Bad Material or User Error - Overview on Tru-Pac

I was talking to Don at Walt Tools the other day 

And we began to discuss several problems in the indusrty .... so here is a FAQ on their Tru pak line....

I will add comments in RED 

What are the differences between the Trupac X and Trupac V?

Tru Pac V is a 20 lb ad pac that is added to a 60 lb bag of TYPE N MORTAR MIX.  It is a traditional vertical mix in that it is designed to be applied from 1-4 inches thick, is considered lightweight and has a long working time. It is recommended for both indoor and outdoor with a proper water proofer. It should always be applied into a proper scratch coat.

Tru Pac X is a very versatile, high strength 16 lb ad pac that is added to an 80 lb bag of TYPE S MORTAR MIX.  It can be applied from approximately ¼ inch up to 4 inches on properly profiles scratch coats. It is non-lightweight, resin and fiber modified and used both indoor and outdoor. Its uses range from decorative vertical, countertops, furniture and some flatwork overlayment.

Rememeber thats TYPE N MORTAR MIX for Tru-Pac V and TYPE S MORTAR MIX for Tru pak X      NV   and   SX

What is the coverage of the products? Vertical mix coverage can vary greatly based on thickness applied and how much loss you actually have carving.  Both X and V provide about the same coverage even though the batch weights are different.  V is an 80 lb batch that is lightweight, X is a 98ound batch that is normal weight.  Generally you can expect approximately 12 sq ft at 1 ½ inches.  If you are going to onloy go ¾ inch thick then double your coverage.  Conversely if you are going 3 inches thick the you will only cover about 6 sq ft per batch.

Do I really need a scratchcoat? Yes, you really should make use of a proper scratchcoat. 

Do I really need lath? Lath is situational.  We highly recommend lath when you can use it to ensure the very best subsurface to which you are going to carve your material.  Since the lath is to be independently secured to the structure you are never going to experience an issue with failure of the material from the surface. If you choose just to use a bonder to apply a scratchcoat to your surface, you are then relying on that bonder for never failing. The mechanical security of the scratchcoat provides far better security.  In most cases we recommend Spider Lath for ease of use and it’s non degradation properties to cementitious materials.

What is a proper scratchcoat? A proper scratch coat is one that provides an adequate profile to support the thickness of vertical material to be applied on top. For thinner applications, under ¾ inch, a strong broom type scratch will be adequate. For applications over inch it is recommended to use a scarifier rake to create adequate 1/8” to ¼” horizontal channeling of the scratch coat. Recommended scratch material is the same simple mortar that is used with the Tru pacs.  Save money, do not use the tru pac mixes for the scratchcoat. 

I actually disaggree with the last line... however I apprciate Dons honesty where most manufactures try to enforce a special scratch coat and will not gaurentee the product with out it... mortar by itself can be used as a scratch coat but i have found over the years that when I do use the "good" mix as the scratch coat it goes up faster and the bond between the two layers is better.... its the scratdch coat so your not using as much material to get it done... why cheat yourself the extra help in application process.... the the materials are all ready inexspensive enough.   The mortar all though will work its not that sticky and if you apply it to thick it will crack.  The add pak ( Tru pac X ) works really well for scratch coats and becaus eit has fiber when you scarafy or scratch it it tears really good making even a better surface for bonding.

Do I need a primer? When using either Tru pac on a proper scratchcoat it is not necessary to use a primer (bonder).  You should only need to wet down your scratchcoat just before you apply your carving mix.  This helps with hydration and natural bonding of the scratchcoat to the topcoat.

Tru pac X is often a material used over EPS(foam).  In this case a bonder is used to either adhere the scratchcoat to the foam or, in a few cases, the carve coat directly onto the foam.

How thick can I put on the Tru Pac?   Tru Pac V – 1-4 inches, Tru Pac X – ¼ inch to 4 inches.

Can it be stamped? Yes, either mix can be stamped as long as it meets the minimum thickness needed for the stamp impression. Bear in mind Tru Pac V should still be applied at a minimum of an inch regardless of stamp profile.

Do I need a bonding agent with Tru Pac?  Generally no.  Walttools recommends that you only need to thoroughly water down the scratch coat before application of the carve coat.  An exception is when one is applying a scratchcoat to a non-lathed surface such as over foam.  The scratch coat will need a bonder to adhere properly to that surface.  As mentioned prior, NO bonder should be needed to for the actual Tru Pac carve coat to be applied that that scratch coat.

How strong is this stuff?  Strong enough!  Tru Pac V cures out at approximately 3000psi.   Tru Pac X will exceed 4500 psi on final cure.  Either are plenty for artificial surfaces.  The X will provide higher abrasion resistance due to the nature of the mix. 


What causes cracks in my vertical? Cracking is one of the most frustrating and least understood results of decorative vertical concrete.  What we ask of a decorative vertical mix may be the most demanding in all of the decorative industry.  We want a mix that is pliable like clay yet stick to a wall like glue, stays workable for extended times, attains a “high psi”, can be colored, stained and sealed with anything and is a reasonable cost. Not easy.  MOST of the time crack issues can be traced back to an oversight in usage.  Nearly all issues can be traced to one of the following: 

1.  Make sure you are using the proper mortar MIX with your Tru Pac.  Mortar CEMENT is NOT mortar mix.  They are entirely different but that is the number one mistake made.  Mortar mix will come in 60 or 80 lbs bags(USA).  If your bag is 55 lb, 75 lb, etc, it is probably not mortar mix.  

