vacuum while casting with catcus juice?

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hanau

Member
Joined
Jan 5, 2007
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Location
thomasville, nc, USA.
Do you let the pump run the whole time while you are drawing a vacuum?

Just got my chamber this week from Curtis( Thanks Curtis)

Just thought about this while putting my first in the chamber.

Also how do I determine the max inHg for my area Thomasville NC 27360
Thanks
 
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Thanks.
I been under pressure for about 45 mins and air is still coming out.
Stablizing Buckeye burl.
I am at 28 inHg

I did find a leak in the quick connect fitting, ended up hard wiring everything.
 
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Depending on the wood it could take a while before the bubbles slow down or stop. Sometimes I will stop the pump if after an hour I'm still seeing bubbles and let the blanks soak in the juice for half an hour then restart the pump. Not really sure if it helps but it's what I do! The blanks don't bubble as much after that so I think it might do something...
 
Just a quick heads up on your setup. I would strongly advise that you put some kind of filter cartridge in the line between the valve and the v-pump. You don't want to contaminate the oil or inner workings of the pump with wood dust or worse. A lot of folks pick up an automotive fuel filter at the local auto parts house or Walmart. Find one that is self contained and has barb fittings on each end. They are similar to what you might see on a rider lawn mower except substantially larger.
 
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Thanks will pick one up tomorrow.
Like this?
0909cct_14_z+fram_g3+inline_fuel_filter.jpg
 
That's a good idea on adding a filter between the stabilizing tank and the vacuum pump. I'm going to get one before I use my system the next time. Thanks for the info.
Tim.
 
How do you clean your blanks up after they get out of the oven?

Didn't like trying to pass the blank thru a jointer to square the edges up before going thru the tablesaw.
 
hanau said:
Do you let the pump run the whole time while you are drawing a vacuum?

Just got my chamber this week from Curtis( Thanks Curtis)

Just thought about this while putting my first in the chamber.

Also how do I determine the max inHg for my area Thomasville NC 27360
Thanks
Click to expand...

To determine your maximum theoretical vacuum for your location, you can use this calculator I put on my site: TurnTex Woodworks - Maximum Theoretical Vacuum Calculator

According to wikipedia, you are 840' above sea level. If you put that into the calculator, it comes up with a maximum theoretical vacuum of 29.01" Hg. That is really close to what my max is. I can get real close to 29" regularly. I would think you could get 28.5" Hg +. You might want to check all of your connections with shaving cream.

As for running your pump...I HIGHLY recommend you keep it running the entire time you are pulling vacuum. This will allow the pump to keep evacuating the air and any moisture that is in the blank from the chamber. If you are concerned about the pump...don't be. Rotary vane pumps are made for the HVAC industry and are frequently left running for many, many hours.

As for the filter...you can add one if you want but I do not see it is necessary with one of my chambers. As long as you control the initial foaming and keep if from rising to the intake on the lid, you will not get anything in your oil other than moisture and a cheap filter is not going to stop vapor moisture. Besides, rotary vane pumps are made for pulling moisture from HVAC systems so getting moisture in your oil will not hurt the pump. It will cause you to need to change the oil more frequently, though.

I also recommend that you put the blanks you plan to stabilize in your oven at 200° F for 24 horus prior to get them oven dry. Wen you take them out, put them in a plastic bag and seal them up to keep them from sucking the moisture from the air right back in as they cool. Oven dry blanks will always stabilize better than blanks that are "dry" in your shop. Dry in your shop means they are at equilibrium moisture content. In most parts of the country, EMC is 10-14% moisture. Any moisture in the wood will make it take much longer until the bubbles stop since the moisture will be boiling off at deep vacuum. Also, if there is still moisture in the wood when you cure them, it will most likely boil and turn to steam. When this happens, it pushes more resin out of the blank and causes a crystal like crust on the surface.
 
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