Safety discussion

[wdrzal]

I just spent 20 minuites typing a warning about using oxygen then when I went to post it the thread was closed. oxygen is a powerfull oxidizer one drop of oil can and has killed people, The first rule of safty is ,If you don't know, DON"T TOUCH. Working with gases is not like mixing koolaide in your moms kitchen. Pressure is DEADLY. I am seeing more and more guys trying to build way above their ability level. while every one wants the coldest and the fastest, STOP for a minuite and truthfully access your abilty. putting 400 psi in the first tube you ever brazed is just plain stupid.Buy a good book and read it cover to cover, reading a thread here and there will get you hurt or killed. By all means ask questions but never,never,never do anything you are not sure of. Start off with a basic refrigeration loop until you build the skills and knowledge to move on. Finally do not experiment with gases unless you are 100% sure you know what you are doing. Allways think of safety first. Walt

:caution: :caution: :explode2: Never, NEVER consider Oxygen & Acetylene as refrigerants.15 psi max pressure for acetylene ,but below7.5 is normal operating pressure. :explode2: :caution: :caution:

[ZENNZZO]

good post... :clap: :toast:

Safety should always be 1st and foremost...
anybody that has done something stupid, will attest to the fact that stupid is supposed to hurt.

Sadly enough,
There will always be those few, who prove the fact that there is no lifegaurd at the gene pool...

[Tyrou]

Safety first, OK,

Making a cascade as a first rig is a bad idea, OK

Having to read a book, cause if you don't, you'll be hurt and die, No.

Every thing I made was above my abilities, I learnt by doing, checking what's wrong and reparing, I don't have the last theoretical competence, and I never got hurt (only burnt several fingers while brazing, but who didn't...)

[n00b 0f l337]

Here's my idiotic example..
When I ran tec, I ran a 437watt dominator. Took 24 volts at 24 amps. SO I got 2 psu's with 26 amps on 12v. I proceeded to mod for 24volts in series. Went perfect. Never actually powered the psu's up. When I was almost done and ready to close them back up, the cat started to move around me and rupped its head on side of psu. I reached over to get it the hell away, and pushed it away. Elbow went into psu. Capacitors that I had never turned on, discharged. Massive massive shock. Headache, disy, and hospital trip came next.

Dont be dumb.
And if your refering to my oxygen question, forgot about that exlposive part, and thats why I asked.

[Sneil]

Safety first, OK,

Making a cascade as a first rig is a bad idea, OK

Having to read a book, cause if you don't, you'll be hurt and die, No.

Every thing I made was above my abilities, I learnt by doing, checking what's wrong and reparing, I don't have the last theoretical competence, and I never got hurt (only burnt several fingers while brazing, but who didn't...)
that's all well and good, but when building cascades you may not have the chance to check what's wrong. I don't think trial and error for cascades is the way to go which is what were talking about here. That error could end up blowing you to pieces and whoever else is in your home, ie. your family

[pythagoras]

Hi Tyrou,

I take your points, but I feel it is important to read a good text on the subject. Trust me it does make you understand more about what you are doing.

It has slowed me down, so maybe thats a down side but maybe it isnt ;)

Regards

John.

[expansionvalve]

Very good post that man!
It makes me wonder sometimes, systems on high pressure gas, no safety switches, bird dropping type brazing. :slapass:

[wdrzal]

You don't allways get a second chance to learn. sure burnt fingers will heal,but a catostropic failure from pressure or a explosion, rarely gives you another chance. once a eye is lost or ear drum blownout thats it,you can't get new ones at the supply shop.I tell every to buy a book because a lot of basic knowledge someone new to refrigeration should know is not even discussed on the boards. Also there are a lot of unproven theriores and just plain wrong information on the web.Allways take every thing you read on the web with a grain of salt.don't accept it as a given fact..... Work Safe Walt

[Sneil]

Very good post that man!
It makes me wonder sometimes, systems on high pressure gas, no safety switches, bird dropping type brazing. :slapass:

yikes!!! :with: that's what im talkin about! very scairy stuff

[gclg2000]

Safety first, OK,

Making a cascade as a first rig is a bad idea, OK

Having to read a book, cause if you don't, you'll be hurt and die, No.

