CNC Aircrete Blocks

Hi All!

First post! Love what everyone is doing here!!

I would like to CNC route Aircrete (lightweight concrete) blocks, approx 12" x 8" x 6" - would a Low Rider suffice for that?

If not, what would be a good fit for something like this? I’d like something fast, reliable, capable, easy to use. I have a budget up to $3,000.

Aloha!
B

I’ve been dabbling with aircrete for a bit now. I suspect you’re going to chew up endmills pretty quick attempting it.

I think the lowrider could do it… but, I’m not sure if would be a slam dunk process to start. I imagine a less than trouble free learning curve. Based on your goal of “fast, reliable, … easy to use.” I’m not sure anything less than $5k will get you that. And even then you’ll be constrained to a small working space at that price.

Are you looking to mill blocks or sheet-like forms?

Oh, and welcome - glad to have you here!

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I’d guess you’d also need to get those endmills that are more burrs than fluted cutters. You’re going to be grinding away concrete, not carving away wood or metal. And you’ll want some serious dust management in place. Both for your sake, and for your machine.

Do you need to keep the bit wet when you’re doing that?

I have no idea how tough aircrete is. What other kinds of tools do you use with it? If it is only chisels and grinders, I think you’ll be punishing any machine that tries it.

The aircrete I’ve been making can be cut with a regular wood saw. Of course the saw is used up rather fast, but that is what I’ve been doing. I will say that the ability to cut aircrete is also dependent upon what is in the mixture and the ratio of bubbles relative to concrete mix. I’m not making structural aircrete though and may be one of the reasons mine cuts so easily.

It’s pretty cool stuff to play around with. Messy, but fun.

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Aloha Friends!

Thanks for the feedback, questions and advise. I feel so welcome. So excited to be on this quest and journey here… I’m trying to make the world a better place by creating affordable housing recycling trash into styrafoam concrete and aircrete cast in forms.

After contemplating further, I am thinking to take a different approach, perhaps it’s faster and easer to just create the forms. I’m trying to make a lot of large concrete block forms fast from 3D models.

Imagine a 18" x 12" x 12" hard foam block (made of something like stiff standard spray foam <can’t insert link here> or perhaps Floral Foam (super soft). What machine would be able to CNC a 3D relief that I. could then make a mold from?

Machine Bonus features:

    • Medium size - How big could the foam block get?
  1. high resolution
  2. super fast in a soft medium like this
  3. “affordable” (<$3-5k)
  4. reliable
  5. easy to use

Thoughts? Ideas? Suggestions?

Gratefully,
B

You can easily mill HD foam with either machine. At 18"x12", the MPCNC is a good choice.

The trouble comes with 12" height. You’d need a 12" bit. And then the machine would need to be 24" tall to mill the top. That’s really large. I’m also not sure such a bit exists, except as a drill bit.

If it was wood. No way a 24" Z would work. In foam, it has nearly zero load. But 24" is still really large.

But, the common solution to this is to slice the pattern into 2"-4" pieces or so, cut those out, and glue them together. An 8" Z with wood is asking for a pain, but it would be fine with foam.

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Someone did a huge pharohs head for their local theater company by slicing it in 2" slabs. Looks really good. Should be easy to carve a mold using the same principles. Or a foam master to make a silicone mold from (with an appropriate support shell).

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That was me

It’s a pity the musical got postphoned by covid, maybe September '21… That makes a lot of time to make additional stuff though, maybe with some aircrete :slight_smile:

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They make extended reach end mills for foam. The problem is the longer they are, the bigger the diameter needs to be. The really long end mills are half inch, or even 1 inch diameter. They also cost about half what the whole mpcnc costs.

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I was trying to rapidly make different shapes of forms for pouring aircrete or concrete into so I can build large structures of any type when broken down into “lego” like parts.

I saw this and thought this could make instant forms with expanding foam if there was such a solution: (I can’t insert links into my posts so if you’re interested, google an article from Engineering DOT com called “Could Dynamic Molding Be Bigger than 3D Printing?”

Then thought there has to be a better way. Am I on the right track with the above answers?

Probably, but not with this machine. To get the length of end mill you need, you need a spindle that can hold a half inch diameter end mill.