Cement Mixers

I'm getting close to starting on my straw bale house. The straw bales are rendered in 3 coats of an earthen render. This is pumped on with a render pump. The earthen renders is made from powdered clay and sand.

I will probably need to have two cement mixers going to feed the render pump. It will take a day or 2 to do each layer of render.

I'm building the house in 2 stages plus I'm going to build a horse shelter and a green house out of straw bales so I'll need 2 mixers for around 20 days.

The questions are:

Petrol or Electric? I'll have power to the site.

Rent or Buy?

Should I buy good ones second hand or buy GMC jobbies?

Should I be asking so many question?

G'day Grunt,
at this stage you should be asking as many questions as you feel are necessary.
To explain:
One year I bought the wommo a book on Straw Bail building. Probably 10 years ago.
Next thing.......railway sleeper posts...lots of holes......big bolts....lots of concrete.......frame up.......cut and bale the paddock........put up the roof.......cure the straw under plastic over winter. Then........here's the big secret!!!!
According to the book I bought, traditionally, only women render the straw bail structure.
True!
My wommo extended this theory to stacking the walls and rendering, which she did by hand.......cement/sand render........3 or 4 coats. She mixed the render in a barrow with a hoe and a rake, used good riggers gloves and rendered each 6 metre long wall by hand......inside and out.
I was gonna send you the book, but maybe I should send the missus!

To seriously answer your question, I would buy GMC jobbies....the reason is......it will take longer than you think....its gonna rain on your parade.....so hire costs will blow out.......and the guarantee safeguards you in most cases....and you will always need a mixer if you're building your own house. And I go electric...costs less to run in the long run.
I'll try and post a photo of what's been done here.

Watson is a wise fellow! :wink:

1) It's women's work, so you might get away with a larry and a barrow.

2) You'll need them for longer than you think, too long to hire them, but not long enough to wear out a good one.

Go the GMC, treat them kindly (no banging the bowl with a spade and stuff like that). Keep them really clean, and flog them when it's done, or flog one of them at least with 18 months warranty.

It's exciting times Grunt. All the best. I look forward to hearing progress reports!

Cheers,

P
:D

Thanks,

I'm planning to start a blog on the project. Haven't decided whether I'll just do a thread here or something a bit more fancy.

I did a Straw Bale building course a few weeks ago. Worth every penny. It was run by a bloke who has been a builder for 30 years. He knows how to build a house.

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1) It's women's work,

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I'll be right at home then.

:D

Grunt,
what's a render pump? Will you be operating it or are you getting a contractor in ? If the latter ask him what's required to keep up/how many barrows per hour. I wouldn't have thought that you'd need two mixers going to feed render to one applicator, even if they were using a pump of some kind, but then I've never seen a straw bale house rendered. Maybe try just one mixer to start with and buy a second if required. One person feeding two mixers won't be twice as fast as one person feeding one mixer, I doubt it would even be 50% faster. If you have to barrow the mix anywhere (ie to the pump or the applicator) then you'd fill the barrow, feed the mixer and then push the barrow whilst the next load is mixing.

Mick

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Originally Posted by Grunt

I
I'm going to build a horse shelter e out of straw bales

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A horse shelter out of straw bales:? Will it be stable? :lb: :D

I hope you do go ahead with the blog, I've never seen a straw house being built, it will be a very interesting thread.

Good luck.

I'm getting a contractor to do it. A render pump is a bit like a concrete pump except it spits the render out at 120psi. Don't want to stand in front of it. I was advised that two mixers was the go.

On render days, I'll need a few bods around. Probably 3 to man the mixers, 1 to pump, 1 to spray water on the straw before the render goes on and 1 or 2 to trowel and smooth.

I'm doing a horse shelter starting in next week or so as a bit of practice. I'll manually do the render on this tho.

Chris

So these four or five extra bods, do you need to pay them? If so it may be cheaper if you can find a bobcat with a quick-tatch mixer to scoop up the render ingredients, mix them and feed the pump. Then you could have one person spraying the straw bales and maybe doing a bit of trowelling and another just trowelling. Also, the render pump bloke, is he used to two large mixers (3.5 cubic foot rather than the 2.2 of the smaller ones) fed by brickies labourers? That's probably equivalent to 4 or more small mixers fed by amateurs.

Mick

G'day Mick,
Really good points there...as to blokes/rate/work/capacity....
Bobcat is a good thought, but I know it'll go slower than planned.....so maybe Grunt should hire my missus..........geez I hope she never reads this stuff!!
So Grunt's using an earth mix render......what additives to the mix???
Just trying to work out how quick it'll mix..........earth renders are notoriously "let soak overnight" type of things.
Interesting stuff.


