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Vacuum treating lumber

buttercup

buttercup

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Probably only me in this world doing this but I thought I'd show what I do for your entertainment if nothing else.

Obviously if you rip/mill fresh wood and cuts it clean there is no reason to do this, but I have done some storm felled spruce and it quickly gather worms and bugs lying on the forest floor. I do this to eliminate any living things in the wood.

I have used moisture barrier foil normally used in houses to make a bag and I seal it along the edges with sealant similar to silicone. The sealant can be just about anything as long as it is viscous/sticky, you don't wait for it to dry it is used as it is.

RIMG0101.JPG The boards are laid down in a "flat" pile.

RIMG0104.JPG The foil is folded over the stack.

RIMG0105.JPG The suction nozzle is packed in some fabric to ensure airflow.

RIMG0113.JPG The bag is closed.

RIMG0115.JPG The bag is emptied of air.

RIMG0122.JPG Vacuum is achieved, water inside has started to boil. Nothing can survive.
 
andy at clover

andy at clover

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Nice tutorial Buttercup!
I've used vacuum bagging to "lay down" veneers onto curved stair stringers back when I had the stair shop.
It's a surprisingly simple method for joining.
I had not though of it as a way to kill insects.

Living in the forest, We use dry ice to kill the bugs on our house plants once or twice a year. (lots of mites here from hemlocks/firs)
You just seal the plants all in a clear bag and put in half a kilo of dry ice and let it "melt".
The co2 is nice for plants during daylight as the bugs die.
You must do this in light. I made the mistake of using a black bag once and the plants suffered as they “breath” O2 during dark time.
 
kimosawboy

kimosawboy

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The title of this thread caught my eye as I'm curious about Vacuum kilns and High Frequency Lumber Vacuum in general..
If I'm reading it right you are not using any heat when you Vacbag your boards.. From what i'm reading you do need heat to get the inside temps high enough to kill bugs, here is an excerpt from another site..
''''I did a little test once, just for fun. I was vacuum bagging some veneer panels, and wondered what would happen to insects in that rare atmosphere, so I caught an assortment, and put them in a jar/filter in the air-line. They all seemed pretty excited, or agitated initially, then stopped moving after about tne minutes.

It was cool weather, and since I was using epoxy, I held the vacuum for about eight hours. When I released the vacuum, I was fairly certain that all were dead, but I left them out where I could see them. After about six hours, while walking by, I noticed the antenna of the cockroach twitch. I tickled it and sure enough, that darn thing had survived, and started getting back to normal. I normally pull about 28" Hg.''

Have a read here..http://www.woodweb.com/knowledge_base/Vacuum_Kiln_Principles.html
 
buttercup

buttercup

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how long do you keep it under vacuum?
The title of this thread caught my eye as I'm curious about Vacuum kilns and High Frequency Lumber Vacuum in general..
If I'm reading it right you are not using any heat when you Vacbag your boards.. From what i'm reading you do need heat to get the inside temps high enough to kill bugs, here is an excerpt from another site..
''''I did a little test once, just for fun. I was vacuum bagging some veneer panels, and wondered what would happen to insects in that rare atmosphere, so I caught an assortment, and put them in a jar/filter in the air-line. They all seemed pretty excited, or agitated initially, then stopped moving after about tne minutes.

It was cool weather, and since I was using epoxy, I held the vacuum for about eight hours. When I released the vacuum, I was fairly certain that all were dead, but I left them out where I could see them. After about six hours, while walking by, I noticed the antenna of the cockroach twitch. I tickled it and sure enough, that darn thing had survived, and started getting back to normal. I normally pull about 28" Hg.''

Have a read here..http://www.woodweb.com/knowledge_base/Vacuum_Kiln_Principles.html
How much vacuum did you apply to the bugs?
I have to look in to that more thoroughly I guess, but anything that contains fluids will start to boil at about 85-90% vacuum. I had about 98.4% vacuum for 6 hours, just getting there should be enough.
It's not about heat, it's about pressure, no oxygen and that any moist or fluids change shape. Most bugs use fluids to move their legs so you should see some pretty interesting things if that fluid starts to boil. Think of that it's internals turns in to expanding foam.
 
buttercup

buttercup

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Osterøy, Norway
The title of this thread caught my eye as I'm curious about Vacuum kilns and High Frequency Lumber Vacuum in general..
If I'm reading it right you are not using any heat when you Vacbag your boards.. From what i'm reading you do need heat to get the inside temps high enough to kill bugs, here is an excerpt from another site..
''''I did a little test once, just for fun. I was vacuum bagging some veneer panels, and wondered what would happen to insects in that rare atmosphere, so I caught an assortment, and put them in a jar/filter in the air-line. They all seemed pretty excited, or agitated initially, then stopped moving after about tne minutes.

