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  1. #141
    Chaz's Avatar
    Lives in Ickenham, West London, United Kingdom. Last Activity: 2 Hours Ago Has been a member for 4-5 years. Has a total post count of 963. Received thanks 67 times, giving thanks to others 42 times.
    Wow, 3 months have gone, I am piss poor at keeping this thread updated.

    So gantry was done, Y motor mounted, some test movement here:-

    https://www.youtube.com/watch?v=5sMb4XmzuXc

    Ignore the last 100mm or so that is unsupported. Long story, That will be epoxied it later.

    A pic of how it all looks, my wife not happy with me taking pics of her. Testing the fit before I attempt to epoxy this lot together.


  2. #142
    Wow, i cant wait to see that monster finished.
    project 1 , 2, Dust Shoe ...

  3. #143
    Chaz's Avatar
    Lives in Ickenham, West London, United Kingdom. Last Activity: 2 Hours Ago Has been a member for 4-5 years. Has a total post count of 963. Received thanks 67 times, giving thanks to others 42 times.
    Quote Originally Posted by Boyan Silyavski View Post
    Wow, i cant wait to see that monster finished.
    Same here but sadly probably still a few months away.

  4. #144
    Quote Originally Posted by Chaz View Post
    1/3 rd equal parts of Cement (52.5R), Sand (Sharp Sand, 0-2mm) and Basalt Stone (6-10mm). 20% Water volume based on Cement used (so in this case, 5 litres per 1 bag of 25kg each above).
    ...seems to be a lot of water.
    In my work place we add circa 30 litres of water to 750kg of mix (all depends how wet is the sand).
    This gives nice mix to form roof tiles. 10% water too much and mix is too wet and have to be dump - happens daily.
    My point is to get correct amount of water - mix it well and we shall get strong cement.

  5. #145
    Chaz's Avatar
    Lives in Ickenham, West London, United Kingdom. Last Activity: 2 Hours Ago Has been a member for 4-5 years. Has a total post count of 963. Received thanks 67 times, giving thanks to others 42 times.
    Quote Originally Posted by Tom J View Post
    ...seems to be a lot of water.
    In my work place we add circa 30 litres of water to 750kg of mix (all depends how wet is the sand).
    This gives nice mix to form roof tiles. 10% water too much and mix is too wet and have to be dump - happens daily.
    My point is to get correct amount of water - mix it well and we shall get strong cement.
    Really? I was under the impression this was a fairly dry mix. Without the plastisizer it wont even bond.

  6. #146
    Quote Originally Posted by Chaz View Post
    Really? I was under the impression this was a fairly dry mix. Without the plastisizer it wont even bond.
    Should add that the mix goes through bed/slipper which is kind of mold and is compacted by packshaft with fingers - layer of concrete is 12mm thick and travel 1m/s speed.
    In your case vibrating plate is a must. Curing process is complex too (4 stages with extra water), retarder is used to slow curing process.
    Since I work there, I use min amount of water (just for mix to be not brittle) - for diy concrete job

  7. The Following User Says Thank You to Tom J For This Useful Post:


  8. #147
    Tom I am not sure you are understanding this way of moulding concrete as it is done with superplasticiser which makes a very fluid mix and MUST NOT be vibrated as it will settle the aggregate to the bottom. The way it works is that it separates all the individual fines and stones in suspension for about half an hour then they come back together for the set.
    This explains it better. https://www.youtube.com/watch?v=9ySyaKb2_b0 and here https://www.youtube.com/watch?v=ICp4...w#t=107.971789
    Last edited by Clive S; 27-12-2016 at 02:40 PM. Reason: added extra link
    ..Clive
    The more you know, The better you know, How little you know

  9. The Following User Says Thank You to Clive S For This Useful Post:


  10. #148
    Chaz's Avatar
    Lives in Ickenham, West London, United Kingdom. Last Activity: 2 Hours Ago Has been a member for 4-5 years. Has a total post count of 963. Received thanks 67 times, giving thanks to others 42 times.
    Quote Originally Posted by Tom J View Post
    Should add that the mix goes through bed/slipper which is kind of mold and is compacted by packshaft with fingers - layer of concrete is 12mm thick and travel 1m/s speed.
    In your case vibrating plate is a must. Curing process is complex too (4 stages with extra water), retarder is used to slow curing process.
    Since I work there, I use min amount of water (just for mix to be not brittle) - for diy concrete job
    Agreed with Clive S, plus, this wouldnt be something I could do from my garage ...

    Plus, there is no air bubbles in my mix, this I am certain of.
    Last edited by Chaz; 27-12-2016 at 01:07 PM.

  11. #149
    Quote Originally Posted by Clive S View Post
    Tom I am not sure you are understanding this way of moulding concrete as it is done with superplasticiser which makes a very fluid mix and MUST NOT be vibrated as it will settle the aggregate to the bottom. The way it works is that it separates all the individual fines and stones in suspension for about half an hour then they come back together for the set.
    This explains it better. https://www.youtube.com/watch?v=9ySyaKb2_b0
    ok, I was referring to cement mix with coarse sand. Got your point guys

  12. #150
    Quote Originally Posted by Tom J View Post
    ok, I was referring to cement mix with coarse sand. Got your point guys
    This works the same with say 22x15 aggregate but they grade it down using smaller and smaller aggregate down to ash.
    I am looking at building a concrete mill with Dean's help using this method. We shall see.
    ..Clive
    The more you know, The better you know, How little you know

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