*Surface Bonding Cement*
By: Pyrotech
3-30-02

Surface bonding is fast strong way to work with block for a small building, the block is dry stack, in a running bond pattern, and making sure the wall is straight and level, you apply the surface bonding to both sides to create a strong durable wall. I first looked into this, while planning the construction of an underground house. The following came from some note and research I did at that time. It may take some searching to find all the ingredients. But places to check are your local ready mix dealer, check with local cement products companies. Most areas will have a company that makes block or large concrete drain tile due to the cost of shipping. Heavy precast concrete products

 

Ingredients:

Portland Cement

Hydrated Lime

Calcium Chloride

Calcium Stearate

Glass Fiber Filament

 

Most all ingredients can most likely be bought from either your local building supply store, or a local cement company.

The following is for a 25lb batch, Also included are the proportions of each so you can scale up or down as needed. A 25 pound batch will cover about 30 feet square feet of block, applied to both sides of the wall.

 PartsPounds
Portland Cement7819 1/2
Hydrated Lime153 3/4
Calcium Chloride11/4
Calcium Stearate41
Glass Fiber Filament21/2

 

Mix in the cement, lime, and calcium Stearate thoroughly. Add the glass fiber and mixes only long enough to distribute the fibers evenly. Mix the calcium chloride with 1 gallon of water, add this slowly to the dry mix ingredients, and mix thoroughly. Continue to add about a gallon of water until a creamy mixture is achieved, that can be applied with a trowel

DO NOT add water after 30 minutes of mixing, discard any leftovers.

Surface bonding cement is applied to BOTH sides of the wall. The block must clean of all dirt, loose sand, cement, and paint. Dampen the block to avoid the block from pulling moisture out of the surface bonding cement creating a weaken structure.

A thin coat is all that is needed. Apply the mix firm trowel pressure pushing upward to achieve uniform coverage. Follow up with longer and lighter strokes holding the trowel at a slight angle to even the surface up. After about 15 to 20 minutes go over once more long firm strokes to create a smooth surface. Make sure the surface of the trowel is CLEAN. Also, Be careful not to dig the edge into the surface bonding. Working the surface too much may cause hairline cracks.

Mist the surface once or twice the first day to help aid curing,


Pyrotech



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