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Jephgag

Propane behaviour at gas cutoff

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Hello,

I built myself a venturi burner for a small heat treating forge and after many online readings, I was able to make a starter propane forge. I took a lot of precaution to make sure that there is no leak (gasline teflon + soapy water test multiple times) and everything seems good.

However, since I am using a highly flammable gas, I want to learn as much of the process before firing the propane burner for a first heat treatment cycle for safety reasons. One subject that I haven't found about is how the burner should normally behave when I cut off the gas.

So my question is: when I shut off the gas, what should happen to the flame? As I reduce the psi of the gas output or as I close the main valve on the propane tank, will the flame "burst out" (not sure what the term is)? Also if I reduce the psi to almost 0, what should happen to the flame? will it go back to my nozzle or should it fizz out before that?

I hope that I gave enough details to get answers, but if not, let me know.

Thanks.

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Welcome to IFI... Have you read this yet? It will help you get the best out of the forum. READ THIS FIRST

You should have used propane rated tape, gasoline tape will degrade over time. When you shut the gas off at the tank, you may get a slight poof at the burner, nothing to be concerned about.

 

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The burner will simply snuff out quietly almost immediately with a short hose, or within seconds with a twenty foot hose. If you didn't wind the Teflon tape onto the fitting's thread, some of it will enter the burner's gas orifice and plug it up. If not, leave well enough alone. If it does occur, clean everything out, and use gasket seal of Trheadlocker next time.

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Thanks for the replies,

1) I did check the IFI FAQ first before posting my question (I've been lurking for a while now). I will make sure to keep it in mind for the following posts.
2) I used propane rated tape for my connections (Harvey 017065). I tried to make sure that no tape was loose on the thread. Will that tape degrade ? Do you have a link to the Threadlocker gasket seal ? I tried looking online, but I am not sure what I am looking for here.

I guess my only fear is the fire going back up the line. So either it will snuff out quietly, or it will poof, just like a BBQ sometimes.

Thanks for your help!

 

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Unlike acetylene, propane MUST have the presence of oxygen to burn. So it can't burn back up a hose filled only with propane.

 

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Welcome aboard, glad to have you. If you'll put your general location in the header you might be surprised how many members live within visiting distance. Propane rated tape won't degrade but if any gets stripped when you screw it together it can be carried through the gas line and block the jet. Look up gas rated pipe thread paste.

Put a propane rated 1/4 turn ball valve right after the regulator for a couple reasons. FIRST is as a fast emergency shut off as far from the fire as possible. The second is to reduce how many times you have a fireball singing the hair off you when you light the forge. A ball of crumpled paper burning in the forge, crack and slowly open the ball valve. 

Propane can NOT burn back up the hose, there is no oxygen to support combustion in the hose. The burner will just go out in a few seconds at most when you turn the ball valve.

You're okay on these issues but there are others you need to consider. The largest two dangers are fire and Carbon Monoxide (CO).  If you plan on using it in any enclosed space you MUST provide good ventilation and you'd be well advised to have CO monitors functioning in the area and any connected areas. 

Fire precautions we can talk about. ;)

Smart move asking these things before you build.

Frosty The Lucky.

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Thanks for the reply frosty.

Regulations here make it so that I need to be outside for propane. My forge is outside so I am not worried about Co2. I also have a fire extinguisher ready for when I will use the forge and I will keep the propane tank as far as my hose permits it. I am also setup on stone to make sure nothing flammable will be coming my way.

I do not have the 1/4 turn ball valve though, so i will grab that tomorrow and add it to my setup. However, my regulator is integrated the hose, so the valve will be between the hose and the burner. Not optimal.

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5 hours ago, Jephgag said:

However, my regulator is integrated the hose, so the valve will be between the hose and the burner. Not optimal.

It'll do. 

The dangerous exhaust gas is CO, carbon MONoxide. Not CO2 Carbon DIoxide. It may sound like I'm being picky but it is an important difference, one makes plants grow and carbonates your soda the other kills people.

Being outdoors should take care of CO worries. 

Frosty The Lucky.

 

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You most likely have read about several people a winter dying of CO poisoning in Canada; it's nasty stuff and does NOT clear the blood stream easily.  Got too much CO2?  Go outside and take some deep breathes and you are OK. Got too much CO?  Go to the hospital and sit in a hyperbaric chamber with increased O2---it is an EMERGENCY sort of thing.  It is also cumulative as CO has such a slow clearing rate, (something like over 5 hours to take a starting concentration in your blood and halve it breathing regular air.)

People keep asking if their propane forge will be ok inside a garage with a window open.  Me I have  20'x30' smithy with 10' high walls and open gables and 2 10'x10' roll up doors aligned the way the normal wind blows.  If I lived in a cold climate I would think hard about using an induction forge if I had to work inside!  I do roll the doors partway down if the wind is strong enough to blow anvils over...

