RW has it
my additions would be, stick with the same brand name product throught the whole process,,,if West stay with west, if Interlux stay with interlux, do not mix brand names. next Grind, the reason, is the blister probably extendes a little past the "Bubble" area, grind to solid fiberglass maybe another 3/8" around the perimeter of the Bulge. ( If you dont have a grinder, Home Depot $49.00) Flush with fresh water, and wait,,,,,depends where the blister is I would recomend keeping it dry for the winter, cover this area with plastic sheeting,,,,tape off the top let the sheet hang down and over the spot, tape the edges but not the bottom,maybe tape an empty tape core under the sheet to keep the sheet away from the blister, you want the water, snow exc to pass over the repair but not seal the whole sheet as condinsation will trap water in the sheeted area, keep it ventilated and dry.wait as long as possible to dry out, if you ask the yard to borrow a moisture meter thats great if not wait until spring that should do it as far as drying out., Next wipe with acetone, (or interlux HUll wash, nasty Stuff and eates latex gloves ) then fill with a fairing compond I used Watertite Interlux.(has the consitency of tooth paste) ( fair on with a spackle knife the larger the knife the better fairing result) then sand within 24hrs, dont wait too long or you will need a belt sander, this gets real hard, wipe again with acetone then epoxy, sand, (barriercoat if you want to go the extra step, but with 1 blister I wouldnt worry about it) then Bottom paint........If you can use a grinder and can spackle, you can do this job......just get some latex gloves old clothes and a mask the suff is not best to breath when in dust form.I did a HUGE blister job last year,,,,,,and so far it still looks good......but dont let anyone tell you its a gaurantee, I mean a yard may redo their job, but Blisters are like gremlins, just because you fixed one doesnt mean another wont pop up a half inch away.....One last thing, make sure your Bilge is completly dry.......no use drying the outside when moisture can migrate from the inside.Good Luck!Rob