portside II right this is the PROPER of masking two tone hulls it is 100% foolproof it is what PROPER paint sprayer use for two colours.
1 get hold of either of the following,1/4" electrical tape,ordinary insulating tape or better still PROPER fine line tape usually
available from Motor paint factors
2 Apply one of the above along the desired area that needs a straight line,rub well into the hull to stick it down
3 Apply ordinary masking tape 2mm over the above tape
4 Mask up the rest of the hull with prefferably BROWN paper,reason for BROWN paper is simple there is no chance of the print
comming off and ruening your other paint work,and more so there is no holes in it!!!! for paint to bleed through
5 De mask within 10mins of final coat,DO NOT LEAVE ON OVERNIGHT,when removing tape whether be it fine line etc remove
at roughly 45degrees back on it's self being CAREFULL not to get it stuck on to the rest of the hull,yes it happens to me!!!!!
6 This is where you have to be extremely brave and a steady hand,choose a finger!!!! make sure it is 1000000000000000000%
CLEAN and I mean CLEAN now quickly and I mean light pressure run it along the join in the paint this will settle that join down
and give virtually a flat join that will not be fragmented but straight and true
Trust me I know I have been painting cars and vans with various different colours etc and have NEVER had a problem with paint bleed through don't believe me then give Tug Kenny a pm he has done it on his Boston Typhon and other boats,and has not had a problem.Yes others will tell you their ways,yes the way DickyD has quoted works but believe you me this is the foolproof way of doing it and a GUARANTEED way of doing things
Stavros