Thanks Mal, it's CA, I only use BSI Thin applied with open cell foam (finish thickness is about 0.006"). The lower barrel is quite long and it took a lot of patience getting the barrel perfectly cylindrical after applying CA. Micromesh then Hut ultrashine polish.
Thank you, Sam. . I sometimes use foam, sometimes a folded piece of blue shop towel, and sometimes a small poly "baggie". . And I don't notice much difference in the results. . One practice I have adopted, which seems to work quite well for me in getting a "close to" cylindrical result is the following. . I apply the BSI Thin CA on the lathe at a very low RPM .... about 60. . This very slow rotation is very important, IMHO.
I "drip" the thin CA from above the blank starting at the right end of the barrel (CA nozzle very close to the blank - almost touching and even touching sometimes; no difference in result).
As the CA "drips" I rapidly but lightly rub the underside of the barrel, with whatever I am using, parallel to the barrel axis. . I move the CA "drip" from one end of the barrel, along the length of the barrel at a rate so that there is about one drip every quarter-inch or so. . I never go back.
When I get to the other end of the barrel I terminate the drip by raising the CA, I give 3 or 4 rubs and that "layer" is done.
I wait about 20 seconds and then give the barrel about 3 misty shots of accelerator along the length.
I then wait about 30 seconds before rubbing the barrel to remove the excess accelerator. . The surface always feels quite smooth, not bumpy.
Then I repeat the whole process twice more and then LIGHTLY sand (180 grit) to remove the high spots of the CA. So we now have 3 layers.
I repeat that process 4 times (usually) ; there are now 12 layers of CA.
It is now time to deal with removing high spots of the CA and making the blank surface smooth and cylindrical by sanding with 180 grit.
While doing this sanding, the lathe is not under power .... I ROTATE by HAND so that I can give extra attention to any places requiring it.
Usually after 2 or 3 minutes of sanding I am quite satisfied with the smoothness and I then move up to 240 grit and repeat and then 320 grit.
At 320 grit, I spend a lot of time striving to smooth and remove all shiny places. . This usually goes quite well. . Always rotating by hand.
I then move up to 400 grit, 600, 800, 1000, 1200, ( sometimes 1500, 2000).
It is now time for Novus 3, Novus 2, and finally Meguiar's PlastX liquids. . I don't ever find it necessary to use MicroMesh.
I tell you all this in detail because you might be interested in trying my method and commenting on it.
It seems to work quite well for me. . I think the key to it is the actual "dripping" ... I think it makes efficient use of the CA ... and I think the CA goes on quite uniformly.
So, if you have any comments or questions I would be happy to try to address them.
If you do try my method, I would be happy for any feedback.
You might want to try on a few practice pieces ... it does take a few attempts to learn the coordinated movements of both hands, the left hand holding the "dripping" CA bottle, and the right hand doing the rubbing (fairly rapid and quite light) of the underside of the blank.
I am always open to suggestions for improvement as well as to feedback. . Thanks !!