Vacuum pressure recommendation?

[Greg O'Sherwood]

I am interested in learning how to do some casting and am ready to buy some equipment.
I already have a good compressor, but want to learn vacuum also.

What is the recommended specs for a vacuum pump?

thanks in advance!

 

[MesquiteMan]

If you are just going to cast, forget vacuum, IMO. I don't use it at all for casting, just pressure.

 

[ldb2000]

Unless you are casting Alumilite or worthless wood or things like that you really don't need the pressure or vacuum . For simple color casts with PR just mix your pigment with your resin and let it sit for about a half hour so any bubbles can float to the surface then mix in your MEKP slowly but throughly and pour into your mold .
I use this process all the time and never have bubbles in my blanks .

 

[Greg O'Sherwood]

I do want to do worthless wood and some other ideas... I get LOTS of small pieces free from my boxmaking, etc...


Perhaps I should explain.
This will be a gift from my wife.
Cost: nothing.

It's either a vacuum pump and chamber, or I have to think of something else.

I don't want to think of something else.:wink:

 

[Glass Scratcher]

Vacuum degassing can be beneficial to both urethanes and polyester resins for the removal of moisture that is absorbed into the resin once the containers have been opened. Urethanes you vacuum degass each side separately. With polyester resin you don't want to take it to more than 27" of HG as the styrene sovent will be pulled out of it at 28". I usually degass PR to 25" as a safety margin for guage variability. Its not a big margin but still...

 

[Greg O'Sherwood]

Would a vacuum pump of 1/2 hp work, or perhaps something stronger?

Maybe a better way to ask this is: What pump do you use?

 

[Glass Scratcher]

Would a vacuum pump of 1/2 hp work, or perhaps something stronger?

Maybe a better way to ask this is: What pump do you use?

I have 2. I use the Japanese one more. It will draw down to 28.5" in about a minute.
http://cgi.ebay.com/2Stage-Rotary-V...in_0?hash=item5ad3be9cca&_trksid=p3286.c0.m14

I also have this one from Harbor Freight, and it works fine.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=98076

If you need a faster draw down you can always make a vacuum reservoir.

I should also add that if you are doing any silicon mold making- many silicons require vacuum degassing after mixing.

 

[TowMater]

Greg,

Theres a guy in Olathe that's been posting several nice pumps on CL.

Might take a peak at them if you get a minute.

 

[KenV]

If you can find it get a gast vacuum pump about 1/2 HP or so -- so you can use vacuum chucking on the lathe as well as pulling vacuum for casting different effects, vacuum drying wood or other interesting opportunities.

Bag gluing of materials becomes available as do other applications.

Suggest you avoid the venturi style vacuum generation gear unless power is really cheap and you have a fairly large compressor -- and ear protectors for the combined noise.

 

[Greg O'Sherwood]

Crap.
I just remembered. I have a holdfast vacuum chuck still in the box that I just got from Hartville. Can I use that for creating the vacuum?

 

[its_virgil]

A vacuum chuck does not create vacuum...it uses vacuum to hold vessels for turning the bottom such as removing the foot of a bowl and making the bottom smooth.A vacuum source is needed to use the vacuum chuck.
Do a good turn daily!
Don

Crap.
I just remembered. I have a holdfast vacuum chuck still in the box that I just got from Hartville. Can I use that for creating the vacuum?

 

[VisExp]

Crap.
I just remembered. I have a holdfast vacuum chuck still in the box that I just got from Hartville. Can I use that for creating the vacuum?

Are you talking about the vacuum generator or the chuck?

http://www.hartvilletool.com/product/12246

I don't see why you couldn't use that. It works the same as the HF venturi vacuum pump. You will just need a pretty decent size compressor for it to work efficiently. My little compressor could not keep up with the HF venturi pump.

 

[Greg O'Sherwood]

Daniel,
that's the one. I SAID vacuum chuck when I MEANT vacuum generator/chuck, etc...

 

[DurocShark]

Here ya go:

http://denver.craigslist.org/tls/1416574983.html