The question of the compatibility of materials in body repair often becomes a stumbling block even for experienced craftsmen, not to mention amateurs who decided to save on the services of service stations. Acid soil (or jet soil) is one of the most effective means of protecting metal from corrosion, but its chemical composition dictates strict rules for further work. Many beginners, seeing a flat surface after drying the aerosol, immediately reach for a can with a polyester putty, making a fatal mistake.
The direct answer to the question “can be put on acid soil” is categorical no, if we are talking about applying putty directly to the dried layer of acidic acid. The chemical nature of these materials is incompatible, and ignoring this fact will lead to detachment of the coating, the appearance of bubbles and a rapid return of rust. Phosphoric acidThe nutrients contained in the soil continue to react with the metal even after visual drying, creating an unstable surface for heavy fillers to adhesion.
To avoid reworking the work and loss of time, it is necessary to clearly understand the sequence of layers in the “pie” of body repair. Acid soil should always be covered with acrylic fillerIt already serves as a reliable basis for putty or final painting. A breach of this technology is a time bomb that will “explode” after a few months of vehicle operation.
Chemical incompatibility of materials
For a deep understanding of the problem, it is worth considering the chemical processes that occur when various components come into contact. The acid soil contains orthophosphoric acid, which converts iron oxides into stable phosphates. This process is necessary to stop corrosion, but it leaves active chemical bonds on the surface that are aggressive against styrenes, which are part of most polyester putty.
If you apply putty directly to the acid, a reaction begins that destroys the adhesive layer. As a result, you will get a situation where the putty will either not dry properly, or fall off in layers along with the ground at the first vibration of the body or temperature expansion. Polymerization putty will be disturbed, as the acidic environment prevents the correct curing of the resins.
In addition, acid soils have low mechanical strength and high hygroscopicity (moisture absorption) in their pure form. They are not designed to create a flat surface or fill up irregularities. Their task is to passivate the metal. Putty requires a rigid, inert base that will not react with its components.
⚠️ Warning: Never try to “strengthen” the adhesion of putty by applying it to fresh, not completely dried acid soil. This will speed up the chemical reaction and will lead to a marriage.
The correct technology of applying layers
Professional body repair involves strict adherence to the sequence of application of materials, known as a layer system. After you have processed the metal rust converter or applied acid soil from a can, the next mandatory step is to isolate this layer. For this purpose, acrylic soil-filler is used.
Acrylic soil creates an inert film that securely seals the active components of the acid layer. It is on acrylic that you can and should apply polyester putty. Acrylic has excellent adhesion to both the acid base and putty masses, acting as an ideal intermediary in this multilayer design.
The process is as follows: first, the metal is stripped to shine, degreasing, then a thin layer of acid soil. After drying (usually 15-20 minutes), 2-3 layers of acrylic filler are applied. Only after drying and grinding acrylic is allowed to work with putty, if this is necessary for the alignment of the geometry.
Comparison of soil types for body
In order not to get confused in the range of autochemistry, it is important to distinguish between the main types of soils and their purpose. Acid, epoxy and acrylic soils have different functions and are interchangeable only. Understanding the difference will help you choose the right material for the specific stage of the repair.
Epoxy soil, for example, creates powerful mechanical and chemical protection, completely insulating the metal from moisture and oxygen. Unlike the acidic, on the epoxy soil possible apply putty (although many manufacturers still recommend a layer of acrylic for better adhesion), but acid - can not. Epoxy is more elastic and durable, but requires more complex surface preparation.
Below is a table that helps you quickly navigate the compatibility of materials:
| Type of soil | Basis | Can I slap it? | Substantive function |
|---|---|---|---|
| Acid (Wash Primer) | Phosphoric acid | No (only through acrylic) | Chemical protection, etching |
| epoxy | Epoxy resins | Yes (preferably through acrylic) | Barrier protection against moisture |
| Acrylic filler | Acrylic polymers | Yes. | Alignment, isolation |
| Antigravium | Rubber/Rubber | No. | Impact protection, noise insulation |
As can be seen from the table, acid soil stands alone in terms of the requirements for overlap. It should not be left open under the putty or paint. Use of the Wash Primer (another name of acid soil) is justified only on problem areas with residual corrosion or on bare metal before the main priming.
Typical errors in body repairs
One of the most common mistakes is the desire to save time by skipping the stage of applying acrylic soil. Self-taught masters often think, “Why buy another balloon if the acid is already dry?” This savings leads to the fact that after a month or two putty is inflated, and the corrosion process resumes with renewed force under the layer of repair.
Another mistake is to apply too thick a layer of acid soil. It should be the thinnest film, literally "cauterizing" the metal. If poured a lot, it will not dry inside, remain sticky and become the perfect environment for flaking any subsequent coatings. The instructions on the can usually indicate the optimal flow rate, and it must be followed.
