Heat gun for reshaping acrylic stems?

Tristano-ite

Well-known member
I have a couple pipes with acrylic stems that have a bend that dips slightly below the point that would be parallel to the bowl. This makes them difficult to clench, as well as uncomfortable to hold and smoke out of, because the pipe has to be held at a downward angle in order for the mouthpiece to be straight in the mouth.

I heard that reshaping acrylic stems is possible by heating with a heat gun. My questions are: will any cheap heat gun from Amazon do just fine? What is the ideal temperature to use on acrylic stems? And how easy is it to mess up (how long does the heated stem stay pliable before rigidifying, etc)?

The pipes in question are not terribly expensive, and if I mess it up I won't cry about it. If I'm successful, I'll have 2 more usable pipes, so it's worth some amount of risk to try it out.
 

Sasquatch

I'm sick but I'm pretty
Staff Member
Yes. I recommend putting a pipe cleaner in the airway just so you don't collapse it by accident (probably won't happen anyway).

The thing with acrylic is it's not like rubber which gets softer the hotter you make it. Acrylic is basically inflexible till it melts, and then it's super floppy. So you heat and test and heat and test it and heat and test it... gently, so gently... and then boom, it's floppy and you can move it and set it. Cold water and you're done.
 

Adui

Well-known member
Yes. I recommend putting a pipe cleaner in the airway just so you don't collapse it by accident (probably won't happen anyway).

The thing with acrylic is it's not like rubber which gets softer the hotter you make it. Acrylic is basically inflexible till it melts, and then it's super floppy. So you heat and test and heat and test it and heat and test it... gently, so gently... and then boom, it's floppy and you can move it and set it. Cold water and you're done.
+1 for what he said. I like working with Acrylic (weird I know) but I do know that it has a narrow window between two stiff to bend and oh crap it's falling flat
 

blackmouth210

Friendly Misanthrope
My recommendation is a general reply for a heat gun, if you decide to buy one: Harbor Freight.
I have one of their heat guns and am thoroughly satisfied.
Could it withstand commercial use? I don't know.
But, I don't need it to. I've relied on it for countless projects around the house and it's given me 0 problems.
 

Tristano-ite

Well-known member
Yes. I recommend putting a pipe cleaner in the airway just so you don't collapse it by accident (probably won't happen anyway).

The thing with acrylic is it's not like rubber which gets softer the hotter you make it. Acrylic is basically inflexible till it melts, and then it's super floppy. So you heat and test and heat and test it and heat and test it... gently, so gently... and then boom, it's floppy and you can move it and set it. Cold water and you're done.
Very interesting, didn't know that. I have a hard time visualizing what that will be like to work with. Thanks for the info
 

Riff Raff

Well-known member
Hobby Lobby and the like carry a light duty heat gun, about $15. I suspect that will do less damage than the Harbor Freight model (probably for removing paint, etc.) I've only used mine to re-shape vulcanite stems. But, I did use it change the angle of my Ray Ban Wayfarers sunglasses (they are very flat across the face, I put a slight bend in my nose bridge area). Acrylic can wrinkle on the bottom of the bend, if done too quickly and too severe of a bend. So, proceed with caution.
 

Mrm1775

Well-known member
Sales
Most any heat gun will work. Take your time, be patient, don't hold the stem too close to the gun (a few inches away), don't hold the heat in one place. Insert a pipe cleaner into the stem before beginning. Slowly apply pressure when bending. You're not in a hurry, acrylic doesn't like to be rushed.

The stem already has a bend in it, that bend should start to relax as it approaches the "bendy" stage.

I use a commercial heat gun (because I already have one). A cheap one from harbor freight, Amazon or ?? will work just fine.

If you don't get the bend exactly as you like it, heat it and bend it again. Be patient and don't try rushing the process, much like waiting on Wifey to be ready to leave.
 

Zeno Marx

Well-known member
Go to your nearest optometrist and ask if you can use their heat tub for bending plastic eyeglass frames. I'm half joking. It's too bad they're pricey. From making my own mouth protectors for various sports, I'd trust using boiling water over flame or hot air. I've also screwed up trying to flatten warped vinyl records with hot air. It's difficult to moderate.
 

DocAitch

Well-known member
As Todd notes above, acrylic will remain firm and suddenly become pliable.
I use a heat gun purchased from Lowes- but I make pipes so I don’t feel that paying a few bucks more is a burden. If I were only going to bend one or two, I would go to Harbor Freight. Candles will work but they are sooty. An alcohol lamp is the next best thing to a heat gun, and can be used in the same way as below
There are a couple of things that I do that might be helpful.
Empty your bladder before starting- this may take a while.😀
1) Keep the. stem in the stummel- this give you an handle and will give you a better idea of how far to bend it without any other reference.. If there is a cap on the shank that you don’t want to heat, wrap a piece of wet cloth or paper towel around the shank-secure with a pipe cleaner (a rubber band will melt). If the stem has a Delrin tenon glued in, wrapping that part of the stem is necessary because when the acrylic is hot enough to bend, epoxy will fail. The wet paper towel keeps the temp in that area low enough that the glue doesn’t fail.
2) Clamp the heat gun in a vise pointing vertically. This way you can move the stem with two hands for better control. Holding the gun in one hand and the pipe in the other is going to tire you out and your control will be poor.
3) Keep the stem moving - I use a back and forth motion 1-2 inches from the nozzle of the gun and rotate the stem at the same time. Heat the entire length of the stem- this allows a smooth bend without sharp angles.
4) as Mrm1775 has noted, when the stem is pliable, it will straighten out because it has a memory.- at this point, you can adjust the bend.
5) I bend to the desire radius, then applly a wet paper towel to cool the stem.
6) remember that you you can always re heat and rebend- don’t force it.

