[the4thseal]

can you buy Teflon to make tour own moglice type stuff?

[ckelloug]

Yes, you can buy teflon powder but you have to buy about $1000 worth. Also, making the moglice stuff is currently a theory on my part: others may know more than I do but I have not tested the idea yet so I don't know the ultimate performance.

The official teflon store from dupont is at:
http://store.fluoroproducts.com/resin.html

--Cameron

[the4thseal]

too bad it is soooo expensive just to do some experiments with to get it right. experimenting is what it is all about!

[the4thseal]

never mind i have found some........going to make some and give it a try.

[ger21]

Yes, you can buy teflon powder but you have to buy about $1000 worth.

Unless you go to Ebay, where you can get it for $6.
http://cgi.ebay.com/Teflon-Powder-1-...QQcmdZViewItem

[lgalla]

the4thseal,I already posted on graphite and teflon,post#1912.

Previous posts have questioned epoxy bearing surfaces.
Epoxy can be mixed with graphite or teflon to make a wear resistant bearing or machine ways.Nuts can also be cast.This is ways beyond my knowledge but an interesting subject.http://www.epoxyproducts.com/2_fillers.html
Source:Add 5+ ounces of graphite per quart of epoxy (15% by volume - other sources suggest 10% which is about 6 tablespoons per quart of epoxy) for a slicker, less frictional surface with improved wear resistance and durability. Improves temperature conductivity, electrical conductivity and reduces friction. Sometimes used on boat bottoms that get pulled up on beaches/rocks. Use on rudders and centerboards, and bottoms of dry sailed racing boats. Also sometimes used in seams on teak decks for traditional 'black seam' look. When mixed with epoxy turns the epoxy a very dark, somewhat shiny gray/black. Leaves 'pencil' dust when sanded. Priced cheaper than other suppliers.


1 pound unit - $14 (about 1 quart volume)

Teflon powder is also used to lube pianos.Check your local piano repair.
Did someone ask,Where does one get Molybdenum powder,copper powder,submicron aluminum,brass,bronze etc?
E-Bay
http://stores.ebay.com/FINE-POWDER-AMERICA

Teflon Powder:

Add 5+ ounces of Teflon per quart of epoxy (15% by volume) for a slicker, less frictional surface. Epoxy actually get slicker as it weathers or when sanded. Not as messy as graphite above. White powder.


half pound unit - $30 (about 1 pint volume)

[jhudler]

I think we need to loose the Microsphere's in the main E/G mix, the specific gravity is way too low. Comments?

Also found this nice little read; http://www.thermosetdata.com/PDF_files/epoxies.pdf

Jack

[lgalla]

jhudler,the spheres specified are Zeeospheres,thick walled ceramic microspheres.
Crush resistance is 60,000 psi.These are not like the generic lightweight microspheres of 5,000 to 10,000 crush resistance.The specific gravity is 2.2 average.No light weight here.
Larry

[the4thseal]

sorry about that.......this is sooo wonderfully long i forget all we have covered. thanks for the reminder, and where to find it.

[walter]

Walter, If you haven't yet done this (by this I mean your 100 lbs test base), look at adding a 1 inch radius where the column meets the base.

I'm very limited here; because of a tight $100 budget and 2 weekend time frame it has to be cast on an angle plate. There will be no mold per se.

Please, I'd like to hear some more comments- how is it likely to fail, etc.

Thanks!

[ckelloug]

the4thseal,

In making your epoxy teflon nut compound, one thing I would do myself to improve the strength is to pretreat the teflon powder with fluoro-etch http://www.actontech.com/fluor1.htm

Unfortunately fluoro-etch is expensive. I don't know if treating the teflon would be worth it or not but it should greatly improve the strength of the resulting part.

Another possibility would be making a sintered teflon nut around an acme screw. This would require pressure and accurate temperature control around 560F.

You're probably on the right track, these are just a few things I've thought of about this topic in the past.

[walter]

Am I the only one having constant problems loading cnczone.com? I can't even reload the page.. I've been sitting here for 30 min trying to reload the page and post the picture. This happens every week.

Firefox won't even open it and Explorer says "Warning: mysql_connect(): Too many connections in /home/cnczone/public_html/classifieds/inc_ads.php on line 26 I cannot connect to the database"

Seriously, am I the only one having these problems?

[martinw]

Am I the only one having constant problems loading cnczone.com? I can't even reload the page.. I've been sitting here for 30 min trying to reload the page and post the picture. This happens every week.

Firefox won't even open it and Explorer says "Warning: mysql_connect(): Too many connections in /home/cnczone/public_html/classifieds/inc_ads.php on line 26 I cannot connect to the database"

Seriously, am I the only one having these problems?

Dear Walter,

I "share your pain". My problem is that I seem to have to sign in at least twice, pages load slowly...and the rest. CNCAdmin will probably give me a slap for whingeing. They won't dare do that to you.

Best wishes,

Martin

[greybeard]

I haven't noticed any problems like that here.....yet.

Progress being at a snail's pace, I thought I would post my current design and plans as both a way of saying I'm still here, and focusing my ideas by spelling them out for your comments.

With the earlier and continued emphasis on multi-component aggregates, my particle separator/analyser is mechanically complete, and only awaiting testing. Then if I can find out what goes into a variety of locally available mixes of sand/gravel, I can work out how to achieve the De Larrard mix for my own use.
This is still to be the spin casting of components which will be assembled to create the variety of frame set-ups I hope to build. All my forseeable needs will be for wood routing, not milling metal, so please bear that in mind re accuracy and strength when reading the following.

