How to disassemble a hilti foam gun

How to choose a foam gun: HouseChief editorial

Manufacturers offer a large range of devices for applying polyurethane foam sealant. Let’s consider how to choose a gun for assembly foam, so it will last long enough and fully meet the requirements. When choosing, you should pay attention to:

  • Material;
  • The possibility of disassembling the mechanism. The non-disassembled models are not repairable. Disassembled, can be repaired, but are more expensive;
  • Tightness of the valves;
  • The purpose of purchase. If you have to perform one-time blowing of seams, you can do with a disposable gun for assembly foam. For constant daily use, it is worth choosing a professional model made of metal with Teflon coating;
  • Spare parts availability. Relevant when buying an expensive professional model.

disassemble, hilti, foam

And now let’s consider specific models and manufacturers.

General description

To perform repair work with the use of assembly foam, it is preferable to use a special gun. The substance cylinders themselves are divided into domestic and professional. The mixture is sold in sealed packages of different sizes. The yield depends on the expansion coefficients, which are several times higher than the original volumes. In a cylinder, the substance is under high pressure.

When using the domestic type of material, the cylinder will be equipped with a tube of plastic, through which the installation material comes out. Products of the professional type assume the use of a gun. The foam itself is used in various areas of construction and repair:

  • during the installation of windows or doors to fill the voids around the perimeter;
  • for sealing the joints of various utilities, caulking cracks and voids in masonry, plastered walls or concrete;
  • In the installation of partitions and other structures in which the use of thermal insulation. In this case, the mixture acts as an adhesive that quickly sets;
  • for removing cold bridges and soundproofing;
  • Fireproof compositions are used in the construction of stoves, chimneys;
  • For fixing foam boards during insulation or to remove voids in roofing work.

Assembling foam can be considered the ideal material for repairs. The only disadvantage. after it hardens, there is a high probability of clogging the tool and the need for disassembly, cleaning, repair. Not all products can be disassembled, in some cases the body is made of monolithic plastic or metal. In frequent work, it is better to buy a collapsible design with a valve for dosing the mixture.

Maintenance and repair of the assembly gun

In practice, there have been cases where the most inexpensive gun, but chosen with scrupulous adherence to the testing procedure, allowed a careful worker to produce up to a hundred cylinders of professional foam. But this is rather the exception that proves the rule: The gun must provide its owner with the possibility of maintenance and repair.

If your gun works perfectly and does not need any intervention. do not disturb it. In this case, it all comes down to following some simple rules:

  • twist the cylinder from the gun only to replace it with a new one, even if the cylinder is empty and you need to take even a long break from work. leave the cylinder on the gun;
  • Regularly clean the nozzle of the gun with a stop valve from the foam residues, but do not allow mechanical impact on the cone tip of the stem;
  • treat the receiving assembly with foam flushing when replacing the canister;
  • keep an eye on the condition of the gasket bolt between the trigger and the gun rod, tighten it slightly if necessary, and lubricate the rod itself periodically with silicone when changing cylinders, before installing a new one;
  • Replace the cans quickly, and even if you do not need to immediately produce a filling, be sure to squeeze a little foam, to replace the remains of the material from the previous can, was in brief contact with air;
  • When stopping work for an extended period, be sure to tighten the adjusting screw all the way.

If your gun is no longer functioning properly for any reason, proceed with the repair, but with the utmost care. The most common reasons for failures when repairing assembly foam guns are:

Use a well fitting tool for disassembly, try not to use excessive force when disassembling a “frozen” gun that has frozen foam. Know that the cans for flushing are practically pressurized acetone, sometimes with a small amount of additives. Therefore, for cleaning gun parts during repairs, you can save three times, using it or solvent 646, which also does a good job.

By the way, for removing assembly foam from hands and other body parts, an inexpensive medical product called “Dimexide” works very well. Its base is dimethyl sulfoxide, a very powerful solvent that is naturally safe for human skin. Sold in drugstores.

When repairing the gun for foam is important not to damage parts during disassembly, do not lose them and assemble everything in reverse order, carefully, but without fanaticism lubricating all silicone grease, of course without leaving in its insides even a hint of the old foam. Fumka tape can be used to loosen threaded connections.

