Molded Mouthpiece for Blowgun

by lennyb in Outside > Launchers

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Molded Mouthpiece for Blowgun

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how to hand form a nozzle out of polyethylene plastic

Overveiw

making a blow gun from a copper pipe is ridiculously easy. its intuitive , its simple and anybody can do it in 3 minutes or less. so why am i writing an instructable about it??
actually this ones about recycling some plastic to make a better nozzle than we usually see on this type of homemade tube.
as an incidental you will be shown how to make a blowgun .
also the reheating and molding techniques used here could be refined and applied to making other items you need IE tool handles , plugs , Model parts, the list goes on}
as always try and use some common sense when doing this
Wear heavy workgloves
Have lots of ventilation so take it outside folks.
Keep a fire extinguisher handy

Materials List

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1 39 to 48 inches of 1/2 or 5/8 inch copper pipe as straight as you can find

2 some HDPE plastic scrap{film bottles, shampoo bottle and various sources}

3 some tin cans {cat food tins are ok}

4 a low heat source {alcohol burner}

5 a high heat source {propane torch}

6 locking pliers or channel lock type

7 stirring tool {stick screwdriver etc)

8 a flame proof surface to work on

9 gloves For safety

Setup and Prep

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1 first sort out your plastic .
get all the same type high density polyethylene type 2 {hereafter known as HDPE}
put it in a low can {im using a steel film tin but any low can or pot will do }

2 setup your low heat source on a flat heatproof surface in this case i used an extinct range that is waiting for the next heavy garbage pickup{ although it is proving useful so it may stay for things like this}.
if you dont have an alcohol burning cat stove like this one ! here is an instructable i wrote last year to tell you how {is good for hiking too}.

carefully fill your burner with fuel and get the bottle well away from the stove before you light up also clean up any fuel spills before moving on.

3 Have your pliers ready too.

4 lightly sand the end of the copper tubing with steel wool or fine sandpaper to roughen it a little.

5 Have nearby a heavy section of pipe clamped so it wont move {i used the cross bar of my bike for this}

Melt N Mold

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light up the catstove burner.
then place your can of plastic on the stove .
be ready to lift it with the pliers as it may{WILL} burn if allowed to overheat .
basically if it starts to smoke a little bit lift it off the fire and stir it a While.
keep adding bits to it until you have more than you will need in the can Stir frequently as it need to be mixed well so you dont get any unmelted lumps in it.
once you have a good load melted and ready Pick up the can with the pliers
then roll the end of the pipe into the plastic( dont worry about filling the hole that will pop out after. i got a head start on this as i used the pipe as a stir stick }
once you have a fair sized wad rolled around on the pipe end Put the can of plastic to one side you dont need it anymore so Move it away from the fire.
keep turning the pipe so the plastic doesnt sag too badly.
before it cools too much upend the pipe and press the plastic end down on a flat surface to flatten the end .
blow into the other end of the pipe to force the plug inside out. if its soft enough it will form a bubble and the centre plug can be pulled out .
use the side of your pliers to roughly form a cone shape tapering in the plastic.

by now its probably too hard to work the plastic so you will need to re heat it over the flame dont get too close as it may ignite.
when it softens up again roll it over the crossbar of the bike to curve the taper better.
with practice youll be able to do this in one reheat

Finishing

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so now you have a rough{very } nozzle on the end of your pipe pretty ugly isnt it?
now you got to smooth it out some . so reheat it and roll the edge onto the flat surface again to round out the end because one side is sure to be wider than the other .
or if you like you can scrape the plastic with a knife or grind it with a surform or file .
the idea is to rough it into the shape you want it to be.
once it all squared up and ready now you unleash the hot fire.
with the plastic cold roll it in the flame of a propane torch for a few seconds at a time .
this will melt the surface and smooth it out
but dont overdo it and melt the whole thing tho just heat it and wait while turning it so it doesnt sag
if it catches fire you held it too long blow out the flames cool it off some and try again

Finish and Use

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ok so as you can see i have two blowguns .the one you saw me form was done on a waste piece of pipe so i could show you the technique, its kinked so it wont shoot.
the other i made last month and decided to redo as an instructable if it worked{which it did}.

for a finish you can spray paint the pipe if you like or wrap it in camo cotton or hockey tape or you can even find a larger cane of bamboo and bore it out to accept the pipe .decoration is a personal thing so just be careful not to kink it as you wrap it.
aiming is intuititive and basically if you point it out straight from your face it will hit where you look all you need to work on is the elevation.
as most copper tubing has a gentle bend in it make sure the bend is in the up /down axis so your gun doesnt shoot to the sides.{i marked the top of mine with the green tape arrows to point out the proper top}
also i marked the muzzle end of the gun with yellow tape for better visibility in low light.
as for darts lord there have been dozens of instructables on darts.
i have tried several types
the paper cones with a small nail hotglued in them work well as do the ones based on a bamboo barbeque skewer.
for a stunner dart a large headed short screw with a paper cone and reinforced with hotglue again.
for the paper cones i use photo paper{i work in a photolab so small bits of scrap photo paper are easy to come by.
but seriously check the other instructables on darts.

Safety Concerns

be very careful with this thing it can put out yer eye real fast.
it is a serious hunting weapon.
dont point it at anything you dont want to damage/kill.
if you shoot someones kitty with this you may go to jail .(if i dont get my hands on you first.)
if you need to chase away pests with it use small balls of wax or blunt ended darts made from plastic.
dont kill it unless you need to{really}
anyway i hope you have enjoyed this and remember the important safety bits
1 lots of ventilation.
2 safety gloves.
3 dont set your back yard on fire.
4 dont burn yourself on the low or high heat sources.
5 be nice to the kittys.

later
lenny