Every thing I made was above my abilities, I learnt by doing, checking what's wrong and reparing, I don't have the last theoretical competence, and I never got hurt (only burnt several fingers while brazing, but who didn't...)

wow....

[f00t]

no joke, safety is the number one thing to respect when undertaking anything of this scale. I have built too many things in my life time to count them all but safety has always come first. before i start a new project I make sure i do plenty of research on every element of the build, no matter how small it is.

and as fo power tools/ torches/ etc, if your not scared/ have no repect for them then you have no right to use them. its as simple as that

[recons]

Having to read a book, cause if you don't, you'll be hurt and die, No.
Theoreticaly safety is great.

But there is nothing like safety tips from an industry veteran, whatever the industry is.

[wdrzal]

Lets all add to this thread by discussing all the potential dangers and the precautions a person should be aware of when working in the hvac/r enviroment. Its what you don't know that will hurt you. I've seen so many things happen I don't know where to start. First there are the evident dangers from shock,toxins ,flammable gases and failures from pressure.add that to all the general dangers in the work place and you must all ways be aware of every move you make. I vote for a on going safety discussion that points out what to do and what not to do.If a project can't be built safely,it shouldn't be built at all. also their is no price you can put on your well being.

[gclg2000]

It seems one of the biggest safety risks involved here...is protecting yourself........from........yourself.

[runmc]

One of my foolish mistakes was not securring a high pressure nitrogen bottle. I had the torch and hose sitting on a table with wheels. I rolled the table not noticing that my torch was sitting on it.
The hose pulled the bottle over and it fell flat to the concrete. Luckily the valve or regulator wasn't broken off.

I have heard some very ugly stories about high pressure bottles being propelled through walls and whatever might get in it's path.

"Always Secure your high pressure bottles to a fixed structure,away from heat and out of the path of traffic." :fact:

[kayl]

One thing that can happen very easily is people forgetting to turn off gas bottles.
Ie leaving a 9kg bottle of r290 on attached to refrigerant gauges, and even attach to phase change systems.
Go away for a period of time and come back to find that the gas has leaked out
Because they forgot to turn things off. This is a big fire risk.
I always disconnect gauges from systems, and from gas bottles once I have finished my work. Leaving them attached might not realise ya left them on. If you disconnect things at least you will hear if there is a leak or something left on.
And please don’t store gas bottles inside.

[gclg2000]

A good one my dad once told me, when he used to weld for Westinghouse, is that someone left the acetylene valve on their torch on (mind you a massive industrial sized one) and it was sitting in a tool box, and of course filled it up with gas and someone else who was welding nearby, the sparks from their work danced into the toolbox and kaBOOM, now my dad was not real close, but close enough to see it all happen and get the :banana: scared out of him. All because some careless dumbass left his torch or gas tank on like Kyle is describing above.

[wdrzal]

I've had propane bottles that were over filled blow off when they warmed up. they wern't empty when droped off for filling and the attendant didn't look at the tare weight(TW) and just put 20 pounds in each bottle.propane bottles are only suspossed to be filled to 80% which is 20 lbs plus the TW of the bottle. Also in propane bottles I seen ice form at the valve were you close it,you think the valve is closed then after it warms up the ice melts and it starts leaking.gases should never be stored in a living space. you never know when a tank can start leaking.

[yasoumalaka]

Books rock!!! Just picked one up on refrigeration it makes me want to build the most extreme phasechange ever built.

[hatemi]

hmm. Preasures, flammable/explosive materials,extreme heat/cold, toxic gases and cemicals, high voltage... You name it. All of the above is just everyday stuff in HVAC that you have to deal with.