Perform at least an abbreviated leak test, the same as when you buy it, before you start.

What model to buy?

If the approximate flow of assembly foam in the foreseeable future is not more than ten to twelve balls, you can buy a cheap plastic gun. Prolonged use is not suitable for this type of model. Masters who plan to use the tool in the long term, but not regularly, should opt for a metal collapsible product. Teflon-coated guns are preferred by those who frequently work with assembly foam. This material is easy to clean and rinse, even without the use of a special liquid. The high-quality plastic foam guns have also proven effective. Both of these models are used, as a rule, by professionals. Home masters will suit the usual metal model.

The design of a foam gun

A professional foam gun is a mechanical device, all parts of which have leak-proof connections and valves. This is necessary to isolate the foam from interaction with oxygen until it comes out of the tip. On contact with oxygen, a chemical reaction occurs, which leads to a significant expansion of the foam and its curing.

Accessories of the gun for installation foam:

  • The tip. Mounted on the end of the gun barrel. Its diameter is 1/4-1/6 of the barrel diameter. This constriction is necessary to create additional foam pressure at the outlet of the gun. The tip is removable and can be replaced if it fails.
  • Barrel. Pistols can be equipped with two types of barrels: collapsible and non collapsible. The collapsible barrel consists of two cylindrical tubes, which are centered (one inside the other). The main indicator of the quality of gun barrels is the degree of roughness of the inner surface on which the foam moves. From the inside the barrel should be as polished as possible. This will facilitate the movement of the foam and cleaning of the barrel at the end of the work.
  • Adapter. The element that connects the can of foam to the gun. The adapter is often contaminated with foam residue when recharging the cylinder. It is located at the top of the gun. This is caused by the necessity of balancing the tool when it is unloaded. Quality guns are always perfectly balanced, so they are very comfortable to use. The adapter is a removable part that must be replaced if it fails.
  • Trigger adjustment screw. This mechanism is designed to manually adjust the output of the rod, which limits the depth of the trigger. This is how the dosage of the foam coming out of the can (some installers call this part. “foam feed”).
  • Barrel retaining nut. It has a fairly fine thread pitch and allows for a tight fit between the barrel and the gun.
  • Trigger. The executive mechanism that presses on the rod and pushes the foam out of the cylinder.
  • Handle. Made of different materials. Professional models are equipped with well polished metal handles that can be easily cleaned of accidentally spilled foam. Quality plastic grips also do a good job, but cheap plastic quickly wears out and gets dirty.

A gun for assembly foam consists of standard assemblies, some of which are consumables and can be replaced

How to disassemble the assembly gun

If you need to repair or simply clean a foam gun, it must first be disassembled. It is quite easy to do. the sequence is as follows.

Before disassembling the gun, the can must be removed from the gun

The adapter is pressed on a metal axis, so a small amount of force must be applied to remove it with a screwdriver or other auxiliary tool

The barrel of the gun for assembly foam is unscrewed with a wrench, for which there are special slits in its base

To remove the cap it is necessary to unscrew the adjustment screw

To remove the inner part of the barrel, you need to put some pressure on it from the tip side

How to Clean a Foam Spray Tool

The ideal solution is to clean the gun with a special cleaner. To do this, the used foam cylinder is replaced with a cylinder of cleaner. Pulling the trigger causes a jet of liquid to move in the barrel, which washes away the foam residue. This procedure should be carried out until a clean solvent appears at the outlet of the barrel.

To clean the gun, a container with a special agent is installed in place of the can with the foam

Solvent cans have a standard attachment and are suitable for all gun types.

Professional installers recommend buying solvent from the same manufacturer as the foam. This approach ensures faster and better cleaning. Different grades of foam and solvent may not chemically work well together. This can make cleaning more difficult.

When using solvent, remember that it is highly flammable.

If the work is finished and no original solvent is available and the foam on the gun has begun to polymerize (solidify), the cleaning process takes longer and requires some effort. In such cases, any building solvent (acetone, solvent and others) can be used to remove foam residues.

