Help with why there is scratches

[beep119]

Hello, I'm a newbie still and trying to figure what I'm doing wrong here...
I have an acrylic blank I turned down and then went through all the micro mesh, but still showed scratches...so I tried sanding from 150-600 then again with the micro mesh...still didn't look good. So I did a light turn with my scraper to get blank back to after a fresh turn and tried micro mesh sequence again...even uglier!
What am I doing wrong?
Ever other arcrylic I have done..about 25 has turned out great, maybe a few small hardly noticeable type of scratches, but not bad....but this blank is an upgrade....paid $10 for, so it's my first expensive blank, but can't figure why I'm getting scratches.

 

[plantman]

I would try turning your lathe off and hand sanding lengthwise. 220 and 900-1200 should do it. Anything after that is just polishing it in my book. You can remove fine scratches and polish with other products on the market made for plastics. Another way to remove these scratches is to use a fine metal file while turning your blank by hand. On the other hand, some plastics stay somewhat soft and are hard to sand, or have soft pockets in them from not curing or being mixed well enough. Jim S

 

[mredburn]

Are you wet sanding or dry sanding?

 

[carlmorrell]

They look like deep scratches from the rougher grits.

There are many ways to skin a cat. You are probably going to get a lot of suggested techniques.

I sand down to 320, stop the lathe and hand sand lengthwise. I always have magnifying glasses on and make sure I get all the radial scratches out.

Then I switch to micromesh. Wet. For the first 5 or six grits, I stop the lathe and again hand sand lengthwise.

 

[beep119]

Micro mesh wet....
But second time when I tried to do another way it was dry then micro mesh wet
And I do sand lengthwise inbetween grits 150-320 when I do 150-600

 

[JimB]

Is your MM clean? Particles in it will cause scratches.

 

[magpens]

Are the scratches going around the blank or are they lengthwise ? (Oh, I see they are going around the blank).

I think you should be doing your sanding with the lathe off, rotating the spindle by hand as you SAND LENGTHWISE.

Starting with 150 grit is probably a bit too coarse in my opinion. I would start at 220 grit and work up to 1000 or higher, even up to 2000 paper.

Wet sand for the grits 600 and above and wet sand with the micromesh.

Finish off with a plastic polish like Novus 3 and follow that with Novus 2. . (there are other polishes for plastic).

 

[mredburn]

lots of whys and hows.
Are you using sandpaper for wood or for paint finishes like automotive finishing.
Cheap sandpaper can be problematic for consistency.
Plastic resin dust can ball up and melt together and stick to your sandpaper causing more scratches than it cures. I usually start at 320 and go up. sand with lathe on lightly then with lathe off and sand length wise around the blank. If I have scratches that the 32o doesnt remove I drop down to 220.

You could have a bad blank thats exceptionally soft or uncured fully, but more than likely you have bad piece of sandpaper some where. Those scratches are large enough that the finer micro mesh grades are only going to make polished scratches they are too big.

 

[Sabaharr]

Wipe off the blank with a dry paper towel between MM pads to remove any residual grit that may have sluffed off the pads of be left over from the sandpaper. Before you try again clean off your MM pads with warm soapy water and use your fingertips to scrub them a little, nothing else. Then try again. If that does not fix it I am lost.

 

[beep119]

How much pressure do you put on the sand paper and micro mesh?
And slowest lathe speed is best always?

 

[BSea]

I don't use a lot of pressure when sanding. In fact I'm careful to make sure and use light pressure. I know that's subjective, but try using less pressure. And I sand at about 1200. What kind of blank is that. If it's alumilite, it will be harder to polish than PR. But I agree that the scratches that is shows are too deep for MM.

 

[nativewooder]

Practice may not make you perfect, but practice will make you better.

 

[beep119]

Thank you everyone for their input.
I will be taking all into consideration and practice practice practice!!!
Thanks

 

[KenV]

May I suggest a move toward being slow and deliberate. Work through the grits, pausing to carefully examine what each process step is doing and what is accomplished (or not accomplished). The time being deliberate will pay out later.

Use light across the pen surface to catch the shadows. Use magnification. Think about what you are seeing. This is skill building, and it is hard using the head work.

 

[randyrls]

I created a Wiki Article on Acrylic Finishing It details my own finishing technique for acrylics.

Anyone is welcome to add to or update the article.

 

[qquake]

I've never ever had scratches like that, even when starting with 150 dry. I'm at a loss, but if I had to guess, I'd say you're building up too much friction and something on the sandpaper is melting the scratches into the blank. In the photos below, the first two are after sanding with 150 dry. The last are after the 9 grades of Micro Mesh wet, then Meguiar's PlastX plastic polish. The blank is inlace acrylester. And I sand at 2000 rpm.