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15 hours ago, Jephgag said:



I do not have the 1/4 turn ball valve though, so i will grab that tomorrow 

Make sure its a propane rated ball valve and not and air or water valve. 

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Just an update,

I successfully heat treated my first knife, The file skated on the blade. I'm annealing it as we speak. Thanks all for the tips, and I am excited to be part of this community for this journey.

I will see you around!

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11 minutes ago, Jephgag said:

 

I successfully heat treated my first knife, The file skated on the blade. I'm annealing it as we speak.

Congratulations on your success, but is this really what you meant?  Are you taking it back to its softest state to do more work and then repeat the hardening process?  Or are you in fact tempering the blade as we speak?   I'm not trying to be too nit-picky here, but annealing and tempering are different processes with different goals in mind, and we try to avoid confusing other people who read the forum.

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Sorry, I am not sure which one is which.
I see annealing all the time for knife making, but it seems like this is a mistake? After looking at the definition, it would be tempering then. I want to give back some softness and ductility to my blade.

Thanks for the correction.

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24 minutes ago, Jephgag said:

The file skated on the blade

Elegant wording; I just love that :)

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2 minutes ago, Jephgag said:

Sorry, I am not sure which one is which.

No big deal.  It takes a little while to learn all the relevant terms. It helps others starting out if we keep our terminology accurate.  Regardless, a success under the belt is a good feeling, and we'd love to see some pics of your work.

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I will post pics later when everything is finished.

I made some blue scotch brite micarta with black epoxy that is still curing as we speak (should be good by tonight).

I made a lot of mistake though during the blade filing. I made a blade with Gough Customs file guide, but I left a lot of scratching marks on the blade. I messed up the plunge line big time so now it is not placed well (too far back). I wanted to go through the full process of making a knife, even with flaws, just to get a feel of how it goes instead of trying to get everything perfect the first try. 

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Scratches are often due to filings getting pinned in the file teeth and then gouging the blade.  Are you using your file card often enough?

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4 hours ago, ThomasPowers said:

Scratches are often due to filings getting pinned in the file teeth and then gouging the blade.  Are you using your file card often enough?

I didn't know those existed, so that's a big no. I was using a paint brush to try and remove debris as much as possible. But the worst offender is definitely the plunge line where I made a big mess as I tried to redo it many times and it left deep scratches.

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So sort of like trying to drive and not knowing that brakes exist...  I was taught about file cards in industrial arts class in middle school---7&8 grade. I't covered in the "General Metals" textbook I picked up for a US dollar so I could learn about how to do things I was not familiar with.

It's also covered in Farm Shop Practice a college level textbook for an Ag degree way back when.  It also mentions that using chalk on the file helps to avoid pinning and it's more likely to happen with new files than used ones...

BTW you do know about draw filing right?  A mandatory skill for folks hand working blades!

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Oh for the days of shop classes where kids could learn useful skills, say home keeping and trades like: carpentry, printing, metal working and construction. <sigh> Below is a link to a decent how to for using a file card. 

https://www.wonkeedonkeetools.co.uk/file-card-brushes/how-to-use-a-file-card-brush/

Frosty The Lucky.

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When I was growing up, we only had a few classes (2 or 3) to teach us very very basic tool handling (filing wasn't included). So I am picking up things as I go. I am aware of draw filing and I used the technique, but that doesn't mean I'm good at it. My domain is electronics and electricity, so I am discovering the skills I need as I go.

This is why I didn't go full on perfectionist mode for that first knife. I already noted area where I need to research more in order to bring my skills to an acceptable level. The only thing I searched extensively is the propane forge as it can be dangerous, but if my knife look like crap, that's not the end of the world.

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Perhaps it would help to read up on the care and use of a tool before using it?  Why I have the old textbooks. Of course I assume that I don't know everything about a new/different tool.  I had a rather hard reset a couple of years ago and so have to go back and re-learn a lot of stuff. I find it's a lot cheaper to learn to use a tool *right* then to mess it up and have to replace it---and I'm all about the cheap!

I have degrees in Geology and Computer and Information Science and have been smithing for about 38 years now with a focus on early ferrous metals technologies---to me the post western use of crucible steel is all "modern" stuff!  Learning how to research something different has been one of the greatest skills I can suggest to a new person.

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You're the only one saying your knife looks like crap. The ONLY thing you've heard from us is an evaluation of your complaints and suggestions for correcting them. I even went so far as to do a basic web search and posted a link that if followed will correct your complaint. The only reason I did your research for you in this instance is you don't know enough to tell good info from complete BS.

Frosty The Lucky.

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