Eliminating CA Ridges with SandPaper

[leehljp]

Recently, I have noticed several posts in which a particular word is used in the same sentence with applying CA. The word: "ridges."

Do a search of threads that contain this word and you will find 15 pages going back to 2004. Not all have to do with CA but the vast majority do.

The main complaint is that when applying CA, there are ridges. Of course some say use plastic, rubber or other applicators. I do. BUT still, there are ridges of sorts. And, these ridges in CA are causing some people trouble. I never gave it much thought because I have never had problems getting rid of ridges while not sanding through on low spots.



HERE is how I sand out ridges without sanding through on the low spots: Use a slightly stiffed backed sandpaper. Soft back, cloth backed, and foam backed SP and MM, and other very flexible sanding medium will sand down IN the groves - as well as the high points (ridges). (USE FINE SP 400, or 600 is even better) Hard backed (slightly stiff backed) SandPaper will remove the ridges without sanding down the whole area. Don't use heavy or even moderate pressure. Use light pressure until the ridges are gone! Once done, succeeding layers will go on smoother, and if needed, the same method will remove ridges on the next layers also.

I use one hand to hold one side of the strip of SP and the other hand to hold the other end of the strip. Holding stiff backed SP with light pressure against the turning blank will apply pressure only at high points and bring it down to the level of the whole of the CA finish. IF you think of rushing it just a tad, or using a bit more pressure to speed up the process, you probably will not accomplish what you wish, and this method will not work consistently. The goal is to get rid of the ridges of CA without disturbing the whole of the CA application - not how fast it can be done.



(This is not the same as when a blank is high on one side and not the other. In this case, use a wide popcicle stick with sandpaper glued on. Hold with light pressure against the turning blank and let it hit the high side only. After a minute or so, the high side will come down. Too much pressure will sand both sides, defeating the purpose.)

 

[InvisibleMan]

I do this, but only after I'm finished with CA. Did you say you sand ridges between applications of CA? If you do this, do you not "lock in" the sanding marks, or do they disappear?

 

[ctubbs]

I have used my very sharp Skew on its side with success on the worst ones. Sand paper on a flat stick also works very well. It is always best to avoid the dreaded 'ridges' in the first place if possible.

Hank's info is spot on. using a stiff backed paper and light pressure is a very good way to go.
Charles

 

[leehljp]

I do this, but only after I'm finished with CA. Did you say you sand ridges between applications of CA? If you do this, do you not "lock in" the sanding marks, or do they disappear?

Well, sometimes I do the whole thing and sometimes I do a few coats and go from there. The determining factor - Is it up to size for the fittings?

I do NOT use bushing to determine the sizing as the pen parts vary at time by .003 to .005. I do not apply finish while bushings are on. So I turn the blanks to undersize about .01 inch or close to that and then build up with CA. If I haven't built up enough, then I apply a second layer - which might be two or three medium coats.

As to "Lock In" sanding marks - No I don't. I mentioned 400 - 600 SP above. I always finish sanding smooth with at least 600 before moving on to another layer, if I have to. I never use anything less than 320 and even that is rare. 99% of the time, I start off with 400 and take my time sanding to get to size. Then move up on grits on bare wood, PR or over CA. I have not had problem with sanding scratches from sand paper in several years. It can be eliminated easily enough by using finer sandpaper and taking a minute longer.

 

[leehljp]

I have used my very sharp Skew on its side with success on the worst ones. Sand paper on a flat stick also works very well. It is always best to avoid the dreaded 'ridges' in the first place if possible.

Hank's info is spot on. using a stiff backed paper and light pressure is a very good way to go.
Charles

Charles,

I have used the scraper at times too. This "ridge" word is something that I have noticed several times lately and I just overlooked it as the questions were geared towards technique of CA application rather than how to get rid of it once it is there. So, I decided to post a thread on "ridges". :wink:

I am not skilled as you and quite a few others are with the skew. I have a DVD video, I have practiced and practiced at different times over 4 to 5 years, but can't get the hang enough to be consistent. I admire the skew users! But, as said above, I use my scraper like you do with your skew for the ridges! :wink:

 

[Wood Butcher]

That's like checkin on yur burgers after they're burnt!
WB

 

[leehljp]

That's like checkin on yur burgers after they're burnt!
WB

Yep, but some folks inexperienced with CA are looking for answers. Just trying to help them.

Some people with natural insticts can figure it out and prevent it, but some don't have these natural instincts. AND I have seen some that took a few tips such as this and then turn into a master pen maker later on. That is what I like to see!

 

[76winger]

Thanks for the post Hank. I hadn't noticed the recurrence of messages before, but only rarely have run into a "ridges" issue myself. When I have run into it, I've basically done the same as you to remove them.

I might also add that I lightly sand not only around, but also lengthwise. This has three benefits I'm aware of:
1. It helps in taking down only the high points.
2. It removes material slightly faster by sanding in two directions.
3. And it helps reduce radial sand scratches.