 

[thewishman]

Sandpaper is a tool. I started with Harbor Freight sandpaper and threw it away after my second pen. I switched to Norton 3X and my pens immediately improved. The good stuff is more expensive, but I only use $0.05 to $0.075 worth per pen barrel.

Try starting with 220 grit. It may take a little bit longer to sand, but you will not have to remove deep scratches from the coarser grits. After sanding (I use a speed of around 1200 rpm) with the lathe on, then sanding lengthwise with the lathe off, wipe off the dust and see if you have any scratches. If you don't see any, except very light lengthwise scratches, move to the next grit. Make sure to wipe off the blank after each grit.

When starting out, I used 220, then 320, then 400. After that I switch to Micro Mesh. As your turning skill increases, you can start out with 320, 400 or even just the MM.

 

[Mortalis]

What is the blank. Maybe its a bit softer than the standard acrylic blank.

I might try a couple light coats of thin CA and then a coat of medium. That would fill the scratches and take you back to a medium that you are used to finishing.

Try not starting with such coarse grit. Normally, when I finish acrylic, I start with 400grit, then go to 600, then go to my micro meshes. I use bare fingers to remove any residual grit from the previous sanding, before moving onto the next grit, I wipe the micro mesh pad against my shirt or pants to make sure there is not grit on the pad before applying it to the blank even with the micromesh. Softer Acrylics will scratch even with paper towels if your not careful.

 

[ed4copies]

I would also ask, "What is that?"

When scratches don't go away, the material is usually more of a "rubber base".

The comments about cheap sandpaper are also consistent with my personal experience.

At each change in grit, you might stop your lathe and look at the blank. Deep scratches can be produced by 180 grit, but when you finish 360, the 180 scratches should be gone. Each subsequent grit should leave your blank looking better. Clearly, looking at your pictures, this is not the case. So, sand longer with each grit until the blank is uniform.

 

[plantman]

Sandpaper is like toilet paper !! The cheaper stuff will bite in the butt. Use cabinet grade or automotive grade cloth backed paper, never garnet paper. It will cost you more, but it will also last longer and do a better job in the long run. Cabinet paper is usually used dry or with some type of oil. Automotive paper can be used wet or dry. Personally, I never let water near my lathes !! Go to Online Industrial Supply Corporation.com for a complete supply of paper. Buy the whole ream, it's cheaper !! 240, 900, and 1200 should get you going. Jim S

 

[CREID]

All my sandpaper comes from the auto parts store paint section.

Curt

 

[wouldentu2?]

Turn another plastic blank and see if it is repeating.

 

[jttheclockman]

Learn to use a skew and eliminate the sandpaper totally. It would be the best lesson you ever learned in turning. It is not the MM, it is the sandpaper. I never touch a pen blank with less than a 400 grit paper. Anthing couser than that especially with any acrylic you are doing it wrong. Practice is key.

 

[campzeke]

After reading this entire thread then re-reading your post, my guess is you may have some contamination on one of your MM pads. There were several previous suggestions to stop between each girt in inspect. That alone should lead you to the source of the problem.

Be sure to let us know what you find.

 

[TonyL]

I no way have close to the experience or skill of this group. I experimented with many processes though and have become very satisfied with one. I will send you my number and you can call me anytime. I use a 10x loop and 20x loop to inspect my work for stretches. Having said this, I have also seen awesome finishes from dozens of pen turners that use other methods. I would be happy to share "mine" which is just one of many. It works for me with skews or carbide, no wet sanding or micromesh. It dose involve buffing. Thanks to the expert and selfless advice of IAP members, I assembled a process that works for me and my I patience for wet sanding. Your experience may not be mine.

 

[Quality Pen]

Hello, I'm a newbie still and trying to figure what I'm doing wrong here...
I have an acrylic blank I turned down and then went through all the micro mesh, but still showed scratches...so I tried sanding from 150-600 then again with the micro mesh...still didn't look good. So I did a light turn with my scraper to get blank back to after a fresh turn and tried micro mesh sequence again...even uglier!
What am I doing wrong?
Ever other arcrylic I have done..about 25 has turned out great, maybe a few small hardly noticeable type of scratches, but not bad....but this blank is an upgrade....paid $10 for, so it's my first expensive blank, but can't figure why I'm getting scratches.

Lots of good advice, but sanding is one of the most hands on things you must experience to actually get good at!

Like mentioned in this thread, there are a million ways to do this, and each person might get a scratch free shine... but another person might not. You just gotta get your lungs dirty... I mean hands! :biggrin:


From the picture, those scratches are DEEP. I would never try to micromesh at this point. It would be a waste of time.

