Acrylic frustration

[scotirish]

I have been turning pen's, of and on since the only kit available was the "Slimline" from "The Woodworkers Store" & Woodcraft/Shop Smith. I tried Corian when it first came available, I did not like the looks much. I felt then and still do that I like the look of wood, not plastic! But alas, my wife saw some pens turned from acrylic and wanted me to do some.
My question is: How do you turn them and not have small scratches? The pens look nice, till the pen is turned and the lite high lites these scratches. Some go all the way around in a circle and some appear as steps as you turn the pen.
Thanks for the time.
Ron

 

[ed4copies]

In light of some other threads, this may sound strange: PM me, I will send you my tutorial on acrylic cigar pens as an attachment to my reply.

Short version: Sand through high grits (1500 or so), Check for scratches before next steps, if none are deep and visible: plastic polish or tripoli, white diamond buff.

 

[karlkuehn]

Hooo...where to start?

If you're not using Micromesh, that's a good start. You can usually get a decent finish even dry sanding with MM, but for the best finish, wet sanding works better. You can also use standard wet/dry paper.

The big key is to go easy with the coarser grits sanding horizontally with each grit after you've used it with the lathe spinning. When you get up into the higher grits, if you haven't gotten the big scratches out, drop down a grit or two until you get them, and then move forward. Each successive grit should take out the scratches from the previous grit.

If you put a lot of pressure with coarse grits, it's really going to gouge, so you need to go lightly with those.

Also, in a perfect world, you'll have a couple of buffing wheels with Tripoli (EEE) and white diamond polish. Those will do a world of good on acrylics. I've been amazed how much sanding I can skip with a quick buffing.

Hope this helps!

Also, check around the library for finishing technique tutorials. There's a lot of good information on the site.

 

[karlkuehn]

Damn. He got me by four seconds. Curses!

 

[ed4copies]

Beat you by FOUR seconds, Karl.

But, you DO have a better answer!!

 

[karlkuehn]

Ahhh, yes, but I beat you by thirty-four seconds on the acknowledgment of the initial beating, so that's got to count for something!

 

[ed4copies]

Clear PROOF:

It does NOT take GREAT minds to think alike!!!!!

 

[karlkuehn]

Don't worry, Ed, just keep working at it! You've shown remarkable improvement of late! [}]

 

[ed4copies]

Are you saying if I get to your level, I can join you in your "nuthouse"???

 

[karlkuehn]

Bring your own straight jacket! 'Cocktails' are provided. heh *sniiiiiiiffffffff* whOOOO! [)]

 

[ed4copies]

Originally posted by karlkuehn

Bring your own straight jacket! 'Cocktails' are provided. heh *sniiiiiiiffffffff* whOOOO! [)]

Nah, I never enjoyed FORMAL affairs!!

 

[stevebuk]

i have just turned a black acrylic to make a slim line pen , sanded all the way through to 12000 MM and it still had scratches or dull patches i couldn't remove, i even resorted to using the skew again on it, and still could not make it shine in places.[:0]

 

[karlkuehn]

Originally posted by stevebuk

i have just turned a black acrylic to make a slim line pen , sanded all the way through to 12000 MM and it still had scratches or dull patches i couldn't remove, i even resorted to using the skew again on it, and still could not make it shine in places.[:0]

If you ride the bevel too hard with your skew, you'll heat up and soften the acrylic, resulting in a kind of 'micro-pitting' in places, almost like rub marks on a hard rubber bumper. You can always rough it up a little and do a CA finish to save it if need be.

You may have gotten a bad acrylic, too. I've seen some that were pretty soft.

 

[ed4copies]

BLACK is a b(iscuit)itch!!!

Sorry, but it is.

Heat is very likely the problem. AS you work on it more and more, the problem only gets worse.

Use different color until you are comfortable with plastics, then advance to SOME black, but don't START there. It shows EVERY MINUTE SCRATCH!! Darnit!!

 

[pipeyeti]

get a good buffing setup, you plastics will shine.

 

[mick]

Originally posted by karlkuehn

Hooo...where to start?

If you're not using Micromesh, that's a good start. You can usually get a decent finish even dry sanding with MM, but for the best finish, wet sanding works better. You can also use standard wet/dry paper.

The big key is to go easy with the coarser grits sanding horizontally with each grit after you've used it with the lathe spinning. When you get up into the higher grits, if you haven't gotten the big scratches out, drop down a grit or two until you get them, and then move forward. Each successive grit should take out the scratches from the previous grit.

