Tungsten tipped rivets

[fourstroke]

Hi
As the above mentioned rivets are as rare as hens teeth I have a question I'm hoping someone can answer
I can find tungsten welding electrodes on line, they come in different grades
denoted by colours
Are these electrodes suitable to braze to screws to make ignition points or not
Any advice would be much appreciated
Thanks
Dougie

 

[Jasonb]

I've used tig electrodes to silver solder onto the contacts of ignitors. best to cut a bit off with a thin cutting disc, solder on and then grind down to the required thickness. Also made spark plugs with them

Hemmingway also do tungsten discs that will do the same job Hemingway Kits Ignition - Electrical Components

 

[fourstroke]

Thanks Jason
Any particular colour code or doesn't it make much odds
I'm enjoying your build in the mag
Dougie

 

[cds4byu]

For points it doesn't matter. The color codes describe small quantities of alloying elements used to make the electrodes work better for welding.

Carl

 

[TonyM]

I read somewhere that green is best. Can't remember why or where.
Anyway for model engines that run mostly on low revs and for short periods wouldn't stainless steel be good enough?

 

[bluejets]

Hi
As the above mentioned rivets are as rare as hens teeth I have a question I'm hoping someone can answer
I can find tungsten welding electrodes on line, they come in different grades
denoted by colours
Are these electrodes suitable to braze to screws to make ignition points or not
Any advice would be much appreciated
Thanks
Dougie

If you were to use transistor assist, there would be no requirement for anything like the point material.
Same for hall effect.

 

[Bentwings]

Hi
As the above mentioned rivets are as rare as hens teeth I have a question I'm hoping someone can answer
I can find tungsten welding electrodes on line, they come in different grades
denoted by colours
Are these electrodes suitable to braze to screws to make ignition points or not
Any advice would be much appreciate I’ve done a lot of TIG welding and have a range of various tungstens my guess would be the pure tungsten to try dirt. These are the green tipped comply used on older welders for luminous . There is a whole new series of alloys for the newer welders you can find them at welding supply businesses they are various color bands and have different characteristics. I’d guess brazing may have more or less success so it will be trial and error at best . There are different diameters to from 1/32 to 1/8” there ar larger too. Keep in mine they are not cheap in the larger sizes I have bitsand purses I could send you. Unfortunately thy are at a sho about 60 miles away that is hard for me to get to I’ll bring some home the next time I get out there and let you know. I know there is green 1/8” but that’s the largest I have

byron

 

[DKGrimm]

This is an interesting topic. I've used tungsten points in the primary circuit of high-tension model ignition for a long time. It's about the best material I have found to avoid pitting, but it does get an oxide film on the points and has to be cleaned from time-to-time. I use a 1/8-inch TIG rod, plain tungsten. (I believe thoriated tungsten electrodes are designed to facilitate arcing and that's the opposite of what you want with ignition points.)

I've tried to find platinum for points, but I've never been able to find a source for that. Platinum points were widely used in magnetos, and have low contact resistance and long life (or so I've heard).

For contacts in low tension igniters, I've had excellent luck with nickel. You can get 99% pure nickel from a stick welding electrode for cast iron welding. I designed an igniter for my Red Wing engine and have run it for ten or more hours at each of 25+ engine shows since 2010, with nothing more than a cleanup every year or two with a brass bristled brush.

 

[rsholl]

I still have these available.

 

[ranger]

Hi
As the above mentioned rivets are as rare as hens teeth I have a question I'm hoping someone can answer
I can find tungsten welding electrodes on line, they come in different grades
denoted by colours
Are these electrodes suitable to braze to screws to make ignition points or not
Any advice would be much appreciated
Thanks
Dougie

Found these in a tin, I can’t remember where I got them from, I’ve had them years. The short ones can be attached to the moving arm, the threaded ones used to adjust ‘points’ gap. The assembly was for a spark conversion on a ‘Glow’ engine in the 1980’s.

Doug.

 

[fourstroke]

I still have these available. View attachment 134598

Hi
I would be interested in some of these
How many do you have
Dougie

 

[fourstroke]

Found these in a tin, I can’t remember where I got them from, I’ve had them years. The short ones can be attached to the moving arm, the threaded ones used to adjust ‘points’ gap. The assembly was for a spark conversion on a ‘Glow’ engine in the 1980’s.View attachment 134609View attachment 134607

Doug.

Do you want to sell them
Dougie

 

[Gedeon Spilett]

You may use silver too,
I did several sparkies engines, 2 strokes models from a vintage (1937 !) magazine, and as suggested in the paper, I did ignition points with silver disks, (3mm dia and 1mm thick), soft soldered on copper rivets, and it worked a threat, and are still working.
I was very amazed, as previous assays with silvered contacts from old relays lasted a few minutes before being completely burned !

 

[DKGrimm]

You may use silver too,
I did several sparkies engines, 2 strokes models from a vintage (1937 !) magazine, and as suggested in the paper, I did ignition points with silver disks, (3mm dia and 1mm thick), soft soldered on copper rivets, and it worked a threat, and are still working.
I was very amazed, as previous assays with silvered contacts from old relays lasted a few minutes before being completely burned !

I love your video. That would be a fun engine to build.

Your experience is consistent with my own. Silver is a very good contact material for general purpose use, but it has a relatively low melting temperature, so arcing tends to transfer material from between contacts and will actually weld the contacts together if the arc energy is high enough. If you use silver contacts for high-repetition current interruption in an inductive circuit (like ignition . . . ) you have to get the capacitor value in the range where it minimizes arc energy at the points. That's a good thing anyway, because it maximizes energy delivered to the spark plug.