How to get rid of micro scratches on a CA finish?

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patmurris

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Feb 25, 2011
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Nice, French Riviera
Hi All.

I'm still struggling to get a glass like CA finish. I tried many ways to apply the glue... thin w BLO 15 coats, medium no BLO 5 or 6 coats, sanding between layers or not.. wait 24h, then MM up to 12k both ways and finally flannel w blue paste both ways... I do manage to get a high gloss but always have micro scratches that spoil the highlight when seen in sun light - it is not razor sharp.

What am i doing wrong?

I was thinking sanding in between layers was the key but it does not seem to make a difference. Maybe i'm not polishing properly?

I read that many do apply a final coat of wax (Renaissance Wax?) over the finished CA. Would that fix the micro scratches? What about a car polish?

Advices welcome! :wink:
Thanks
 
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Papo

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Winter Haven, Fl.
Are you using Scotts Blue Shop Towels to apply ca
are you dry sanding lightly with 600 grit sandpaper after your last ca application
Then do wet mm to 12000
Here is how I do it
I cut one sheet of Scotts Blue Shop Towels into 1/4's fold each four times
that prevents ca from coming thru towel and makes a real nice pad to apply ca
1-Apply 4 coats of thin ca then dry sand lightly with 600 grit and then do wet mm to 12000
2-apply 4 coats of medium repeat sanding procedure
3-redo step 2 as many times as you like 2 do it for me
then I do car polish scracth remover still using scott towels
then do car wax.
Move steady across blank while applying ca you need to find a happy medium with how fast to move across blank.You will be able to see the lines left by the application.
Soon I'm starting to do woodturners finish this ca stuff is starting to get to me.
I think I'm becoming allergic to it.
Other turners will be shiming in on this subject just stick in there.
We all know there's a learning curve
Good Luck.
 

AlanHil

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Jun 14, 2011
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Aberdeen, Wa
I learned this method from my days painting cars.

I start by using 3 coats of thick CA and a little accelerator. Too much can make even more work as it causes the CA to bubble.

I start sanding with 220 and sand until the scratches are uniform.
Then I apply one coat of water thin CA.
Sand with 400 until the dullness is even.
Sand the 400 scratches out with 1000. You can see the finish smooth out and clean up.
Sand with 1500 to a finer finish getting it even more shiny.
Sand with 2000, this should leave a matte finish.
Polish with rubbing compound or polishing compound. Rubbing compound is about 10000 to 12000 grit
Polish with swirl remover.

I don't use wax on CA as it's really not needed but it also doesn't hurt.
You might also let the CA dry for a few hours or overnight before starting the sanding.
Usually finish scratches come from a finish that is soft when you start sanding or not sanding the previous scratches out completely.
I don't wet sand but I'm going to try it since a lot of guys here do it and the result should be even better.
Good luck
 
Last edited:

soligen

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May 11, 2010
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Sterling Heights, Michigan
In my experience, 3 things are key:

1) Make sure you use each grit long enough to remove the all the prior grits scratches.

2) Stop the lathe and sand with the grain on every grit. Seems the more time I spend doing this, the better the results

3) Make sure your MM or sandpaper is CLEAN - no swarf or it will make bigger scratches that the current grit wont remove.

On that third point, I have stopped using MM on CA simply because I find keeping the MM clean is a hassle. I use wet try sandpaper up to 2000 grit - using a fresh piece each time, then Hut Ultra Gloss.

I still keep the MM for certain acrylics where It seems to work better than wet/dry, but for those I only use the last 3 grits after going to 2000. That way I only have to worry about keeping 3 grits clean.
 
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Steve Busey

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Sounds like you have the basic steps right, pat.

You didn't mention wet sanding - the water helps build a slurry/paste that I believe helps smooth the finish. And I always finish with Blue Magic Metal Polish Cream, which has a very fine abrasive action to it, moreso than just a car wax.
 

