Advice for Wetting End Grain Fibers for Cleaner Cuts

[Charlie Myers]

I'm a newbie at bowl turning, and I've gotten to the point in my efforts that I'm doing what I can to reduce the time that I put into sanding. I'm talking about face grain oriented bowls, and right now my biggest culprit seems to be torn end grain on the inside of the bowl along with short gashes made by the tool right near each of the two end grain areas. I'm still trying to improve my sharpening & turning skills, and I've been trying various bowl gouge grinds & scrapers - these will all be a work in progress.

Recently though I've had my best success by soaking the end grain with a little boiled linseed oil and then making some light passes with a freshly sharpened 1-1/2" round nose scraper. I'm actually happy with the results from that method. I chose BLO because so far I've finished my bowls with a Danish oil which contains BLO so there shouldn't be any incompatibilities with the finish, but I'm a bit concerned about the potential fire hazard with BLO drying in the shavings. So my question becomes what else can I use rather than BLO that will be compatible with Danish oil?

I've tried water. Although it works, it didn't work nearly as well as BLO. I've seen others suggest mineral oil and paste wax (not together) which should be fine as far as a fire hazard is concerned, but would either present problems with the finish? Mineral oil won't cure, but I don't know if maybe it would be diluted enough when I soak the bowl with Danish oil, and I'm afraid that any residual paste wax might leave some discolored areas once the finish has been applied.

So far I've primarily worked with sycamore which might be contributing to the problem...I have some roughed out walnut & cherry bowls but they're not ready to finish yet.

Any thoughts or suggestions?

Thanks,
Charlie

[Reed Gray]

Sycamore generally isn't prone to tear out, so i am suspecting tool cutting edge presentation might be the culprit here. I do wet dry wood some times, and mostly use just water. It needs to soak in for a minute or two, then fine cuts. If you are getting okay results with a scraper, that is surprising. A scraping cut, with a scraper flat on the tool rest will always leave some tear out, with that being pretty minimal if you are cutting an end grain bowl, and pulling from the center up. A shear cut, with the scraper at a 45 or higher angle cut will leave a much cleaner surface. For gouges, I like a more C to ( shaped flute so when you roll the gouge on its side, you get a better slicing cut than you can get with a V flute. The V flute works better if you drop the handle and roll the flute towards the cut (note here, only with the handle dropped, not with handle level).

You mention that this is happening on the inside of the bowl. If it isn't happening on the outside, then you are doing some thing different on the inside. The inside is more difficult than the outside, in part because you can't see the profile, and also, most use a dropped handle on the outside of the bowl, but this is more difficult to do on the inside. A freshly sharpened tool for the finish cut every time.

robo hippy

[Charlie Myers]

Thanks for the reply Reed...I appreciate you taking the time to respond.

If you are getting okay results with a scraper, that is surprising. A scraping cut, with a scraper flat on the tool rest will always leave some tear out...

Actually I failed to mention that I'm holding the scraper at an angle to get the shear cut.

I have little doubt that my main problem lies in sharpening & technique, but I'm hoping that the end grain soak & shear scrape will keep me interested enough in bowl turning to develop those skills.

You mention that this is happening on the inside of the bowl. If it isn't happening on the outside...

The tear out of end grain is happening on the outside too, but not nearly to the extent that it occurs on the inside. On the outside I'm able to clean it up well enough doing a vertical shear scrape with a bowl gouge that it doesn't pose as much of a problem.

I'm hoping to get hooked up with a local turning club sometime soon which will be quite a help I'm sure, but "local" is a relative term because the nearest club is a two hour drive for me.

Thanks again,
Charlie

[Jon Prouty]

Why not use some Danish Oil as your wetting agent?

JP

[Prashun Patel]

Danish oil contains BLO and is more expensive than the pure oil.

[Charlie Myers]

Why not use some Danish Oil as your wetting agent?

Danish oil contains BLO and is more expensive than the pure oil.

Prashun is right, but for me it's the risk of fire from the drying oil soaked into the wood shavings that's my concern. Otherwise I'd continue to just use BLO and be done with it. Or maybe I'll just continue to use BLO but be sure to clean up my shavings before & after doing the inside finishing cuts...

Charlie

[Wally Dickerman]

In my own turning I use a finishing oil for taking care of any tearout. I especially recommend it for oil sanding with the coarse grits also. I use the same oil that I use in my finishing. Cost is negligable becuse it doesn't take much.

Paste wax such as Johnson's, also works well. I don't like to use mineral oil because it never dries completely.

Actually, appying water or oil to the surface won't help when you take another cut because there isn't enough penetration. It will work well with shear scraping however

If you are experiencing tearout on the outside of the bowl it just about has to be tool use. Are you cutting with the grain? Are you rubbing the bevel if you're using a gouge?

[Harry Robinette]

I've been using whatever finish I'm putting on the piece for 12 years now oil,shellac,poly whatever. The fire thing I'm not understanding? Are you talking about the shavings catching fire while your turning or your not cleaning them up and afraid they well catch fire after you leave the shop.

