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Heating and bending a blowgun?
Posted: Mon Oct 11, 2010 7:28 pm
by Gun Freak
I might try bending one of these blowguns on the nozzle part, so should a propane torch do the job and will it still be able to hold pressure (100-150 psi)? I'm going to cu tthe curvy thing off.

Posted: Mon Oct 11, 2010 7:33 pm
by Benjg555
I believe if you get it red hot in a clamp then use something else to bend it when it's still red hot you bend it then quickly dump it into a bucket of cool water to harden it. It should still be able to withstand the pressure
Posted: Mon Oct 11, 2010 7:34 pm
by Gun Freak
Cool, my only concern was whether I'd be able to get it red hot or not.
Posted: Mon Oct 11, 2010 7:34 pm
by Mr.Sandman
It's possible to do, although you'll need to remove the valve core and possibly the rubber on the handle. Other than that, as long as its steel or aluminum, it should be fairly easy to do.
Posted: Mon Oct 11, 2010 7:37 pm
by Gun Freak
Yeah I was going to do that after I modded the flow so all of the internals would be out, and the rubber on the trigger slides right off so that's good.
Posted: Mon Oct 11, 2010 7:39 pm
by Benjg555
Gun Freak wrote:Cool, my only concern was whether I'd be able to get it red hot or not.
Ya with out a doubt with a torch you'll be able to get it red hot just move it slowly back and forth on the area you want to bend
Posted: Mon Oct 11, 2010 7:41 pm
by Technician1002
To prevent kinking and collapse, fill it with sand and cap the ends. Be sure the sand is completely baked and dry first to prevent a steam explosion.
Posted: Mon Oct 11, 2010 7:55 pm
by Gippeto
Most blow guns I've seen are cast from brass and then machined and plated.
I don't think you'll be able to get it hot enough with a straight propane torch even if it were possible to do what you want. (In a proper furnace...no problem) Castings are VERY unforgiving when it comes to bending. Most simply break.
Good luck.
Be sure you take pictures.

Posted: Mon Oct 11, 2010 8:33 pm
by Gun Freak
Ok Gippeto, I'm taking your word for it, looks like I'll just use my spare 1/8" fittings

Posted: Mon Oct 11, 2010 8:37 pm
by jhalek90
you will also obviously see some flow restriction if you bend the nozzle, which for a BBMG may actually be a good thing, depending on your pressure and application.
my current project has a ball valve, which i only slightly crack open, to minimize the flow.
This comment is directed at JSR:
I have a new gun in the works that would make even you happy. (although it is epoxy free

) a HPA bbmg, with adjustable firing pressure that uses a o-ring to seal the bb., and a small lever on the breech to control the pressure that the bb pushes through the oring. adjustable from 100 to 650 psi.
Posted: Mon Oct 11, 2010 11:54 pm
by ThornsofTime
Prob a good idea to go ahead and use and elbow instead of trying to bend it. gippeto is correct in saying that castings are usually more prone to breaking instead of bending
also- the chrome plating that is usually used to makem all shiny is super brittle. At the very least I would assume that the plating would chip off... making it look ugly and possibly even cut up your hands. chrome is nasty stuff.
If for some reason you're just DEAD SET on bending it... follow technician1002's directions... and heat the metal in a low light environment. annealing is usually best done in the dark because it makes the glowing metal more visible. finish the piece by sandblasting to remove the chipped chrome.
Posted: Mon Oct 11, 2010 11:55 pm
by Crna Legija
why dont you use a hack saw?
Posted: Tue Oct 12, 2010 1:01 am
by jackssmirkingrevenge
-_- wrote:why dont you use a hack saw?
Seconded
I have a new gun in the works that would make even you happy. (although it is epoxy free Confused ) a HPA bbmg, with adjustable firing pressure that uses a o-ring to seal the bb., and a small lever on the breech to control the pressure that the bb pushes through the oring. adjustable from 100 to 650 psi.
You have my attention, any chance of a WIP thread?
Posted: Tue Oct 12, 2010 8:55 am
by Big-E
You may not be able to bend it, but if your blowgun is brass, here is what you can do:
Use a grinder, files, whatever, to remove the chrome plating where you want the bend.
Using a cutoff wheel, or a saw, make a pie cut, or a relief cut where you want the bend, and bend the blowgun so your cuts are butted up together, if the casting cracks, no big deal.
When you get your angles roughly in the shape you want, just get a MAPP torch and some brazing rods and braze your seams, and fill your gaps. Viola! you have a bent blowgun. may not be the prettiest job, but it'll work. a little filing and finishing work will make it look nice. You may want to paint it when your done, as re-chroming the blowgun may not be worth the expense.
Using relief cuts, bending, and welding or brazing works wonders when you build exhausts or headers for cars, but don't have a tubing bender. I've used this method to "adjust" exhausts that didn't quite fit right on bikes and cars. Of course, I weld steel tubing. With brass, you need to use brazing rods.
Of course, you need to know how to braze in the first place, but it's not much harder than soldering. Just putting an option out there.
You may be better off using fittings to get the angle you want, but sometimes, a little brazing can do wonders; My brother fixed a broken floor shifter in his old buick with brazing rods about 20 years ago, and the repair is still rock solid.
Posted: Tue Oct 12, 2010 11:28 am
by Technician1002
Brazing brass is using a similar filler metal as the base metal. This by definition is welding. Brazing is using a differing metal to join pieces of metal, usually steel, copper, stainless and such. Brazing includes both brass and hard silver solder as the fill metal. Brass is often used for iron and steel, and hard silver solder is used on copper, stainless steel, and brass with flux. Soldering is like brazing but at a lower temperature with a softer fill metal, often tin based and almost always a flux is used.