Sent from my iPad using Forum Runner

 

[robutacion]

Yes, the "ridges" seem to be the cause of many people's CA finish process nightmares and problems of all sorts. Like everyone else, we all tend to use the technique that works best for us and in my case, I found that stopping the lathe and start my wet sanding process from 600 to 2.500 (600, 800, 1.000, 1.200, 1.500, 2.000 and 2.500) works great. I use the 600 grit to sand across the blank or with the grain, from left to right strokes and rotating the blanks slowly as I go.

I use medium pressure doing this and after I completed one full turn, I wipe the water and residue from the blank with a paper towel. This will show you very clearly how much of those ridges you have removed. Often I repeat the process and when I see the ridges that by this time, are dull looking against the shiny bits (valley's) that the sandpaper hasn't touched yet but not far off, I then turn the lathe on and continue on with my next grits, making sure the sandpaper and sanded area are sufficiently wet.

In fact, as soon as the 800 grit pass through, any of those small lines of shiny surface left from the 600 grit, worked the way it did, disappear and all the following grits are used softly and quickly to void removing more CA than what is absolutely necessary. As soon as the ridges are gone, the use of the various grits are merely to remove the scratches from the previous grit right to the point where, you use the polishing compound to bring the shine to it...!

I can also say this, I have tried lots of different types of applicators, from cheap paper towels to the expensive blue industrial paper towels used in many factories and garages, some did work better than others but, the amount of CA left behind on each coat and the amount of ridges they produced in the end, where in fact, all very similar however, and recently after I heard about the "craft foam" ability to apply the CA better than anything tried before by those promoting it, I decide to buy some and give it a go.

Like all others said, I wish that I had tried it long ago as the results are quite impressive and if many of the problems experienced with other applicators, such as fumes, set to quick, get stuck, burn you finger, and so on...!, I discover that, the same number of coats (thin or medium) used previously, are leaving behind twice as much CA with a lot less ridges...!

The first time I used it was on that Vine pen and stand that I made from that supplier in the USA and not taking too much notice, I done my 10 coats (2xthin, 8xmedium) and I noticed lots of CA over the bushings, anyway, I proceed to do my wet sanding stages, polished it and when I got then out of the bushings I knew that something wasn't right as the amount/thickness of CA that I saw when sanding the ends straight was far too thick.

I put the pen together just to see how much over/rich that CA finish was and I couldn't believe how "fat" that barrel was...!

Pulling it apart was no problem and I put the barrel back in the mandrel and cut all that CA out, as I liked the depth of the finish but I had too much wood for that so, I cut it down to the wood and then a little more.

The second time around, I knew the approx. thickness my 10 coats would produce using the craft foam so, I reduce it to 6 coats which was OK, but I should have kept the 10 coats and I did cut enough wood to accommodate that thickness and my decision to give only 6 coats, made the overall, diameter, a tad under/shy of the correct size but barely noticeable...!

So, and like I mention previously, what works for some, doesn't work for other but, among a number of possible ways to get it done, I hope you guys find yours...!

Good luck,

Cheers
George

 

[1080Wayne]

I do this, but only after I'm finished with CA. Did you say you sand ridges between applications of CA? If you do this, do you not "lock in" the sanding marks, or do they disappear?

I make better ridges than Hank , so I frequently start sanding with 320 , or even 220 if things haven`t gone well . Sanding marks in CA won`t lock in , even at the 220 level , if 1) the first coat after sanding is a thin one and 2) the CA is not fully cured - and I`m not totally sure that the last is important . If you see sanding marks after CA application , they are almost certainly telegraphing through from the wood .

 

[leehljp]

I do this, but only after I'm finished with CA. Did you say you sand ridges between applications of CA? If you do this, do you not "lock in" the sanding marks, or do they disappear?

I make better ridges than Hank , . . .
If you see sanding marks after CA application , they are almost certainly telegraphing through from the wood .

Wayne, you are funny! :biggrin:

AND, thank you for bringing up another issue that happens on an occasion - "telegraphing."

"Telegraphing" is an issue in wood in which the CA finish over a knot, natural fracture line or indention in the wood settles after a day to a week. When CA is as smooth as it can be and you are very happy with it - about a week later you may notice that it is no longer smooth but rather "sunk in" over the spot that was once smooth with the rest of the pen. This is what we refer to as "Telegraphing". Not much you can do to prevent this except set the pen aside after finishing and wait a week or two and check and add more finish. The underlying cause is the indention, crack, knot etc and for reasons unknown it slowly changes shape by dries out or moving in one way or another. It would not be noticeable without the CA finish on top. One way of prevention in a few cases will be to CA with thin CA on the spot two or three times and let it cure for 5 to 10 minutes or so between each layer of CA. Then finish it. The purpose is to stop the movement IF possible. In most cases, we don't even notice the spots that will "Telegraph" until after telegraphing happens.

This is not bad, but it is a distraction on an other wise perfect finish. It usually happens on the first pen in which you make a "perfect" finish!