Thumper--a 1 3/8" bore i.c. engine

[Brian Rupnow]

I wanted to buy a spray can of John Deere green today for the flywheels, gas tank, and rocker support, but the hardware store is closed because of Covid. I wanted to practice some more tig welding today, with special attention given to the foot-pedal, but it was too cold in my main garage. I wanted to take a longer "fat mans walk" but I've got bad arthritis in my left knee. I wanted to go see my grandkids, but I can't because wife and I are "social distancing". All in all, I haven't done a hell of a lot today except cruise the internet and read the forums. I've had a very much "useless old man day"!!!

 

[awake]

Sometimes you just have to realize that a particular day is not going to turn out the way you planned ...

 

[petertha]

I don't have a TIG (yet) my only experience was a course at local technology college. We wiped the rods & certain alloys with acetone. Maybe a more experienced welder can chime in but varsol might be a little on the oily side & anything like that can cause issues. The instructor mentioned that specifically. Acetone evaporates almost immediately on contact.

 

[Brian Rupnow]

It's still to cold to go and play Mr. Welder in my main garage (In fact it's snowing hard as I post this). So----Today, just to escape the "Old man stuck in the house syndrome", I found a piece of 304 stainless close to the size I wanted and made the take off pulley for Thumper. The 3 grooves are sized to tale 0.100" cross section O-rings, and all three are knurled in the bottom of the grooves to prevent slippage.

 

[Brian Rupnow]

Petertha--I know about the acetone. I don't know if it was an absolute necessity for tig weld prep, or not. I will google a bit and try to find out. Acetone is very smelly, and I think it's quite explosive, so I would rather not need it.

 

[petertha]

Acetone has a distinct odor but personally I find it slightly less offensive than varsol.
I just googled auto-ignition temperatures. Acetone = 465C, Varsol = 260C. That makes acetone safer from that perspective doesn't it?

Well, some info but lots of danger precautions. I suspect be careful with any solvents in the shop especially around welding equipment, hot metals, sparks.
https://envirofluid.com/articles/acetone-use-for-welding-surface-preparation/

 

[Brian Rupnow]

Acetone cannot be used without risk of fire or explosion in any workplace which has sources of ignition. Despite the chemical’s widespread application as a surface preparation solvent prior to welding, it remains a serious hazard for workers. Acetone’s flammable and explosive properties are very difficult to adequately and consistently control.

The prevalence of the chemical in welding workshops can create familiarity and a false perception of safety. Fires and explosions from acetone will happen because of the chemical’s extreme flammability and ready evaporation. And when these accidents occur they can be deadly. The only way to fully protect workers from acetone fire and explosion risk is to use a suitable non-flammable and low evaporation chemical substitute for surface preparation.

 

[Peter Twissell]

I like the 'grooves knurled in the bottom to avoid slippage'. I'll use that one next time my grooving tool chatters!

 

[L98fiero]

Acetone cannot be used without risk of fire or explosion in any workplace which has sources of ignition. Despite the chemical’s widespread application as a surface preparation solvent prior to welding, it remains a serious hazard for workers. Acetone’s flammable and explosive properties are very difficult to adequately and consistently control.

I'm sure there are others but Walter has a product that will do what you need, it's promoted as a replacement for acetone. According to their Canadian site, 500 ml spray bottle is $19.20. SURFOX™ Pre-Weld – Walter Surface Technologies No connection to them, I just knew there was such a product. Personally I use acetone, I don't have the container where I'm welding, don't keep large containers of it, store it in a metal cabinet when not in use and I can get it at the hardware store a block away from home.

 

[awake]

Whatever else you may use, do NOT use brake cleaner for weld prep. As I understand it, it can break down into toxic components under the arc.

 

[L98fiero]

Whatever else you may use, do NOT use brake cleaner for weld prep. As I understand it, it can break down into toxic components under the arc.

