FAQ

We sell welding rod in 5 & 10# packages. You can purchase continuous coils or 48” long sticks.

PVC = 320°C (608°F); +/- 5°C (9°F)
Polypropylene = 320°C (608°F); +/- 5°C (9°F)
HDPE = 300°C (572°F); +/- 5°C (9°F)
CPVC = 360°C (680°F); +/- 5°C (9°F)
Kynar (aka PVDF) = 375°C (707°F); +/- 5°C (9°F)

In order to choose the most appropriate welder, you need to answer the following question:

Will welding take place in the field or in the shop. If in the field, choose between our 46RW (if welding speed --- approximately 1 foot per minute --- is not critical) or 47RW (if welding speed --- approximately 5 feet per minute --- is important) models.

If in the shop, there are more choices. Use the 41HT or 42TM (a 41HT welder plus some accessories) if welding speed --- approximately 1 foot per minute --- is not critical. 43HS welders are best if welding speed --- approximately 5 feet per minute --- is important. Our 44AW model will allow you to weld at both slower and faster speeds.

Yes we do. Our FUSION Series welders provide several important features and benefits as follows:

1.    Ability to hold welding temperature (once reached) within 2 – 3°F throughout the entire welding process (whether 10 minutes or 8 hours for example).
2.    Rapid heat up (to selected welding temperature) and cool down (to room temperature) of the welders = it takes approximately 60 seconds --- versus 5 – 6 minutes for standard series type welders.
3.    We offer both digital display and analog (variac/dial) type FUSION Series welders for both shop air and field applications.
4.    No more burned out heating elements due to operator error (example = shut off air supply with the welder still plugged in and glowing hot). The FUSION welder’s heating element automatically shuts off when too low of an air flow value is detected.

In order to choose the most appropriate tip, you need to answer the following questions:

1.    What plastic material(s) will you be welding. If PVC (or CPVC), we carry tips to accommodate both round & triangular shaped welding rod of various diameters. For all other commonly used plastics (PP, HDPE, Kynar, Halar, PFA, etc.), use any of our other round & triangular shaped tips.
2.    What is the thickness of the plastic sheets you will be welding. For 1/16” - 1/4" gauge, use 1/8” diameter tips. For 1/4" – 1/2" gauge, use 5/32” diameter tips. For 1/2” and above sheet gauges, use 3/16” diameter tips. Note that these recommendations are only suggestions and the best tip to employ will depend greatly upon your application.
3.    1/8” diameter tips are normally used for repair work (cracks). 4. Normally, triangular tips are recommended when a lot of inside corner welds need to used in fabricating the finished product (1 triangular bead takes the place of 3 round beads --- save time/$).

It is strongly recommended that you weld these materials using an inert gas (Nitrogen or Argon). Welding with air can result in an inferior (less strong/less penetration/lower welding factor) weld. This means that the welds in your finished product (examples = plating tanks, chemical holding tanks, ductwork) will fail much quicker, resulting in chemical leaks, crack development & other premature failures.

We recommend 1/16” as the thinnest and 3/8" as the thickest sheet to bend. Depending upon your width requirements our models allow you to bend to a maximum width of 28, 54, 96 or 144 inches.

Yes. Kamweld is a total turnkey corporation. We manufacture, assemble and test all of our product lines here in Norwood, MA (for the past 50+ years), as well as market a full line of replacement parts. As a service to our customers, we do repair estimates and repairs at your request.

No we do not. However, we can provide you with the names of several fabricators who may be able to help you with your request.

As a convenience for our customers, we provide numerous products in our eShop that would be of interest to plastic fabricators.

Please visit our website (www.kamweld.com) & click on the “User Manuals & Training” tab at the top of the page. You will then be taken to another screen. Please click on the tutorial entitled “Plastic Welding Using Kamweld''s Durable Welders”.

More information can be found by clicking on the “User Manuals & Training” tab at the top of our website home page as mentioned above. Then click on the tutorial entitled “Plastic Sheet Bending with Kamweld''s Heating Tools”.

Click on the “User Manuals & Training” tab at the top of our website home page.Then click on the tutorial entitled “Operating & Maintenance Instructions For Kamweld Plastics Welding Equipment”.

The following errors are the most common when welding plastics:

1.    Over-heating
2.    Under-heating
3.    Improper root penetration
4.    Air inclusion in the weld
5.    Stretching of the filler rod
6.    Incorrect handling of the welder:
wrong angle
too slow or too fast travel lack of fanning motion
heat too close or too far away from work heat source not centered on weld bed

7.    Incorrect gas used for heat source
8.    Improper or no bevel preparation

Application, practice and the right tools will prevent faulty welds and tough secondary repairs.

