If you’re asking about smoothing you need to build a fume chamber. You want the print bathed in a low steady steam bath of acetone (for ABS) or IPA (for PVB). A sufficient fume chamber isn’t difficult to build, you can find instruction all over. But, again, vaporized acetone is hazardous.
Depending on the amount of detail you need to keep, you really can just paint a little acetone straight into the print. You wouldn’t want to do that on, say, the face of a figurine, but for flat uniform surfaces is great, and much faster.
If you’re asking about smoothing you need to build a fume chamber. You want the print bathed in a low steady steam bath of acetone (for ABS) or IPA (for PVB). A sufficient fume chamber isn’t difficult to build, you can find instruction all over. But, again, vaporized acetone is hazardous.
Depending on the amount of detail you need to keep, you really can just paint a little acetone straight into the print. You wouldn’t want to do that on, say, the face of a figurine, but for flat uniform surfaces is great, and much faster.