HPMC for Wall Putty Top 4 Learn Points

HPMC for wall putty has unparalleled advantages in practical application. How to maximize the effect of HPMC is still the goal that users continue to pursue. If problems encountered and mistakes are avoided during the construction process, it will be beneficial for HPMC to play the greatest role in wall putty.

I. Preparation of materials and tools before construction

1. HPMC quality should be strictly controlled

   • HPMC (Hydroxypropyl Methyl Cellulose) is the core additive of putty, you need to choose the regular brand, purity ≥ 95%, to avoid adulteration (poor quality HPMC can easily lead to poor water retention, caking).
   • It is recommended to test in advance: take a small amount of HPMC dissolved in water, observe whether it is transparent and free of impurities, and leave it for 24 hours without obvious delamination.

2. Wall putty formula should be precisely controlled

   wall putty formulation must be precise control, this is the wall putty can play the most important step, a lot of customers in the actual operation of all kinds of wall problems, and not in accordance with the formula proportion has a lot to do.

   

   • Base proportioning reference (take ordinary interior wall putty as an example):
     • Double-fly powder (heavy calcium powder): 70-80%
     • Gray calcium powder (or white cement): 15-20%
     • HPMC (viscosity 100,000-150,000): 0.3-0.5%
     • Dispersible latex powder (optional): 1-2% (to enhance adhesion)
   • Key points: too high a proportion of gray calcium will easily lead to brittle walls, and too much HPMC will prolong the drying time.

3. HPMC adapts to the environment

   • Summer high temperature: HPMC dosage can be slightly increased (0.5%) to prevent water evaporation too fast leading to cracking.
   • Low temperature in winter: using cold water to dissolve HPMC will prolong the dissolution time, it is recommended to pre-dissolve with warm water (≤40℃).

Ⅱ. Operational details to be mastered during construction

1. Mixing process

   • The order should not be reversed: add water first → add HPMC → add powder last to avoid agglomeration.
   • Stirring time: electric stirring ≥ 5 minutes, resting for 3 minutes and then stirring for 2 minutes to ensure that HPMC is fully dissolved.

2. Scraping technique

   • Thin coating multi-layer: single thickness ≤ 2mm, too thick due to the strong water retention of HPMC leads to uneven drying inside and outside (wet inside and dry outside).
   • Finishing time: before the putty surface drying (about 10-15 minutes after scraping) finishing, otherwise it is difficult to sand after HPMC film.

3. Special Substrate Treatment

   • Walls with high water absorption (e.g. aerated bricks): apply the interfacial agent first, otherwise the water-retaining effect of HPMC may cause the putty to peel off from the base.
   • Renovation of old walls: Remove the chalking layer, otherwise the bonding power of HPMC cannot be effectively exerted.

Ⅲ. Post-construction care and problem prevention

1. Drying control

   • Dry naturally for 24-48 hours (forced drying is prohibited), the water retention of HPMC will slow down the drying, sufficient time should be reserved.
   • Avoid direct ventilation when not dry to prevent the surface from cracking.

2. Responding to Common Problems

   • Foaming: the grass-roots level absorbs water too quickly or mixes in air when mixing → moisten the wall before scraping and leave it to defoam after mixing.
   • De-powdering: insufficient amount of HPMC or poor quality of gray calcium → increase HPMC to 0.4%, or add 1% latex powder.
   • Cracking: single layer is too thick or grass-roots level is not treated → shovel out and repair in layers, and reapply after each layer is dry.

     

Ⅳ. Environmental and Storage Precautions

1. Health protection

   • HPMC itself is non-toxic, but you need to wear a mask when mixing the powdered putty to avoid dust inhalation.
   • Ventilate promptly after construction to accelerate the evaporation of formaldehyde (possibly from the glue powder).

2. Material storage

   • HPMC needs to be sealed to prevent moisture, caking failure; putty powder is not used up when the bag is tied tightly to avoid moisture absorption caking.
   • Finished putty (with HPMC) should be used up within 3 days after opening to prevent deterioration.

Ⅴ. Core advantages and application scenarios of HPMC putty

• Advantages: good water retention (reduce hollow drums), smooth construction, strong crack resistance.
• Recommended use: Wet areas (with water-resistant gray calcium), emulsion paint substrates requiring high flatness.
• Scenarios to be used with caution: very low temperature (<5°C) environments or projects in a hurry (long drying times).

Construction effect = 50% quality of materials + 50% details of the process, it is recommended to do a small area test before full construction.

In short, before you are ready to use wall putty, you must make adequate preparations and master the HPMC wall putty construction strategy. In addition, choosing a high-quality HPMC supplier is conducive to the development of work. For example, Melacoll, Melacoll can not only provide high-quality HPMC products, but also provide you with free guidance on basic formulas, which can minimize your losses.