Tips for immersing a piece in finish?

[George Overpeck]

Hey all - I have been looking at some of the work out of Hawaii and a lot of the Cook and Norfolk Island Pine is getting finished with a multi-day dunk in a PU mixture, presumably with thinners added. I was kind of interested in learning about this technique if anyone has used it much.

My questions are - is it going in green or dried? Are you relying on the thinners to migrate the water out of the wood if it is green and so do you have to refresh the thinner element of the mix often?
Can you rely on the soak somewhat to stabilize the wood against checking and cracking? Is there any need for special drying techniques after it comes out of the finish? What kind of mixes have you heard of and what has worked for you?

If I don't hear anything back I might just dive in and report back on what works, if anything.

[Reed Gray]

Ron Kent, who lives over there some where developed the process for the Norfolk Island Pine. I believe he had some health issues and doesn't turn much any more. I did get in touch with his a few years back about the soap soaking, and he was very friendly and sharing.

robo hippy

[George Overpeck]

I actually was in touch with Ron about the soap soak as well a few years ago, he seemed very nice - sad to hear about his health problems. Are they respiratory/turning related?

One of the pictures on his website is a piece drying over a vat - ok, just checked his website and he actually describes his process a bit. He says the trick is not the soaking but the multiple runs through the finish and the drying time and sanding in between.

Someone please chime in here and tell me that the sanding in between is not actually needed.

He says regarding the varathane stalactites "This same substance permeates and becomes integral with the cell-structure of the wood in the finished vessel.", and attributes the color and translucence to the finish technique. I'm wondering if maybe the varathane is kind of propping the fibers open in some way as it dries to let more light through.

My experience with translucence in the mostly birch that I'm working with is that pieces have good translucence while wet, lose it when they dry, and regain it with a thick application of oil. Maybe soaking in a hardening agent will make it more pronounced.

At any rate, does anyone have experience using this technique with green wood?

[John Keeton]

George, our own Bill Donahue has done several vessels of NIP using a modified version of Ron Kent's method. This is a link to one of them and he indicates his method will be discussed in more detail in the February issue of Woodturning Design.

[David E Keller]

I've done a few piece with NIP soaked in 50/50 mineral spirits and boiled linseed oil. I soaked for a day then wet sanded with 600 grit briefly between soaks. I wiped away excess oil a time or two after removing the pieces from the oil. I let them dry for a month after the last soak then coated with gloss wipe-on poly. The wood was green when it was turned, but at 1/16", it doesn't take long for the piece to dry... I put then straight into the oil after turning.

[Scott Hackler]

George,

I am fortunate to own a NIP piece from Kelly Dunn (lives and turns on the big island). He told me that he uses a homemade brew of tung oil, some thinner and various other oils (he didn't elaborate at the time). His process is to turn it really thin at about 1/16" walls, soak it for a day, dry for a day, repeat at least every day for several weeks and then after fully cured and dried....he sands and buffs the finish smooth.

The end result is a very translucent piece that "feels" more like plastic than wood.

I have also seen folks apply the oil or a resin to the outside of a freshly turned bowl while upside down on a homemade shop vac powered table. This pulls the oil or resin through the piece. I thought that looked faster and is something I might concider trying if I ever find some NIP to play with.

[Scott Hackler]

I've done a few piece with NIP soaked in 50/50 mineral spirits and boiled linseed oil. I soaked for a day then wet sanded with 600 grit briefly between soaks. I wiped away excess oil a time or two after removing the pieces from the oil. I let them dry for a month after the last soak then coated with gloss wipe-on poly. The wood was green when it was turned, but at 1/16", it doesn't take long for the piece to dry... I put then straight into the oil after turning.

You ever finish those lamp shades??

[Sparky Paessler]

I have never tried it with a bowl but I use a vacuum jar to pull finish into pen blanks. Would probably work well on bowls also if you had a big enought vessel to get the bowl and finish into. I think the idea is that the vacuum pulls all the air out of the wood and then finish is injected into the wood as pressure returns. I have done penblanks and knife scales. I might try a small bowl to see what happens.

[David E Keller]

I just installed them last week... I'll try to take a picture of them at some point.

It only took me a year and a half... I thought that was pretty good.

[George Overpeck]

Well, here's a report on immersion and vacuuming in a 5 gallon bucket - if anyone else gets this bright idea you can just move to the next step.

I threw some Deft (mostly because it's cheap) and some thinner into a sturdy five gallon bucket, soaked some pieces in it and they look pretty nice. The translucence is not really more than you would achieve with a thorough oiling, but the feel of the pieces and their resonance definitely changed. They are super green end grain NE pieces which would have checked/cracked for sure and they haven't yet - I'll probably keep soaking them some more. It doesn't give a magic finish after one or two soaks but it might start to accrete and give a little more surface quality with some more soaking.

Then this morning I had a great idea and brought my hand pump up to the shop. I did some conversions from whatever metric the vacuum guys are using and figured I could get it to -10 to -12 psi with this pump which is about what a lot of the vacuum jars are pulling. I cut a hole through the softer plastic of the pour spout and put the nozzle in, had a good seal so I started pumping.

Did I mention I had a nice little spalted piece in there? Nothing spectacular, but a nice little 6 inch thin bowl with great whites.

After just a few pumps I heard the bowl release it's air - it sounds like a soft drink being opened. And then the bucket crumpled up on itself. It cracked the bowl irretrievably.
The bowl was thoroughly saturated though.

I think if (when) I try this again the two tricks that might come to mind would be either to fit some kind of steel frame inside the bucket, or to do it in a pressure cooker.

This may sound kind of time consuming but it would solve the problem of having different levels of penetration on end vs. side grain and could, if properly set up, be quicker even then wiping or brushing on. I'll probably continue to chase this down because I've been attempting some very thin work with some very compromised wood, also trying to beat the cracks w/o CA on end grain work, and would like to mix stabilizing with finishing.