First casting

[holmqer]

Did my first casting yesterday morning and turned them today.

http://www.penturners.org/forum/topic.asp?TOPIC_ID=34846

This was also my first ever attempt to turn anything other than wood.

Making the blanks was realy easy, but turning the pens I ran into two problems,

First, for the first time ever the tubes came loose. I used a different glue this time. Normally I use Gorilla Glue, but since that depends on swabbing the wood with water and the PR does not wet like wood, I used thick CA. This was the first slim that I've turned and the tubes seemed a bit looser in the blank than I am used to on other kits (I used a J bit). So I'm not sure if it was the loose fit or the wrong glue for this material.

Second, I was never able to get the scratches that the first grit of sand paper put in. I wet sanded 180, 240, 320, 400 then MM wet 3,200 through 12,000 followed up with HUT Ultra Gloss Plastic Polish. Is PR nomrally harder to get the scratches of of then wood?

 

[dalemcginnis]

Congratulations on your cast.

As for the tubes being looser in the blank, the same size drill in PR will produce a bigger hole if you drill too fast as the PR could melt from the heat of drilling. I use epoxy with PR a lot as I can mix a color in it to match the blank and it is less likely to dissolve the paint on the tube (also gives me more time to work than CA)

According to your progression of grits you listed you skipped a lot of grits between 1500 and 3200. I never sand with a rougher than 240 and most times start with the micromesh. MM starts at 1500 which is the same as 400 in regular paper and also has grits of 1800 and 2400. and I use it wet on PR and CA. And remember never move up in grit until the scratches from the previous grit are gone, ie don't go to 320 until the 240 has removed the scratches from the 180. I also wipe the blank dry between each grit and examine it to see how it looks. The water from the sanding will make the blank look better than it is.

 

[holmqer]

Doh! for some reason I mis-remembered the MM chart and thought 400 sandpaper was 2400 MM. Now that I look, I see you are right 400 sandpaper is 1500 MM.

 

[BigShed]

I can hardly say I am an expert in turning and finishing acrylic, having only about 6-8 acrylic pens under my belt, but I never use anything coarser than 320.

I start with 320 dry, then 400 dry, then 600 dry, 800 wet, 1200 wet and 2000 wet. After each of these whilst running the lathe, I stop the lathe and sand longitudinally.
Finally I take it off the lathe, still in my adjustable mandrel, and polish it on the buffing wheel using white diamond paste.

So far I have been happy with my results.

I have also used Ubeaut EEE as the final stage on one or two pens and that comes up very well as well.

 

[stevers]

Thats the ticket Big. You should be able to start at "at least" 320, if not higher. 180 may put scratches so deep, you could have trouble removing them. Especially in plastics. It just takes practice and in no time you'll be starting at 320 or 600. Then the ticket is "buffing", but thats for another post.[]

 

[Blind_Squirrel]

If you have not embraced the skew yet, now is the time to do it. Skews (when properly used) leave acrylic in much better shape. If I sand my acrylic blanks at all, I only use 320 grit to even things out. After that I use the Beall buffing system. Three steps, about three minutes total (this includes changing the wheels out on my buffer), glass shine.

 

[holmqer]

I clearly have to improve my skew technique. I started with my normal fingernail profile spindle gouge and that was clearly a path to disaster so I honed up my skew and went back to it. The skew worked much better, but I use it so seldom that my technique is poor.

 

[Blind_Squirrel]

Some of the best skew videos I have ever watched are Ed Davidson demonstrating how to make various things: http://www.penturners.org/forum/topic.asp?TOPIC_ID=16939