Dishwashing liquid drying blanks... what is your experience???

[Gary Baler]

This morning I ran across an article by Ron Kent about using liquid dishwashing detergent and water solution for drying bowls and preventing cracking and movement. I've tried to follow it up through searches on the net, but seem to see mixed messages ... and it seems that some of these threads are quite old. What is your experience? You could save me (and perhaps others) a lot of time and hassle by letting us know your results from using this method. What works? What doesn't? Does any of it work?

Looking forward to your responses.

[Bob Vavricka]

I haven't tried it, but it has been a topic in the past. Try a search for LDD (liquid dish detergent) and you will find some past discussion.

[Reed Gray]

I use it on just about every bowl I turn. I turn green to final thickness, and the more they warp, the more I like them. I think they sell better for me. The soap was applied to Ron's Norfolk Island Pine bowls to aid with sanding. It is kind of a lubricant, and the pine trees all have a lot of sap in them, which really gums up your abrasives. I have found that a 24 or more hour soak in a mix of 1/2 LDD (clear, brown or yellow, not green or blue because they can stain the wood) and 1/2 water, rinse, then dry, really is a big help with sanding, especially any wood that can be 'difficult'. On the once turned bowls, the LDD, and DNA soaks do absolutely nothing in aiding drying so you reduce cracking, or speed up drying times. The DNA makes sanding more difficult, no idea why. On twice turned bowls it may make a difference, but I haven't done that type of bowl turning. I don't work walnut any more, but I would soak it in a separate vat. I have been trying a thinner mix of the soap to see if it still works so I can cut down on mess a bit. I think the 1/2 and 1/2 mix is a bit better, but it drips a lot when you are carrying it outside to rinse off, or in to the kitchen sink when weather is bad. Why does it work? My guess is the glycerine that is in most hand dishwashing soaps. Can't think of anything else. Every once in a while, I will not soak some, and it is a huge difference. I had hoped that I could just spray the soap on and let them sit, but the soaking just works better.

Crack prevention is an art, and every wood species is different. Only basic rule is too fast and it cracks, too slow, and it molds.

robo hippy

[Trevor Mills]

Hi Reed, I'm not clear if you mean you are soaking the bowl in LDD after turning it, or soaking the green blank before turning.
can you clarify?
thanks
Trevor

[Reed Gray]

Turn first, then soak. You would have to soak for months if you put the green blank in before turning.

robo hippy

[Gary Baler]

Thanks for your input. Think I might try to soak a few over the winter and work it out. Easier sanding is attractive if nothing else.

[Don Frank]

Reed, Do you do all your sanding after soaking in detergent or do you some beforehand? When you are ready to put the bowl on a shelve to dry do you do anything to slow the drying process like wet shavings and paper bags or any of the other methods people use? And one last question- How much final sanding is necessary after the bowl has warped and dried? Thanks!

[Reed Gray]

Soak first. Rinse off so there is no sludge left. In the summer I take them outside in the gravel and use the hose, winter it is in the kitchen sink. I make sure the rims are rounded over when I turn them, which is a crack control method because the sharp edge will slice you like a razor saw, and since it is so fine, it will dry more quickly and want to start cracks. Finish before going into the tub is totally off the tool, sanding wet wood is a mess and extra work. I wrap the rim in stretch plastic film, about 1 inch over the rim, and the rest on the outside of the bowl, and stretch it out as you wrap the rim. This puts a bit of compression on the bowl which helps drying stresses. It also slows the drying of the bowl wall and rim. I start them out on their bottoms on the concrete floor in a nice shaded cool corner of the shop. After about 3 days or so if I remember, I put them up on a wire rack. They are dry and ready to sand in 7 to 10 days max. No wet shavings as those leave mold and other color marks. I do too many to bag them, and the stretch film seems to protect the most vulnerable part, which is the rim. I turn to about 1/4 inch thick, though some times, depending on the wood, may go as thick as 3/8 inch. I generally don't wrap bowls under about 10 inches, or maple. Maple is usually pretty stable, and fairly easy to dry without cracking issues. Because of the sugar in them, well maybe, maple likes to mold under the plastic. How much final sanding is needed varies depending on the wood and how good of a job I did off the tools, but I can usually start at 120. With dry wood, when I do turn it, generally I can start at a finer grit. I used to think that was just me, but I am starting to think that it is just how green wood works. My lathe will go down to almost 15 rpm for sanding the warped bowls. I also made an arm rest to support my arm and sander while I spin the bowl with my other hand. You can't keep abrasives on a spinning bowl if it is going over about 20 or so rpm. I have a Robust, and had Brent walk me through programming it to go that slow.

robo hippy

[Don Frank]

That's great info Reed. Thanks much