Another Sanding Question......

[tray999]

I am new to both this forum and turning, but I have been a lurker for a while..... I am in the process of turning my fourth bowl and I am having issues with sanding the end grain. I seem to get what appears as fine sawdust in my end grain so I know I must be doing something wrong but I am uncertain as to what....... I have enclosed a picture of my bowl (cherry) still on my lathe to show what I am talking about.

As you can see I am now officially addicted to this new craft and thanks in advance for any help!

 

[Donna Banfield]

Welcome to the addiction.

The fine dust particles in your bowl appear beause you have tear out in the endgrain. Getting clean smooth cuts across endgrain require very sharp tools. In addition, some woods are more prone to endgrain tear out than others, and cherry is one of those woods that can be a real problem.

You can try several things on your next bowl. One, before you make your final cut, go back to the grinder and return to the bowl with a freshly ground edge.

You can also try using a shear cut, that can be done with a bowl gouge with an Elsworth grind, and the tool held with the flute nearly facing the surface you're cutting. The tool is also held vertical, or with the top of the tool pointing up towards the ceiling, and the bottom, or handle of the tool facing down. With this method you want to take VERY light cuts, because that's what you're doing is shear cutting.

A third method is to use a scraper that you've slightly rounded the edges (to avoid getting a catch) held at an angle so that you're shear cutting with the just the edge.

Another thing to try is to stop the lathe from spinning, and periodically hand sand that area WITH THE GRAIN. Notice in your photo that there are lines that wrap around the bowl, and this can be caused by sanding with the lathe under power, sanding too fast, or with too much speed on your lathe. Many fruit woods, cherry especially can be sensitive to heat when sanding. Trying to sand with too much speed will generate heat buildup and you'll end up burnishing your wood, instead of sanding to remove the tools marks.

I hope this helps. Other things you might try are videos/DVD's, especially to show you the various tool techniques I described above. Even better, if there's a turning club nearby, attend one of their meetings, where you might be able to hook up with a mentor.

 

[Peter Skellenger]

some sanding tricks

You are probably sanding by hand and not power sanding right? The latter is better but def not necessary! Donna has a lot of good info in her post. I have a cpl thoughts.
If you turn and then finish the bottom, rechuck the bowl and then finish the inside (like I do), you will probably still have enough wood to follow Donna's ideas. Otherwise and maybe even afer you try those suggestions and you still have tear-out, start with 80 grit paper... good cloth backed paper is best (I like J-weight). STICK WITH 80 GRIT until the tear-out is gone and you just have scratches from the coarse paper. Progress through the grits, removing the scratches from the prev grit each time. DO NOT HURRY. This is part of the process... you have to figure out a way to enjoy sanding. Its a skill worth taking time to learn. Get yourself a spray bottle and fill it with distilled water (only distilled, especially with cherry!!). Spray the bowl after each grit with lathe running. Just a mist will do. This will raise the grain which you will cut down instantly. You can do this as often as you like and with torn grain, do it a lot. It will save you time for sure. The other option is to wet sand. I did this a lot when hand sanding. I would have paper in one hand and water bottle in the other and with lathe running, hose the bowl down while sanding it. Its a little messy but it really works well. I found it does not work well on the inside of the bowl as the water is forced INTO the wood and through to the outside of the bowl. It warps pretty quickly and now sanding really sucks! Anyway- the key is to stay with the 80 grit until the tear-out is gone. You have to sand as deep is the grain is torn and you can see that is pretty deep!
If your fingers get hot, its too fast (but don't think it doesn't happen to everyone.. its easy to sand too fast until you figure it out!).
I think the key to enjoying sanding is actually getting good with tools. When you see you have a good cut with no tear-out, you already know sanding will be a breeze and it is. If you have tear-out... well, this is when sanding is really a pain. Practice with the tools! Donna is right about cherry too. Its more difficult than say.. sugar (hard) maple. Try sugar maple if its available. How's that for a long answer!

 

[Ed_McDonnell]

Another fix for tearout if you don't have enough wood left to take another finish pass with a sharp tool or to try and sand it away is to fill and sand flush.

If it's only a little bit, pack with fine sanding dust mixed with some larger chips and saturate with thin CA. Then hand sand the area smooth.

If it's a lot (like the picture) and you plan on using a surface finish (rather than a penetrating oil) then wet sand your first coat of finish with 100-150 grit paper. The tearout areas will fill and can be sanded flush when dry. (If you are going to use an oil to highlight the grain before the surface finish you should do that first).

This helped me save some of my early bowls before I learned how to avoid the problem.

Ed

 

[Charlie Harley]

I find that using a sharp scraper for my final pass eliminates the end grain tearout. I used to spend hours sanding and getting frustrated trying to get the right finish. Now it happens in minutes with the scraper and I'm ready to start finish sanding.

 

[MichaelMouse]

Bunch of contradictions, what? The marks are from scraping rather than cutting, so an inappropriately applied scraper can get you worse as easily as better. Cutting is superior, to my way of thinking. http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=CherryPeelOut.flv for my setup and technique. Note that where the surface is not round I don't reference the bevel, but pivot the tool on the rest to take off the high spots. The tool is cutting a thicker shaving on the leading edge than the skewed and slanted trailing edge, where the shaving feathers on the inside of the curl. Bigger gouge for visibility. http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=35mmGougeRounding.flv Other contradiction in the business of wetting and softening to make cuts versus adding something to stiffen the fibers. Since both have their proponents, I'll say that it's the edge presentation, not the liquid or solid that makes the difference.

Power sanding's the way to go, of course. It allows you to make the initial passes across the gouge ridges, reducing them quickly. I use my sander as another tool. Sort of a depth-limited variable-axis scraper. http://s35.photobucket.com/albums/d160/GoodOnesGone/?action=view&current=150Sand.flv Work easy, as cherry is prone to scorching from sanding or pressing too hard with the bevel of your tools and checking in the end grain to boot.

 

[Peter Skellenger]

many methods

tray999- My revised advice on this particular bowl...... reverse it, finish the inside however you want... cutting, scraping, whatever. It is your 4th bowl, it's not critical! Throw some finish on it (walnut oil is best if you want to use it for food IMHO) and use it! Go out and buy some books on turning, either right now or after you finish this bowl, it doesn't matter. If you want, get some videos but books are great. Richard Raffan has one that is readily available: Taunton's complete illustrated guide to Turning. It covers a lot of info, projects, good pics. Its a pretty darn good book. Try some of the methids he uses for cutting, scraping, etc... As you can see here on the forum, you get a lot of different answers to the "right method". These may be right for me or anyone else but that has to do with turning style, bevel angle, speed of the lathe, so many other variables. A book will give tyou the methods of that particular author and will give you the bevel angle, the lathe speed, etc... then you just practice! Get another book (say "Turn a bowl" by Ernie Conover) and try these methods. They will be similar and different. You will love this bowl right now and want it to be perfect, that is fine but in a year, you will laugh at it because you will have gotten so much better! I am no veteran but have turned a lot of bowls. I still use one of the earlier ones all the time and it is loaded with end grain tearout!

 

[tray999]

Thank-you all for your great advice! I can see that I have joined in with a caring community that is willing to share both it's time and knowledge with a beginner. Unfortunately that is becoming harder to find these days. Thanks again for the help and I am sure I will be asking more questions in the future. Hopefully one day I'll be able to help a new turner.