Ketchup bottles to stabilize blanks?

[gerti]

The Ketchup bottle thread reminded me of something I always wanted to try but never found the time for:

I wonder if a Ketchup bottle could be used to stabilize blanks: fill with stabilizing fluid and blank, squeeze and close. Would the steady (though low) vacuum from the bottle trying to get back into it's normal shape be enough to force the fluid into the blank over time?

[jdon]

In a word, "no" (to the best of my knowledge).

If the blank is submerged in the stabilizer, it is not exposed to any vacuum.

In pressure treating wood the process sometimes begins with exposing the wood to vacuum to draw out moisture and air trapped in the wood. This makes it easier for preservative- immersing the wood after the vacuum is released- to penetrate the wood at high pressure (~ 10 atmospheres).

Theoretically, you could improve penetration of stabilizer into your blank by exposing the dry blank to vacuum before placing in the stabilizer. However, I doubt the slight vacuum produced by a squeezed ketchup (or catsup) bottle would have any significant effect.

Also theoretically, if you could create a seal around the blank, such that there is a pressure differential across the blank (vacuum on one side, stabilizer at atmospheric pressure- or higher- on the other side), you could increase the penetration rate; think of the blank as an inline "filter".

[AlanWS]

Probably the easiest way to cause a vacuum to help a stabilizer of some sort to penetrate wood is to submerge the wood and boil the liquid for a while. Boiling not only heats the air in the wood's pores making it expand and escape, but it also forms vapor from the liquid that gradually replaces remaining air. When you cool the mess with the wood still submerged, the vapor condenses and the resulting vacuum pulls liquid into the wood.

The main difficulty with this approach is that many of the things you might want to use as stabilizers will react at high temperature, and some will give off fairly toxic vapors. But this approach would be as effective as use of the very good vacuum pump needed. The poor vacuum of a catsup bottle or vacuum cleaner would likely not help much at all.

[leehljp]

in listening to a fellow that is one of our "experts" on the IAP forum, vacuum works best at the highest (or "losest" depending on the terminology you want to use) you can get. Where as there are numerous opinions on the amount of "pressure" needed when casting PR blanks. There are those that use pressure at no higher than 40PSI for PR resin casting and do every bit as good as those who cast at 60PSI and above. But for Vac pressure, 2 stage pumps are more consistent for vac to clear out the air than even single stage pumps. This is in effect the deeper you want penetration.


By the way, for those who are wondering, in general:
PRESSURE is used more to reduce bubbles in casting PR resins for blanks. Technically it does not reduce the number of bubbles but shrinks them to a size that makes them insignificant.
VACUUM is used to pull air out of wood blanks that are submerged in a liquid stabilizing agent. When the vacuum is released normal air pressure forces the liquid deep into the pores of the wood, stabilizing it as the agent cures.

Vacuum on Cast PR resin will cause all kinds of bubbles and render it basically useless.

On wood blanks, some people pull a vacuum, leave it under a vacuum for a while, then release and add pressure for a while.

[sscherin]

I think this video series shows the effects of vacuum on blanks submerged in stabilizer.

Loading and vacuuming
https://www.youtube.com/watch?v=uvII1FTm3YM


Release
https://www.youtube.com/watch?v=BBdevc5Y_g0

I picked up a pair of Robinair 3cfm High Vacuum pumps last week so I might have to try this after I get done showing the kids what it will do to a marshmallow