Small scratches left over from orbital Sander...

BBeyer

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Kind of a noob question.. but I’ve sanded the clear off this birch Tama superstar shell, gone up to 240 grit pads on my orbital palm sander, and there are little circular scratches left over on the shell still.
My question is, how much of these small sanding marks actually show through once you lay the clear on? Does the clear fill these small marks and pretty much hide them, or do I need to keep going with finer grit?
I don’t have anything finer than 240 for the Sander, and I’ll get it if I need it.
I have 1000 wet or dry paper that I just went over the shell with after dabbing the paper in a little water to try and speed the process.. , but I’ve probably wasted my time jumping from 240 grit to 1000
 

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amosguy

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Wipe down with some thinner and see what that look like until it evaporates. (Water will raise grain).

You likely will need some finer grit and with the orbital, it sould not be much work to take it down at least a couple of grits for final sanding.
 

Fat Drummer

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Not a noob question at all, it fact, this is a very common issue for many folks. Their are several of us here in the cabinet / casework building trade and one of them will surely chime in with more detailed information than myself but I will start with a general over site. We often refer to this as "pig tails" and no, it will not visually be filled in during finishing. You can use a good sealer and level it to the point of not being able to feel it, but you will always see them if left in the wood.

The three causes of sanding swirls or pig tails is the wrong sander for the application, the wrong paper or, and this seems to be the most common reason I have discovered, too slow a speed on the sander itself. At this point, you dont need to go smoother or finer in the paper, you are going to have to go the other direction and return to a heaver grit to level these back out. Remember that sanding is nothing but "scratching" the wood to level it, you start as rough as you need to begin the process then you gradually move through finer grits to remove the scratches the previous grit left behind. For example, you cant sand with 100X then skip right to 220X grit... the finer 220 will simply not be able to remove any deep scratches, abrasions and swirls left behind by the heaver 100X grit.

You may need to return to 120X or 150X, and once those seem to be gone, go 180X then 220X. If I was staining the drum, that is as far as I would go as you will start to burnish the wood fibers and seal them off with finer grades. If I was going natural, I would go to 280X and stop. All the visable scratches should be gone at that point. If you are using an air powered sander, increase the air as too low a pressure will cause this by running the tool to slow. If using an electric sander, try again and work on keeping the sander level with the convex surface the best you can and dont apply a lot of downward pressure, let the paper do the work, not your arm pushing down.

Hand work will do it as well, but use a sanding block to keep the paper in more level contact on the rougher grits and sand with the grain, not against it. I always finish up with my palm and a soft sanding sponge of fine or extra fine. Again, others will give you better advice but this will get you started with at least why the swirls are there. Good luck and keep us posted. This will sand out no problem.


Ward
 
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Fat Drummer

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Hey BByer, so I just reread my own post... wow, sorry for coming off so condescending. I did not mean that at all.
 

BBeyer

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Hey BByer, so I just reread my own post... wow, sorry for coming off so condescending. I did not mean that at all.
I don’t see any problem in your post!

I stopped at the hardware store and grabbed some 150 and 220 (240 maybe?) for my sanding block/pad and went at it for the last hour or so. It’s looking good, the “pigtails” are pretty much GONE, but my arms are killing me!
 

loach71

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I don’t see any problem in your post!

I stopped at the hardware store and grabbed some 150 and 220 (240 maybe?) for my sanding block/pad and went at it for the last hour or so. It’s looking good, the “pigtails” are pretty much GONE, but my arms are killing me!
Are you using a RANDOM orbital sander? If not, you should. I work my way through ALL of the grits from 120 until I reach 600. Between each grit change I clean the shell with compressed air, then a tack rag then compressed air. After the 600 grit sanding I to the clean routine, and then wipe down the shell with lacquer thinner. I learned this method from an old cabinet maker. He emphasized "don't skip any grit level."
 

BBeyer

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Are you using a RANDOM orbital sander? If not, you should. I work my way through ALL of the grits from 120 until I reach 600. Between each grit change I clean the shell with compressed air, then a tack rag then compressed air. After the 600 grit sanding I to the clean routine, and then wipe down the shell with lacquer thinner. I learned this method from an old cabinet maker. He emphasized "don't skip any grit level."
yeah its a random orbital
 

jccabinets

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Fat drummer said it all, especially the last line. The only way to get rid of them is by hand, sounds like thats what you did. And, I hear all the time guys saying they sand up to 600 grit, WOW! really? They must be using some totally different products than I do for top coat because my rep at M.L. Campbell and all of the finishing seminars have stated that anything over 180 is polishing the wood so much that you could have some adhesion problems. I usually stop at 150 then start my clear process, my cabinets/drums are smooth as glass. One key thing I have learned is to change the paper out frequently, dont try to "get all you can" out of it. Removing the dust by blowing air on it works good but your sending all the dust in the air that your breathing. It can be removed with a cloth with good results. And when you do use a RO sander make sure the paper is in good shape, if it has a little tear in it or a bent corner then get it rid of it and start with a new piece.
Good luck with your project, lets see some pictures!
 


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