Sanding marks???

[cowchaser]

When finishing a pen I finish in CA. Between each coat I sand to about 8000 MM. I don't see any marks until after I polish the pen I can see marks although very light even after going to 12000 MM. They appear to be under in the coats of CA. I am having a heck of a time trying to figure out how to get rid of them even though I don't see them when sanding. I am very careful about sanding the seperate coats of CA and needless to say I am not happy with the end results of the pen. Kind of becomes frustrating after awhile and just want to start ripping hair out. Any suggestions? I am already almost bald and can't afford to lose anymore. It's not receeding it's retreating.

 

[LostintheWoods]

Are you sanding with the grain between grits, and wiping off your barrel between grits as well? These two practices will greatly improve your finish. Also, try polishing your completed CA finish with Novus 2, or a VERY GENTLE automotive polish, keeping your soft polishing cloth moving rapidly over the surface. This may help, as well.

 

[gketell]

I don't sand between coats of my CA and here is my reasoning: when you sand you make sanding dust (in the case of CA very bright white sanding dust) and if you don't get 100% of that dust out of every nook and cranny the next coat will seal it in and make it a permanent part of the pen.

Here is what I do: turn the blank leaving just barely high over the bushings. Use a backing block and using 320 grit (220 if I've done really badly) sand down to the bushings with the lathe on moving the sandpaper as fast as I can left to right. Lathe off and sand lengthwise until all sanding marks from above are gone. Repeat with each of the next grits to 400. Repeat with 0000 steal wool. Remove all the dust you can.

Using a paper towel apply one small drop of BLO to the spinning blank and scrub it in (this hides any remaining sanding dust and pops the grain).

Apply two coats of thin CA each one going in the opposite direction starting at the bushing and stop adding new CA just before the other bushing (just finish off the last bit using the residual on your applicator). Hit each coat with aerosol accelerator.

Apply 2-4 coats of medium CA using the same "direction reversing" and accelerator method as the thin.

If you have done this well the bumps and ridges from the accelerator can be easily sanded out using either 400 or 0000 on a sanding block so you only get the high spots. Once you have it all even sand with the grain. Next grit, etc, until 400, 0000 steel wool, 4000 grit MM, 6000 grit MM. Now study that blank under the harshest lighting you have. If you have any signs of a "flat spot" you have gone through the CA so apply more and redo from start. Once it looks good go on to final buff.

I use three buffing wheels from TAP plastics chucked into my hand held drill. The first is loaded with red rouge, the second with white rouge, the third with Flitz metal polish. I take 2-3 times as long on the first wheel. Turn on the lathe on slow, angle the buffing wheel to about 45 degrees so that you are hitting it counter rotation (so the downward moving blank is hitting the upward moving buffing wheel. Watch your reflection and you will know when you have stopped getting shinier. Then turn the buffing wheel parallel to the blank for the final polish of that "grit". Repeat with the next two. On the parallel pass of the last one I turn off the lathe and hand roll the wheel so I get a nice slow turn.

The whole process (if I don't go through the CA) takes about 20 minutes and I would put these pens up against any pen anyone else has made using their more involved method.

Thanks to Cozee for the demo of this method.

GK

 

[leehljp]

Are you sure that the sanding marks are on successive layers of CA rather than in the wood itself?

I can see sanding marks in bright light (outside in the sun) on a couple of my pens, but the marks are in the wood. These are not always visible from inside light.

IF it is coming from the sanding on the CA, try this: Wipe clean after each sanding step. I do not use alcohol but a dry soft paper towel. Sometimes alcohol will leave a film that causes the next CA step to fog. Not often, but enough to cause some people problems. After each wiping, I sand again.

The purpose of wiping (in my logic) is that the lower grits will cause larger particles to float on the surface. If not removed, the next step up in sanding will take the large grit of particle and cause a scratch proportionate to its size rather than the smaller size caused by the finer sandpaper.

Another problem could be sanding time. I spend at least the same amount of time with each grit, sometimes a tad more with each successive grit.

ALL of this in addition to stopping and sanding with the grain often.

 

[cowchaser]

Yes between every other coat I have been sanding with the grain. I don't use a sanding block as I see most do, which might be contributing to the problem. I sand the wood to 400, and then throught MM. I then use DNA to clean the blank then after it dries I wipe off all of the white haze before reapplying the next coat.

I am pretty sure it is in the CA. I see where the lines are against the grain. I am sanding at 500 rpm (slowest the lathe will run). Well off to work and I'll check back later. Man, I think 3:30a.m. gets earlier and earlier.

 

[leehljp]

One other question, is the streak whitish or dark?

Darker would indicate it is probably in the wood; lighter would indicate it is in the CA/finish.

Tonight in making a duck call, I went from 240 to 320 to 400 and finally 600 on Asian Rosewood. Looked beautiful. Popped the grain thoroughly with BLO, wiped it off, turned on the lathe and held paper towel against it for about 30 - 40 seconds to dry it out. I let it set for a while and added a coat of CA. Surprise, Surprise - a dark sanding mark smack in the middle all the way around. I had to go back and sand that out with 400, 600 and then 800 sandpaper.

 

[cowchaser]

It is in not dark. It's more like hundreds of little bitty less than 1/16th inch clear coat marks like on a vehicle after polishing if that makes since. I do knot it's not on the top coat is the problems so I can't get them out without sanding down the CA finish to find them. Ah, crud it's hard for me to explain. I'll try and get a photo if possible of some this evening.

 

[leehljp]

I had to sand mine down to the wood and to get the one scratch out of the duck call. Took about 10 - 15 minutes. It's something that goes with the territory. It will gets less with experience but it won't go totally away. Once in a while, like this one - one will show up on you when you aren't expecting it.