Stabilizing Pen Blanks---Need Some Details??

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Randy_

Randy_

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I have done a search of the board posts and read as much as I can find on stabilizing wood. There is lots of information on how to do it; but I can't find anything on how the process actually works?? What puzzles me is what purpose does pulling a vacuum on the wood serve. Because the vacuum totally surrounds the wood, there is no pressure differential that can "pull" the stabilizing material into the wood, so what's the point?? Other question is about the degree to which the wood is saturated with the stabilizing material. Does the stabilization occur only on the outer fraction of an inch of the wooed surface or is the wood completely saturated with the stabilizer?? Thanks in advance for any comments!!
 
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I don't know how a bumble flies but it does.
My home stabiliztion works for what I want it to do, that's all I need to know.
 
I have vacuum impregnated samples at work but not wood. The vacuum removes air from the pores in the material and when you remove the vacuum the material tries to fill the void. At work we use a thin epoxy with a very finely ground florescent dye. BTW did you know that if a DA Scientist spills very finely ground florescent dye on the floor it is a b to clean up and when the a tries to clean it up with alcohol it just makes a bigger mess?

Our system only penetrates about ¼†in salt rock (solid piece 6â€x2â€x1/8†to ¼†“thin section).
 
The wood gets pretty saturated. I did a buckeye burl piece, cut but not drilled, and when I drilled it you could see that it was not dry in the middle, by dry I mean that there was no saw dust coming out just chips, and when you looked inside it was rather shiny.
It works more-or-less like Ron says. Vacuum sucks the air out of the pours and the resin (or poly) naturally moves from a higher concentration to lower, which fills in where the air pockets were.
I did it as an experiment and invested about $3 plus a quart of fast drying polyurethane. My home method is a mason jar with a hole in the lid with a barbed fitting screwed through it and a hose attached to my little hand vacuum brake bleader. The only thing I noticed is it does darken the wood slightly, but not so much that I worry about it.
 
OK.....that helps a lot. But a few more questions?? When you pull the vacuum, do you actually see air bubbles coming out of the wood and how long do you need to leave the wood under vacuum to fully remove all of the air??

I am also wondering how much of a vacuum needs to applied for the process to work?? I have seen some threads where glass containers were used and wonder if there is any danger of an implosion if too strong a vacuum is created??

And finally, it would seem to me that not much migration of stabilizing material would actually occur during the vacuum phase; but would more likely take place as the the wood was repressurized and atmospheric pressure forced the stabilizing material to migrate into those areas of the wood where the air had been evacuated. If that analysis is correct, it would seem to be important for the wood to remain in the stabilizer for a while after the wood is represurrized or stabilization might not be fully complete. I don't remember seeing any information on whether wood was allowed to sit for a while after stabilization or whether the wood was removed immediately?? Does anyone have any thoughts??

A most interesting subject!! Thanks again.
 
MY guess is dumb a$$.
Your post is exactly why I choose not to write tutorials.
I had started stabilizling last August.In your seach for information you will find exactly the same information I found at that time.(The only information I used was what I found was on this site.)
What I found was enough to get me started DOING it.I had excellent results.( I did not use everything I found exactly as it was explained)
You have said you read all the information and still haave questions.
O.K. the learning curve is different for some.The bottom line is you are still "reading" and not doing.
The method can be as simple or as complicated as you want,If you have a compressor in your shop the whole thing including fittings can be built for as little as $25.00.
In my efforts to explore the various aspects of this craft I have learned far more by experimenting and doing things on my own than reading about other peoples successes.
Those that can, do, others want it "done" for them.
One last thought about your"research" the subject of the jar breaking was mentioned numerous times in the posts/threads. I am surprised with your research you didn't see where it was discussed)
 
Originally posted by Randy_
<br />OK.....that helps a lot. But a few more questions?? When you pull the vacuum, do you actually see air bubbles coming out of the wood and how long do you need to leave the wood under vacuum to fully remove all of the air??

I am also wondering how much of a vacuum needs to applied for the process to work?? I have seen some threads where glass containers were used and wonder if there is any danger of an implosion if too strong a vacuum is created??

And finally, it would seem to me that not much migration of stabilizing material would actually occur during the vacuum phase; but would more likely take place as the the wood was repressurized and atmospheric pressure forced the stabilizing material to migrate into those areas of the wood where the air had been evacuated. If that analysis is correct, it would seem to be important for the wood to remain in the stabilizer for a while after the wood is represurrized or stabilization might not be fully complete. I don't remember seeing any information on whether wood was allowed to sit for a while after stabilization or whether the wood was removed immediately?? Does anyone have any thoughts??

A most interesting subject!! Thanks again.
Click to expand...

Randy, Did you see the article by Lee Biggers?

http://www.penturners.org/content/polyurethane1.pdf

My setup is very much like his, I use an old 1 gallon pickle jar. Pickles come vacuum sealed so I think the jar would have to hold vacuum. I have never had any problems yet anyway.
You will actually see the air coming out of the blanks at 18-20 inches of mercury according to my gage.