Phillyjer

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Philadelphia PA USA
I use the Meguires PlastiX ( a polish and scratch remover for plastic headlights). It seems to work well as my final coat.

Also, after the first 3 coats of CA , I like to wet sand at 600 grit to smooth it out before applying any more layers of CA.
 

Justturnin

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Houston, Tx
I think what you are doing is fine. You may want to spend a little more time w/ each MM to make sure you are removing the last ones scratches. When I have this issue I throw it back up there and start in the middle of the MM pads and polish it up again. One thing that I started doing is when I start sanding my finish I do it w/ a new piece of wet 600, when I am done w/ that I clean it up w/ an older 600 usually from the last pen and that helps smooth out the 600's scratches then I do to the MM. Once I finish MM I use Huts Ultra High Gloss (its what I have, others use Car Polish and when I run out of this I am going to try that) and run it at high speed for about a minute with very light pressure, you dont want to create heat.

Just keep trying. Applying the CA is the tricky part. Sanding just takes a little practice to get a feel for it. I look at some of my first CA finishes that were awesome back then and laugh at them now.

Edit:
I also use a spray bottle for my water not a pot so it always clean water. I place a plastic shopping bag over the ways and then and shop wash cloth to soak up the water so my lathe stays dry.
 
Last edited:
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Pat - Lots of good info above. One thing I picked up here recently is to be careful to not contaminate the next sanding level with the previous sanding's waste (the technical term is "swarf" above). Even a little can make your day go from good to not so good. When I'm wet sanding I keep an open container of fresh, clean water to rinse the paper in BEFORE I start sanding with it. Being slightly OCD helps.

Also - I was applying my polishes, etc with paper towels. Seemed to be OK. But I recently switched to cut up pieces of old 100% cotton T-shirts. I swear I'm getting better results.
 

Chasper

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My approach is much different. I believe that I get scratches from sanding CA. I apply my CA with a paper towel, 10-12 coats of thin, no accelerator, no time between coats, then buff with white diamond within minutes of finishing CA applications. Don't put any scratches and contaniments on and there are none to remove.

Also I don't use polish. If you don't have glass before polish, you can get it with polish, but in a month or two the polish will wear off and the finish will be dull. If you have glass without polish you don't need polish.
 
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76winger

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I used to go through the MM steps dry but have found doing so wet helps in reducing the sanding scratches considerably. I've also found using light pressure has helped as I used to apply too much pressure, which was especially noticeable when done with the coarser grits. This just takes keeping an eye on your progress and backing up a step or two if you notice more scratches that should be there at a given point in the process.

Stretching the question a bit further:
Does it count if you still see scratches with a jewelers loupe, even though they aren't visible to the naked eye?
 

NewLondon88

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Also I don't use polish. If you don't have glass before polish, you can get it with polish, but in a month or two the polish will wear off and the finish will be dull. If you have glass without polish you don't need polish.

The word 'polish' often confuses .. because the way we most often use
it is as a sanding medium suspended in a liquid or a paste. But there are
products out there that say 'polish' when they really aren't a polish at all.
(Think Pledge .. it doesn't polish anything, it temporarily fills in scratches
with oils and/or waxes)

But for penmakers, the polishes we're using don't wear off, because they
are never left on to begin with. A polish is just another way of applying
that sanding grit.. using the liquid or paste as a carrier instead of using
paper of cloth backing (like sandpaper, MM or emory cloth)
 

NewLondon88

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Stretching the question a bit further:
Does it count if you still see scratches with a jewelers loupe, even though they aren't visible to the naked eye?

Good question.. I think if you can see it with a decent loupe, chances are
that you will see THE EFFECT of the scratches with the naked eye .. even
though your eye cannot discern the individual scratches without help.
It may not look like scratches to the naked eye .. but perhaps a hazing?
 

wouldentu2?

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Many times the scratches are from the sanding between CA coats. Pressing too hard between coats and not taking your sanding progressively through the grits.
 
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