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Drying time shortcuts

16920 Views 39 Replies 7 Participants Last post by  CAS14
I wanted to start a thread to discuss ways to shortcut the drying time require for wood. Please post methods that your know of.

Here are a couple I know of.

The microwave
For smaller pieces of wood you can fit them in a microwave and expose them to a large number of short burst. Winces microwaves heat by exciting the water molecules, it causes them to off-gas and exit the wood.

Vacuum chamber
Once the wood has moved past the green state, you can fill a sturdy container with stabilizer and, after the wood is inserted, use a pump to remove the air from the chamber. You then leave it under a vacuum(or close) for a day or so. You then release the pressure slowly over a couple minutes. This causes the stableizer to be drawn into the voids in the wood.
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Aaron, on another topic, you referenced this:


What sort of tube do you use for a "chamber?" Without reading the literature on this, I'm guessing that PCV pipe might soften with this, but that sure would be an easy way to build a chamber. Just use a glue-on end cap on one end and a threaded cap with an o-ring to seal on the other. A port with a valve could be in the threaded cap.

I would be pleasantly surprised if pentacryl and PVC were compatible. Do you know?

And, what about disposal of the leftover pentacryl, or even better can it be reused? I wonder how volatile it is in terms of vapor pressure. I will research a bit, but thought that you may know first hand.

Also at $60/gal., unless cost is no object, you wouldn't want much extra void space. Straighter sticks, and probably standardized lengths and diameters would minimize waste, although if pentacryl is easily stored for reuse, that affords more flexibility.

All thoughts are appreciated.
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Also, I'm guessing that if the plan is to remove the bark eventually, removing it before immersion is recommended to minimize pentacryl waste (that which adsorbs into the bark), and speeds adsorption into the wood. Seems obvious, but I know nothing and should ask.
I would think that PVC would be fine, but you would probably be safer with some steel pipe. I would think a six inch ID would be fine, put a permanent cap on one end, and a screw-on with a good seal on the top. You would just need to drill a hole in the top cap for a nipple to be installed that would attach to the pump for removing air. You might install a second nipple to attach a pressure gauge to, so you could keep an eye on it. You wouldnt want the pressure to go to low, but you want to make sure you get to the right level.

Here is a small scale version:


I would remove the bark to ensure complete penetration. As far as the Pentacryl go, I do think that you could reuse it after filtering it with cheesecloth or something. There should be minimal waste if you are careful.
MSDS: http://www.preservation-solutions.com/msds/pentacryl.pdf

Looks like you shouldn't pour it down the drain or in the back yard, but use it up. I'm guessing that it will become diluted with use as it solubile / miscible in water. Still haven't located a chemical formula, so I can understand what's going on.
This article improved my comfort level still more: http://www.preservation-solutions.com/turningtopics.php

Another website posted some interesting comments:

Q: Will PENTACRYL keep the bark on?

A: It will help. Since PENTACRYL will reduce the shrinkage of the wood it will help to keep the wood from pulling away from the bark,

however, there is no guarantee that the bark will stay on. For best results to keep bark on, the tree should be cut during the dormant

period (winter) when the sap stops running and the wood has hardened off.

(The "keeping the bark on" issue was of interest, as my most recently cut stick proved most useful in climbing some rock escarpments with my worn out knees, partly due to the great grip provided by the bark.)

Q: Can too much PENTACRYL be applied?

A: No. Too much PENTACRYL can not be applied. The wood will absorb just so much. Any excess can be cleaned off the surface.

Note: If using the soaking method, any PENTACRYL left over in the soak can be reused to treat other wood.

(This addresses my concern about possible dilution of Pentracryl with sorbed water. Apparently it can be reused, but note Aaron's comments about filtering solids.)

Q: How do I know when PENTACRYL is done soaking?

A: Using the soaking method, 2-3 days is generally sufficient for a piece 1-4 inches thick. It will not hurt the wood to soak it longer.

Bottom line: I'm sold on this. I will give it a try on my prized Black Locust. However, I do not plan to wet the stick with water first. Some websites state that Pentacryl works best on very green, moist wood and that you should wet it by wrapping in wet rags overnight if somewhat dried out for improved penetration. This seems counterintuitive, and I'm not going to do this, To me, if it's already dried out somewhat without checking, then I'm not going to rewet it. KISS principle.

Next step for me is to build a reuseable tube. For the first trys, I'm not going to worry about the vacuum enhancement.
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Wow! That's good info! This stuff seems like it is the miracle cure for green wood!
Today, I emailed the following to the manufacturer of Pentacryl:

Pentacryl: I participate in two forums where Pentacryl has been discussed recently. I am excited to try it, first on walking sticks, often made from green or fairly green wood. I want to make a dipping tube to try this. I do not plan to apply a vacuum, but just store the sticks in Pentacryl for some days and then see how they dry and perform.

