PVC VISE ADAPTER -- for Holding Pipe




About: I'm a refugee from Los Angeles, living in backwoods Puerto Rico for about 35 years now and loving it. I built my own home from discarded nylon fishnet and cement.

My vise has jaws that were designed for holding flat material, not round pipe. The adapters I made hold the pipe more securely and without damaging the pipe. I made adapters for different sizes of pipe.

The adapters are easy to put on the vise and to take off. They just slide over the jaws.

Step 1: Safety While Heating PVC

We love plastics for what they do for us, but plastic manufacture and decay tend to pollute the environment and negatively affect our health.

Vinyl Chloride, one of the components of PVC, is carcinogenic. When it is locked up in the polymer, however, it is much safer to be around. In my years of experience working with PVC, I have not noticed any adverse effects on my health from being around it.

Always work in areas with good ventilation. If you do get caught in a cloud of smoke, hold your breath and move to clean air.

When heating PVC with a gas stove or propane torch, try not to let it burn. Smoke from burning PVC is bad. With experience one burns it less and less. Don't panic the first time you do burn some. It scorches, but doesn't immediately burst into flame. Move the material away from the flame and try again. Don't breathe the smoke. Smoke avoidance comes naturally for most people.

While heating PVC over a gas flame, keep the plastic an appropriate distance from the flame to avoid scorching the surface before the inside can warm up. It takes time for heat to travel to the center of the material being heated.

Keep the plastic moving, and keep an eye on the state of the plastic. When heated, the PVC material is flexible, like leather. Beyond this stage, you risk scorching it.

A word from James, the plastic engineer -- "Just a word of warning, PVC can handle some high heats but if it catches fire, you wont be able to put it out, it does not need oxygen to burn so don't do this inside".

I do work inside, but my house is made of cement and has good ventilation. MAKE SURE THAT YOU HAVE GOOD VENTILATION. PLAY WITH FIRE -- CAREFULLY.

Step 2: Planning and Layout

I used a piece of paper to substitute for the PVC while I visualized how big a piece of plastic I needed. The height of a stack of four CD's was about how deep in the vise I wanted the pipe to rest. The plastic had to be long enough to allow that and wide enough to cover the vise jaws and leave some extra material for tabs to fold down later.

Step 3: Preparing the Vise

The plastic will be heat formed directly over the vise, with a piece of pipe in place to assure a pipe of that diameter will fit in it later. In order to work quickly when the time comes, making sure the pipe goes in only as deep as desired, a piece of wood is placed in the jaw area for the hot plastic to bottom out against.

Step 4: Cutting and Opening Up the PVC

If you ever need to cut a piece of pipe nice and square, wrap a piece of paper around the pipe and use the edge of the paper as a guide for marking the cut line. As you saw around the pipe, keep turning the pipe so you can make sure you stick to the line.

Cut the pipe section down one side. Hold the material with pliers, and soften it over a gas stove. When it is floppy, like a piece of leather, it is ready for heat forming.

Step 5: First Heat Forming

After getting the material soft and pliable, force it into position in the vise jaws. Fold over what protrudes from the top and hold it down until it cools.

The next step will be to fold down the tabs on the sides of the jaws. Pencil in where you need to cut and then make the saw cuts.

Step 6: Fold Down the Tabs

Heat the tabs with a propane torch and bend them over the jaws. I did them one at a time, heating them away from the vise and then putting the adapter in place on the jaws for bending the tabs down.

Round of sharp corners when the plastic cools. I used snips and a file to round the corners.

Step 7: Drill a Hole for Hangin

I hang my adapters on nails near the vise for easy access when I need them. Hanging things is a good way to keep things organized and visible.

Step 8: Adapters for Different Sizes of Pipe

I have adapters for all the common pipe diameters I work with.



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    19 Discussions


    3 years ago

    hey im new to instructables! you seem like a person that really knows how to work with pvc pipes. im actually working on a project and would really appreciate if you can give me some input and advice.