[robert baccus]

Any of the "curing or hardening"oils will catch fire especially in rags or sawdust/shavings. think of them as hot coals out of the fireplace. i told a friend about oil and old rags and he found his shop in big flames. i didn't mention sawdust per say. he barely put it out. these oils react with oxygen rather than dry like shellac or laq. in doing so they generate heat like new hay and will gladely self ignite. i know of 1 highschool that bu

rned down due to workmen oiling oak floors and piling the rags. much dangerous!--------old forester

[Charlie Myers]

Actually, appying water or oil to the surface won't help when you take another cut because there isn't enough penetration. It will work well with shear scraping however

I'm using the water/oil/whatever to help support the end grain fibers while shear scraping with a scraper...as mentioned before my hope is to use this method to clean up my cuts until I'm able to improve my sharpening/technique/etc to get a cleaner cut with a bowl gouge (1/2" Thompson "U" gouge at the moment).

If you are experiencing tearout on the outside of the bowl it just about has to be tool use. Are you cutting with the grain? Are you rubbing the bevel if you're using a gouge?

With the gouge I'm taking cuts from foot to rim on the outside and from the rim to the bottom of the bowl on the inside. But again, the tearout on the outside isn't nearly as much of a problem as on the inside.

The fire thing I'm not understanding?

Any of the "curing or hardening"oils will catch fire especially in rags or sawdust/shavings.

Robert has your answer Harry. My shop is in my basement, and I really don't want to burn the house down for the sake of getting a nice smooth surface on a wooden bowl. Sounds like for now water is the only reasonable answer that won't burn the house down and won't cause problems with a Danish oil finish.

Thanks everyone for the responses!

Charlie

[Reed Gray]

A little oil in shavings probably wouldn't be much of a problem, but why take chances. I use water because I am cheap. It works, but you have to let it soak in. Big secret there. I would use Mahoney's walnut oil, but again, the water is cheaper. The walnut oil will oxidize as it cures, but the rate is so slow that it does not generate any noticeable heat, but again, why take chances.

Cleanest cuts in the most difficult woods require sharp tools, very gently rubbing the bevel, and a high shear angle. Easy to do on the outside of the bowl with a swept back grind, and a dropped handle. More difficult to do on the inside. I hold my tools more level. On the inside, I prefer Doug's fluteless gouges for the transition and across the bottom. You can roll them over to 70 or 80 degrees, and they have a long sweet spot for cutting. A V gouge has a very narrow sweet spot (bottom of the flute). If I am using a U or C shape gouge, I roll the gouge over to 45 or more degrees. If you use a gouge on the inside, and the flutes are straight up, you are cutting with the wing. If you have the handle level, this is very prone to catching. You can do the same bevel rubbing cuts with a scraper as well. Important when cutting, just like a skew, cut with the lower 1/3 of the blade. Go to You Tube and type in robo hippy. I turn a bowl with only scrapers, and with only gouges. You can see some of what I am talking about.

robo hippy

[Prashun Patel]

Since we're on this tangent, I suppose you could use mineral oil. That's not a drying oil. Heating the MO will increase penetration. Wally, have you ever used mineral spirits as a wetting/sanding agent? I know it evaporates fast, but wld be keen to hear how it performs as a lube vs the finishes/oils you typically use...
- p

[Charlie Myers]

I use water because I am cheap. It works, but you have to let it soak in. Big secret there.

Reed you've mentioned letting it soak in before. Can you elaborate a bit on that? When I tried water I soaked the bowl with a wet rag just to the point of water forming a drip...then let it soak in at least long enough to take my time in resharpening the round nose scraper. Is that long enough or should I maybe try 5 or 10 minutes?

Since we're on this tangent, I suppose you could use mineral oil. That's not a drying oil.

Prashun, I thought of mineral oil too (see my first post), but because it doesn't cure I was concerned that it might try to bleed through the Danish oil finish or otherwise cause problems with finishing. So far nobody has confirmed or debunked that as a concern. Still looking like I need to give water another try and if all else fails just rely on BLO but be careful with cleaning up before & afterwards.

Thanks ya'll!
Charlie

[Wally Dickerman]

Reed you've mentioned letting it soak in before. Can you elaborate a bit on that? When I tried water I soaked the bowl with a wet rag just to the point of water forming a drip...then let it soak in at least long enough to take my time in resharpening the round nose scraper. Is that long enough or should I maybe try 5 or 10 minutes?



Prashun, I thought of mineral oil too (see my first post), but because it doesn't cure I was concerned that it might try to bleed through the Danish oil finish or otherwise cause problems with finishing. So far nobody has confirmed or debunked that as a concern. Still looking like I need to give water another try and if all else fails just rely on BLO but be careful with cleaning up before & afterwards.

Thanks ya'll!
Charlie

I suggest that you use a finishing oil for oil sanding and for shear scraping. Mineral oil works but it doesn't dry. It will definitely work better than water. You won't be using enough to create a fire hazard. I've been using that system for many years and so have thousands of other turners. I've never heard of oil used that way causing a fire. You simply don't apply that much oil.

[Reed Gray]

I let it soak about the same amount of time that you do, a minute or two. A shear cut with a scraper will leave minimal tear out in dry wood. With green wood, almost no tear out. Just no getting around it. That is the difference between a bevel rubbing shear cut and a non bevel rubbing shear cut, which some call a shear scrape. Rubbing the bevel leaves a slightly cleaner surface. I get it pretty wet so it is slinging some water as I make more cuts.

I don't think there would be any problem with mineral oil and cutting if you use a solvent based finish. If you are using more of a surface finish, it could interfere, but I don't do those types of finishes.

Some times you just have to use the 80 grit gouge.

robo hippy