Oops just looked at the time....going to bed.....not saying "nitey night"....just won't answer anything until tomorrowday.
and I know I've been spelling bale incorrectly all night. Nite

I've got a GMC mixer and it is good enough for little jobs
EXCEPT its horribly underpowered,
so stick a bigger motor on and you'd have a real good mixer

I bought a mixer from Bunnies (I think, may have been Mitre 10), thin bowl but as I am not a builder it's been OK, we mixed up a 40kg bag of concrete with a big bucket of dirt and another of cement last weekend and it didn't pull up, fair amount of water to make it a real sloppy mix that would pour and self level.
I don't know what size the motor is but looks like about 1hp induction.
Only problem I have is instability when the tyres deflate a bit.
The mixer is not a GMC but probably comes out of the same factory.
I have had this for almost three years and for our occassional weekend warrior efforts it has worked out OK.

If you decide to go with the two cement mixers, I would look into the second hand market. I reckon heaps of people buy the best on the market, use it a few times, then flog it for the next toy.

Worth a look anyway!

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So these four or five extra bods, do you need to pay them?

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No, I intend to burn a few friendships. :)

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So Grunt's using an earth mix render......what additives to the mix???

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The mix is about 5 to 1 sand to clay depending on how much clay is in your sand. The render goes on in 3 coats. The first is only clay and sand. The second would have about 5% lime maybe up to 10% if the weather is a bit damp and the last coat is 10% lime.

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Just trying to work out how quick it'll mix..........earth renders are notoriously "let soak overnight" type of things.
Interesting stuff.

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On the course I did we mixed it and whacked it on straight away. We looked at a number of houses that were built using this mixture and one was 6 years old and looked brand new.

I used to have an electric mixer many years ago and it was great for my needs. Always started when you turned on the switch unlike petrol driven ones when they are only used intermittantly.

Unfortunately I sold it about 10 years ago otherwise you could have borrowed it. Maybe others have some available for loan?


Peter.

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Unfortunately I sold it about 10 years ago otherwise you could have borrowed it

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Damned inconsiderate there Peter. You should have know I would need it.


:D

I've had both petrol and electric all lightburn models, and petrol is great when there are no power points, otherwise electric everytime. There are no fumes, they are quieter, power is not an issue they really don't need much grunt Grunt. They are a little lighter and work just fine, the main thing is to keep them clean, don't leave 'em spinning without water and for the lazy a couple of half bricks tossed in will keep the bowl clear, but at the end of the day a quick scrub and sluice is needed. I'd get the ????? GMC models, you've got the warranty so who cares, just make sure bowl size is adequate, the is a big difference in speed between the 2.2 and larger models if you are try to batch up large volumes.

John

Iain, block the mixer up on a couple of bricks to make it more solid.

Tools

Couple suggestions if you buy a portable mixer: Consider replacing undersized wheels; mine has "toy" wheels about 8in diameter - work fine on pavement, but not so great on bare ground. Replacement with bicycle or barrow wheels pending. Also, add extensions to short folding handles at the other end, so you don't bang your shins on the lower cross brace when moving it.

Joe

If I was mixing that much that quickly I would look to buying two second hand tilt forward type mixers (3.5 cube) (westmix/easymix style not those chuck away orange swivelly things). Electric is easy and cheaper to buy. The reason I say this is the new light (2.2 cube) mixers do not have gear boxes and are direct drive off the motor. The short of it is they run to fast and when you are mixing all day they soon give you the sh##s. I have a westmix 2.2 as my tilt forward died about a month after I stopped landscaping full time so I could not justify buying a new one for jobs on the side. This is no better than a GMC in my opinion (I have used both and they both have the same problems) which is not surprising as they pretty much cost the same. Even if you only get one of these and a GMC special to back it up, you won't be sorry. Look around you will get a second hand one for the same price as a new GMC, even if you have to spend some time cleaning it out, it will be time well spent.For good second hand mixers try the trading post and also ring around the auction houses and hire companies (they regularly change theirs out and sell off the old ones).

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Originally Posted by Burnsy

the new light (2.2 cube) mixers do not have gear boxes and are direct drive off the motor.

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Mine has a belt and pulley reduction drive, would you class this as a 'gearbox' or are you referring to a mechanical/cog/gears device?

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Originally Posted by Iain

Mine has a belt and pulley reduction drive, would you class this as a 'gearbox' or are you referring to a mechanical/cog/gears device?

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Sorry for the delay in responding. The gearbox I am referring to is cog and gears as was used on the old mixers, not the reduction via small pulley on the motor up to a large pully on the mixer bowl spline.

Which way have you decided to go if you have moved forward?