As for the pipe cleaner in the draft thing- I suggest that that you take one of your pipe cleaners and while watching the end while it is end on to you, pinch the the end between thumb and index finger- it will flatten to a tiny fraction of inch-there is nothing there but 2 wires twisted together and some fibers. If the airway should collapse that tiny flatten oval is whats going to remain. But I have never, in hundreds of stems of various materials bent, had an airway collapse.
DocAitch
 

rectifythis

Well-known member

Tristano-ite

Well-known member
As Todd notes above, acrylic will remain firm and suddenly become pliable.
I use a heat gun purchased from Lowes- but I make pipes so I don’t feel that paying a few bucks more is a burden. If I were only going to bend one or two, I would go to Harbor Freight. Candles will work but they are sooty. An alcohol lamp is the next best thing to a heat gun, and can be used in the same way as below
There are a couple of things that I do that might be helpful.
Empty your bladder before starting- this may take a while.😀
1) Keep the. stem in the stummel- this give you an handle and will give you a better idea of how far to bend it without any other reference.. If there is a cap on the shank that you don’t want to heat, wrap a piece of wet cloth or paper towel around the shank-secure with a pipe cleaner (a rubber band will melt). If the stem has a Delrin tenon glued in, wrapping that part of the stem is necessary because when the acrylic is hot enough to bend, epoxy will fail. The wet paper towel keeps the temp in that area low enough that the glue doesn’t fail.
2) Clamp the heat gun in a vise pointing vertically. This way you can move the stem with two hands for better control. Holding the gun in one hand and the pipe in the other is going to tire you out and your control will be poor.
3) Keep the stem moving - I use a back and forth motion 1-2 inches from the nozzle of the gun and rotate the stem at the same time. Heat the entire length of the stem- this allows a smooth bend without sharp angles.
4) as Mrm1775 has noted, when the stem is pliable, it will straighten out because it has a memory.- at this point, you can adjust the bend.
5) I bend to the desire radius, then applly a wet paper towel to cool the stem.
6) remember that you you can always re heat and rebend- don’t force it.

As for the pipe cleaner in the draft thing- I suggest that that you take one of your pipe cleaners and while watching the end while it is end on to you, pinch the the end between thumb and index finger- it will flatten to a tiny fraction of inch-there is nothing there but 2 wires twisted together and some fibers. If the airway should collapse that tiny flatten oval is whats going to remain. But I have never, in hundreds of stems of various materials bent, had an airway collapse.
DocAitch
Thanks for the great, detailed advice!
 

Maddis

Well-known member
As Todd notes above, acrylic will remain firm and suddenly become pliable.
I use a heat gun purchased from Lowes- but I make pipes so I don’t feel that paying a few bucks more is a burden. If I were only going to bend one or two, I would go to Harbor Freight. Candles will work but they are sooty. An alcohol lamp is the next best thing to a heat gun, and can be used in the same way as below
There are a couple of things that I do that might be helpful.
Empty your bladder before starting- this may take a while.😀
1) Keep the. stem in the stummel- this give you an handle and will give you a better idea of how far to bend it without any other reference.. If there is a cap on the shank that you don’t want to heat, wrap a piece of wet cloth or paper towel around the shank-secure with a pipe cleaner (a rubber band will melt). If the stem has a Delrin tenon glued in, wrapping that part of the stem is necessary because when the acrylic is hot enough to bend, epoxy will fail. The wet paper towel keeps the temp in that area low enough that the glue doesn’t fail.
2) Clamp the heat gun in a vise pointing vertically. This way you can move the stem with two hands for better control. Holding the gun in one hand and the pipe in the other is going to tire you out and your control will be poor.
3) Keep the stem moving - I use a back and forth motion 1-2 inches from the nozzle of the gun and rotate the stem at the same time. Heat the entire length of the stem- this allows a smooth bend without sharp angles.
4) as Mrm1775 has noted, when the stem is pliable, it will straighten out because it has a memory.- at this point, you can adjust the bend.
5) I bend to the desire radius, then applly a wet paper towel to cool the stem.
6) remember that you you can always re heat and rebend- don’t force it.

As for the pipe cleaner in the draft thing- I suggest that that you take one of your pipe cleaners and while watching the end while it is end on to you, pinch the the end between thumb and index finger- it will flatten to a tiny fraction of inch-there is nothing there but 2 wires twisted together and some fibers. If the airway should collapse that tiny flatten oval is whats going to remain. But I have never, in hundreds of stems of various materials bent, had an airway collapse.
DocAitch
Same. Over 10 years I never inserted a pipe cleaner and never had an airway collapse. Go slow and carefully. I also used automotive repair gloves to keep my fingers from burning.
 
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