John's Alu Profile build

[Evengravy]

Not sure if anyone's still following along, but I'll pop stuff in here regardless for sake of completion.

Concrete top has been poured. All in all it wasn't very difficult with the help of my brother in law and a cement mixer. I ended up pouring just over 500KG of my initial glass fibre mix scaled up. I was a bit nervous that the mould wouldn't hold up to the pressure/weight, but it seems to be okay (touch wood).

Just for reference, the mixer held:

50KG of sand
50KG cement
to this I added:
150g of super plasticiser
1.5KG of glass fibre
circa 8L of water, added gradually to play the mix by ear a little.

I ended up with five of these mixes in total in this top section. I don't envy the person that has to remove this, and hope that it isn't me....



I've covered this in plastic sheet (not shown) to prevent it from drying out too quickly so that it can cure properly and I'm going to have to give this a mould at least a week before touching it. What I'll likely do is leave the mould sides in place and cast the epoxy top before removing the sides. I do need to do some careful figuring out to maximise the use of my z travel though. There may be a case where I'll have to increase the height of the Y rails to this top to give me sufficient clearance to fit my vice etc. but that is to be determined and most likely unnecessary.

[Kitwn]

I don't envy the person that has to remove this, and hope that it isn't me....

Don't worry. The next owners of the house can turn it into a poole table

Looking forward to seeing the final machine and how you make the gantry to match the base.

[Evengravy]

Don't worry. The next owners of the house can turn it into a poole table

Looking forward to seeing the final machine and how you make the gantry to match the base.

That's a good point! Next up epoxy layer, I'm still looking around for materials atm. If anyone has any heads up on a low viscosity resin I'd appreciate it. I used one years ago on the Momus CNC base but completely forget the manufacturers name. I'm sure I'll find something though.

[Clive S]

That's a good point! Next up epoxy layer, I'm still looking around for materials atm. If anyone has any heads up on a low viscosity resin I'd appreciate it. I used one years ago on the Momus CNC base but completely forget the manufacturers name. I'm sure I'll find something though.

Wests system https://www.westsystem.com/the-105-s...ins-hardeners/

[Evengravy]

Thanks Clive, I'll take a look at that one.

[Mister Mills]

Coming along nicely John. I really looking forward to seeing her up and running. :)

[Evengravy]

Me too! It's been a long time but we'll get there. I'm actually pretty glad I did the wiring aspect earlier, I think that the thought of tackling that again right now would be overbearing.

The top is drying well but not as flat as I would have liked, there is an area in the centre where the concrete is 5mm or so lower than the rest, I'm not entirely sure if it was bowing under the weight or just due to some factor related to drying but it's not the end of the world.

I have sourced the resin, it's here with me, I ended up going to a crowd in Northern Ireland but I'll fill in details later around that.

Prior to pouring the top I intend to flatten it as much as possible, reason being the resin isn't cheap and I want to have a nice even layer across the surface. To that end I have ordered a Diamond Cup for grinding/polishing concrete that will fit to my 4" grinder. It's on the way so should be here soon. It shouldn't take too much effort to knock down the high spots of the top with this tool to prepare it for the epoxy layer. I might combine the grinding with some filling of the very low area with epoxy/granite to minimise grinding but we'll see how we go.

I have a good respirator and will likely try to work wet with the grinding if possible, I know silicosis from breathing concrete dust is nothing to toy with. I really would have liked to have avoided grinding the top but those are the breaks, it will all work out I'm sure. As soon as the grinding disk arrives I'll be getting started.

One thing I'm a little concerned with in relation to the epoxy pour is the temperature in the workshop, looking at the resin data sheet we need to stay above 15 deg. C to avoid issues. I'll have to plan ahead with weather and some external heating source (heat lamp maybe) but I'll have a think, I'm sure we can come up with something.

[mekanik]

You might be better off trying self leveling floor compound, it runs like water.
Regards
Mike

[Evengravy]

You might be better off trying self leveling floor compound, it runs like water.
Regards
Mike

Thanks Mike, I'm kind of committed to this way of approaching it now as I have all the bits and bobs ordered. The resin I have is really low viscosity so it's really just a case of roughly evening the concrete surface before hand, shouldn't be a massive chore but without doing so the majority of the resin would sit in the centre leaving an overly thin layer at the sides where the rails will sit. It's not far off as it is though, about 5mm in the worst spots so it'll be fine with some gentle massaging. Appreciate the point though, I might source some of that to level any low spots on the floor of the space itself before painting it.

[Doddy]

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