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so...i spent the day wacking a epoxy granite sample with a screwdriver, how about you?

Executive summary: I don't think i'm smarter now than i was this morning...maybe more confused, but not...

Yeah, well, my reasoning was that they aren't connections between "loadpoints" during normal operation, so i don't think it would be an issue...but i'm not an expert on this by any means :-) I opted...

Thanks! I'll look into it!


I bought 4 of them because i knew i'd mess something up;-) I glued it since i wanted to make sure it did not "move", not sure how much of an issue it actually is...but...

Yes, I have multiple M16 threaded rods through each casting. They served two purposes:
1. I was worries that the weight(750kg and 1000kg) was enough to make the forms "bulge", making the sides of...

So, i tried something :-)

I superglued a "cheapo accelerometer"(https://www.digikey.com/en/products/detail/adafruit-industries-llc/163/5353580) onto the end of one of the samples and tried to fix...

...i agree with Peter, you need webbing...it is a lot of weight! Also consider the surface below...it it isn't straight and flat, your mould will bend! The floor where i poured mine was uneven and...

A lot of talking to my self here, but i just ordered a couple of accelerometers. I'm going to see if something can be concluded from that...

/Thomas

Maybe an acceleration sensor, fix the sample in one end and "hit it with a hammer" in the other? I'm unsure if the damping is frequency dependent or not? If frequency can be ignored then length and...

Yeah, well, i have a lot of stuff, but high speed cameras is sadly not on the inventorylist :-( Apart from this, the deflection will be very small with these sample-sizes...so i don't think this is...

Yeah, i'll see if i can order the stuff for a test af that...it will take a couple of weeks since i have a lot of traveling in the upcoming weeks...

Maybe i should figure out a (simple) way to...

Yeah, when i see cutouts of "professional machinebases" they usually have very large aggregates embedded(guess: size=50-80mm!) within them. But it also makes sence, less flexible epoxy=stiffer. The...

Yeah, i could, but not sure if there could be anything interesting to figure out in the process?

PS: I've been thinking that i should try adding larger aggregates to see what it changes. The...

So...the results are in...short answer: 22-23Gpa...for a 12% by-weight Silimix282 with R&G ResinL + GL2 Hardner. Cured for 2 weeks at 30c, no postcure treatment.

I've attached an excel spreadsheet...

The biggest size is 4mm in the Silimix282...if this works out fine, i think i'll cast a couple more, but with some larger aggregates in...

I'm not sure if i can calculate anything that will tell...

Yeah, i made a spreadsheet that does the calculation:
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Its just a calculation for a midspan load on a beam supported between to points. So with a guestimate of E=20Gpa a load of 100N will...

How much weight did you use in your tests and what sort of deflection did you measure at what distance? Did you do a cantilever test or at 2-point setup with load in the middle? I'm planning on doing...

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...casting done... i tried the blue die this time:cool:

They've been placed to cure in the furnace room at around 27-28c...so demolding in a couple of days i think...

...i think i'm...

I had some spare phenolic plywood laying around, just enough to make two forms for 40x40x800mm test bars:
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...i'll cast some billets with my EG very soon and post the results here...

Defently :-)

I was planning on making 40x40mm square billets for testing, 800mm long... does that sound reasonable or ? I think my largest aggregate is around 4mm, so i'd figure 10x in size.... i was planning on...

Yeah, well, i've never been fully convienced about the dry-stacking idea for EG, however i don't think this is even an option with the Silimix282 ayways. Some of the aggregate is very fine, like VERY...

I was going to build a chamber for this. Some Ø150mm steel tube with flanges on the ends and then compressed air. And before the internet police arrest me, yes, i know it is "a bomb", but heavy duty...

Impressive planning! I've used soooo much money on shipping because i almost ordered each part individually...and sometimes the same part twice because i broke it the first time ;-)

Apart from the...

https://www.youtube.com/watch?v=24e8sDDS0ag

Got the controlpanel wired up:
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...now i just need the mounting arm for it...and attach the backplate :-)

...on to the next part: finish wiring the main electronic enclosure!

Waiting for CycleStart/FeedHold and potentiometers(for feed/spindle overrides) in the mail...everything else got mounted:
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...its starting to look like something now :-)

A couple of...

The controlpanel starts to take shape:
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...next up: buttons and a ton of wires!

...not sure i understand you correctly here, but isn't the floating end of the ball-screw really "floating"? Mine is resting inside a bearing which sits in a housing with no(!) axial limits at...

No, not yet :-( But i have moved it around many times since it arrived because it is always in the way of something ;-) But hopefully VERY soon as the electronics is almost done and i'd like to test...

I'm sorry to "hijack" your thread here, but I'm curious if you have any pictures of the setup doing this? I'm about to do the same with my EG mix to compare and i'd like the tests to be somwhat...