I know what it’s like standing at the concrete aisle and getting that odd look from the guys at the building supply store… Since I get a lot of questions about which concrete to use I’m going to eliminate some of the guesswork. Follow me as I Compare Concrete Mixes for Crafting
So many Concrete Mixes for Crafting:
When I started buying concrete many years ago, I’d be quite puzzled reading and checking the packages. Someone would often think I was sent by my husband to buy ‘normal’ concrete. After a few attempts of trying to explain what I wanted to do I would just buy what I felt was right since they usually thought I was a bit crazy… Even nowadays there are so many that it’s quite daunting.
Cement and Concrete is not the same:
Do be aware that concrete is usually a mixture of portland cement & other things like sand and aggregates. The ingredients like the gravel give the concrete mixture strength, make it into a rock-like substance once cured.
I did know what I did not want; large aggregate in my mix, which is what the regular Concrete mixes usually have. They are quite cheap and can work for large pours in molds (planters), sidewalk slabs or fence posts. I am usually making smaller projects that are going to be cast in molds or hand shaped for decorative home use.
‘Leaf-casting’ was perfect to make my Concrete crafting tests since I like to work quite thin. These leaves are made with my new favourite; Savoy Cabbage!
Since time is always short around my place so I like to see my projects finish quickly and I am constantly improving or redesigning so I can’t wait weeks or even days!
I really do love the ‘fast set’ mixes but am not exactly sure about what makes them set & cure so quickly and also so much stronger. There are special additives in the concrete mix resulting in a dense and less porous finish. The sand in these mixes is so much more fine than regular sand as well. Fast set mixes have special chemicals that make curing quite quick. Each manufacturer usually has some version of fast-setting concrete mix. These mixes also come with quite a hike in price, but it’s worth it in my eyes!
All concrete mixes go through curing process that involves hydration. The water is needed in order for proper curing to happen, and ensure that strength is achieved. Traditional bricks are made by firing clay in a kiln, much different than concrete.
The above Rapidset Cementall is probably my all-time favourite! The specs say that it can be used at different consistencies and it will cure much harder (up to 9000 psi compressive strength) than regular concrete. I am sure there are specific additives like polymers for strength and those also make it quite moldable at a thicker consistency. This mix does not contain large aggregates.
I learn by testing and it has worked well for many of my projects. Usually readers who have had concrete problems it’s because of their choice of concrete mix.
Rapidset Cementall Concrete Mix will start to thicken in about 30 seconds and can usually be taken out of the mold after 1 hour. The molds that I make are quite stiff and this mix will withstand the vigor needed to sometimes take them out. This mix is super fine, will pick up all the details and provide a super smooth white finish. A shiny finish can be achieved if the mold is also shiny material. It tends to not have many bubbles since the consistency can be fairly fine & does not need as much water as other mixes.
So Strong Concrete:
When reading the specs for different mixes it will give you a clue at how it can/should be used. ‘Featheredge’ means that it can be used at a very thin edge layer. Some mixes will state not to be used above a certain thickness.
The Rapidset Cementall mix can also be used at a thick; sculptable consistency. It will still slump ( a high pile of mix will flatten and sag) but not usually run away. That makes it work well for leaf casting such as the Lacy Circle the Smiling Stones. The workflow can be quite fast since sections harden quickly allowing more material to be added such as around an Orb or a Face sculpture fairly quickly. Temperature will also accelerate the setting/curing.
Dampening the drier sections is good practice before adhering new mix so there is good adhesion..
Quikrete Fastset All-crete:
Different brands offer similar products. Since entering the Quikrete contest I wanted to use a Quikrete product that compared to the RapidSet Cementall. I find this mix is almost exactly like Rapidset Cementall. It does seem like it comes under a few different names; Dual Purpose Grout & Structural Repair, Fastset Repair Mortar and Quikrete Fastset All-Crete. (See a selector guide here) It may be a difference of countries (here in Canada) Do NOT confuse it with any regular Fastset Mix though, as it will have large aggregate in it. If it says that it is meant to make sidewalks, post foundations and foundation walls then it usually contains large aggregate.
When comparing different types of concrete mix read the fine print and specifications.
Quikrete Fastset AllCrete has much of the same qualities, workability and also stated it can be used at all kinds of consistencies. It also a fine powder but the colour is more like a true concrete ‘grey’; darker than Rapidset Cementall.
The DIY Gigantic concrete Leaf Orb used this mix. It performed well at less than 1/2″ thick and the quick-setting allowed great workflow.
Make sure to consider enough overlap as this will make the open-work structure strong.
Quikrete Vinyl Concrete Patcher:
This product will also work well if you can wait a bit longer. Quikrete Vinyl Concrete Patcher also has additives to make it really strong but does not set as fast as the first 2. It has a window of 30 minutes of work time (conditions can affect it) and will be hard in 24 hours. It has good bonding abilities so layering works great as in this Giant Orb making.
You can see it still is a fine mix but I’d say it feels a bit more sandy. It cures to a similar concrete colour to the Fastset. You can see a slight bit more texture in the final product.
Sakrete Top’n Bond:
This is another of the bonding mixes with great strength and it performs very much like the Quikrete Vinyl Patch. Sakrete Top’n Bond will work for the continuous building around an orb shape (ball of some type) or casting of thin leaves. It will set & cure in about day as well.
My 20″ Giant Orbs have lasted well through the canadian winters and are light enough to carry with one hand. Amazingly only 1/4″ thick. These are considered ornamental garden sculpture so if it was stepped on it would likely break.
So, there you have 3 direct comparisons (left to right) Quikrete Fastset Allcrete, Rapidset Cementall, and Quikrete Vinyl Concrete Patcher. This is by no way the only available mixes but it does give me quite the selection. Also notice the difference in colours…
As for sealers; you will notice I often do not seal my orbs since I like the look of old patinated concrete. I am also happy to report I have not had any issues with cracking with these mixes. If you have issues about cracking see this post.
If you are still a bit apprehensive about working with concrete visit my tips post. Believe me; it does not mean that you need to be ‘covered in concrete’ to make some easy concrete crafting treasures! Concrete crafting is like making a cake mix that does not need baking… And you can almost keep it forever! Concrete crafting – made simple…