Gardiners brushes?
Ours went curly, dual trim ones, but reading Gardiners site, there are some guidelines about which are suitable for warm and hot water.
WE DESTROYED SOME GARDINER SILL BRUSHES WITH WARM ONLY ..
the warm water really softens them up and you could probably step up bristle choice if constantly using warm.
my preference on a cold brush is medium mixed , on warm u could probably use a stiff brush and achieve the same feel. if you get what i mean.
Yeah, we did the same, curled up and just lost all shape.
From Gardiners site:
Using Hot Water with the Super-Lite Brush Range
Product Overview
As winter approaches we are getting more enquiries about using hot water with our brushes. We have recently spent much time in research and experimentation of our brush bristles with hot water.
The good news is that our bristles are all already of the highest quality material which is capable of withstanding temperatures up to 80°C. We have tested all of our bristles types on all of our brushes in varying temperatures of hot water to find out their temperature compatibility range. We have compiled this as an easy to view chart for reference.
Whilst all of our bristles can technically resist hot water up to 80°C the softer bristle brushes (Xtreme soft, Sill soft) will deform if used with water that is too hot for them, as combined with the pressure of use it will make them flatten as the bristles become softer when hot.
If using a brush with hot water then it may be worth choosing a bristle type that is one bristle version stiffer than you like using with cold water. This will give you a similar 'feel' on the glass when using hot water. For instance if you currently like using a Soft Radius-Sill brush then for use with 50°C water you would need to choose the medium bristle version to achieve the same 'feel' on the glass.
Particularly in colder weather it is worth remembering not to turn the water heat up too much as this can result in cracked windows. As a general guide in warmer months the average 'at the brush' temperature range would be 30-60°C, but in the colder months 30-45°C would be sufficient for most work.
It is worth noting that if, with extended use, the bristles start to 'flatten out' with hot water it will be because of the following:
It has exceeded the temperature range of the bristle type, or
The brush has been used with excessive force for the bristles in combination with hot water.
Bristles that have 'flattened' out like this can simply be 're-set' by submersing just the bristles (but not the stock) in near boiling water for 10 to 20 seconds. This will return the bristles to their original shape. They can then be left to cool with bristles facing up and can be used again as normal when cool.