One of the chemicals in most brake cleaners is tetrachloroethylene/perchloroethylene and with temperatures above 500 °F (260 °C) or strong UV light it decompose into phosgene and hydrogen chloride, both are toxic. Phosgene can be lethal with as little as 4 ppm, there are stories that say people died or were seriously injured even by smoking while using brake cleaner. They are stories so take that for what it's worth, on the other hand, once exposed, there is no antidote for phosgene poisoning and even if you recover you may end up with chronic emphysema and bronchitis.

 

[NickP]

It's still to cold to go and play Mr. Welder in my main garage (In fact it's snowing hard as I post this). So----Today, just to escape the "Old man stuck in the house syndrome", I found a piece of 304 stainless close to the size I wanted and made the take off pulley for Thumper. The 3 grooves are sized to tale 0.100" cross section O-rings, and all three are knurled in the bottom of the grooves to prevent slippage.

Hi Brian, newbie here. Please can you share how you knurled the bottom of the pulley you machined in post 244. It’s quite a narrow groove and the only types of knurling wheels I’ve seen are much wider. My knurling tool is the clamp or scissor type but I guess you could push a ‘bump’ knurler into the groove if you have a suitable wheel? If the later did you make or buy the wheel? Love the idea but have few ideas on how you go about it or the actual equipment needed. So much to learn - hope you don’t mind me asking.
Thanks in advance, Nick

 

[ALEX1952]

When I was in the company fire brigade we had a beutifull Austin Gypsy fire engine complete with very pretty brass pump action fire extinguishers complete with carbon tetra-chloride filling, which was all well and good until it was laid on a storage heater and leaked, fortunately it was spotted and nobody came to harm. I'm ,told that they were developed for electrical fires in aircraft which was fine untill they realised they were losing aircraft due to the crew being overcome not air frame damage, how true I dont know but it seems entirely possible

 

[a41capt]

Acetone has a distinct odor but personally I find it slightly less offensive than varsol.
I just googled auto-ignition temperatures. Acetone = 465C, Varsol = 260C. That makes acetone safer from that perspective doesn't it?

Well, some info but lots of danger precautions. I suspect be careful with any solvents in the shop especially around welding equipment, hot metals, sparks.
https://envirofluid.com/articles/acetone-use-for-welding-surface-preparation/

Auto ignition is the point where a flammable liquid or solid will spontaneously ignite. ALL flammable and combustible liquids are dangerous if their properties are misunderstood. Flash point is the critical number in that it determines the temperature where the flammable/combustible liquid produces vapors at a percentage where they become flammable if an ignition source is present.

Flammable liquids have a flash point below100 degrees F, and combustible liquids are above 100 degrees F. Many of the safety degreasers have flash points well above 130 degrees which makes them “safety” cleaners. The interesting point chemistry wise is that generally the higher a product’s flash point, the lower its auto ignition temperature and the higher its BTU production when burning. Gasoline (flash point -60 F) versus diesel (flash point +140 F) makes the point more easily understood, and proves the efficiency of diesel fuel.

and that my brothers, ends today’s chemistry lesson from the old retired Hazardous Materials Technician!

John W

P.S. Acetone is the generally recommended cleaner for surfaces to be welded, especially wit TIG. Grease and oil are big enemies of clean welds.

 

[awake]

One of the chemicals in most brake cleaners is tetrachloroethylene/perchloroethylene and with temperatures above 500 °F (260 °C) or strong UV light it decompose into phosgene and hydrogen chloride, both are toxic. Phosgene can be lethal with as little as 4 ppm, there are stories that say people died or were seriously injured even by smoking while using brake cleaner. They are stories so take that for what it's worth, on the other hand, once exposed, there is no antidote for phosgene poisoning and even if you recover you may end up with chronic emphysema and bronchitis.

When I first learned to weld, this was the sort of thing that made me wonder if I really wanted to learn it - though in my case, it was reading about how dangerous it was to weld anything with cadmium in it (or on it, e.g., cadmium plating).

