I have successfully hooked my acetylene headlamps to an acetylene tank that I have hidden out of sight.
I know that all modern acetylene torches have flashback arrestors as a safety device.
Obviously flashback arrestors were never in place with original Prest-o-Lite tanks, but would it be prudent to put one in the line? They are not just a cheap fitting, and the type for an "A size" regulator (mc tank) are not commonly carried. However, I can make a special order for one, at around $50.
Is this a situation of:
A) They never had 'em, so they are not needed.
B) Your roll your dice and take your chances. There probably would never be a problem.
C) You'd be stupid not to have one.
We have lots of OSHA regulations to save us from ourselves, and I admit that I have been know to occasionally remove a safety guard so I can actually see a saw blade. So is a flashback arrestor something important?
: ^ )
Ask Wile E
It could be as simple as a bit of copper "wool" in the rubber hose close to the light and that would be simple and effective
I have some questions about the Gas headlamps.
- What kind of gas is in a Prest-o-Lite tank?.
- What pressure go to the lamps?.
- Can you regulate that pressure?.
Thanks for your answer.
Anthonie, the gas is acetylene. The lamps use a very small amount of pressure and I have seen people use a pressure valve but I do not know what pressure they use. I have always just cracked open the valve a tiny bit. I then light the lamps and adjusted the valve for a decent flame. To my knowledge they did not have pressure regulators back in the day. Less pressure to start is best and it is important to leave the doors on the lamps open before you open the gas valve on the tank to avoid building up too much gas in the lamps. People are intimidated by them but they are actually very easy to use and it does not take long to get the hang of it.
Flashback arrestors for torches are really check valves in both lines by the torch
I have seen pictures of original regulators and at least one in a museum. It is possible they were intended for acetylene starting systems though
Prest-O-Lite did make automatic pressure regulators back in the period that attach directly to the tank. They are about 3.5-inches in diameter and made of bronze. The housing is round and made in two pieces with a metal diaphragm in the middle which does the regulating.
I have used them on cars when I set up a gas-lighting system run off a tank and they work fine. I also have one that it use here in the shop to run a big Rushmore spotlight for light when the power goes off.
If you cannot find one get a small modern regulator and hide it. Start out w/low pressure (1 pound or less) and work up from there to see what you lamps work best at.
If you can find an original inline water trap meant for these systems, pack it with copper "wool" as Les Schubert mentions above and it will work fine.
You really do need a regular to prevent sooting w/to little pressure and over heating and damage to you lamps w/to high a pressure.
I will soon be sharing for everyone what I did for my gas lamp set up. I will include a list of hardware I used, including part numbers and the mounting bracket I designed.
Val was a tremendous influence and help in my results, as I used his set up as a guide. Thank you, Val.
I'm just wondering if I need to include the flashback arrestor or not. I want to make sure to give instructions for safe gas headlamp operation.
One I found is made by Western Enterprises (FA-91) which would attach at the regulator. This type I know I can get locally. It has also been suggested to use two in-line type, put between each headlamp and the rubber hose. I found one of this type on line made by IBEDA (Model TT) The 6.3mm barb fits 1/4" hose. (I don't know about the availability of this type.)
Thanks everyone for your continued input.
Keith (the guy who generally removes the safety guards)
: ^ )
There is a drawing where an in line fuel filter is used as a flash suppressor when tapping the exhaust pipe to pressurise the fuel tank. Tinkering Tips Vol I page 77.
Kieth, Here's a high five...... ah I mean a high four!
You do not need a flashback arrestor in your gas line. The hole in the burner is too small for flame to travel back through (without oxygen, acetylene won't burn. No oxygen in that tiny space while gas is moving/present. That's how flame arrestors work.)
I recently converted my headlamps back to gas, and found out (by trial) that my generator bottom tank is full of painted-over holes; so I'm using bottled acetylene. I researched it first, mainly because of the conflicting information given by different people on this forum.
Regulators were generally not used in the old days. The valve on the acetylene tank was fine-threaded and easy to adjust. The valves on the "B" tanks available today are coarse-threaded (because they're meant to be turned on and off, not throttled) and are somewhat difficult to adjust. My best information is that the burners operate at about one and one-half inches of water column (that's WAY less than one PSI!) My experience so far backs this up--probably less than 2 ounces of pressure, although I have not tried to measure it yet. When my gas is properly adjusted there is no noise from the tank valve and no noise from the burners until they are lit. That's low pressure.