   
The list is short but very important as follows:


1.    Thorough root penetration
2.    Proper balance of heat on the weld and pressure on the welding rod
3.    Correct handling of the welder
4.    Correct sheet preparation

To insure complete root penetration, make certain that the proper gap is maintained at the weld root, on both single “V” and double “V” butt joints.

Overheating of the weld is a common fault with the novice plastic welder. By paying close attention to a weld’s color, you can tell whether overheating is occurring. When PVC is overheated, it will begin to discolor from a yellowish tinge to a brown, and it eventually will char. When PP or HDPE is overheated, it becomes    
 
transparent and eventually flows away like hot wax from a candle.

Under heating of the welding rod, the base material, or both, will also result in a poor weld. Once the welding rod cools, you will be able to remove it from the base material with very little effort.

A poor weld bead should always be removed from the weld bed and a new weld made. Under no circumstances should a new pass be laid over a burnt weld or one not properly bonded.

Improper stretching of a welding rod can be detected by measuring the rod before welding and measuring the length of the pass. The latter should not be more than 10 % greater than the length of rod used.

Some testing of materials, tools and your application techniques prior to an actual application is well worth the time. You’ll be much better prepared to produce high quality welds on your plastic job.

For field use, 47RW is what works. If done in the shop, use one of the 43-HS Series welders. 43-HS-600 is totally adequate. Note that both the 43-HS-750 and 43-HS-900 give the fabricator somewhat more welding speed.

For field use, 47RW is what works. If done in the shop, 43-HS-600 is the welder of choice. 43-HS-750 & 43- HS-900 also work and gives the fabricator somewhat more welding speed. But, for the customer’s application, 43-HS-600 is best to use (FYI, application = welding 10” diameter CPVC duct).

Yes, but it’s not always a matter of just one model welder that works for the application ----- and it also depends on the application (example: fabrication versus repair work). To repair cracks in PVC chemical holding tanks, for example, many of our model welders will work --- but many [due to element wattage] could be overkill, namely, pull &/or burn the plastic weld rod and surface of the holding tank. So for this specific application, 46RW (field work) or 41-HT-350/-450 are what’s best to use.

1.    Close valve on air-pressure regulator by pulling upward on the plastic knob until a clicking sound is heard, and then proceeding to turn the knob counter clockwise This will prevent possible damage to the gauge from a sudden surge of excessive air pressure.
2.    Connect the regulator to a supply of either compressed air (which should be free of oil or moisture) or inert gas. The Kamweld air-pressure regulator is rated for 200 lbs. (90.72 kg) of line pressure. If inert gas is used, a pressure reducing is needed (obtainable from a gas supplier).
3.    Turn the air supply on. The starting air pressure for each model is indicated in the chart on the next page. Please note that the heated air temperature depends on the wattage of the heating element AND the air pressure. The operating air pressure requires slightly less air. The chart shows the approximate temperatures obtainable with 120 volt AC supply:

Caution: if the round spanner nut (which holds the barrel to the handle) becomes too warm to the touch, the gun is overheating. If this occurs, increase the air pressure immediately, according to the instructions in the right column. By increasing the air pressure, the air temperature decreases.

4.    Connect the welder to a common 120 volt AC outlet. A three-prong grounded plug is supplied with each unit and MUST be used.
5.    Allow the welder to warm up at the recommended STARTING pressure according to the temperature chart on the following page. It is essential that either air or inert gas flows through the welder at all times, (from warming up to cooling off), to prevent burn-out of the heating element and/or further damage to the gun. AT NO TIME SHOULD THE ELECTRICITY BE CONNECTED WITHOUT AIR FLOWING THROUGH THE GUN.
6.    Select the proper welding tip and install it into the threaded outer barrel with pliers to avoid touching the tip and barrel while they are hot. After the tip has been installed, the temperature will increase slightly due to back pressure. Allow two to three minutes for the tip or outer barrel to reach the required operating temperature.
7.    If you find the temperature is too high to weld the material you are working with, increase the air pressure slightly until the temperature decreases. If the temperature is too low for your application, decrease the air pressure slightly until the temperature rises. When increasing or decreasing the air pressure, allow at least two or three minutes for the temperature to stabilize at the new setting. Damage to the welder or heating element will not occur from too much air pressure: however, the element can become overheated by too little air pressure. When decreasing the air pressure from the recommended starting pressure, never allow the spanner nut to become too hot to the touch. This is an indication of overheating. Maximum operating temperature with the minimum air pressure is obtained when the spanner nut is only slightly warm to the touch. A partial clogging of the dirt screen in the regulator ora fluctuation in the line voltage can also cause over or under heating.    