    1 reply

    Reply 3 years ago

    I have already posted all I know on the subject on Instructables, so you could follow my posts and figure things out.

    What kinds of input and advice are you looking for.


    Reply 5 years ago on Introduction

    I'm sure that might be useful at times. The rigid plastic is better in this case, because if the pipe wants to travel upward, the plastic stops the upward movement. Leather might flex and let the pipe pass.


    5 years ago on Introduction

    Great idea for shaped vise jaws!

    I have used boiling water to soften PVC to a bendable state on many occasions. PVC gets soft at 100C (boiling water). It's melting point is 100 - 260C. If you need more heat than 100C, use some type of heated oil as the bath.

    This project is a perfect size for boiling water immersion. Plus, no bad fumes from PVC decomposition to worry about. If you don't get the right shape the fist go, just put the piece back in the bath to re-soften

    It goes without saying, but please make sure you use gloves when handling hot plastic.

    You will have to experiment as to the time needed to fully soften the material for your purpose; dependent on the size and thickness of the work piece. Sand filled tubing is a bonus, as it should hold the heat to allow for a longer working time provided the sand also gets +100C.

    I will admit though, it takes a bit of ingenuity to use this process on a 20' stick of PVC.

    I've thought about steam, but have yet to try it.

    1 reply

    Reply 5 years ago on Introduction

    Note that there is very little burned plastic from heating it over a flame, if you keep the work at an appropriate distance from the flame and in constant motion.

    Heating it indirectly by using hot water seems like you would be wasting fuel heating the water first. Still, if it works for you, go for it.


    Reply 9 years ago on Introduction

    Not a device, but a technique. Fill the pipe with sand, ends capped with masking tape. Heat the pipe, bend it, let it cool, empty out the sand.


    Reply 5 years ago on Introduction

    For copper, fill the pipe with soapy water, and freeze it. It can be bent without heat, and the ice will melt when you are done. This is how brass trumpets and trombones are made.      http://youtu.be/8NAaRQUTp9g


    Reply 9 years ago on Introduction

    I never tried it. It seems like the general idea would be the same. The sand keeps the pipe from pinching shut when bent. Bending it inside a channel, like a pulley wheel might help, too. Also, maybe heating one side more than the other, perhaps to favor stretching over compression.


    Reply 8 years ago on Introduction

    I just found a great new fast easy technique for bending pvc pipe.

    I have used this with 1/2 inch internal diameter schedule 40 pipe, but I have heard it can work with larger pipe as well. The one tool you need is a long spring (like the springs on old time screen doors) that is close to the inside diameter of the pipe you want to bend.

    After attaching a string to one end of the spring, you insert the spring so it is centered on the area the bend will be in. Grasp the pipe on either side of where you want the bend to be and smoothly pull it against your bent knee (or any other sturdy rounded form) until you have bent it to the curve you want. Magically the spring will prevent the pipe from collapsing or kinking on the bend. You may have to slightly unbend it to remove the spring, but you can rebend it after the spring is removed.

    For larger diameters (up to 4 inches) you might need a pipe bender (like they use for metal pipe bending) in addition to an appropriate sized spring to give you enough leverage to bend the pipe.

    Here is a video of how it works with a fancy purpose made ($30) spring, but at least for the 1/2" pipe I find the $2.95 spring from the hardware store works just fine.

    For the larger diameters it is hard to find the right diameter spring, so you might just have to bite the bullet and get the "Pipeviper" pipe bending spring:

    Phil B

    9 years ago on Introduction

    My brothers gave me a gift certificate to a home improvement store on the occasion of my birthday. After a lot of thinking about a practical way to use it, I bought a heavy duty heat gun. I can already tell it will be very handy for any project in which I want to bend and form PVC. This Instructable is a good idea. A person could make simple covers for vise jaws so soft materials can be held without marring them. I may make a set for myself tonight. Thanks.

    1 reply