[lgalla]

walter
I'm so excited,
And I just can't hide it,
I'm about to lose control
And I think I like it.
I'm so excited,
And I just can't hide it,
And I know, I know, I know, I know
I know I want you,ESP
I did a quick check on the plates and apparently the robot testing is done on air bearings which require an extremely accurate surface.Anybody know about air bearings?Quoting an ancient Chinese proverb."good enough for NASA good enough 4me"
Galo

[walter]

...
We’re here to entertain as well as to inform so we hope you enjoy your time here, maybe laugh a little. Look, we know you don’t want to waste your valuable free time reading some boring blurb that looks like it was lifted right out of a press release. And that would be no fun for us.

Besides, you can’t take stuff too seriously. It’s just stuff. Even if we do love it with every fiber of our beings...

[lgalla]

Martin is .003 over 16ft good specs for your application,optics?.003 sounds good for me for woodworking.Sorry if I don't really understand the specs.Please elaborate if these specs are good for your application.
Larry Galo

[lgalla]

Walter nice E/G planter.Gives me ideas for new products.
Right on,on press releases which we have posted.Promo for large co's.The plate and spacecraft uses have carved my direction in stone,or I have made concrete decisions or E/G decisions,whatever.Hope my possibly weird humor is accepded.Martin, being British should understand the puns well.Iwill try one on him now.Martin where does this come from?"the youth in asia"or"Therapist"
Lgalo

[Geof]

....Anybody know about air bearings?...

In the context of flat floors, more or less very low clearance Hovercraft.

Think of an Air Hockey table in reverse; a very flat table surface and pucks with holes on the bottom that compressed air blows out of. The air forms a thin film between the 'air puck', or 'air bearing' and the table surface and there is practically no friction.

Floors for air bearings do not need to be flat to within thousandths of an inch; I think hundredths are good enough. Air bearings are used for moving heavy equipment like large electric power transformers.

Air bearings do not need much pressure, one foot square supports 1400 lbs at 10psi, but they need high volume. The flatter the floor the lower the air consumption.

[walter]

Ok, I’m locking myself in the lab.

picture:
-400-700 micron quartz
-200 micron Zeeospheres
-fine quartz (3 micron avg. size)
-furnacerub.

(that's what they call it in Germany..)
_

[gt3073b]

Something that was hinted at 5-10 pages back was using ultra-low viscosity epoxies. From what I've read elsewhere, these are designed to be used in resin injection rather than wet-layup vacuum bagging.

The idea is to do a dry layup of all your layers (or aggregate) and bag the mold. Vacuum is pulled from several ports near one end of the mold or around the perimeter. Resin inlet tubes are placed as far from the vacuum ports as possible. By pinching the resin tubes, you can then test and find any leaks at your leisure since there is no resin to worry about yet. The vacuum lines run into a sealed catch-can with the vacuum pump drawing from the top of the can so resin that ends up in the vacuum lines gets trapped and doesn't foul the pump.

Mix the resin in a bucket and drop the resin tubes in. Keep the resin tubes pinched. Turn on the pump and suck all the air out of the layup (or in this case, the aggregate). Now open the resin tubes and let the water-thin resin rush in and fill the voids. Once the layup is saturated, close the resin lines and keep the vacuum going. Be sure to not let the resin bucket run dry or you suck air into the mold and ruin it. Any excess resin will get removed once the pump is pulling against the closed bag, just like in a traditional wet-layup vacuum bag.

Since you don't have to stir the aggregate into the resin, you shouldn't get any air entrained in the resin in the bucket. The vacuum removes the air from the aggregate so at no point is air ever in the system!

This eliminates entrained air and has a lower final resin content than even pre-preg due to the low viscosity. Some of the resins have ridiculous curing properties though that make it necessary to hold the vacuum for a long time or to control the temperature. Hardener selection becomes much more difficult, but there are tons of advantages, especially for big one-offs.

Having all day to find your vacuum leaks without worrying about that expensive resin curing before its fixed would be a huge relief.

Bryan.

[ger21]

Earlier thoughts on this method (vacuum infusion) were that the resin wouldn't easily flow through the aggregates and you'd have dry spots.

[lgalla]

The vacuum infusion process involves trial and error,mainly error.It looks good to try,but I would experiment with water first.
Harbour freight has a paint shaker for $99.Wonder if it would work.Pour in mixed epoxy add sand, aggregate,fill to top so no air and shake'in allover.Maybe the larger aggregates would settle to the bottom?Would work with one aggregate size,shurley?If the unit did not work use it to shake your mold.Any thoughts on this?
Larry Galo

[walter]

Larry, how about this:

5 LB. METAL VIBRATOR/TUMBLER



20 volt, 0.6 amp, 48 watts, Opening diameter: 7-3/4'', Overall dimensions: 12-1/2'' H x 9-3/4'' W, Weight: 9.3 lbs.

ITEM 93252-0VGA

$59.99

[walter]

Or this:

HANDHELD CONCRETE VIBRATOR



*110 volt, 2.5 amp, 120 watts
*3440 vibrations per minute
* Skid dimensions: 7-5/8'' D x 11'' L
* Overall dimensions: 11-9/16'' L x 8-5/16'' W x 8-1/2'' H
* Tool weight: 16 lbs.
* Shipping weight: 18 lbs.

