By hsf - 11/6/2018 12:52:06 PM
Hi,
I am doing surface quality studies an want to seal a cnc milled cavity (surface roughness approx Ra 0.8µm) on a new/unused Sika M960 board (1,2g/cm3 density) with S120 sealer.
The laminates shall be of very high surface quality.
1) For this purpose: How many S120 applications do you reccomend? My plan is 4-5. Enough?
2) Referring to "De-Nibbing" a tool making professional explained to me, that he sands tooling boards after every sealer application with gradually decreasing grits from 400 to 1200: Do you reccomend this as well? How long do I have to wait until i can sand a S120 layer? 20min @RT enough? Or better 20min @60°C - The data sheet is a bit unclear here, unfortunately.
Many Thanks
Holger
|
By f1rob - 11/7/2018 11:12:51 AM
Most dealers need a de nib but not all the grades
Spray application is by far the best way
Marcacote sealer is the best out there at the moment for hand finishing.
With that each coat can be cooked at 60 for 20 mins and onto the next coat
After about 6/8 any block should be fully sealed,bake that then de nib with 1200 an put a nice wet coat on and let it dry naturally,don't force it.
Each sealer is different to give you some idea the chemlease sealer will probably take 10/12 coats before it's ready to de nib an that then will need 3/4 coats to get the final Finnish onto it
|
|