Home made silencers.

[richard]

bob doesn't recognise this as Bond so any ideas anyone ? 1 1/2" pipe

[Bob Purton]

I hasten to add I'm not a Bond expert but have owned some and looked at a lot of others.

[richard]

just asked stan at BOC and he doesn't recognise it , as he said people tried others to make them quieter. the mounting points are not Bond

[Bob Purton]

After following up various leads and getting nowhere I have decided to go ahead and make my own silencer. I have bought the tubing but am still deliberating on what material to pack the silencer with, there are matting materials you can now buy that you insert and when heated expand to fill the chamber, this or correect grade wadding. Think I will not risk using domestic F/G insulation, as I intend to weld the silencer up to be non dismantleable I will not have the option to replace it if it fails. I estimate to cost to build this will be about £25. Maybe I will take some pics as I go in case this helps anyone intending to do the same, thats if it works of course! 

[Chris Thomas]

Dear Bob

Rockwool insulation could be suitable as it is impossible to burn or melt as it is not made of glass but rock fibres. I was privilaged to be shown the heart of the process at their factory in South Wales. It is a giant candy floss machine into which they pour moulton rock from a small blastfurnace. You can buy it in many desity grades from loose quilt it high density slabs, as well as acoustic grades. Wire wool when it burns is lethal, Rockwool is by comparison very safe.

Chris Thomas

[Big Al]

Rockwool, made by Dragons, it is. Welsh Dragons. From Wales, Boyo.

I assumed this sort of wadding was that used in some more modern silencers I have had. Prior to that I suspect it was asbestos wool, the dangerous type. Fortunately I have some asbestos string for my roadster and other super whizzo pipes as I expect trying to buy it will result in 8 years in Staleg LauftBicester 21. Without that I have no idea how you seal the tunable and demountable endcaps.

[Bob Purton]

I've ordered some E Glass, from what I read you need reasonably thick stranded stuff to prevent it coming through the baffle holes. I think the rockwool type stuff has to be behind a layer of stainless steel wool for the same reason. I know what you mean about wire wool being volatile though Chris, I'm always catching my supply alight with sparks from the angle grinder! It goes up like a firework! I dont think it behaves the same way once enclosed in a can though with no oxygen supply. I think if one was going to use wire wool in a silencer it would pay to use stainless as exhausts do harbour moisture. I'm going to trust Laurie Bond technology.

[Bob Purton]

This afternoon I tested my home made silencer, I ran up the engine in the bench with silencer attached and am delighted to report it sounds exactly like a Bond minicar as predicted! Obviously its a bit louder than a modern scooter but has just the right period sound I was looking for. I forgot to photograph the components before welding it all up but its just a 1 3/4" tube through the center with about 150 holes drilled in it then the cavity between the inner tube and the outer casing is stuffed with E glass that I bought on Ebay. Making it was childs play. My biggest mistake was that in my excitement to assemble it I welded the end stop on forgetting to stuff the wadding in first! I had to cut the end off and start again! The dimensions are 3" diameter, 13" long [main body] It  has a 60 dregree 1" diameter tail pipe also bought on ebay from someone called The pipe bender. Total cost just under £20.00.  All I have to do now is paint it, as you can see I have run out of primer.

[richard]

just wish i was half as clever -  a very tidy job!

[Bob Purton]

You may be surprised what you can do Richard when you are prepared to have a go!

[richard]

learning to weld might be a start !!

[Big Al]

The advantage of a made system is that it fits. I can see the prob what with a slight angle and a larger in pipe than would seem to normally be with a silencer that size on a Bond. But they had a fair bit of room as long as things were in line with the wheel. I assume an original was either to complicated or extinct to copy. All nice and shiny.

[Bob Purton]

The problem was Al that I had to use a motorcycle type pipe that curved around under the engine. The Bond pipe has a sharper bend and kicks around the side of the primary chain case quite high up which would foul my battery tray. The only pipe I could buy off the shelf for a villiers 9e fitted motorbike was for a Greeves roadster and they happen to be a wide 1 3/4" pipe, it fits fine and maybe albeit unintentionally I have fitted a moderate expansion chamber! Well maybe not. As observed the bend where pipe joins silencer would have kicked the silencer out to the side and the silencer would have not cleared the bodywork so making up a bespoke silencer with an inlet at the correct angle solved that prob as well. I did start going down the Bond minicar route but hit a brick wall. Pipe angle was wrong, the silencer was too long and the rotten toe rags wouldn't sell me one anyway! 

[Jonathan Poll]

Looking great!

I may have a go doing something with the exhaust on my moped, I was given a couple more mopeds from my village, one of them for parts (the other is in lovely perfect original condition!), and the one for parts has a damaged front pipe, I may mod it to have a spare different silencer for the sports moped

[Rusty Chrome (Malcolm Parker)]

Bob - forgive me if you've mentioned this on another thread, but can I ask what this is going to be when its finished? It does look very tidy so far.