ITEM 90304-1VGA

$39.99

[lgalla]

Walter I like the concrete vibrators as they will work with higher epoxy ratios.We are trying to find a solution for the 5to10% guys.
Thought you were locked in the lab?
Larry

[walter]

I'm still in the lab, fighting bubbles!

Here's the preview:









To be continued...

[lgalla]

Walter lookin good.
I assumefrom pic#3 you went with 20% epoxy and raw epoxy in pic#4 for surface plate.You are almost there as the epoxy must over flow the frame to produce a plate.Keep us posted.
Larry

[lgalla]

Walter don't remember if anyone posted on amine blush which may appear as a waxy cloud on the surface one or two days later as a result of reaction with humidity.This must be sanded off before more pours.For a plate TT epoxy is formulated not to blush.
Larry

[brunog]

Walter,
Nice work, I am curious about the sand, zeosphere etc ratios..

best regards

Bruno

[brunog]

Or this:

HANDHELD CONCRETE VIBRATOR



*110 volt, 2.5 amp, 120 watts
*3440 vibrations per minute
* Skid dimensions: 7-5/8'' D x 11'' L
* Overall dimensions: 11-9/16'' L x 8-5/16'' W x 8-1/2'' H
* Tool weight: 16 lbs.
* Shipping weight: 18 lbs.

ITEM 90304-1VGA

$39.99

Nice item Walter,
The good part about this one is that the skid plate can be unbolted and you can fasten the vibrating motor on a table or a mold. You can even by a few and bolt them.

Best regards

Bruno

[lgalla]

Here is something I found which may be interesting to Martin and others.





Richardson's astronomical interests include binary stars, which he researched in graduate school, and the small bodies of the solar system, such as comets, asteroids, and meteors. But his newest interest is so demanding of his time and talents that he's had to go on sabbatical for a semester to get into it.

Richardson's newest project is the result of an inter-institutional collaboration with a group of bio-chemists at University of South Carolina. They are working together to make a new kind of telescope mirror, using epoxy instead of glass, which will make the mirrors lighter in weight and cheaper in cost. The mirrors are made by spin-casting the epoxy, which just means spinning it in a dish until the liquid is hard. "Lo and behold, the natural surface of a spun liquid is a parabola, and that's the ideal surface for a telescope mirror," Richardson explained.

The difference between the spun epoxy and spun glass is that after the glass is spun, it will still need to be polished smooth, which can take up to a year to do, not to mention the high cost of the equipment used in the process. Also, there's only a certain size that glass mirrors can be before they begin to sag and become distorted. The epoxy mirrors are lighter and can therefore be made bigger. "The bigger the mirror, the deeper you can see into space and clearer the objects will be,"
Richardson said.

Lisa Brodhacker is a graduate student at USC who is working with Richardson on this project. The group at USC needed help in developing the testing method of the mirrors, which is where Richardson came in. "We had the mirrors, but we didn't know how to test them," Brodhacker said. "Had it not been for his expertise in physics, we wouldn't have been able to continue the research." Brodhacker has known Richardson for about three and a half years and has been greatly inspired by his expertise. "His expertise is very high, but he's very humble and always willing to explain things," she said.

NASA is also interested in this collaborative effort. The space agency is funding $250,000 to Richardson and his research partner, USC's Wally Scrivens. The project is expected to take at least two and a half years to complete.

NASA enlisted the expertise of Richardson and the USC group to manufacture and test four of these epoxy telescope mirrors, measuring two meters across, for a project that involves infrared laser communication with Mars probes. The idea is that NASA can send more information with infrared lasers than with radio, back and forth from Mars to Earth. "The head of the project came out to see us," Richardson said. "I was pretty impressed, he didn't send out any gofers."

Richardson is so excited to be involved in this project with NASA that he's losing sleep over it. "I've been working 14 hours a day for the past four days to try and get ready to test these new bigger mirrors," Richardson said. The group at USC does most of the manufacturing of the mirrors, while Richardson tests them in Charleston at his makeshift optics lab. "My wife let me take over our rental apartment, and our rental apartment is now my optics lab," Richardson said. "It's a one-room studio apartment and it's really long, so I can send laser beams back and forth."

Richardson shows off a photo he took of the moon. "This is the first astronomical picture taken with a mirror like this," he explained. "It's done with our mirror, and no one else has done this. No one's ever gotten anything this good before." The photo was taken by a telescope Richardson made, complete with his epoxy mirror inside.


###

[walter]

Bruno,

The mix was prob. 60% large quartz/25% Zeeospheres/15% fine quartz (by volume).

I will have to go back 100 posts and re-read the formulas- they went over my head the first time...

But I think I'm close. You can feel it, it really moves. The compaction is a wonderful thing.

Have a look at these pictures- 3 micron powder made all the difference.

[lgalla]

Walter calm down,looks like your on track,but you didn't say the epoxy ratio or your vibrator.
Galo