Question about Vaccum Pot

[Schkeeters]

I am just getting into casting PR planks, and I built the HF Vaccum and Pressure pot. I happend to have an old 1hp Vaccum pump that I thought would be more than enough to pull vaccum with. I hooked it up and tested the pot and it held 50 PSI for 24 hrs. Today I hooked my Hilti vaccum pump up, and it would only pull down to about 26 HG, but it would do it in about 15 seconds... Two questions...
1) Why is this huge pump only able to pull 25HG when I have heard of the vaccum block pulling 30?
2) Will 25HG be enough for stabilizing and degassing PR?

Thanks for your help on this,
ds

 

[its_virgil]

Dan,
(1) I don't know.[:0]
(2) Yes! Actually less will work. When I had the clear plexiglass top on my vacuum chamber so I could watch, the resin would begin to bubble (the gas escaping) before 25 hg was reached.

I no longer use vacuum, but degass using an ultrasonic jewelery cleaner and I'm convinced it works just as well if not better and is much easier to do.

Do a good turn daily!
Don

Originally posted by Schkeeters


1) Why is this huge pump only able to pull 25HG when I have heard of the vaccum block pulling 30?
2) Will 25HG be enough for stabilizing and degassing PR?

Thanks for your help on this,
ds

 

[gketell]

It also depends on your relative height above sea level. They higher you are the less vacuum you will be able to pull (but the less you will need to pull too).

GK

 

[Mudder]

I use deep cycle vacuum pumps nearly every day and I must say I've never seen anything pull a vacuum of 30 hg.

30 hg is a perfect vacuum at sea level, the higher you get the less vacuum you can pull. At work we are about 460 feet above sea level and I've only seen our calibrated gages top out at 29.34. At home I am about 600 feet above sea level and the best I have seen on my uncalibrated gage is about 28. I have been told that barometric pressure and relative humidity have an effect but I have not found anything to prove or disprove this.

In my opinion, if you can consistently pull 24" plus of vacuum you should have no problems at all.


I am a little curious to hear more of Don's technique with the jewelry cleaner, it sounds quite interesting

 

[OKLAHOMAN]

Scott, Both Don and I are useing and ultrasonic cleaner to degas, Don got the idea from Bruce Robbins, What happens is that yuo fll the cleaner about 2/3 with water and what I do is I put my PR in a 9 oz. cocktail plastic glass for 4 min. w/o catalist ten I add my catalist and back in the cleaner for another 4min. you can see the bubbles racing to the top and dissapearing. I really like this much better than vacuume and the results are 90% bubble free and the other 10% all the bubbles are on the top and are turned off.
I am a little curious to hear more of Don's technique with the jewelry cleaner, it sounds quite interesting
[/quote]

 

[Schkeeters]

Thanks for all your help. I am looking at getting an ultrasonic cleaner cleaner, however I have spent more on penturning in the last month than I have on all my other bills combined... I think I have a problem...
Thanks Again,
ds

 

[Monty]

Originally posted by Schkeeters

... however I have spent more on penturning in the last month than I have on all my other bills combined... I think I have a problem...
Thanks Again,
ds

I don't see a problem here. Does anyone see a problem with this [?][?]

 

[TowMater]

Any recommendations on an ultrasonic cleaner both brand and where to purchase?

 

[TBone]

Originally posted by Schkeeters

Thanks for all your help. I am looking at getting an ultrasonic cleaner cleaner, however I have spent more on penturning in the last month than I have on all my other bills combined... I think I have a problem...
Thanks Again,
ds

Anything you find odd about that statement? That seems to be pretty standard around here.
And if you have any problem accomplishing this, there are plenty of people on this site who are more than willing to help you spend it. Either by telling you what to spend it on or by sending you wood in exchange!!!!!!!!!

 

[its_virgil]

Scott,
I was introduced to using the ultrasonic cleaner by Bruce Robbins. I do much the same as reported by Roy and I really really like the results. It's so much easier than getting out the vacuum pump. Watch the container used to hold the resin...some will spring a leak during the process and cleaning the resin impregnated water from the cleaner is no fun...That's what Roy told me. Actually, I had the cup leak and empty it contents into the water. I now use glass jars from the kitchen. I save them as we empty them.

TowMater:
The cleaner I use is from Harbor Freight. Here is the link to it: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95563
I caught it on sale for $49.99 and had a 20% off coupon. They have several choices. I think Bruce got his off of ebay.

Do a good turn daily!
Don

Originally posted by Mudder


I am a little curious to hear more of Don's technique with the jewelry cleaner, it sounds quite interesting

 

[crashgtr]

Don,

I am curious as to the use of the ultra sonice... Do you simply put the poly that you mixed in a jar and put the jar in the ultrasonic before you put it in the pressure pot? For how long do you keep it in the ultrasonic

thanks,
Liz

Originally posted by its_virgil

Scott,
I was introduced to using the ultrasonic cleaner by Bruce Robbins. I do much the same as reported by Roy and I really really like the results. It's so much easier than getting out the vacuum pump. Watch the container used to hold the resin...some will spring a leak during the process and cleaning the resin impregnated water from the cleaner is no fun...That's what Roy told me. Actually, I had the cup leak and empty it contents into the water. I now use glass jars from the kitchen. I save them as we empty them.

TowMater:
The cleaner I use is from Harbor Freight. Here is the link to it: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95563
I caught it on sale for $49.99 and had a 20% off coupon. They have several choices. I think Bruce got his off of ebay.

Do a good turn daily!
Don

Originally posted by Mudder


I am a little curious to hear more of Don's technique with the jewelry cleaner, it sounds quite interesting

 

[its_virgil]

Hi Liz. You've been quiet lately (I think). Here is how I use the ultrasonic jewelery cleaner. I add the recommended amount of water in the cleaner. I then pour the resin into a glass jar but do not add the catalyst. I set the jar in the water and run the unit for several minutes. The timer goes to 4 minutes and I do 4 minutes twice. I then add the catalyst and run 4 more minutes. I now pour the resin into the molds and into the paint tank and go to bed. In the morning the magic is done. I awake to beautiful crystal clear bubble free blanks (well most of the time..the failures are far between. I hate to say this...I'm casting some tomorrow night). Good to hear from you again. I hope you are getting some shop time.
Do a good turn daily!
Don

Originally posted by crashgtr

Don,

I am curious as to the use of the ultra sonice... Do you simply put the poly that you mixed in a jar and put the jar in the ultrasonic before you put it in the pressure pot? For how long do you keep it in the ultrasonic

thanks,
Liz