So some of the mistakes I have made/ had happen:

1: I left the CO2 botle open and connected to the manifoild for a weekend....You can guess it had leaked from one hose and was practically empty the next tiome I would have needed it.
2.Several cuts with grinder. Always wait for the disc to stop spinning before you put it down and start doing something else. You can stop it pretty quickly if you push it against some wood etc.
3. Some slight frostbites from disconnecting hoses with liquid refrigerant in them.
4. Burns to myself and the linoleum floor on my apartment. I dont do any brazing in here anymore, since I can do it at work where it is much safer.
5. Electrical shock from a compressor connected to a ungrounded extension cord.
6. Overcharging the second stage with CO2 thus resulting in a shut down by the high preasure cut off. I would not do a cascade without one. 40€ is a cheap price to pay from something that can save your life.
7. Some other stuff I might have forgot to mention.

[wdrzal]

Thermodynamics is a very addicting subject.The more you know,the more you know you don't know, the more you want to know. :D I guess KNOWLEDGE is the key.

[Tyrou]

I think what I wrote was nor properly understood: I'm not a kamikaze, and as you said, i put safety at the first place. My HP tanks are secured to the wall, I dont work without an extinguisher close to me and I don't play with pressure.

What I said only meant what i wrote, I never read a book about refrigeration, I began with a simple single stage made with a friend (didn't know how to braze it), and filled by a pro, then, next time I tried to copy what I saw, brazing and chargin it by myself, now I have a cascade running fine... I learnt everything i know here, on cooling-masters.com and most of it by experience.

When I'm not sure about the risk, I ask before doing, that's probably why nothing serious happened to me.

Some of my mistakes :
- burnt, burnt and burnt fingers, when I learnt brazing, my hands learnt more than me :(
- blew a charging hose due to pressure (CO2 w/o regulator + hose clogged)
- frostbites due to liquid in hoses

That's almost all i remember, I worked quite safely :)

[Tonic]

1). Use goggles during brazing, there are high temperatures. Once time a rod
heated to 700*C jumped to my eyeball, it wasn't nice :D

2). Remember about closing bottle valves (i.e CO2, R290, torch gases etc.)

3). Clean from time to time your workshop. With that, there's less risk with accidents

4). Clean from time to time torch's nozzle. When I was in hospital, I listened
a story about welder, which had accident - his gas torch was dirty and it
caused a fragmentation and his eye had 180 small thingys

5). Have a fire-extinguisher

[wdrzal]

On burnt fingers and frosbite I'll give you a pass,but blowing a hose!!!! even the cheapest hoses have a working pressure of over 500 psi and a burst pressure of over 2000 psi.I'll bet you ruined your gauges if you had your manifold hooked up.This is a good lesson for every to learn from. You should NEVER open the valve on a tank unless you know what chemical it contains and what pressure it is under.you must also know what type of equipment is needed to safely dispense it.

while the goal is for mistakes not to happen,we can't go back in time so posting them hopefully keeps someone else from doing the same thing. Thanks Tryou for the lesson. "work safe" walt

[n00b 0f l337]

Heh, thats a question I was just thinking about. How do you get ur hoses off, as there many be refrigerant still in them? Wear gloves or something?

[wdrzal]

Eye injurys are the most prevalent injury in the industry.I can't stess enough how important good eye protection is.Everyone knows how painful a spec of dirt can be,now think of a 1500 degree welding splatter burnning into your eyeball. Allways wear good eye protection.Even regular glasses are not enough,splatter can get behind them.I wear safty glasses plus use those flip down sheilds,they protect your whole face from splatter and are comfortable to wear.everyone should buy one. "work safe" Walt

[wdrzal]

Heh, thats a question I was just thinking about. How do you get ur hoses off, as there many be refrigerant still in them? Wear gloves or something?

frostbite used to be common on the finger tips, now is the usa all hose must have check valves so the manifold dosn't drain. Look for this feature when purchasing hoses. they are called anti-blowback or seal-rite hoses . if you hose don't have this feature you can buy adapters with check valves . quick disconnect fittings are also available. Wearing gloves will protect from frostbite. "work safe" Walt

[kayl]

Heh, thats a question I was just thinking about. How do you get ur hoses off, as there many be refrigerant still in them? Wear gloves or something?


