How do you make perfect slots?

I'm at the stage where I'm serious about cutting the final stringing slots in my joints but am having a lot of trouble getting them perfect. I think it would be a lot easier in paperclay but unfortunately I'm refining my master in resin and apoxie sculpt. I've tried hand cutting with exacto, round dremel bits, drill bits, files, but it's just very hard to get them precise. What are your tips and tricks for getting those perfect crisp straight slots that finished resin dolls have?

 

Sorry for the late reply, my puppy got spayed last week and she's needed lots of attention so I've been distracted

@Zardi, they're really rough, like jagged, as I was just trying to get the holes large enough for the elastic and tweaking it several times until they worked right. So a hack job . It really sucks cause they weren't too bad on the sculpey master as it was way easier to cut initially, but transferring it to resin changed how the jointing worked and the resultant tweaking made a mess of things. With some perseverance I can get them looking pretty good by hand again, I just have a feeling the pros must have some trick to get them so absolutely perfect. On many company pro-casts of artist sculpts the slots look machine precise after the refining process. But maybe it's just practice and long work.

@Alewife I have almost every bit known to human lol. I haven't tried a flat cutting bit yet since it would certainly slice too far up the ball joint, but on second thought the extra cut could just be filled again, hmm So I might try that afterall. Thanks for the idea! The problem with dremel is I have a hard time keeping both my hand and the part steady which tends to make the cuts too big or wobbly, but it might not be an issue with a circle bit since it's flat. Worth some experimenting.

@ira_scargeear That's what I was dreading . But it may be the best most effective course of action, I guess it will just take lots of patience and work! This doll will never be finished, lol.

Thanks all for the help

 

@ira_scargeear thank you so much for the suggestions, I do have these files and did think to file the channel with the flat straight one but it still came out a little imperfect imo, so maybe I just need to slow down and be more careful, or I'm expecting too much x'D This is for a 50cm doll, though I have tiny files too so it could also work for tiny dolls I think.

For the channels I bought a round rasp but found it too tedious and difficult in resin, might work better with a handle-less one so you could put it in a drill. Actually what works wonderfully is this tool meant for enlarging holes in wood, a taper reamer (I bought this one, the more flutes the better https://www.amazon.ca/Woodstock-D41...005W17DFC/ref=cm_cr_arp_d_product_top?ie=UTF8). You can buy them with removable handles so it barely fits in a drill and it slices through resin like butter leaving a perfect smooth tapered channel. I'm hoping this will help with casting and to reduce finishing drilling. Probably only works for msd size dolls though.

 

@ira_scargeear No you're right, for sure the rasp would be the best tool for that size of doll! Also I think the apoxie is slightly easier to carve than resin, so if the doll is solid apoxie it would work best. (I regret casting a resin master that needed so much finishing work, but even more so I regret making him first in well cooked sculpey that was impossible to sand lol.)

I just prefer tools that don't require me to overuse my bum shoulder joint haha, I have a bit of injury from years of repetitive motion working on other art hobbies, it's starting to take it's tole.

On the one hand I'd love to let someone else do the messy work, on the other it's so expensive and also I feel bad giving up any sort of creative control. But I may change my mind after attempting to cast more than a few dolls.