8. If the threads at the end of the barrel become tight, clean them with a 9/16”-18 tap. Occasional application of high temperature grease on the threads (both at the outlet end of the barrel and on the spanner nut) will prevent seizing and keep threads free.

When welding is completed, disconnect the electricity and allow the air to flow through the welder for about four to five minutes or until the barrel becomes cool enough to touch.

Push the end of the barrel against a solid object (such as the side of a bench). Hold the handle tightly and push inward. The pressure on the barrel compresses the element spring, Use the spanner wrench to loosen the spanner nut. Keep the pressure on the handle and back off the nut all the way by hand. Hold the barrel and place the complete welder on a flat surface. Remove the barrel and gently pull the element out of the handle. Grasp the socket at the end of the wire tightly and jiggle or rock the element while pulling until the element is completely dislodged from the socket. To reinstall the element, reverse the above procedure. Turn the element clockwise (about 1 ½ turns) while pushing the wire gently back into the handle. This prevents kinking of the wire during reinstallation. To reinstall the barrel, reverse the above procedure.

To remove the plastic grip from the handle, remove the screw at the end of the grip. Slide the grip back over the hose. Hold the handle firmly and grasp the tail piece and hose. Use a slight twisting motion while pulling back until it becomes free. Then the wire and socket can be completely removed. To reassemble, reverse the above procedure, making sure to line up the screw holes in the tail piece and the handle.

Tack Welding
 
Tack welding is a shallow fusion of the mating surfaces of the material. It possesses little tensile strength. It holds the pieces together until the regular bead is welded. Tack welding eliminates the need for clamps, jigs and additional manpower.

For practice welding, prepare the material as follows:

1.    Take two pieces of 1/8” thick PVC sheets, each about 2” wide by 6” long. Bevel one of the long edges of each piece to about 30º for a total included angle of 60º. Do not bevel to a feathered edge.

2.    Remove all dust and chips. Do not use a solvent. This will soften the material and result in a poor weld.

3.    Clamp one of the beveled pieces flat on a work bench with the bevel pointed upward. Place the other pieces so that the beveled edges face each other. Install the tacker tip. Hold the welder upright at an angle of about 80º perpendicular to the surface of the material.

4.    Hold the loose PVC piece firmly against the clamped piece. Touch the point of the tacker tip quickly but firmly along the mating surfaces, making short (½” to ¾”) tacks at intervals of about 1 ½ to 2” along the joint.

5.    Then draw the point of the tacker tip along the entire joint, fusing the edges together. This operation must be performed quickly. Hesitation at any point can result in charred spots that must be removed before further welding. The two pieces are now fused together with sufficient strength for handling.

Welding Operations - Hand Welding

Hand welding can provide very high tensile strength, if KT properly accomplished. It is recommended for welding corners, short runs and small radii. It also provides the beginner with a chance to determine the correct balance of heat and pressure required to produce a good weld.

1.    Install the round tip and allow for warm-up time. Hold the welder in one hand and weld rod in the other hand.

2.    Preheat the base material at the start of the weld by fanning the heat about ½” from the material’s surface.

3.    Hold the rod, which has been precut at a 60º angle, perpendicular to the joint of the material, and slightly above the preheated point, with the face of the 60º cut toward the direction of the weld.

4.    Direct the heat to the beveled surface of the material and the bottom and front surfaces of the rod. Continue the fanning motion of the tip. Make sure that the air stream is directed straight to the joint of the rod and beveled area. When the rod and the base material become shiny and “tacky”, touch the rod material. They will stick together.

5.    Now lean the rod forward in the direction of the weld. Push the rod down so that the first part will adhere and not “skid”. Maintain enough pressure on the rod so that the softened end of the rod presses into the softened surface of the material.

6.    Now lean the rod back at a slight angle, away from the direction of the weld, causing the rod to bend just above the point where it is flowing into the bevel. Maintain the fanning motion with the welder tip and enough pressure on the rod while proceeding with the weld.