if you remove the high side (red hose) from a phase change system thats running you are almost always guarantee to get frost bite. (as its pumping refrigerant out) and if you have the schraider valve connection after condenser (best place to have it reads pressure better due to temp)
liquid refrigerant will leave the system and freeze ya hand.
try it and freeze those fingers :nono:

to remove refrigerant hoses from a system, turn it off and leave it for a while say 5 mins (noobs) and now remove. there will be little to no refrigerant that comes out of the refrigerant hoses and wont get frost bite :D





also when brazing have a bucket of water and rags handy. I also got a fire extinguisher as well just in case things go wrong.
once you have brazed a join let it set and cool a little, then take the wet rag and cool the hot pipe back to room temp.
now you wont get nasty burns if ya accidentally touch something.
also watch out for the steam that leaves the hot pipe being cooled.



always use regulators that are rated to the pressure gas being used (ie cascade users) of the gas that you are woking with. cant remember which member but when ppl first started using ethylene i remember a refrigerant gauge poped (not sure if it hit them) but they also received a big wip lash from the flying refrigerant hose.
This happened because a suitable regulator wasn’t used.

[Unknown_road]

always use regulators that are rated to the pressure gas being used (ie cascade users) of the gas that you are woking with. cant remember which member but when ppl first started using ethylene i remember a refrigerant gauge poped (not sure if it hit them) but they also received a big wip lash from the flying refrigerant hose.
This happened because a suitable regulator wasn’t used.

lardarse was the one with flying manifold, it didn't hit him but it killed his door

[wdrzal]

When removing hoses it is best to remove the the low side(blue) hose while the system is still running.it is at a lower pressure and less refrigerant will be lost. the system should be shut down and let to equilize before the the high side(red)hose is removed,this will allow the high side pressure to reduce so less refrigerant will be lost.

[kayl]

lardarse was the one with flying manifold, it didn't hit him but it killed his door

thats right, got to love the pioneers that start all phase change builders.
in those days it was only a hand full building. processes only just started to need supa cooling.
i read everything and learnt from the best :toast: thanxs guys.

[ZENNZZO]

frostbite used to be common on the finger tips, now is the usa all hose must have check valves so the manifold dosn't drain. Look for this feature when purchasing hoses. they are called anti-blowback or seal-rite hoses . if you hose don't have this feature you can buy adapters with check valves . quick disconnect fittings are also available. Wearing gloves will protect from frostbite. "work safe" Walt
Are those quick connects that claim to seal off the hoses any good?
The ones that are add-on...
I didn't know they were available till recently after I bought a new manifold...
Or would it be best to just replace the hoses?

[cold_ice]

When removing hoses it is best to remove the the low side(blue) hose while the system is still running.it is at a lower pressure and less refrigerant will be lost. the system should be shut down and let to equilize before the the high side(red)hose is removed,this will allow the high side pressure to reduce so less refrigerant will be lost.
This isn't a good idea when the system is running in a vacuum, as most of our units do. This will suck in air.

[gclg2000]

Walt is speaking from commercial point of view where they do not run in vaccums, and honestly you shouldn't be running a vaccum on our systems.

**Generally speaking.

[Tonic]

I have question, wdrzal, if my low side gauge has scale from -1 to 10 bar, what would
be with him, if I connect red and blue hoses to unit and yellow to bottle and set at
regulator, for example, 15 bar? Will it make a low side gauge less accuray?

[wdrzal]

Yep,cold ice, is correct you shouldn't remove a hose if pulling a vacuum(below 0 psig) on the low side.shut off unit and wait till you have a positive psi before removing hose. This only applies to systems running below 0 psig .if running positive psig the above procedure should be used.fogot you guys run in vacuum,sometimes.

[wdrzal]

if you over pressure gauges you will ruin them,but look more closley at your low side gauge, the scale usually goes to 8 or 10 bar in large increments then to 24 or 30 bar at the very end of the scale in a small increment .most manafolds handle at least 24 bar. you must allways be aware of the pressure your equiptment can handle.