It was cool weather, and since I was using epoxy, I held the vacuum for about eight hours. When I released the vacuum, I was fairly certain that all were dead, but I left them out where I could see them. After about six hours, while walking by, I noticed the antenna of the cockroach twitch. I tickled it and sure enough, that darn thing had survived, and started getting back to normal. I normally pull about 28" Hg.''

Have a read here..http://www.woodweb.com/knowledge_base/Vacuum_Kiln_Principles.html
As I understand it that guy try to dry his wood using vacuum, not to kill bugs. Not what I would do to dry wood...

Now the Imperial measure for vacuum is Inches of Mercury "inHg", the metric measure for vacuum is "milliBar" or "kiloPascal".
InHg maxes out at about 29.6 (dependent on temperature), millibar maxes out at -1000, that is the same as -1 bar or -100 kiloPascal. This is the definition of absolute vacuum.

However, if the atmospheric pressure is low (rainy and stormy weather) lets say at 950 milliBar, then -950 milliBar is what your vacuum pump would need to extract to achieve absolute vacuum or a true 0 pressure like what is out in space.
If the atmospheric pressure is high (sunny and blue sky) lets say at about 1050 milliBar, then -1050 milliBar is what your vacuum pump would need to extract to achieve absolute vacuum or a true 0 pressure like what is out in space.

If the atmospheric pressure is 1000 milliBar and the vac.pump was able to extract it all (which is not possible), then the perpendicular pressure to the outside of your bag would be 10 metric tons (about 10 small cars) each square meter.
That is the weight of the entire earths atmosphere at that atmospheric pressure.
If the atmospheric pressure is 1050 millibar, the perpendicular pressure to the outside of your bag will be 10,5 metric tons each sqm, if the atmospheric pressure is 950 millibar it will be 9,5 metric tons each sqm.

The same pressure is always and constantly acting on your body as well, if you all of a sudden was exposed to absolute vacuum or a true 0 pressure like is what is out in space, you would be just like a deep water fish pulled quickly to the surface.
It's eyes and guts pops out and and it certainly don't survive it.

I guess when it comes to bugs they might be more tolerant than something bigger and more complex, they might have chemicals in their systems that makes them more resilient too.
I have not tested bugs in a glass jar at near 0 pressure to see what happens, perhaps that would be a good idea.

Anyway, you can get water to boil at a lower vacuum if you rise the temperature, so that might be a good idea too. I just think that if the vacuum is high enough you don't need to do that to kill bugs.


rotary-vane.jpg
 
buttercup

buttercup

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That sounds like a great idea. I'll have to give it a try!
Start with something simple till you get the hang of it, not too big and as flat as possible, perhaps at your workbench. The thicker/taller the bag package is the more wrinkles you get and you need experience to handle them.
What I do when bagging something that is not "flat" is that I fold the vacuum foil with caulk/sealant in between the edges where it wants to fold along the edge. Work "with" the folds/wrinkles, not against them.

When the vacuum starts to rise above 80-90% pointy things like rough edges might puncture the bag.
If I get a puncture I draw a ring around the leak with the caulk gun and just apply a piece of thin elastic food packing plastic foil on top and it will suck in place.
The edges might open up somewhere if there is a wrinkle too because the pressure makes the vac.foil move as it contracts, just apply some more caulk/sealant and close it. When the vacuum is stabilized at high it will keep that way.

You need a gauge to see what happens - it don't need to be expensive and it don't need to be accurate, it don't even have to have a scale or numbers on it at all. It's just to know if the vacuum goes up or down (leakage) and when max vacuum is achieved.

Some caulk/sealant is easier to work with than others, the more thick and sticky it is the better.
When done I just cut off the caulk edge of the bag with a pair of scissors to avoid getting the caulk/sealant smearing out all over the place.
 
buttercup

buttercup

Gone fishing
Joined
Aug 8, 2019
Messages
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Location
Osterøy, Norway
The title of this thread caught my eye as I'm curious about Vacuum kilns and High Frequency Lumber Vacuum in general..
If I'm reading it right you are not using any heat when you Vacbag your boards.. From what i'm reading you do need heat to get the inside temps high enough to kill bugs, here is an excerpt from another site..
''''I did a little test once, just for fun. I was vacuum bagging some veneer panels, and wondered what would happen to insects in that rare atmosphere, so I caught an assortment, and put them in a jar/filter in the air-line. They all seemed pretty excited, or agitated initially, then stopped moving after about tne minutes.

It was cool weather, and since I was using epoxy, I held the vacuum for about eight hours. When I released the vacuum, I was fairly certain that all were dead, but I left them out where I could see them. After about six hours, while walking by, I noticed the antenna of the cockroach twitch. I tickled it and sure enough, that darn thing had survived, and started getting back to normal. I normally pull about 28" Hg.''

Have a read here..http://www.woodweb.com/knowledge_base/Vacuum_Kiln_Principles.html
I guess I should do some bug testing, I don't mind killing bugs in my wood - but I do mind killing anything if it's not strictly necessary.
Thanks for your reply, maybe my method is no use after all.
 
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