- 🚫 Attempt to dry acid soil with heating - this can lead to boiling of the solvent and damage to the coating.
- 🚫 Grinding acid soil “to zero” before applying acrylic – you remove the entire protective layer, leaving the bare metal.
- 🚫 Using putty on nitro-based over acidic – such materials are also chemically incompatible.
⚠️ Note: If you accidentally splashed acid soil, do not try to save the situation with a dryer. The only way out is the complete removal of putty and soil to metal and the repetition of the cycle in compliance with the technology.
Instructions: how to properly prepare the surface
To achieve a qualitative result, it is necessary to adhere to a clear algorithm of actions. Preparation of the surface takes up to 80% of the time of all work, but it depends on it the durability of repairs. Negligence at this stage will negate all further efforts.
First, the metal is cleaned with an abrasive (usually P80-P120) to a pure shiny state. All corrosion foci must be removed mechanically. The surface is then thoroughly degreased with antisilicone. It is important to use lintless wipes to avoid leaving villi, which can become centers of corrosion.
Then the acid soil is applied. If you use an aerosol spray, shake it for at least 2-3 minutes after the ball appears. Apply 1-2 thin wet layers with interlayer exposure of 5-10 minutes. After drying (usually 15-20 minutes at +20°C), the surface is ready to be covered with acrylic.
☑️ Checklist for preparation for priming
After the acid soil has dried, it is necessary to apply acrylic soil-filler. It will cover the pores and create a flat surface. If the geometry of the body is broken, putty is applied either to bare metal (preliminarily cleaning the acidic acid at the place of application, which is uncomfortable), or, more correctly, first pass a thin layer of acrylic, then putty, then again soaked. But the classic scheme for a beginner: Acid -> Acrylic -> Puttyovka (if necessary) -> Acrylic -> Paint.
Use a developing powder when grinding acrylic soil - it will show where the pits are left and where the soil is knocked down to metal, which will help to perfectly align the surface before painting.
Selection of materials and tools
There are many brands on the market that offer acid soils in aerosol cylinders. For one-time repairs or work with small areas format spray It's the most convenient. It is important to choose products from proven manufacturers, such as Body, Motip, Jeta Pro or Reoflex. Cheap analogues may contain insufficiently active substances or, conversely, too aggressive solvents.
When choosing, pay attention to two-component systems. Some professional acid soils require mixing the base and activator before application. Canisters often use a system with a separator, when before use you need to squeeze the contents of the capsule inside the balloon. This ensures the correct chemical composition of the mixture.
Application may also require:
- 🛡️ Respirator with carbon filter (acid and solvent vapors are toxic).
- 🧤 Nitrile gloves (protection of the skin from chemistry).
- 💨 Compressor and spray gun (if you use soil in banks).
- 📄 Abrasive materials of different grains (P80, P180, P240, P400).
Work should be in a well-ventilated room or on the street, avoiding direct sunlight and dust on the fresh coating. The ambient temperature must be within the limits specified by the manufacturer (usually from +15°C to +25°C).
Why can't acid soil be polished?
It is not recommended to grind acid soil, since its layer is very thin (about 10 microns). When grinding, you can easily peel it to metal, depriving the surface of protection. If there are defects on the ground (dust, shavern), it is better to cover it with a thin layer of acrylic soil, which can already be sanded.
Frequently Asked Questions (FAQ)
In conclusion, we will analyze the most frequent questions that arise in motorists when working with acid soils and putty. These nuances will help to avoid common mistakes.
Can I paint immediately on acid soil without putty?
No, you can not paint directly on acid soil. It does not have covertness, does not hold pigment well and can react with paint components. A layer of acrylic soil-filler is required, which isolates the acid and creates a base for enamel.
How much acid soil from the canister dries?
The drying time "on the stick" is 10-20 minutes at a temperature of +20 ° C. However, full polymerization and evaporation of solvents take longer. Cover with acrylic soil is recommended after 20-30 minutes. The exact time is always indicated on the packaging of a particular product.
What to do if the squirrel is still peeled off?
It is necessary to completely remove the putty and soil at the site of the defect to pure metal. Clean the edges of the transition, degrease and re-conduct the entire cycle: acid soil -> drying -> acrylic soil -> putty. Attempts to glue the exfoliated piece back are useless.
Is there an alternative to acid soil?
The alternative is epoxy soil. It is also applied to bare metal, has excellent anti-corrosion resistance and, unlike acid, creates a stronger film. On some epoxy soils (check in the manufacturer's instructions) is allowed to apply putty, but the layer of acrylic is still desirable for the ideal result.
The main conclusion: Acid soil is the foundation, but not the finishing coating. Always cover it with an acrylic filler before putty or painting to ensure the longevity of the repair.