ends up with detergent residue in the fibres, this could help water soak in quicker/deeper, so hopefully the service wash will reduce this.
Second, follow the finishing/curing instructions closely. Years back a colleague evaluated different treatments, and said the final heat stage (radiator, cool iron, tumbledry etc) was the critical point to 'activate' the DWR.
Realise it's a bit of a faff, cleaning the machine, reproofing, heating/finishing etc so do a joblot if possible - or your friends kit too.
And yes agree with the reproofing advice; Go with Grangers or Nikwax, and follow the instructions.
If doing in a machine, it's recommended to run a service wash first. This thoroughly cleans out detergent residue, which contain water softners & surfactants, designed to improve water/soap ingress into the fabric/fibres, and optimise cleaning effect. If your garment ends up with detergent residue in the fibres, this could help water soak in quicker/deeper, so hopefully the service wash will reduce this.
Second, follow the finishing/curing instructions closely. Years back a colleague evaluated different treatments, and said the final heat stage (radiator, cool iron, tumbledry etc) was the critical point to 'activate' the DWR.
Realise it's a bit of a faff, cleaning the machine, reproofing, heating/finishing etc so do a joblot if possible - or your friends kit too.
Let us know how you get on!