I've been concentrating on designing a gantry beam that will be formed with the simplest possible mold, yet offer a shape that might be modified, post molding, to try a range of bearing methods for the moving components. A test-bed for designs.
The dimensions will be determined by experiment, with whatever large plastic pipes I can aquire locally.

General considerations for spin casting.
I started by assuming that a cylinder would be the safest x-section to spin at high speeds for the setting time of the resin, but started again when I realised that a high speed spin, ~ 1000rpm producing ~ 45G, was only necessary for the initial compaction and de-airing of the mix. Once that has occurred, only a slow speed, ~ 120rpm, is needed to prevent gravity slumping the mix.
Unless the mold is very rigid, there will be a tendency for the G force to dilate the middle during the fast spin, but if this can be allowed, the slow spin will allow the mold to return to its proper shape during the gel/curing period.
In order to facilitate the removal of the mold cylinder from the casting, it might be useful to have it split along its length. This would be a danger area for loss of resin/mix, and would need a sealing component. This is provided for by incorporating a rectangular bar along the split which in the cast produces a channel for adding, post-casting, a variety of bearing tracks.
End caps would then locate the elements to the axle shaft.

Current design
I've gone on to consider several x-sections, but I now favour a triangular one with channels at each apex. The assembly is designed to be inserted in an outer tube to act during spinning as a reinforcement and resin proof container. A central tube acts as a guide for the initial distribution of the fresh mix into the mold, likewise helping the spread of the mix during spin-up, and a cover for a central shaft which acts as an axle for the whole thing.
After casting, there is the possibility of either having threaded inserts cast into the channels, or complete precision ground tracks, depending on requirements.

Development
A further possibility that I'm now considering is that using low viscosity resin to form a new surface, each flat of the triangle could become the bed for an air bearing.
With a surface cast using thin epoxy as a reference flat, setting the triangular section up aroung a shaft in bearing blocks on it would allow each flat surface in turn to be reformed as a more accurate plane.
A moving part could then be cast around this, possibly with a thin separating layer as air gap, and with a network of fine channels cast in situ to form a suitable distribution path for the air film.
But perhaps that's for the future......

Regards to all,
John

[HelicalCut]

HelicalCut,
At any rate I’ve read all his papers and I do understand the math, it just the empirical data he once eluded to concerns me… but that’s in the details. I wouldn’t attempt hydrostatics at this time for the simple reason that I’ve already go too much on my plate.

Got to admit though… it is intriguing!!!

Cheers, I know where you are coming from, I have a hydrostatic spindle project in the background for when the bearings on my 2 grinders fail. No epoxy, conventional turning and grinding from steel stock along with all the heat treating and aging. I wouldn't worry about the empirical stuff mentioned, the various design iterations show up in the papers, all critical dimensions and models are shown in the images. The calculated and measured performance track closely which is a good sign. When I collect the machinery and materials to do the spindle I will post it on this board, probably next year sometime.

[the4thseal]

no problems here, the forum is working great

[ckelloug]

I've started seeing random forum problems too. I sent a message to the administrator a few minutes ago and we'll see what they come up with.

--Cameron

[the4thseal]

for leveling out the eg structures some people have said that they would level out surfaces by pouring on some leveling epoxy. how does this work?why do you not have some kind of meniscus if you contain the poor or sloughing if you just poor and let the stuff poor over this sides? I love the idea and have looked up the stuff and everyone seems to love the stuff. I just can't get over the boundary areas. what do all of you think? or is this a case of it just works get over it.

[greybeard]

Hi 4thseal.
I've assumed I'd pour the thin epoxy with an outer barrier in each channel in my drawing to catch the excess, but the boundary is the edge of my flat area I'm re-coating, so I've got to pour carefully just enough to cover the area without filling the overflow channel up.
Hope that makes sense.
By the way, I'm not familliar with the word "sloughing". Could you explain the term please.
Many thanks
John

[dfro]

Yes!!!! I have finally found how I want to make my cnc lathes and mills! Thanks to you guys for this thread! I was up all last night skimming through all 170 pages. I am very inspired to give e/g a try.

I am currently interested in building a cnc lathe from scratch. Here is my thread:

http://www.cnczone.com/forums/showthread.php?t=42308

On the second page, there are some pics of an attempt I made at a Gingery type lathe. That project came to a grinding halt when I could not get the top of the plate co-planar with the underside way surfaces that extend out from the lathe bed.

I was going to use a reground Atlas 52" lathe bed as a foundation for attaching linear guide rails and bearings, but now I think I would like to cast the whole thing out of e/g with imbedded steel buttons and rails for attaching stuff.

I very much like the idea of casting the main mill table or lathe bed, leveling it as much as possible and then pouring an epoxy leveling surface.

I am sure these questions have been asked and answered all ready. I am going to read this thread much more carefully in the next few days:

Should I scuff up the top surface before pouring the epoxy leveling surface?

Once the leveling epoxy has cured, will it withstand the compression of the screws that hold down the guide rails and the headstock?

Is there an optimal thickness for the epoxy leveling surface that one would suggest?

I plan on making box sides for the leveling pour by "gluing" aluminum rail to the sides of the rough-cast mill table or lathe bed with oil-based molding clay. I have used this a lot when making silicone molds. How far will the edge fillet (meniscus), that forms along the aluminum sides, extend into the surface of the table? I intend to just chamfer it off with a file, when I pull the aluminum sides off after it cures. But I want to leave an inch or so of non-critical surface area around the edge of the mill table or lathe bed. Any thoughts?

Also, a comment for some of you guys wanting to find some teflon powder for experiments. Teflon power is used to dry-lubricate piano action parts. You can find 1 to 24 oz. bottles of it at a piano supply company.

http://www.spurlocktools.com/id39.htm

I can't wait to get started on this! E/G rocks! (Very bad pun intended.)