My process is as follows:

Cut wood to about 3" or close to the size you need for turning.
Drill a 3/16" hole on center.

Put blanks into the pickle jar.
Fill jar with enough Polyurethane to keep the blanks floating well off the bottom. ( I usually fill it half full and do about 10 half blanks at a time)
I will draw a vacuum and let it sit for a couple of hours and then I will release the vacuum and draw it again. (seems to me I can draw more air bubbles out but I have no scientific proof of it.)
Very porus wood such as Box elder burl will soak up a lot and sink to the bottom of the jar.
I let it sit for a day or two under vacuum, releasing and redrawing the vacuum a couple of times and then I take them out and let them dry for a week or two (I'm not in a hurry to turn them)
For me, this method seems to give me blanks that are fully saturated with Poly.

So far I have done this successfully with :
Spalted beech
Spalted maple
Box elder flame
Box elder burl
Maple burl
Big leaf maple burl
Red palm
Black palm
And a couple of other woods whose name escapes me at the moment.


Hope this helps.
 
Well my process is not quite as extensive. Because I have a little hand pump that isn't perfect I have to periodically have to "re-apply" vacuum. I put usually 4 blanks (2 pens worth) in my jar pull vacuum for a few hours (4-ish) then let them sit over night and the vacuum leaks off in that time. Then pull them out and let sit for a week or two on 2 sticks cut into triangles (cut-offs from trimming corners off on the bandsaw) so there is very little contact and air flows from all sides. I also flip the blanks fairly often as they dry, don't know if that helps but I thought it may keep uncured poly from settling to one side or another.
 
I have seen some threads where glass containers were used and wonder if there is any danger of an implosion if too strong a vacuum is created??
Click to expand...

Yes, While the pressures involved are much lower then is normally encountered in positive pressure work (approximately 14psi or 1 atmosphere) and should be too low to burst the glass but if the glass breaks the glass will go flying. In the lab we enclose all of our glass vacuum vessels. When we are fancy we buy vacuum vessels that are coated but if things are tight or we need something right now we use a very specialized scientific tool (duct tape). At home I would not bother just be careful and don’t bump the glass.

Oh BTW some folks like to play the hard a**. Don’t let them get you down. I once worked with a guy that thought since when he started they did not have air tools all of the new mechanics should use only hand tools. Go figure. I am just glad DeVinci or Einstein did not have the same attitude.
 
Originally posted by Mudder<br />Randy, Did you see the article by Lee Biggers?
http://www.penturners.org/content/polyurethane1.pdf

Pickles come vacuum sealed so I think the jar would have to hold vacuum. I have never had any problems yet anyway.

Cut wood to about 3" or close to the size you need for turning.
Drill a 3/16" hole on center.
Click to expand...

Mudder: Thanks for the information!! I did see the article by Lee. There was no mention of what sort of device he used to pull the vacuum. What do you use? I know Kevin uses one of those little hand pumps that is used to bleed brake lines. I saw a set of plans for a device that used a shop compressor and a venturi to pull a vacuum; but the venturi was $160....a little beyond my budget!!

As to the pickle thing, I would guess the vacuum in the pickle jar is less than what you are pulling for your stabilization process. But it really doesn't matter.....I am just reminded of a high school physics experiment where you are asked to close your hand around a fresh egg, squeeze it and try to break it. Most folks can't do it or only with a great deal effort. The strength of the egg has to do with liquid that is inside the shell and the fact that the liquid redirects and equalized all of the forces. If you draw a vacuum on an "EMPTY" glass jar the potential for an implosion is very real, however, if you fill the jar with a liquid, the danger is greatly reduced.....or, at least, I think that is how it works??

I understand your stabilization method but for the 3/16" hole.....why not drill a 7mm hole?? Thanks again!! Very helpful....to me and others who will read this thread in the future!!
 
Kevin/Ron: Thanks for the input!! The hand pump is a clever application and will allow folks on a limited budget to try stabilizing without spending a fortune. And wrapping those stabilizing jars with duct tape sounds like a good safety precaution to me!!
 
Randy,

I use a 1.1 cfm Gast vacuum pump that I bought on Ebay for $41.00. I do not believe that how you draw the vacuum is as important as weather or not you can hold the vacuum once it is drawn. I use a valve to close it off and I also use a little mineral oil around the seal to keep everything from leaking. I have also used a hand operated vacuum pump designed for bleeding brakes and I believe that there are a couple of folks here that use them.

As far as the pickle jar goes, I'm not going to debate the safety of it. I have used it and not had a problem. The glass is pretty thick. At work we use Bell jars to impergnate sintered bronze bearings and they are made of plastic that is 3/32" thick and I have seen them bow in when we draw vaccum on them. There is always an inherent danger involved. If I were to feel unsafe with the jar I would enclose it in a wooden box similar to the tire cages that are used when big rig tires are changes.

The reason that I drill a 3/16" hole is because I have experienced a couple of blanks that have warped or bowed while drying since they were drilled at 7mm I could not use them for a slimline pen. This is just how I like to do it, you should experiment and find the way that works best for you.