QUESTION: Can I simply use schedule 40 PVC, or will Pentacryl soften the PVC or dissolve the PVC cement? If so, I will plan to use iron pipe. Please advise. Thanks
When I receive a response, I will post it here.
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From the manufacturer of Pentacryl, at www.preservation-solutions.com, Ms. Kim Kimbro:

Vance - Using Pentacryl in a PVC tube with your walking sticks is fine.

You actually want to use a plastic or fiberglass container with Pentacryl as metal containers will react with the Pentacryl and could cause your wood to darken.

I have attached some additional information for you on using Pentacryl. Thank you for your interest in our product.
The additional information referenced is a .pdf attachment, I've seen on their website. If I locate it again, I will post a link.
Hey, that's great news! PVC pipe is strong and easy to work with! Very good!!
Here is a good DIY on making a PVC vacuum chamber. For our purposes, the pipes would need to be 5 or 6 feet long.
  • (1) approx. 3' of schedule 40/80 4" PVC
  • (1) approx. 3' of schedule 40/80 3" PVC
  • (1) 4" to 3" PVC reducer
  • (1) 3" PVC Test Caps
  • (1) 4" PVC Male to Male Coupling
  • (1) 4" PVC Cleanout fitting with Plug
  • (2) 1/8" ID Barb x 1/4" NPT fittings
  • (2) 1/4" FIP x 1/4" NPT elbows
  • (2) small hose clamps
  • (1) approx 3' of 1/4" OD clear(it's actually only semi-transparent) polyethylene tubing(Avoid any other type of tubing as it may collapse under vacuum or dissolve when exposed to solvents)
  • (1) small can of PVC cleaner
  • (1) small can of PVC cement
  • (1) roll thread sealing tape
  • (1) valve stem assembly
  • Hand drill or drill press and drill bits
  • Bandsaw, hacksaw or other tool to cut PVC pipe
  • Dremel tool with sanding drum or a spindle sander
  • 1/4" NPT Tap
  • First cut two pieces of PVC to length. In this example, the chamber is about 36" long, overall. You may want to make yours shorter or longer depending on the size of veneer or turning blanks. Remember that you can coil up the veneers inside the tube, so narrow, long veneers don't require long pressure chambers. Make the 3" pipe about 2.5" longer than the 4" pipe. The ends of the tubes should be smooth and even so sand them if necessary. This is particularly important for the 3" tube due to the nature of the test caps that will be fit to it later. The completed 3" diameter PVC assembly is used as a filler. The volume of air that is used by the 3" PVC simply eliminates the need for excessive solvent/dye in the vacuum chamber.
  • Next, measure 2" away from each end of the 4" tube and mark the tube in each place. The 2" will accommodate the fittings that will go on either end of the 4" tube. Make sure both marks fall on a line parallel to the direction of the pipe. Drill a 27/64" diameter hole and tap it using a 1/4" NPT Tap. Only use one half the length of the tap as over tapping the hole will yield a loose fit.
  • Wrap the male threaded portion of each of the 4 brass fittings with thread sealing tape. With the threaded portion facing you, wrap clockwise around the thread to avoid unraveling the tape when the pieces are screwed together.
  • Screw each 1/8" ID Barb x 1/4" NPT fitting into a 1/4" NPT x 1/4" NPT elbow.
  • Attach each barb/elbow assembly into the holes that were drilled and tapped in step 2 as seen in the picture. When installed, the two barb fittings should be pointing at one another. You may find that the male end of the elbow sticks out about 1/4" on the inside of the 4" pipe. To remedy this I sanded down the excess with a Dremel and sanding drum. However, you may wish to use a bench grinder or sander to remove the excess before installing. Leaving the extra threads protruding will make it difficult to put project material into the chamber, once assembled.
  • Cut the polyethylene tubing to length. It should be able to be fitted onto both barb fittings while as straight as possible as shown in the picture. This tube will serve as a solvent "sight tube". It will show you how high your solvent is inside your chamber. Attach a small hose clamp to each end to ensure a positive seal on the barbed ends.
    About the sight tube...
    The site tube is merely there to check the fluid level. It's helpful in that if you know how wide (or tall) the veneer is, you can easily make sure you have enough fluid in the chamber. It should be noted that if there is not a good seal between the site tube and the brass nipples, the site tube will not function correctly when vacuum is applied. If air can get in, the fluid in the site tube will just constantly be "pumped" up the site tube while the vacuum is on. This isn't a big deal as long as you adjust the volume prior to turning on the pump, as it's not really practical to add dye after you start the dying process anyhow.
  • Next, you will have to remove the lip inside of the 4" to 3" PVC reducer. I did this with a Dremel and a sanding drum. You can do this part however you see fit. Be careful not to sand the inside of the 3" portion of the reducer. This may prevent a good seal between the pipe and the fitting.
  • Clean the inside of the 4" side of the reducer and one end of the 4" pipe (about 2" is sufficient).
  • In a well ventilated area, apply PVC cement to the two cleaned surfaces and fit the reducer to the 4" diameter PVC tubing.
  • Next, clean the inside of the 3" section of the reducer and about 6" of one end of the 3" pipe.
  • Apply PVC cement (once again, in a well ventilated area) to the cleaned surfaces. Slide the 3" pipe section into the 4" section, cleaned end first, and mate the two areas that just had cement applied. You'll likely need a rubber mallet to get these to fit together well. Pound the 3" section into the reducer until the 3" pipe is sticking out of the reducer by about 4", as shown in the picture.
  • Clean the section of 3" pipe obtruding from the reducer and the inside of the 3" end cap.
  • Apply PVC cement (once again, in a well ventilated area) to the cleaned surfaces. Mate the 3" end cap to the 3" pipe obtruding from the reducer, as shown in the picture.
  • Clean the outside of the remaining end of the 4" pipe and the inside of one side of the 4" coupling.
  • Apply cement to the cleaned surfaces and mate the coupling to the 4" pipe as shown.
  • Clean the inside of the remaining end of the coupling and the outside of the cleanout fitting.
  • Apply cement to the cleaned surfaces and mate the cleanout fitting to the coupling.
  • Now, drill a 7/8" hole in the direct center of the cleanout plug. To get the inner washer to fit into the cleanout plug, you'll need to grind a bit off of the perimeter as seen in the first picture below. Install the male vacuum fitting as shown in the second picture.
  • Wrap the threads on the cleanout plug with thread sealant tape. I found that the cleanout plug alone did not create a good enough seal to hold a vacuum. A few wraps of tape is enough to get a nearly perfect seal on the threads. I let the chamber sit with a vacuum on it for about half an hour and my vacuum pump did not need to cycle even once.
  • Make a small metal rod to aid in removing the project materials from the chamber, as the gap between the 3" and 4" pipe is pretty small. I simply used a coat hanger that I straightened out. I bent one end of the coat hanger to fit between the two pipes.
  • You'll now only need to make a stand or wall bracket to hold up the vessel since it has an end cap on the bottom.
This pressure chamber is designed to be operated in the upright position. Operating the chamber on its side will result in liquid being sucked into your vacuum pump, thus destroying the pump. When operating the chamber, make certain that the chamber can not tip over or use a catch basin between the chamber and the pump to catch any fluid before it can get to the vacuum pump.

