I personally have not used any flip top bottles so I can't speak to that but in my short time of wine making, bottled two batches, I use synthetic corks and have used a few screw tops. The screw tops seem to work fine.
Grolsch beer bottles are very sturdy and easy to re-use. This is the only flip-top experience I have had...I keep them around to put the residual wine left over at the end of a bottled batch and gift them in a wine variety basket. Too fun.
I use the flip tops all the time. They are the most versatile of all closers IMO. No corks or corkers required and they can be used over and over. The only thing that has to be changed is the rubber seal (maybe every 2-3yrs) and they're cheap.
I have a person saving me his 3 liter jugs now and I have gotten five from him. These are all screw tops.
Is there anything I can do to make certain that the top seals good.
If they can do it with a new bottle, there has to be some way to do it with a used one.
I know that it probably isn't the best for long term storage, but something that is going to be drank in just a couple months it should be okay.
Buy new high quality screw caps. The polyseal caps are good, you probably need 38mm caps. They can be used repeatedly. You may be able to buy metal caps with a plasticy liner (similar to lids for canning jars. Although some people use them repeatedly, they should probably be only used once. The metal caps may be difficult to find, I have not seen them in a Canadian LHBS in a long time.
When sizing caps it is best if you can take them to the HBS for a test fitting. I realize that this is difficult for many on the forum.
all wines are screw tops.. ( except imported wines, and unless you prefer watery french wines..don't buy them...OK! OK! I'm joking!... well not entirely....)
I recycle my screwtops more than once.. all wine bottles are standard size.. so all caps fit everything. You do need to check the inside condition of every screwcap before using.. this takes 2 seconds max, at bottling time.
Sanitise everything properly..I have not had even one bottle of wine go off in my cellar.
Well they didn't get wasted. I set them off at the "transfer station", our version of dumpsters and am certain someone knew they could be used, so not all wasted, I did, afterall, get all the cork types free, so we all benefited! Gotta love that recycling.
the caps have an 'inner.. it's foil side in contact with wine and a poly side that is flexible, so the cap holds it firnly to the rim.. the foil is attatched to.. I check the inner is perfect and of course everything is sanitised.. then screw the tops on tight.
no failures so far with this method.. and no vinegar etc...