If you use a regulator, put it ON the tank valve, not remote from it. Acetylene is unstable (read: Not Good) at pressures over 15 psi unless dissolved in acetone. You do not want a high-pressure line from your tank to your regulator!
By the way, I've read that you should not discharge an acetylene tank too quickly, so as not to risk entraining acetone from the tank (leaving un-dissolved acetylene in the tank).
My headlight burners are rated at 3/4 cubic feet/hour. Two headlights, that's 1 1/2 cfh. MC tanks are rated at 3/4 cfh maximum discharge.....I will use a "B" tank. My "safety valve" is that I have no hose clamps at all. If I get clumsy with the tank valve and over-pressurize the gas line, a hose will blow off and vent to atmosphere. (This made my gas supply guy alot more comfortable with what I am doing. Now he thinks it's cool.)
I'm toying with the idea of putting a small regulator and gauge on my tank, knocking the pressure down to a couple of pounds and then through a needle valve to the line, just to get easier adjustment of the flame (and an idea of how much gas is left in the tank). Has anyone else tried this? I'm wondering if the regulator will respond to this small volume with enough sensitivity to give a steady burn.
Anyway, bottom line, be careful to keep the acetone IN the tank and the pressure well below 15 psi outside the tank and you should be okay.
I hope this helps.
When i tryed it the first time with a B tank and my torch set regulator. I found the 1.5 psi was easy but i needed a valve to control volume.Way to much trouble to keep on with carbide so i will go back to the bottle.Bud in Wheeler.
Greg, and Kenneth , What is a B tank . Pictures please.
Some current available 40cf "B" tanks on eBay.
Just for reference this is what an original Prest-O-Lite regulator looks like. It uses a metal diaphragm and valve to regulate
Toon, that tank on ebay has the valve in the center of the tank, which is not good to use laying on its side. here we can also get that same tank but with the valve off to one side, so it could be used laying down. they are just smaller portable tanks used by plumbers etc. gas companys will not fill the original prestolite tanks, and these are about the same size but new
The B size tank is 6" in diameter and 19-1/2" tall. Here is a B size tank with a offset valve that can be mounted horizontally listed on T-bay:
They hold 40 cubic feet of gas. Here is a restored B tank on Gary London's car:
The next smaller tank is the mc tank. It is 4" in diameter and about 13" tall. The hold 10 cubic feet of gas. Early mc tanks had a offset valve and were designed to mount horizontally across the handlebars of a motorcycle, hence the "mc" designation. These generally have a gauge on the bottom, are scarce as hen's teeth, expensive, and generally, "not refillable," by acetylene suppliers unless you have some special privileges.
Here is an old mc tank on a motorcycle:
Prest-o-lite made an mc tank for plumber's torches in the early part of the 20th century and often had "Prest-o-lite" in script on the side.
Modern mc tanks are the same size and have no script. They use an type A regulator (or size A) , which is smaller than a B tank, or the 75 CF tank which are often is shops.
Oh, and here is a light switch:
The 3/16" square hole is for the valve.
: ^ )
When I was a teen my father and I restored a 1913 model t touring(still running today). We drove the Ford from Seattle to Sacramento to the 1959 HCCA National tour. There were some 10 brass model T's driving together. One day got rather late due to some mechanical breakdowns. We had to light the headlamps as well as the tail lamp.
After all had their lamps lit we cranked up the cars and were off. Here is a very good lesson learned, I reached down grabbed the crank, placed my left hand on the bonnet of the right hand headlamp to steady myself while cranking. Guess what????? I had the imprint of the Jno Brown and Ford script burned into the palm of my hand. I learned a life lesson that evening them thare lamps get damn hot !!!!!!!!
We often drove with gas lamps in those days and I can tell you they do not place a lot of light on the road, yes you can turn up the gas but still not much actual light on the road. We used to have a "real" gaslight tour once a year with the Seattle model t club.
The B tanks work great, but be sure you use the tank with the offset outlet, not the common one with the outlet in the center. The acetylene is dissolved in acetone.; if I remember correctly the tank is filled 42% with acetone before the acetylene fills the tank. The offset keeps the outlet high enough above the acetone for the tan, to be kept safely on it's side. Don't place a common B tank on its side.
Thanks for the information