Over time, the hyper-anxiety subsides, which is probably good up to a point ... and bad as well. From time to time I run across a thread on some horrific lathe or mill or other accident, and though it makes my toes curl, I always force myself to read it, as a way of reminding me to practice good safety.

 

[Brian Rupnow]

Nick P--It's a neat trick. A hundred people have asked me how I do that. I had a piece of 1" diameter 01 oil hardening steel. I chucked it up in my lathe and drilled and reamed a 1/4"center hole in it. Then I used my cheap old squeeze type Chinese knurls to knurl the outer diameter x about 1/2" long. Then I parted off a slice 0.100" thick which had the knurl on the outer diameter. Used my oxy acetylene torch to bring that slice up to cherry red, then dumped it into a tin can of old motor oil. This hardened the round slice harder than the devils horn. Then I put a .125" slot in the end of a piece of 1/2" square mild steel, with a hole thru at 90 degrees for a 1/4" mild steel axle. Loctited the axle in place, the hardened slice of knurled material is free to rotate. After the slot in the pulley I'm making has been cut with a parting off tool, I mount my newly made skinny knurler into a tool holder for my quick change toolpost and use the topslide to bring it in against the bottom of the pulley slot, with the lathe turning at about 150 rpm. a little bit of pressure, and there you are.

 

[a41capt]

Nick P--It's a neat trick. A hundred people have asked me how I do that. I had a piece of 1" diameter 01 oil hardening steel. I chucked it up in my lathe and drilled and reamed a 1/4"center hole in it. Then I used my cheap old squeeze type Chinese knurls to knurl the outer diameter x about 1/2" long. Then I parted off a slice 0.100" thick which had the knurl on the outer diameter. Used my oxy acetylene torch to bring that slice up to cherry red, then dumped it into a tin can of old motor oil. This hardened the round slice harder than the devils horn. Then I put a .125" slot in the end of a piece of 1/2" square mild steel, with a hole thru at 90 degrees for a 1/4" mild steel axle. Loctited the axle in place, the hardened slice of knurled material is free to rotate. After the slot in the pulley I'm making has been cut with a parting off tool, I mount my newly made skinny knurler into a tool holder for my quick change toolpost and use the topslide to bring it in against the bottom of the pulley slot, with the lathe turning at about 150 rpm. a little bit of pressure, and there you are.

And now I have one more piece of tooling to make! I’ve made my own custom knurl before, but never considered one to add “traction” to slim belts. Now my Webster has something to look forward to for actual work. I’ve got an old 12 volt motor from a drill, and with a little extra electronics work, I’ll be able to charge my cell phone!!!

Thanks for the tip Brian!

John W

 

[a41capt]

When I first learned to weld, this was the sort of thing that made me wonder if I really wanted to learn it - though in my case, it was reading about how dangerous it was to weld anything with cadmium in it (or on it, e.g., cadmium plating).

Over time, the hyper-anxiety subsides, which is probably good up to a point ... and bad as well. From time to time I run across a thread on some horrific lathe or mill or other accident, and though it makes my toes curl, I always force myself to read it, as a way of reminding me to practice good safety.

Andy, I started my welding career(?) in the Navy, and welding on galvanized steel was just one of the hazards associated with non-OSHA regulated working conditions. You have never been as sick as you get from Zinc poisoning caused by welding in non-ventilated spaces! I shudder to think what else is circulating in my blood, even 50 years later...

John W

 

[awake]

I've worried about zinc as well, having done some welding on galvanized parts - but fortunately I've never had enough exposure to have a reaction. As I understand it, that one isn't lethal unless it gets to really high concentrations ... ?

 

[Brian Rupnow]

I have suffered from "Zinc chills" brought on by stick welding galvanized stuff. Not fun, and kind of scary, but it didn't last very long.