[ZENNZZO]

My very first screw up was an overcharged DanFoss...It included a brand new keg of R402a and a high pressure side that pegged the gauge at 500psi so hard it is now on my desk as a constant reminder that I am on borrowed time...
as Walt would say...safety first ;)
http://www.xtremesystems.org/forums/attachment.php?attachmentid=30643

[Tonic]

There's pic of my low side gauge - link (http://img.photobucket.com/albums/v613/Cinot/freon%20cooler%20MK%20I/pressure_test1.jpg)

Is it possible that this gauge can handle more than 10 bar?

EDIT : The max pressure which I use for tests, is 15 bar

[Tyrou]

The hose which blew up was connected to a closed valve and at the other side to a full CO2 tank (secured to the wall, fortunately), the CO2 valve was a bit messed, and I forced to open it, than it filled the hose very quickly... the hose itself was torn close to the flare fitting :(

to avoid frostbites, good goggles are a must have, now I always wear one when disconnecting a HP hose :)

[wdrzal]

There's pic of my low side gauge - link (http://img.photobucket.com/albums/v613/Cinot/freon%20cooler%20MK%20I/pressure_test1.jpg)

Is it possible that this gauge can handle more than 10 bar?

EDIT : The max pressure which I use for tests, is 15 bar
That gauge dosent have the extended range markings like all the ones I have, it appears it can only handle 10 bar,but check with manufacturer.that is based on what I see. they may have the "retard" segment just not printed on face. gauges are made for specfic pressures yours can't handle more than 10 bar from what face shows.you usually can go a little past that till your neddle hits the peg, then you have a gauge like the one zennzzo posted. my gauges that are for r22 and 134a have a maxium of 24 bar or 350 psi on the low side.

This is a good place to mention all manifolds,gauges hoses and regulators are not created equal.you must be aware of your application and purchase the correct equiptment. If tonic looks those gauges are scaled for r22,134a and 404a which are medium pressure refrigerants.

edit: if refering to these refrigerants using the epa guideline these are high pressure refrigerants. the epa uses low, high and very high pressure to describe refrigerants

[shadowing]

I would also suggest that you should have a guy experienced with refrigeration with you. This way you can avoid many possible safety risks and etc. Plus, there is the assurance that someone is there to help you.

[n00b 0f l337]

Yeah, my moms boyfriend used to own a refrigeration business. He's still got EVERY certification. I can probably get my refrigerants from him, and help is assured.

Safety First.

[shadowing]

Yeah, my moms boyfriend used to own a refrigeration business. He's still got EVERY certification. I can probably get my refrigerants from him, and help is assured.

Safety First.

Thats a good idea. Its a good idea to always have someone experienced in this field with you. That way they can help you if you are inexperienced with brazing and other stuff.

I am planning to start making my first single stage with the help of my dad.

[wdrzal]

My very first screw up was an overcharged DanFoss...It included a brand new keg of R402a and a high pressure side that pegged the gauge at 500psi so hard it is now on my desk as a constant reminder that I am on borrowed time...
as Walt would say...safety first ;)
http://www.xtremesystems.org/forums/attachment.php?attachmentid=30643

ok zennzzo fess up,I just looked as a pressure/temp chart for 402a and you didn't blow that on a new keg unless the ambiant temp of the refrigerant was above 150f. thats a 500 psi gauge.

edit: sorry you did say overcharged danfoss. just cylinder pressure won't do it. my applogies

did you have a fan on the condensor? was this a single stage?

[Tonic]

No any informations on pack nor on internet. It's Proex CT-536G testing manifold

BTW, I'm asking again - how does look reaction between acetylene and copper?

And another question, what exactly oil has that make explosion when it reacts with oxygen?

