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Bowl Sanding Technique

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Forum topic by PittsburghTim posted 412 days ago 1168 views 0 times favorited 11 replies Add to Favorites Watch
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PittsburghTim

213 posts in 927 days


412 days ago

Topic tags/keywords: question lathe turning sanding

I am new to turning, having made some pens, tool handles, and a few other small items with good results. This past week, I tried my first small bowl from a piece of 2.5” thick walnut left over from a coffee table project. I am using the Easy wood Tools full-size chisels. I am very happy with them, but when I arrived at the final shape, I started sanding with regular sandpaper, 80 grit through 220 at a fairly high speed.

The bowl looked great until I applied beeswax as a finish. When I did that, the bowl turned a beautiful dark color, but several stripes appeared. I am hoping someone can help identify the problem. Here are someof my thoughts:

- I did not sand thouroughly enough (it did look great and felt smooth before applying the wax.)
- I sanded at too high of speed, burnishing the finish in some areas, causing the stripes.
- My turning technique needs improvement as far as tool speed across the piece.

I do not have a problem with using one of power sanding methods, if it will help with these issues. A recommendation there would be appreciated.

Thanks,

Tim

-- She asked me, "Who are you going to please with that?" I said, "Me."


11 replies so far

View jap's profile

jap

1225 posts in 659 days


#1 posted 412 days ago

Pictures would help some of the turners to identify your problem.

My guess is that you didn’t sand enough at the coarser grit and remove all the tear-out from the gauge.

-- Joel

View TheDane's profile

TheDane

3659 posts in 2268 days


#2 posted 412 days ago

+1 on jap’s feedback … sounds like you are dealing with some pretty significant tool marks.

FWIW, I use my carbide tools for roughing only, and use gouges, skews, and scrapers for finishing cuts.

I have never been happy with finish cuts from carbide cutters.

I know a lot of guys use carbide only and get some great results … just hasn’t been my experience.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View PittsburghTim's profile

PittsburghTim

213 posts in 927 days


#3 posted 412 days ago

Here is a pic. I do think that it is a combination of my turning/sandling. I made a few passes on another item at a slower tool movement rate and then used a ROS with 80, 150, 220, and 320. I put a bit of finish on it and there were no marks. Does anyone recommend a foam sander that I can use? The 5” will not work for most projects.

-- She asked me, "Who are you going to please with that?" I said, "Me."

View Wildwood's profile

Wildwood

962 posts in 740 days


#4 posted 411 days ago

I get my discs from Vince:
http://vinceswoodnwonders.com/blue-flex-discs/

Use 2 3/8” blue flex disc, backup & interface pads.

Vince more than happy to answer any questions you have. Have both inexpensive air & electric angle drill. Bought extra backup * interface pads in addition to assortment of grits. Light pressure all you need.

I get my AL & Garnet sanding sheets from
http://www.woodworkingshop.com

They also sell disc, backup & interface pads, shipping cost reasonable too. Also very helpful people to deal with.

I strive for off the tool finish, but still end up removing tool marks, burnished wood from riding tool bevel and evening out surface. I may start hand sanding trouble spots with lathe off before breaking out my discs and set lathe RPM’s to about 50 to 80. Nominally use about 250 to 500 RPM’s to go through grits of sandpaper.

I wet the surface with either water or mineral spirits looking for blemishes did not remove or created sanding before applying finish.

-- Bill

View Jimbo4's profile

Jimbo4

1124 posts in 1368 days


#5 posted 411 days ago

I agree with Gerry about carbide. What kind of sandpaper are you using, the old “regular” big chunky stuff? The best grades are “P80, P120, P180, P400”, etc. They are much finer grit, and do not clog.

-- BELT SANDER: Used for making rectangular gouges in wood.

View Dark_Lightning's profile

Dark_Lightning

1674 posts in 1714 days


#6 posted 411 days ago

Even with the scratches, this is a nice bowl. I like that shape.

View essexry's profile

essexry

30 posts in 535 days


#7 posted 411 days ago

I like to use 3m automotive scuff pads, starting with a coarse primer prep scuff, going progressively smoother to a polishing pad. I like the scuff pads because there’s no “sand” or pieces of grit. I find grit leaves marks, whereas abrasive pads have no “grit” the abrasive is the pad itself. and the automotive pads go right up to over 1000 “grit”

View ScrubPlane's profile

ScrubPlane

187 posts in 801 days


#8 posted 393 days ago

Those are turning tool marks and while good sanding will remove them I find it best to remove them with tools prior to sanding.

Turn your piece at the highest RPM you can safely, ensure your tools are razor sharp, and then make several very light…delicate even, pull passes with your tool over the piece. You’ll find with little practice most if not all of those marks disappearing.

Nice thing about turning…there are many ways to accomplish the same thing, it frequently relies on what you feel comfortable doing.

View Cindy's profile

Cindy

14 posts in 2032 days


#9 posted 379 days ago

You should slow down your speed and then stop the lathe and sand with the grain. Some of your marks are tool related, but if you only sand with the lathe running then you will get circular marks. I sand with the lathe off and go with the grain. You also need to wipe the dust off after each grit so that any residue is removed so you do not have bits of one grade mixed with the finer grit.
Don’t push too hard and fold your sand paper, if by hand, so that heat build up does not occur.
Carbide tools are okay, but using bowl gouges and a negative rake scraper will give you a much nicer finish.

-- Cindy

View REO's profile

REO

582 posts in 679 days


#10 posted 368 days ago

When you make your cuts some of the fibers can fold over instead of cutting. when you sand these fibers they lay down tightly where there has been tear out to begin with. They do not cut when sanded they just move around the grit. Eventually they will sand off but they use up a lot of time , energy, and paper. They always appear in the grooves where it is more difficult to get at them in the best way. A cleaner cut off the tool is what you are wanting.

View moke's profile

moke

465 posts in 1381 days


#11 posted 323 days ago

+1 with Cindy. My father was my lathe mentor and he always said sanding is a slow ans stopped function. Now Having said that He has been gone a long time and since his death the advent of sanding with sanding discs on a rotating sander his become popular. Inside the bowl, and given room to use it, these little two inch discs can save a great amount of time. There is an art to this technique. I am sure utube has instuctional videos. I bought my discs and holder from Kingspor and I use a right angle close quarter drill from HF. I figured it won’t last long constantly sanding in close quarters but it about five years old now.
Mike

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