Generally speaking, the base material will take more heat than the rod, although the distribution of the heat necessary can be determined by observation. If the tip is not kept in motion or if it is held too close, browning or charring will occur, resulting in an unsatisfactory weld. If the tip is held too far away or at an incorrect angle, an uneven weld will occur. If the rod is pushed too hard into the base material, it will stretch, resulting in a flat, highly stressed weld, which will break if an additional weld is laid over or abutting it or if it is subjected to routine environ- mental stress.

7.    The weld can be stopped at any time by merely removing the heat from the weld area. The weld may be continued from that point with the same rod, or an entirely new start can be made, using the procedure above

8.    When the weld is completed, cut the rod off close to the base material with a knife or a pair of cutting pliers.

High Speed Welding

 
The conventional hand welding method now becomes a faster and more uniform operation. Once started, the rod is fed automatically into the preheating tube by the motion of the welder being pulled along the joint. The

The necessary pressure is no longer provided by holding the rod in the hand. Instead, a shoe on the end of the tool furnishes the necessary pressure and, at the same time, smooth’s out the rod for uniform appearance and higher tensile strength. Gentle pressure on the rod results in better control of the weld.

The principle of high-speed welding incorporates the basic methods utilized in hand welding with specially designed and patented tools. Here too, the requirements for constant heat and pressure must be fulfilled. The accelerated rate of speed in high-speed welding is possible because both the rod and the base material are preheated before they reach the fusion point. A round or triangular rod is preheated in a tube, while the base material is preheated by the hot air stream from a vent in the underside of the welding tip.

The necessary pressure is no longer provided by holding the rod in the hand. Instead, a shoe on the end of the tool furnishes the necessary pressure and, at the same time, smooth’s out the rod for uniform appearance and higher tensile strength. Gentle pressure on the rod results in better control of the weld.

The conventional hand welding method now becomes a faster and more uniform operation. Once started, the rod is fed automatically into the preheating tube by the motion of the welder being pulled along the joint. The Kamweld high- speed tools automatically give constant balance of heat and pressure.

1.    Select and install the proper size high-speed tip for the appropriate size welding rod. Allow for warm-up time.

2.    Grasp the welder firmly and hold it in an upright position, with the point of the high-speed tip approximately ½” above base material, directly over the starting point of the weld. Insert the rod into  the welding tube and hold it there until the base material turns shiny and starts to soften.

3.    Push the rod down until it sticks to the base material.

4.    Continue exerting downward pressure on the rod, which will then bend and lower the shoe to the rod. The shoe of the tip will rest on top of the exposed part if the rod (see figure 5, illustration 1).

5.    While continuing to exert moderate pressure with the shoe, lean the welder to about 60º toward the operator and start pulling the welder in the same direction of the weld, at the same time helping the rod into the preheating tube with light hand pressure (see Figure 5, illustration 2).This technique requires practice. If the weld progresses too slowly, discoloration and charring will occur, and the rod will buckle in the feed tube. If it progresses too quickly, a cold weld will occur.

6.    Continuously observe the condition of the welding rod as it appears under the shoe as the weld progresses. Uniform flow lines should be visible along both sides of the rod, without discoloration or charring.

7.    After completion of the weld, the rod can be cut off in two ways:

1.    Withdraw the welder completely so that any remaining welding rod will slide out of the tube. The rod can then be cut with a knife or cutting pliers as close as possible to the end of the weld. DO NOT allow the rods to lift at the end of the weld.

2.    Bring the welder quickly to an upright position and push down hard with the point of the shoe. This action cuts the rod at the end of the weld. The remaining rod is pulled out of the tube by  hand (see Figure5, illustration 3).

High Speed Welding for Plasticized Strips

Follow the same procedure as for round or triangular rod high-speed welding as previously described, except


1.    Precut the strips to required length to complete the weld.
2.    Start the weld by tamping the shoe section of the strip in the direction of the weld. Do not drag for the first inch of the weld until the strip appears firm. Then continue welding with proper downward pressure and speed, showing slight flow lines along both sides of the strip. If performed properly, slight flow lines along both sides of the strip will appear.

If the weld progresses too slowly, the strip will soften excessively and the shoe will stretch the strip. A quick recovery can be made by immediate motion, such as in the start of a weld, proceeding in the direction of weld at the same time.

Please download the Product Manuals PDF files by clicking on the links below.

Fusion Series Welder

Bending Devices

Kamweld Brochure

Kamweld Welder Instruction Manual

Plastic Welding Manual