Getting a smooth surface on acrylic

[pds0006]

I just made my first two pens (both acrylic) and I had some problems. The first one has several gouges, but they are mostly poor turning technique on my part. The second I felt very good about but not entirely pleased. I turned to size and then saw that there were numerous small rough spots, like I had whittled the pen rather than turned it. After applying Novus 1 and 2 I got a fairly consistent surface, but it's not perfect. How do you get a perfectly flat, uniformly smooth surface on acrylic? New to this and I want to learn right the first time so thanks in advance for any info.

 

[darbytee]

Patrick, What works best for me is to use a very sharp skew at high speed taking, light cuts until I get close to the shape I want. Then I wet sand, starting with a gouge grit (80 or 100 depending on how much shaping I want to do) and sand all the way up to 12000 MM. I usually top it off with a coat of Ren Wax buffed off with the Beall wheel. There are a couple of pictures of some of my home cast acrylics in my album. Hope this helps.

 

[atvrules1]

Patrick, I find that if I use a scraper it tends to pull chunks out of the acrylic so in agreement with Fred, high speed, sharp skew, then follow with the wet sanding until you have a perfect surface. Then you can go with the Novus 1 and 2.

 

[ed4copies]

Patrick,

I believe there is no "right" way. After turning several hundred acrylic pens, I have turned fast, slow, used scrapers,used skews and with each and every method I have screwed up at least a few blanks. I have also succeeded about 98% of the time.

Acrylic is not all created equal. Some blanks come with instructions telling you to scrape and turn at slow speed. I would say, if you are having problems, this is the most "fail safe" approach. When you get really comfortable, yes, you can turn them at high speed and use a sharp skew; however, if you push just a little too hard, most plastic will break, leaving an indentation. These CAN be repaired with CA, but that's not all it's cracked up to be, either.

In short, DON'T let the blank get HOT. Until you are comfortable, best to turn slowly and scrape off a very little at a time (this can be done with a skew or scraper). The wider the contact with the blank, the less likely you are to really mess it up. Try a very slow turn with a large roughing gouge-it worked for me early on.

Hope this helps!

 

[53Jim]

I don't know if I should reply to this, as I can't say how I turn acrylic (It's a governmental secret... Actually, I'm just forgetful - I can't remember how I do it)

I usually start with a 1 inch roughing gouge, than switch to a spindel master, than finissh up with a skew.

I still screw up, but that's part of the learning curve.

Good luck,

Jim
(I'm not a fast turner, I'm not a slow turner. I'm a half-fast turner.) []

 

[wayneis]

I use a 1/2" spindle gouge start to finish and then I sand with Micro Mesh pads through 12,000. Then I have a Beall buffing system and so I buff with the tripoly and then white diamond and then ren wax. This is how I do all of my plastics and it works very well for me.

Wayne

 

[JimGo]

Wayne, after the Tripoly stage, do you notice that the blanks are shinier or duller than when you're done the 12,000 MM stage? For me, when I tried it, I thought it gave a CA finish I did a haze. I'm using a knock-off, so that's why I'm asking.

 

[Old Griz]

OK, I guess it is my turn to step up the plate...
I turn all my acrylics using a skew... I start by rounding the blank with planing cuts, being careful not to take too much and heat up the blank... acrylics are very very heat sensitive and will crack or split if overheated... I always keep a damp cloth close by to wipe off the blank occassionaly, this keeps the blank cool and keeps the curls that come off under control...
When I get down to just about the final dimension, I switch to a scary sharp skew and use that like a scraper to take very very light cuts that take very fine ribbons and dust off the blank until I get the final dimensions...
At this point, I can VERY lightly sand the blank with 600 grit paper to smooth out and skew marks...
I then switch to automotive rubbing compound on a damp cloth, clean with water, then automotive polishing compound, clean again, then Hut Plasic polish for the final gloss... all of these are used with a light hand and constant motion keeping the rubbing and polishing compounds damp.
For protection against finger prints a light coat of Ren Wax is applied...
This is what works for me... not the end all or be all of doing acrylics, but the way I do them..
Here is one I just finished for a customer... Pearl Pipe Material on a Platinum Jr Gent...

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[TheHoneymooners]

Griz, I'm still a newbie here compared to some and don't really know the difference between acrylics, plastics or celluloids, but I've turned 2 Celluloids and do it very much like you do.I round my corners off very slowly, tiny bites with a gouge until it's round enough for my skew not to bounce around. Then I work back and forth with my skew taking off tiny ribbons of material, dang stuff is static prone so I'm wiping it off my skew as much as I'm cutting. I get it down close to where I want it and check for gouges or holes from chip outs. I f there isn't any I turn it on down and then sand lightly with somewhere between 240 and 600 grit depending on how much is left of my skew marks. Once I've got it smooth and are sure there are no marks or holes I switch to the pads used for Acrylics or corian, using water and wiping between each grit. once I'm down to the last pad, 12000, I believe , I use a polish I bought at Woodcraft. I'll have to wait til I get home to tell you the name, but it's simuchrome or something like that. once done its`as smooth and shiny as glass. Heres a red celluloid I've been meaning to post.

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[JimGo]

Connie (or is it Mike?), that looks great! The pattern in it is VERY cool!

 

[Old Griz]

Connie and/or Mike... I treat them all the same way... they all get the same finish.. they are all sensitive to heat also... some are just a little softer than oters and need a gentler touch...
Try spraying your tool rest and skew with anti-static spray for laundry... it works about 70% of the time for me...

 

[jdavis]

Turn our acrylics with the skew, high speed, light cuts, sand to 12000, and finally Novus 1&2.

 

[atvrules1]

Tom, you mentioned automotive compounds, I must admit I've never looked at them. What kind specifically do you use.

 

[vick]

I used the rubbing compound for clear coat finishes to polish my plastics.