[Sneil]

oil is flammable and cumbusts readily when reacting with oxygen and heat. Bring pure o2 into the equation and you have a very fast, very violent reaction with so much o2 available to react.
ie. why an OXY acetlyene torch burns so much hotter with o2

[wdrzal]

I know of no reaction between acetylene and copper, but actylene is extremely pressure sensative,maximium pressure is 15 psi and normal working pressures are below 7.5 psi.

oil exploids when compressed under pressure and since oxygen is a great oxidizer(fuels combustion) the detonation is violant. Think of a disiel engine oil explodes and is supported the the 21% oxygen in air, now think of 100% pure oxygen in a tank. even the oil from on you hands can cause a pop,so it is very important that oxygen equiptment be completly oil free.

as to your gauges tonic, you must accept the highest indication on the dial as its maxium operating pressure .in your case 10 bar. if no other info is available. seems low thats why I told you to check manufacturer.for "retard segment"

[pythagoras]

Final paragraph on here:

http://www.c-f-c.com/specgas_products/acetylene.htm

Regards

John.

[wdrzal]

Final paragraph on here:

http://www.c-f-c.com/specgas_products/acetylene.htm

Regards

John.
what are acetylides? I never knew that!

[wdrzal]

Wait a min .here, I got a set of quick disconects sitting on my desk made for oxy/act torches and the one nut for the acet .side is made of copper,the one for oxy is brass!!! I will try to scan and post pics.

[pythagoras]

Acetylides ia just the given name for the compound formed when Acetyline reactions with a metal.

Acetyline is pretty dangerous stuff, I didnt know some of the acetylides explode when they mix with flourine and light :slobber:

http://www.ab.ust.hk/sepo/chem_info/Shock%20and%20Explosive%20Chemical.htm

Regards

John.

[wdrzal]

the black one for oxygen is brass that was anodized,the one for acetylene is clearly copper. these came with a airco torch, a very respected gas products company.

[pythagoras]

It maybe a copper alloy Walt with less than 63% copper.

[wdrzal]

thats possible but sure look like copper to me, I even just took a file to it to test hardness, acts like copper?

[wdrzal]

now that i,m thinking about it why would they even use a copper alloy? they could have used brass like the other one.makes no sense to me.

[pythagoras]

Just read a powerpoint on the proper use of oxy/acetyline the quick connects and flashbacks look to be brass on both:

http://www.dep.state.pa.us/dep/deputate/minres/dms/website/training/inventory/oxyacetylene.ppt#277,2,Just a note

Regardless I think EVERYONE should view this ;)

Regards

John.

[pythagoras]

http://www.brown.edu/Administration/EHS/lab/assets/SA-2.2003.pdf

Brass too :( Maybe some acetylene accidents reported earlier werent necessarily operate error :(

[Stewie007]

15 psi max pressure for acetylene :explode2: :caution: :caution:

I would never pressurize it over 7PSI. 15 is too high, and too risky.

[wdrzal]

These are made by koike japan, go to www.koike.com and look at pdf file under products then couplings. these are maked ul listed on them. they have check valves in them also. the site does not mention their compasition.

[pythagoras]

Cant find the couplings but look at their oxy/acet cutting machine.

The red hose has brass fittings:

http://www.koike.com/pdf/products/beaver.pdf

These are brass too:

http://www.koike.com/pdf/products/SentielPlusFlashbackArrestor.pdf

[wdrzal]

I would never pressurize it over 7PSI. 15 is too high, and too risky.

stewie do you know what maxiumum means, also i have written a number of posts 2 in the last day explaining while 15psi is maxiumum ,normal working pressures are not over 7.5psi. 15 psi is the OSHA standard. guess I'll say it again,samm!!! it worth repeating!!!! I just edited that post so every one would see it as soon as they started reading this thread

[wdrzal]

click on gas apparatas then safty z couplings then the pdf file you ca see the differace between the brass and copper. Their office in NY will be getting a call if I can't find the answer these are over 60.00 a set

[Unknown_road]

now that i,m thinking about it why would they even use a copper alloy? they could have used brass like the other one.makes no sense to me.

brass is a copper alloy ;)

[pythagoras]

Thats what I would do Walt. Safety first ;)

The reason I knew this is that a number of months ago a found a fantastic azeotrope of Acetylene and another compound, it would have been great for our use, until I found out about its problems with copper.

BTW:To anyone who wants the composition. Please dont ask me for the mix either on the forums or in pm, I dont feel it safe to divulge!