2. Water amounts can be a big factor is cracking.  Too little or too much can result in cracks either right away or near future.  You should almost always be within 8 ounces of the instructed water amount with these mixes.  If you are finding you need much more or much less water than the data suggests, see 1 as that is probably the issue.  

3.  Weather conditions. Hot temps, low humidity, wind and direct sun can all contribute to a loss of moisture on the surface of the mix and can result in cracking. The thinner the carve coat, the less time you will have to work with it period.  If you factor in harsher conditions you need to factor that in.  Often times, misting the surface every 15 minutes or so will help control moisture loss.  This type of water addition is NOT detrimental to the mix as explained in 2.  You may also consider a sun shade for the obvious and draping plastic over the surface as you proceed to help with wind drying. 

4. Overworking your mix.  This is especially true for thinner applications.  Once the mix starts to set up on the scratch coat it has a fragile bond with that surface.  If you keep manipulating the surface and constantly fracture the bond to the subsurface, you can end up with micro-cracking once cured. 

Also when doing table tops... the desire to trowel and trowel and trowel and trowel to get  the surface perfect is compelling.... if you go back and watch the VDO's on this section I lay the materai down .. screed it off and slick it not over trowel the flat surfaces that you make...   Also the temptation to allow a wetter mix on the top because it will not slide off is also a bad idea.... the mixing guy compromised the mix and your stuck with it... 

If you have a mix that is too wet... breack it down into to buckets mix another mix dray and split it up back into the two wet ones... if you cut this corner you run the risk of cracks ... 

Finally on this topic Watch Herb Nordmeyer " Stopping Cracks in their Tracks " class  this will add even more understanding to the crack issue for any mix.

5. Improper scratch coat. Aggressive scratch coats are very thirsty for water. If you plan a thicker carve coat, 1-3 plus inches, you need a heavy profiled scratch coat. If you plan a thin carve coat of Tru Pac, then your scratch coat need not be too aggressive(broom scratch).  The less aggressive scratch coat will put less of a water demand on your Tru Pac carve coat, thus less drying out.  No matter the style, keep the scratch coat wet down. 

6. Thorough mixing of batches.  Any cake baker can tell you that if you toss 5 ingredients in a bowl, shuck it around a dozen times with a spoon and throw it in the oven, you likely not get a good cake. Same here with Tru Pac.  There are many ingredients in Tru Pac and all of them need to be mixed thoroughly with the prescribed mortar mix.  If not thoroughly blended you have a mix with both light and heavy spots of critical ingredients.  That makes for a botched cake for sure. Follow the instructions on the bag and/or data sheet for mix details. 

7. This is more obscure but is relevant with Tru Pac V.  V is meant to be “carved” meaning plenty of deep cuts creating stones and other artifacts.  All of these deep joints provide plenty of stress relief from potential cracking.  Using V for just a texture coat is not recommended for this reason.

Can I color my Tru Pac? Certainly. It can be colored in several ways.  Integral color which is a designated amount of powdered color mixed in each batch. This is especially useful when you need an easy base color overall.  Tru Tint WB is the most common way to color.  This uber simple water base stain is just simple spray on and let dry.  Acid stains work well but are not recommend for vertical due to drip marks.  Concrete Dyes also work very well.

Do I need a release to stamp Tru Pac? Yes.  Either powder release or liquid release should be applied to the stamps or texture tools when manipulating the surface.

How long does it take to dry? Tru Pac will CURE out at varying rates depending on thickness and ambient conditions.  Tru Pac X is usually in 24 hours if under 1.5 inches.  Tru Pac V can take up to three days especially if 3 plus inches thick. 

Do I need a sealer? Yes and No.  If indoors such as a fireplace surround then you really do not “need” a sealer but it is still recommended for preserving the look.  Handprints, dust, incidental splashes, etc could have an eventual impact on the look.  Using a good invisible sealer such as Tru Block will guard against all of the above.  Tru Pac is fully prepared to handle the outdoors but we will always recommend protection from the effects of the elements to preserve the decorative aspect of your work.  Preventing water absorption provides long term stability and providing UV protection helps maintain color integrity over the years. Tru Block will provide all the natural protection needed. It penetrates and provides a thin film forming component protecting two fold. Other types of sealer are also an option.  Just make sure whatever sealer you are using meets your aesthetic value since many sealers can alter the look of your surface.

What else can I use Tru Pac for?  In general Tru Pac V is best suited for high build vertical and faux finish design.  It can be used for wear tops such as large tables only if completed with a professional grade high build sealer such as epoxy or polyaspartic.  The Tru Pac X is highly versatile with its good strength and workability. It can be used for vertical projects as well as furniture, flatwork repair, low traffic overlayment and even countertops

Teaching Living Tree Art at the West Coast Trainin...
Up and Coming West Coast Training Center Class #3

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