I have owned several older machines. Most have needed pins & bushings. I'v always had a rough time getting new bushings into the bore. I've tried everything I can think of: Freezer.....Fail! Canned air upside down....Sort of worked Heating the bore & canned air.....Sort of worked. I've explored liquid nitrogen. Initial investment would be $1000. & the nearest source is many miles away. I've pondered the dry ice concept, that is more doable. My Father's day gift was Omaha Steak. It comes with a bag of dry ice. Of course I had to play with it. Put it in water. It boiled vigorously, for a while until the water lost most of its heat. Filled the bowl with a dense fog, then the sink. Slight air current created smoke rings. I was surprised it never did freeze the water. According to science, water cools at about 1 BTU per pound to 32 degrees F. Then it must surrender 746 BTU to become ice. I guess there wasn't enough dry ice to freeze the water.
Dry ice is just the thing to shrink something so you can press it in, but be prepared to go all the way together once you start. If you have so tight a press fit you really need the dry ice, if you stop moving, you may not get it going again. Been there. Ordered another bushing after we had to cut the half in/half not in bushing out so we could try again.
Freezer = 0° Freeze spray = -15° Propane = -44° Dry ice = -109° Liquid N2 = -320°
if you have a vertical bore to get that bushing in, be prepared to stop it from going all the way through as well... We had the push frame on a 550 line bored and got new bushings made which were oversized. Used a forge over the push frame ear that holds the angle frame on, dropped the bushing in that sat in dry ice, and the dam thing clanged right onto the floor. I want to say the bushing was a thou per inch oversized or so. ended up using vise grips to hold a piece of steel on the bottom, and dropped the bushing in again after another re-cooling.
What was your liquid nitrogen setup going to consist of? I’ve toyed with the idea but never got any further. How were the steaks? Wife and I love just about everything that comes from Omaha steaks.
Ok so now I have to ask the question, other than the obvious explosion hazard, how well does propane work? It's available just about everywhere, and although not as cheap as it used to be could be a good option if the -44 is cold enough. I've heard that laying a propane tank on its' side (and therefore inverting it I presume) is bad for some internal part of the valve in the tank from the manger at my local propane place. YMMV
What's wrong with a good ol' CO2 fire extinguisher? Of course, we mostly use them to instantly freeze our beer cans once the bushing is fully in, and we're celebrating!
Even better!!!
I used to work in propane and spilled and spewed it all over the place. I have not used it for this but know it would work. I would only use it to freeze something on a day with a good breeze so fumes can't accumulate. Also the smell is likely to annoy any neighbors and it will get in your tools, gloves, and clothes.
I always call Kenny Logins first and tell him “Danger Zone” before shrinking with liquid 1075. It certainly works, cheap, always available but I don’t recommend it. We had a real good discussion about our home made liquid nitrogen set-ups a couple years ago. For $125 bucks on the Amazon you can get a 3liter nitrogen container and a steel pail from Homey D and you are in the nitrogen cooling biz.
When using dry ice, a bath with a liquid like acetone or gasoline will help out the heat transfer. With liquid nitrogen, a metal container can be used. I've done a lot with a coffee can, as our insulated container wasn't large enough to hold a cylinder sleeve. If you want to improve on the coffee can, put it in a cardboard box and fill the void with packing peanuts. If you are used to picking small parts out of liquid nitrogen with your bare hands, don't try it with dry ice and acetone. You will get instant frostbite.
I haven’t played with dry ice that much. It’s too difficult to acquire most of the year. Only available during the summer. Recently, the one and only Alaska supplier had their machine die. Not sure if they are going to replace it. Until recently, the local industrial/medical/pharmaceutical mafia was hogging it all to keep their special gravy cold. Get this, some bright individual at my wife’s clinic dumped 30lbs of it in the kitchen sink in the break room to dispose of it. Fogged up the place. Safety person had to explain how it can displace oxygen in a confined space, blah blah.
I have used propane to freeze parts. Yep, it works good, it’s certainly a bit dangerous for obvious reasons, but do it outside away from any ignitions and your good. Just tip the cylinder completely upside down and fill up your choice of container and then put your part in it. It will boil like mad until the temps equal out. Works pretty slick.
Thanks for that I'll put a note in my phone for future reference.
Wonder how that works with the new style propane valves, probably have to tip it over very slowly and open the valve slowly Also a can of propane is safer than a can of gas, but the propane tank stays in clothes way too long.
New style propane valves are no obstacle to anything except inbound propane. Sometimes they lock up when they shouldn't but only when filling an empty too rapidly. Outbound they do not care, it comes right out.
New style valves shut off because they hate you, you have to make sure you don't tip them and open them very slowly or they shut off.
That is not the tank valve if it shuts off the gas due to outflow. It is the nose fitting of the regulator that you are using. It has a little ball in it that locks up at the slightest provocation. They can be unscrewed from your bbq regulator or whatever and replaced with another style. Sometimes with difficulty.
No regulator, weed burner
The problem is still in the nose thing that you screw in and out of the cylinder valve. This thing. The valves themselves do not have those safeties in them. I was just burning brush the other day, screwed an open copper pigtail into the tank, lit the fire and then let the propane rip right onto it.
Is this the container?
Somebody on here, possibly @TOM V has a dry ice maker that runs off bottles of CO2.
I tried using an upside down CO2 cylinder cracked open, with a short heater hose into a foam cooler to keep ice cream frozen for a picnic in the park. Cylinder ran out quickly, ice cream was not cold. Very disappointing. They do have a dry ice place very near here, easy to get. Not sure about LN2.
Most welding supply stores will have liquid nitrogen. Many will rent you a dewar (storage container).
Pretty much.