Rocketeers are pretty cavalier fellows look at the few things that are highlighted in red on this page :slobber:

http://ourworld.compuserve.com/homepages/pagrosse/h2orocketlaunchercutube.htm

Regards

John.

[wdrzal]

what are the welding and cutting tips made from?, for oxy/act torches.I assumed copper

torch tips are made from "c14500 phosphorus deoxidized,tellurium bearing copper alloy",I suspect the quick coupler i poster is the same. dept of labor states acetylene should never be exposed to un-alloyed copper.

[wdrzal]

Theres more to this ,I have a feeling copper with acetylene is safe in our application,every tip on all my act /oxy torches is copper, where did you get that 63% pyth? Does the reaction have to be under a given pressure?

[pythagoras]

Even the brass connectors you can use with acetylene have to have a composition of copper less than 63%:

http://www.australwright.com.au/DataSheets/Alloys/Copper%20&%20Brass/Brass%20-%20Yellow%20C26800.pdf

I would assume a manufacturer would supply the correct copper concentration for use.

Its a good safety tip then to not just use any old fitting lying around that happens to fit!

Regards

John.

[pythagoras]

Here Walt:

http://www.ab.ust.hk/sepo/chem_info/Shock%20and%20Explosive%20Chemical.htm

End of first paragraph.

[wdrzal]

they started produceing aluminium regulators for oxy in the 80's a bunch blew up before it was halted.they still can have alum. housings but brass internials

[harleybro]

Anyway to have this thread stickied?
A warning for anyone new and doing their own work. If a system has to be opened and a part replaced be very careful of flareups once the oils ignite. I have burnt my eyebrows a few times. Another if you have a leaky reg. on your tank don't use it! I thought I could sit my acetylene tank far enough away the other weekend. Forgot about the slight leak turned and next I new the top of my tank was on fire. No exstinquisher near so I am on my front porch blowin and blowin till it finally went out. Just figured I'd add my 2cents to an excellant thread. :)

[Stewie007]

stewie do you know what maxiumum means, also i have written a number of posts 2 in the last day explaining while 15psi is maxiumum ,normal working pressures are not over 7.5psi. 15 psi is the OSHA standard. guess I'll say it again,samm!!! it worth repeating!!!! I just edited that post so every one would see it as soon as they started reading this thread

Good, you edited it. Because some novice might browse and read that, then blow himself up. :p

[wdrzal]

torch tips are made from " C14500 phorphorus deoxidized,tellurium bearing copper alloy".that why acetylene dosn't react with them.

all these years I was completly unaware that unalloyed copper reacted with acetylene. :confused: It is because I followed accepted practices and used the proper equiptment that a accident never happened. :) This is why I get so concerned about guys inventing their own practices, you have no idea of the chemical reactions that may happen and other dangers that may be present. This is just another example of why to do things the approved way.


ps Thanks for the heads up Pythagoras :clap:and Tonic for asking the original question :toast:

[Tonic]

And, in order to be not lonely, thanks for making an interesting topic, wdrzal :D

I've talked with Raven, he also has gauge manifold like as mine and I
concluded a few things - if I overpressure low side gauge, it gots recalibrated
and it shows (at real 0 bar) a little more than 0 (a few psi more). Luckily, it
can be be corrected - I found on gauge a small screw which calibrate. In
order to have acces for it, you must remove a glass/plastic (my gauges have
glass which can be unscrewed). After 2 minutes, low side gauge was
measuring correctly 0 bar :) And for future I won't overpressure this gauge,
but only use high pressure gauge (I will connect red and yellow hose to
low side and high side pressure on phase change unit, open red valve and
connect with another service hose CO2 bottle to unit and test it :D)

[Unknown_road]

torch tips are made from " C14500 phorphorus deoxidized,tellurium bearing copper alloy".that why acetylene dosn't react with them.

all these years I was completly unaware that unalloyed copper reacted with acetylene. :confused: It is because I followed accepted practices and used the proper equiptment that a accident never happened. :) This is why I get so concerned about guys inventing their own practices, you have no idea of the chemical reactions that may happen and other dangers that may be present. This is just another example of why to do things the approved way.


ps Thanks for the heads up Pythagoras :clap:and Tonic for asking the original question :toast:

acetylene is tricky stuff, a propane/oxy torch is much safer and works fine.