I saw a set of plans for a device that used a shop compressor and a venturi to pull a vacuum; but the venturi was $160....a little beyond my budget!!
Click to expand...

look at these:

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=3952

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92474

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=39522

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=2068

The last one is the hand unit that I own and have also used.

Hope this helps.
 
Anybody ever used this?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5986010699&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

From the post it says:

History of Unit:
This Air Vacuum Pump - Air Vac Gas Pump is brand new, never been used. Comes in original manufacture's box and is perfect for the do it yourself mechanic or for home air conditioner maintenance!

Remove moisture from your air conditioning systems with this Venturi effect vacuum pump. This Air Vac pump will allow you to safely add refrigerant. This pump is easy to operate! All you have to do is connect an air line and the pump will pull full vacuum within 2 minutes. Perfect for Home & Automotive Air Conditioners, Freezers, Refrigerators, and more!

Product Specifications:

Vacuum level: 28.3" of mercury at sea level
Air consumption: 4.2 CFM
Air inlet: 1/4'' NPT
 
Answered my own question. Here are two vacuum pumps from HF:

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=3952 ($15.99)

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92475 ($16.99)

Although I agree with Frank that free is the best price, sometimes it's nice to have something you know will work (or at least is supposed to, and that you can take back until it does!).
 
Jim,

Be careful...some of these are pneumatic and needs a compressor to be used. There are electric ones though. I didn't know that it comes from HF so now Ill just go there direct if I ever need to buy one.

Thanks!
 
Ahhhhh...so you're saying that the "just connect an air line" means that it isn't self-contained, but rather that it needs a compressor to power it?
 
Originally posted by JimGo
<br />Ahhhhh...so you're saying that the "just connect an air line" means that it isn't self-contained, but rather that it needs a compressor to power it?
Click to expand...
That's correct.
I have been using the same $10.00 unit for almost a year.Also using a H.F. compressor.
I made a few modifications to the fittings.Addition of 2 valves, one on the supply side one on the suction, and a vacuum gauge.
The use of the replacement tire stems that Smoky Tom used on his set up let's me pull a vacuum of 24" and it holds over nite using a gallon Pickle jar or a Ball canning jar.
 
LOL...I think so!

Check eBay and compare them...some are listed more honestly and mentions it. Some slyly say "air operated"...guess what that is [;)].

There is a totally similar looking unit that is electric and it does have its own pump.

Just making sure you are aware before you pull the trigger [:D]
 
Thanks guys! I think I'll wander down to HF in a few weeks and see if they have any in stock. I have some other ideas for vacuum work, so I'll be curious to see what's available. I have one of their hand-operated pumps, but we moved shortly after I purchased it, and I haven't come across it yet!
 
Sorry, Jim, I lost track of this thread, but you found the pumps. They are venturi pumps. As Eagle eluded to, and as described in an article that was referenced in another thread for building your own venturi pump, they require an air compressor to operate. That being said, "Just connect an air line" refers to an air line from a compressor. That forces air past the venturi and pulls the air out of the what the pump is connected to, the same way that a paint gun operates, but with much higher efficiency. I checked into the old refrigerator compressor thing and while you might be able to get one for free, converting one to a vacuum pump would cost me about the same as the venturi pump from HF. Since I already have an air compressor, it doesn't make sense for me to throw more money into this than necessary. And like Eagle says, it works and pulls plenty of vacuum. That's the only thing I was curious about, but that's now been answered. Thanks for the confirmation, Eagle!
 
Billy B. said, "I checked into the old refrigerator compressor thing and while you might be able to get one for free, converting one to a vacuum pump would cost me about the same as the venturi pump from HF." Why? Where is the expense. Some hose and a simple fitting to the jar. Right? Wrong?
 
Frank, I can't remember exactly now what the refrigeration guy told me I would need, but all-in-all it came out to about $25. I know that isn't much, but considering I can go to HF and pick up a "new" venturi pump and not have to worry about how long a "used" refrigerator compressor will last me... I also seem to remember seeing a parts list needed break down either on the internet or in one of my woodworking mags, but which escapes me at the moment. My sometimers is acting up. [B)] Which way one decides to go, is more a matter of preference in the long run really.
 
Good luck with it Billy! I would need a compressor, so I'm still searchin' for something else (for now). I gotta find that darn hand-pump!
 
Originally posted by alamocdc
<br />Frank, I can't remember exactly now what the refrigeration guy told me I would need, but all-in-all it came out to about $25. I know that isn't much, but considering I can go to HF and pick up a "new" venturi pump and not have to worry about how long a "used" refrigerator compressor will last me... I also seem to remember seeing a parts list needed break down either on the internet or in one of my woodworking mags, but which escapes me at the moment. My sometimers is acting up. [B)] Which way one decides to go, is more a matter of preference in the long run really.
Click to expand...

I have an old refrigerator at the farm that I used to use for storage of vet supplies. I'm going to go out and yank the compressor. If it is a simple thing, with one inlet that sucks air and another that pumps it out, I believe that just simple connections should do the trick. Maybe the information you got from the refrigeration guy included his use of equipment to recapture the freon in accordance with some tree huggers laws.
 
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