Lots of good info you have extracted! My meager two cents: I am not surprised at any of your findings; as I have used pentacryl several times (have some in my shop), I have found that it is very user-friendly, and not volatile, as long as you don't put any in your coffee. I will say that it does work well as a stabilizer for unstable material. As a carver, I have used it to "firm up" punky areas in driftwood that have gone soft or crumbly. After treatment, those areas are actually carvable. Good stuff, but not cheap.
Regarding dyes in Pentacryl: I was concerned that particles in the Pentacryl might inhibit its penetration. That is not so, says the manufacturer:

Vance - I have spoken with Dale, our technical person regarding your question and he has done testing with water and oil soluble dyes in Pentacryl and both seem to work fine. Most all dyes have a small molecular size and it will not inhibit the penetration of the Pentacryl in the wood. The Pentacryl will actually help carry the dye.

For dyes that do have a large particle size, the particles may tend to lay on the surface, especially for tight grained (dense) wood. This will not inhibit the Pentacryl, but instead the Pentacryl will separate from the dye and penetrate into the wood while the dye lays on the surface.

An additional comment on the PVC tube: Let the PVC cement dry thoroughly prior to putting Pentacryl in it. You may want to try using Silicone around the end cap and letting it cure as well. If you are unsure about the seal, you can put the end of the tube in a 5 gallon pail to catch any Pentacryl that may leak.
They seem really helpful. That's good to know for future projects.
My first dip tube was completed today, schedule 40 PVC, the lower half 3" to conserve Pentacryl, and the upper half 4" with a threaded sewer cap. I am hoping that this can be used to store the Pentacryl between uses. I will watch for leaks. I only allowed a couple of hours for the cement to dry.

A gallon of Pentacryl wasn't quite enough to completely cover my locust stick, so I will pick up another gallon on Sunday. This will be expensive enough that the Pentacryl will have to be reused, and hopefully simply stored in the tube.
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Using two diameters is smart thinking!
Even so, a gallon plus another quart (~$80) didn't fully submerge this stick. That's all Woodcraft had in stock, and no more for more than a week.

I can flip it upside down periodically, but the cleanout plug threads slowly leak, and I don't want to mess with Teflon tape. So I will just turn it upside down briefly several times each day.

This won't be an issue once I have more Pentacryl.
  1. That locust is still in the PVC tube without quite enough Pentacryl, so I flip it over twice before I go to work, and several times during the evenings. Can't wait to replace the locust with my oak stick this weekend.
  2. For the (hopefully in the future) cane I cut, I will try to make a shillelagh with it. My granddad (Welch lineage) talked about those. So, I will use the very black dye from Woodcraft to see whether I can stain it as I treat it with the Pentacryl. I'll have to purchase something else, as the handle of the cane won't fit in the 4" PVC.
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