Sanding: Is it necessary?

[ScottEnglish]

Before bonding a rubber outsole to a leather insole I sand the leather on the flesh side to, apparently, improve the bond. Has anyone observed whether the sanding stage is actually necessary?

Thanks.

Scott

[tsunkasapa]

I do not sand the flesh side but if I am gluing anything to the grain side I sand or otherwise 'rough' it up. To give the adhesive more to bond to. There should be enough 'roughness' on the flesh side.

[Tugadude]

Roughening surfaces before gluing is always a good idea.  That holds true for lots of materials, including concrete, for example.

Regarding leather specifically, it is super important if the leather has a finish on it that might diminish the bond strength.

It doesn’t take a lot of time to properly prepare leather for best adhesion.  Better to be safe than sorry applies here.

[ScottEnglish]

Thanks tsunkasapa. I shall try not sanding next time and see what happens.

Tugadude: Thanks for the reply.

[Aven]

Scott, if you are talking about gluing a rubber soling to a leather sole, I don't sand.  I use a rougher.  Rough up both of them before gluing.  Carre Ducker is on your side of the pond.

https://www.carreducker.com/shop/shoe-making/tools/roughing-tool/

[ScottEnglish]

I've only just seen your post Aven! Thanks for the link. I'll have a look.