The time of complete curing of assembly foam after contact with air is indicated on the cylinder. The level of humidity has a great influence on this indicator. In sufficient humidity a five centimeter layer of foam hardens within 2-3 hours, but the final polymerization of the foam may last another 7 to 12 hours. In frosty or dry weather polymerization time increases up to 24 hours.

For rough cleaning of the gun from the dried foam a construction (stationery) knife is suitable. Use it to clean the outside of the gun and its nozzle. Work carefully to cause minimum damage to the polished parts of the tool. After the foam is removed, the surface should be wiped with a soft cloth soaked in any solvent.

If no special solvent is on hand, the rough cleaning can be done with a construction knife

After treating the exterior surfaces, gun valves must be cleaned of foam. Almost any construction solvent will do.

In order to clean the assembly gun, you can pour solvent into it and blow it through the barrel

Do not abuse solvents that are not designed for foam cleaning. Frequent cleaning of the gun interior with improvised substitutes will result in faster wear of the tool parts.

In the case of complete curing of the foam and long-term storage of the gun in this condition (more than three days in any humidity), you can also try to restore it. The most problematic part of removing fully cured foam is. It can also be done in an ordinary solvent and the entire gun must be disassembled and each part mechanically cleaned from the foam. Wire and acetone are used for cleaning the barrel. Be careful not to make any sudden movements.

If the foam inside the gun has polymerized, it can only be cleaned after it has been disassembled completely

It is difficult to clean the gun from the cured foam and not to damage its surface. This method is a last resort. It is much more effective to buy a cleaner in a timely manner and use it as directed.

There is also a “folk” method of removing the assembly foam from the gun and various surfaces. It involves the use of a drug Dimethoxide (Dimethylsulfoxide), which is available at any drugstore and costs inexpensive. When using it you must ensure that the drug contact with human skin was minimal, so it is better to work in rubber gloves. The drug is applied directly to the foam and allowed to stand for 30-40 minutes. The foam can then be removed with a cloth. Using such a remedy, you should remember about the specific smell of Dimeksid. some people simply can not stand it.

When using the drug Dimexid you must be careful. it causes skin irritation and a very specific smell

In case the foam gets on your hands and other areas of the skin, it is advisable to wash it off with vegetable oil, which should be applied to the work surface, hold for 30 minutes and then wipe with a rag. This method is the most painless for humans.

The gun for assembly foam, how to properly flush

The foam gun is a useful tool for any renovation or construction project. This device is not only necessary for fast work, but also for saving. The accuracy of application is greatly improved, and this leads to savings. In the following, we will show you how to use a spray gun for foam. It’s actually easy, but certain rules must be followed.


The gun can help in the following situations:

  • When squeezing out the necessary amount of foam, which contributes to the application of an unmistakable portion of the substance;
  • in saving material consumption: thanks to the gun will require 3 times less foam than with a conventional nozzle on the cylinder;
  • in adjusting the flow of material depending on the size of the cavity to be filled;
  • The foam flow can be adjusted as needed: after releasing the lever, the flow of foam stops and the excess foam does not remain;
  • retention of residual material: the foam does not freeze in the gun after work is stopped
  • maneuvering at height: the tool can be used with one hand, which is very useful if the builder is standing on a stool, ladder or holding something in the other hand.

It is worth noting that during operation, the tool can fall down. But thanks to the metal base of the gun, the container with the foam will not break. Additionally, it should be noted that an ordinary cylinder hardens in the open air, unlike the gun.

Disassemble a HILTI CF-DS1 foam gun

Thanks to the valve and the adjusting screw, as much foam as needed can come out of the cylinder.

The following is the composition of the gun:

The device consists of three parts: the handle, the feeding mechanism and the can holder.

By its frame the gun can be collapsible and monolithic. On the one hand, the monolithic design seems to be more reliable, on the other hand, the collapsible model is easier to wash, and in case of minor damage it can be repaired. Which one to choose depends on the builder and the related characteristics of the device.

It is necessary to consider models either with a built-in ergonomic handle, or with an overlay to it in the kit. You have to work long hours with professional models, so it is important that your hand is not tired.

Metal is notoriously easier to clean away dirt, so the metal spout can easily be cleaned with an ordinary construction knife.

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