[Sneil]

acetylene is tricky stuff, a propane/oxy torch is much safer and works fine.

oxy mapp is much better then oxy propane. propane wastes oxygen way too quickly and doesn't burn as hot

[cold_ice]

Propane/oxygen is more than enough for brazing, propane is also a lot cheaper than actetylene.
You never had an oxy/propane setup Sneil, didn't you?

[Sneil]

i have one yes. it just uses my tiny o2 bottles up within munutes. i use mapp with o2 instead and actually works when brazing around the evap block. propane will practically use the whole o2 bottle before the block gets hot enough. I only said oxy mapp is better since your going to be needing to braze a block and not just pipeing when building your own unit.

also mapp is basically the same price as propane here in canada

[cold_ice]

This toys from DIY store is not a real oxy/propane setup, I know what I'm talking about ;)
This is mine und you can braze everything with it, evaps, LN2 containers...
http://www.extremecooling.net/pics/1/1/werkzeug/48.3.jpg

[Sneil]

mine's from pvmart :D $69canadian with gasses included
tanks are way smaller then those monsters. a cheap sol'n for the small brazing jobs we do on these systems

[wdrzal]

Mapp gas is LPG (either propane or buetane,or both) plus some acetylene mixed in. The Acetylene in the percentage that is mixed in is stable though.

my hope is that this thread stays active and on the front page.Everyone needs to keep talking!!! I was completly shocked what I learned yesterday about acetylene. A collective disscussion with everyone taking part is the best way to promote Safety on this site. "work safe" walt

[harleybro]

I personally just use a straight acetylene tank a b-tank. It cost about $25 to fill and you can probably make 5 cascades with a full tank. Using turbo torch tips of varying sizes I had no problem brazing the 1/2 base on my gpu container. :)

[Unknown_road]

Mapp gas is LPG (either propane or buetane,or both) plus some acetylene mixed in. The Acetylene in the percentage that is mixed in is stable though.

my hope is that this thread stays active and on the front page.Everyone needs to keep talking!!! I was completly shocked what I learned yesterday about acetylene. A collective disscussion with everyone taking part is the best way to promote Safety on this site. "work safe" walt

kind of ironic, I have absolutly no professional training in this line of work and I knew this. professional training doesn't tell you everything I geuss :eek:

[wdrzal]

In the last day ,I re-veived 3 refrigeration books and looked at the literture packed with acetylene regulators, No mention of this reaction. Only the warning to use proper equiptment and use no oil. I still am trying to find out more about this reaction and how dangerious it is. If anyone is a chemical engineer I would like to hear more.While their is mention of it on the web,I can't find a single site that explains it in detail.It may , be no more than acetylene causes copper too corode faster. is it a explosive reaction ? I don't know. If is was dangerious I can't imagine why it is not mentioned in any literture.

[Unknown_road]

acetylene H-C≡C-H reacts with copper to Cu-C≡C-H or Cu-C≡C-Cu these 2 molecules are called acetylides. acetylides can get detonated by friction or a shock.

[wdrzal]

backflow preventers and flame arrestors. on acetylene /oxygen tourches these are 2 saftey devices that should be used, first a backflow preventers(check valve) should be used on the torch handle.It does just as its name implies,it keeps the gas from reversing direction carring the flame with it back thru the hose to the tank.On the regulators a flame arrestor should be used, these mount on the regulator low pressure side and keep a flame if sucked down thru the hose from making it into the tank. they have some sort of screen or baffleing material that prevent the flame from making it in one end and out the other.good ones also have another backflow valve in them also. along with these only open tank valve 1/4 turn so it can be shut off quickly if need be.Keep a fire extingushier close by and most important allways wear personel safety gear, "work safe Walt