If you put a lot of pressure with coarse grits, it's really going to gouge, so you need to go lightly with those.

Also, in a perfect world, you'll have a couple of buffing wheels with Tripoli (EEE) and white diamond polish. Those will do a world of good on acrylics. I've been amazed how much sanding I can skip with a quick buffing.

Hope this helps!

Also, check around the library for finishing technique tutorials. There's a lot of good information on the site.

Karl's got a great point there about not overdoing it on coarser grits. But I've got another slant on that.
Don't use the coarser grits. I don't know what tool you use on your acrylics but if you don't use a skew start. If you don't know how learn.... you'll be glad you did!
At the least finish up with a skew. you'll have a smoother "finish" to begin your sanding with. I seldom if ever start with anything coarser than 400 grit and sand through 1000 grit using Klingspor Gold paper. To polish it out I use Hut Plastic Polish, but you can use any fine auto polish designed for clear coats......or even Brasso. Even so as ED said Black is still a real bear! I've found that a light hand and a very clean application clothe helps there. I hope I haven't stepped on any toes as this is what works for me and isn't meant to be the be all, end all of finishing.. Hope some of this helps!
Mike
BTW ...Ed and Karl...I posted way after both of you and that makes me the loser and we all know how important the biggest loser title is here at IAp!!!!

 

[ldb2000]

I'm always last...
Mick is right the best way to go is with the skew...learn how to use it and your finishing will be much less work.
I start my sanding at 320 grit and advance up from there then buff with tripoly then white diamond and then apply several coats of Renwax then buff with a very soft CLEAN cloth and get 99.999% of the scratches out (you'll never get them all) which is good enough for the naked eye .
Even black looks great at that level of finish .
You dont need anything special to buff them out , I use Ryobi buffers (that i got from the Big Orange box store) in my drill press or on the lathe w/my drill chuck .

 

[ed4copies]

"scotirish" sent me an e-mail with info we should post.

He mentions the scratches appear WORSE after buffing with his plastic polish (IF I read the e-mail correctly, if not, feel free to correct me!!)

IF this is the case, look at the rag or paper towel you are using to apply the polish. I have switched to Kleenes (Yeah, nose-blowing type) and the scratches I was having with paper towels disappeared. Took me a while to dream up this solution and I was astonished when it worked!!!

SOME paper towels apparently still have WOOD in them!!! They scratch plastics.

 

[pipeyeti]

The answer is still invest 60 or 70 bucks in a good buffing system. if you are making pens to sell you can justify the money. I can drive nails with a screwdriver, but it sure works better when I use the right tool.

 

[ed4copies]

Larry is correct. However, not everybody has $70 laying around - just us old guys!!!

When there are kids in the house, there is FAR less "disposable income".

 

[ldb2000]

"Disposable Income" Whats that...I've got 2 teenage boys who think that money just flows out my a..... ooops , anyway they think dad is their personal ATM so $10 bucks at HD for the Ryobi buffers is about all I can afford and still have money for the important things like...more blanks and pen kits and taps and....[}]

 

[karlkuehn]

Well, my system works good for me, although the initial cost is probably in the $70 neighborhood.

I have a MT2 keyless chuck that I got for about $35 from WC, but I bought it for other stuff too, so I'm not sure if it counts in the final price.

My wheels are the Ryobi ones that you can get at Home Depot, along with the little mandrels that hold them.

I use two differnt wheels, the tougher, much-sewn one for Tripoli and the loose-sewn one for white diamond. For the two buffing wheels and two mandrels, I'm out about $22. Add another $10 for buffing compounds.

After swapping the wheels around so much, however, I'm going to buy/build a 3 wheel system that will mount and live permanently on my little old Shopfox lathe. It'll save me lots of time, but I'll have to keep it covered in between buffings to make sure they stay clean.

 

[pipeyeti]

With what most of us charge for a pen the profit from 2 pen sales should easily cover it.

 

[ed4copies]

Now, THERE'S motivation. (And I agree, get out there and SELL!!!) Don't think of it as SELLING your pens, think of it as a means to MAKE BETTER pens!!

Good suggestion, Larry!!!

 

[pipeyeti]

Thats what I do. No money for my hobbies comes from household money. I take almost all my profits and put them back into it in the form of better tools and better supplies. I started with a crappy drill press my wife bought me for a gift one holiday. Began turning solid brass pipe tampers right on the drill press and shaping with files. I now 8 years later have a very well equipped work shop and no cash was taken from my family.