The first thing I would do is order abranet sanding paper so you get a consistent high quality sand paper. Are there others? Yea... but remember what I said earlier? :wink:

Next, I would stop sanding after each grit and inspect. Will this take a LOT more time? YES. But everything takes a lot more time until you are good at it! Getting a loupe helps. Eventually you won't need it for these sub-1000 grits.

Next, "cross" sanding will help too. The biggest thing it will help is for you to find out where your sanding skills are lacking.

When it's all said and done, sanding is as much an art as a science. Some folks are a lot faster than others, but early on, if you rush it you will pay the price.

Next step... buffing! :biggrin::biggrin:

 

[Rink]

I would echo everything I've seen in this post. So many ways to success, and everyone pieces together the bits into something that works for them.

For me, the things that improved my finish the most (not that mine is fabulous, by the way, but it's "pretty good"...still learning) was Abranet instead of regular sandpaper and then stopping the lathe to sand lengthwise with each grit. Also, be sure to wipe off the blank between each grit to get rid of rogue particles that will cause the bigger/deeper scratches.

One of my learnings: scratches should be a "uniform" pattern. If you can see scratches of different sizes/depths, then it's a good chance you will need to step back down to a coarser grit and sand lengthwise to get rid of the bigger scratches before moving on to higher grits.

My process is roughly one that I read in our library here on IAP. I haven't mastered the skew yet, so I have to compensate for that somewhat with sanding. I start sanding with Abranet 240 usually. Progress through 400. Then on to wet-sanding with all the micromesh grits (9 of them). I also cross sand lengthwise through the first four MM grits (lengthwise sanding is also wet).

To me, sanding is not the fun part of penmaking. But it's the make-or-break part in the perceived quality of the final product. So I have disciplined myself to take my time and proceed very deliberately through all of the tedious steps.

Good luck. And by the way...when you think you have it mastered...then try it on a solid black blank...yeah, no forgiveness there...amateurs need not even apply...very frustrating!

 

[Drowevil]

I had this exact same problem. I bought those little micromesh type pads from rockler that go all the way up to 12000 grit. what I did to fix the issue i used sand paper up to 600 grit then wet sanding with the little pads I would use each pad with the lathe on, I would then wipe the blank dry and remove the little dust, I would then rewet my pad and with the lathe off I hand turn the lathe while sanding length wise. once I get through the 12000 pad i have one of those HUT polish sticks. Now I am no expert farely new to pen turning actually but this worked really well for me. I hope this help.

Lance

 

[mecompco]

I had this exact same problem. I bought those little micromesh type pads from rockler that go all the way up to 12000 grit. what I did to fix the issue i used sand paper up to 600 grit then wet sanding with the little pads I would use each pad with the lathe on, I would then wipe the blank dry and remove the little dust, I would then rewet my pad and with the lathe off I hand turn the lathe while sanding length wise. once I get through the 12000 pad i have one of those HUT polish sticks. Now I am no expert farely new to pen turning actually but this worked really well for me. I hope this help.

Lance

This is exactly what I do. ALL radial scratches must be removed before moving up to the next grit, as must as much dust (and slurry wend set sanding) as possible. I do my sanding at around 500 RPMs. They final polish with McGuire's plastic polish is done at full speed.

PS I really like the little 5 roll boxes of sandpaper. Very convenient and high-quality fabric-backed paper.

 

[Joey-Nieves]

All of the above answers are correct, but what works some wont work for others. As for pressure, as we say in PR; it's not that Pepe can hug, it's how he does it!
I prefer to sand wet for many reasons; less friction, less heat, eliminates fugitive dust, provides a higher shine, etc.
First some acrylics don't have a very high luster, on those I apply some CA. Assuming that yours does, this is how I do it. I dry sand with silica based sand paper(the green stuff) from 220 and 400 with a light hand. Then I apply some Dr Kirk's or equivalent sanding wax to bring up the finish and the scratches.
Lite scratches are OK the will come out with the wet sanding. Here is were I defer from other people, I use wet and dry SP wrapped around an old micro mesh sponge; 320, 400, 600, 800 grit also a 3m micro mesh 2500 and 5000 sponge.
Purple is acrylic acetate. kitless

Gently sand with water going through all grits and feeling your way through every grit. Clean with a rag, At this point you can use a dab of the sanding wax to clean a verify your work, if no further touch ups are necessary then you apply the secret weapon, Blue magic or mothers with a damp cloth.
Now this works for me I've done this month alone close to 225 pens and I will be doing about 60 more this week(starting tomorrow).

The black is Ebony. Neopean kit Parker refill