Spark plug boots

[stevehuckss396]

Hello Gents!

I see the question came up again concerning spark plug boots. The 1/4-32 plugs are easy because there are some Dorman vacuum fittings that can be modified and look pretty good. Unfortunately for 10-40 and smaller there is not much out there. In the next few weeks I'm going to try to recreate my mold for the 8-40 (little demon) boots and also design and make molds for the 10-40 and 6-56 plugs. I will make them available on the website as soon as they are completed. I ordered some silicone material but have no idea when it will be delivered per the current state of the worlds health. I might make 1/4-32 boots also but I will have to see if there is any demand for them and the other sizes. They will be grey in color just like the MSD peformance wires using a soft silicon 2 part putty. I will update this thread if and when they become available. Price will be decided when I get a real life feel for how long the boots take to make.

http://www.miniaturesparkplugs.com/

 

[petertha]

Hi Steve. I'm not too sure what system you will be using, but generally the suppliers of RTV & flexible urethane also usually provide color tint additives to turn it opaque. A little goes a long way, Its generally advisable to use their systems so you don't have any curing surprises. For example.
https://www.smooth-on.com/category/color-and-fillers/

 

[leerkracht]

Just my way
gr

 

[stevehuckss396]

I use a 2 part silicon putty. Boots for 10's, 8's, and 6's get very small so pouring liquid would be a crap shoot. The putty can be mixed and then rammed into the mold using a pin. I get 100% fill every time and the putty sets good enough in 10 minutes to open the mold. Thats 6 an hour if everything goes perfect. Even at 5 an hour the cost could be 5 bucks each and still be worth the time to make. The putty is also very easy to mix and there is no mess because it wont stick to anything. Just wipes off.

Super easy to use and cleanup. Dale Detrich had good luck with some black powder dye but it was a huge mess. He looked like a coal miner when finished and slowed things way down. Doing that would double and maybe triple the price so I don't see going through all the trouble.

I would like to stick with silicon because it is a good insulator that resists breaking down and also resists surface tracking. 2 things that can come in handy when trying to contain ignition voltage levels inside the boot.

 

[stevehuckss396]

Well they are done. They will be on the web site soon but are available to purchase. I'm asking 5 bucks each. I have #10, #8, and #6 available

To connect your wire take a piece of 1/8 brass rod (3/32 for #6) and drill a hole in it about 1 or 2 thou smaller than the brass cap and part it off about .093 long. Then slit it with a .020 saw

Pull the wire thru the boot and strip it.

Solder the wire on across from the slit

The brass ring will have a nice tight sliding fit

 

[stevehuckss396]

Use the spark plug to guide the brass ring in as you slide the boot over the plug

The boots are sized to have a good fit over the insulator. The brass ring once installed will have a good fit inside the boot so not only will the spring pressure from the brass give a good connection but the rubber boot will also give some pressure to the brass ring and help the connection.

 

[awake]

Very nice! What is the type of wire that you are using?

 

[stevehuckss396]

That's the S/S (Roy Sholls) 10KV wire. 10,000 volt and only .099 diameter

 

[awake]

Thanks!

 

[bluejets]

Can also use the Belden 8899-010 Black.

Steve, care to show the silicon cap product you used?

 

[stevehuckss396]

https://www.micromark.com/Silicone-Putty-1-lb-_2

 

[CNC-Joe]

As usual - Nice Work, Steve! Those look really sharp. (Maybe something to bring to "Show and Tell" at the next MDMC meeting (if this Covid-19 stuff will ever die out).