please help. I have cut hole for sink exactly to size template and when have put sink in I can see foam seal you stick on even tho it's right on edge the cut opening and when fix down can see foam around edges am I right in thinking the sink should sit flush against worktop with no seal visible. Would it be acceptable to remove foam and put silicone around the edge instead which I would imagine would allow the sink to sit flush against worktop advice please ??
That's not unusual. It might settle down a bit more with time as the foam seal compresses. Or it might not. First, check that it isn't a case of your fixing clips running out of 'tightening' - ie the screws come to their ends before the sink is clamped down fully tight. What thickness tops are you using - is it 30mm? If this is the case, try fitting spaces such as small pieces of ply under the clamp to allow more screw tightening. Bt, to answer your Q, yes it's ok to use silicone instead of the foam. In fact I would personally prefer that as being neater and more reliable.
It's a 40mm top and have had to put kd blocks in to tighten the clips to but if I tighten anymore the clip pulls off sink and foam still visible I think I would get a nicer finish with silicone like you say I am assuming the idea behind the foam is to just create a barrier stopping water entering cupboard.
I think the OP is probably referring to the foam 'splaying out' wider that the sink perimeter. In which case carefully trim the excess. A small neat silicone seal afterwards if needed. Mr. HandyAndy - Really