Submitted by wotmate t3_zrcch6 in DIY

Using premix concrete bags, I put some water in first, then dump the bag of concrete in, and without fail I end up with clumps of half wet concrete stuck to the bottom of the mixer. I've got to get in there and scrape them off, and there's usually dry concrete mix underneath a wet layer. I've got to do this two or three times for every mix.

Is there anything I can spray on the inside of the mixer to stop this from happening? Lanolin maybe?

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Comments

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Nightgaun7 t1_j12tuqa wrote

For starters, pour the concrete in slowly and allow it to mix evenly, not just dump it all in.

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lOGlReaper t1_j134lon wrote

Slow pour like you would a beer. And remember rushing projects only ends up costing you or the client, this time it was potentially wasted product, next time could be a structural support buckling, slow and smooth is fast.

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davethompson413 t1_j13gcc4 wrote

I put the water in, turn it on, then slowly add the mix so that it's dropping mostly into the water.

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bcanddc t1_j141cqq wrote

The concrete guy I work with have a spray bottle of diesel fuel. They spray all their tools etc so nothing sticks. Also pour in slowly.

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Peopletowner t1_j147k67 wrote

Lay bag flat, cut a slit in the center of the bag, width wise. Lift bag slightly from bottom on either side of slit. Bag should now be two little bags. Cut the connecting paper. Pour each half bag slowly into mixer. Should help. Plasticizer can help smooth the mix but shouldn't be needed unless the pour requires it. Also spray the mixer inside to keep the high sides wet. I usually leave a good bit of water out and add by spraying sides until I get the right mix.

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TechJunky1 t1_j148iyb wrote

In the trades you can use a light coat of form release or diesel and that will keep any concrete from sticking to the inside of the tank

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Big-Spend-2915 t1_j14nj2a wrote

You're using one of those small DIY mixers that holds like a few bags max, right? You're doing it backward. Spray the sides to wet.
Add in the bag. Dry mix for about 30 seconds. This helps remove soft clumps. Hard ones, you won't get out. Then spray in water slowly until it is what you want.
Let mix like 2 minutes or so.

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HarryHacker42 t1_j14q46w wrote

Mythbusters used C4 and it removed the problem.

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Trigs12 t1_j15dxsh wrote

Havent used premix concrete bags before, but id assume do it much the same as mixing your own stuff. Wouldnt faff about trying to spray anything, personally.

Dont just dump it all in at once. Set it spinning, add some water, then add some of your mix. Let it mix in a bit before adding more mix and water.

I usually keep it fairly wet with the small mixers, only letting it get to your desired consistency near the end. Helps stop it sticking if its wetter while mixing. Make sure you can dry it up enough before full though.

The little mixers are bad for stuff sticking at the back though, no matter what. You can bash the drum with a hammer on the outside to dislodge it. Dont let the mixer owner see you though!

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forwheeler t1_j15ew9i wrote

We use a piece of plywood on the ground. Drop bag on plywood, cut with a square shovel. Add to mixer one shovel full with water until desired consistency is achieved. I usually do 2.5 bags per load. That is about what I can fit in my wheelbarrow. Or you can order a truck that will bring it pre mixed. Anything over a pallet worth, I have a truck bring. Mixing 100 bags will take you all day.

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Youper0 t1_j16npcw wrote

I bet anything that the bag says pour in slowly, anytime I've worked with premix concrete I slowly added it to my water until it comes up to a consistency I like. Usually it's not the ratio of the bag says because of factors.

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