Friends, I'm embroiled in a battle to get a welsh shock mount off one spring (separate thread), but this led to interesting discovery. My share:

The welsh mount is 3 layers aluminum base, rubbery cushioning material let's call it poly, and the top metal discs (2 riveted together) with the mounting bolts. As I pealed the onion to get to root cause of this stuck mount, I decided to remove useless layers. First the aluminum base. Too thick for tin shears so out comes my grinder.

That was easy enough. Cut a side, bent it back to remove it. Then I stared at the poly layer. Though to self "well its blocking direct contact with top metal section, there is sure to be hammering motivation tomorrow, so let's remove it.

Turned the grinder on ( not the way to go!) And started to cut a slit in it - ha ha (as Mr Murphy laughed). The poly instantly melted and almost before I could get the blade out - solidified! For future reference, cut this poly with the tin snips to get started, then a stubby hacksaw and or coping saw finishes the job easily

Back to the properties of this poly. I don't know about you but I find it's a pita to get hold of good welding material for my plastic welder. This "poly" material is gold! Melts easy, hardens right back without losing strength or anything!

Its going in my welding box. Wish I had it a year ago! Enjoy.

John

 

can we have a picture of this ?

 

Polyurethanes are generally heat resistant and should not be melting. Some thermoplastic polyurethanes however will melt and your experience may indicate Welsh are using this for their mounts, maybe this is a factor in the problems being associated with the welsh mounts of late.

 

My front mounts are in good shape but I have my eye on some 10mm thick "poly" cutting boards ..hack to rough size on band saw . Centre hole and put in the lathe to turn to size then I think two (20mm) would be about right .
Do you think Red blue or yellow? Maybe blue and yellow sandwich to support Ukraine.

 

You can buy poly sheets of 70 duro in any thickness.
I use Discount Rubber Direct for a top spacer on the strut for weak springs of 1/4 inch with very good success. Kind of dangerous with a flying cutter but does a nice job. You can pick your thickness and don't get the wide sheets, too difficult to work with.

 

Found a source in UK any thickness up to 40mm

 

It would be useful if you could give me the diameter and thickness of the original poly disc

 

I think this thread has every bit of information you might need.
https://www.jaguarforums.com/forum/x...-issue-242977/
somewhere @ page 6 or 7
the 'poly' is indeed a thermoplastic, I don't recall the exact temp but I think it melted @ 235f, got gooy a little lower. I tried to make them more stable several years ago and did the temp measurement.
also...
https://www.jaguarforums.com/forum/x...0-bucks-77884/
wj

 

P., i will share measurements. Look for it later or tomorrow

John

 

If welsh are using a thermoplastic polyurethane for top mount and spring pads it may very well explain the issues owners are having.
Thermoplastic poly is simply not suitable for the job or the environment in which they live.
The properties of thermoset poly are far more suitable for load bearing work.

 

Pistonb, do you still need measurements? If yes what dimensions of which piece?

John

 

Well the poly I can get comes as a square sheet 100mm/125/150 etc so I need to know what size to order to reduce downtime. 5/8 seems to be the standard thickness( 15mm)...Confirm if you can.
It looks like when I have it trimmed circular in the lathe I could cut the 45 deg bit from one side then turn it over and cut in square from the back.
My centre bushes look fine but I need to get under when it stops raining to see if we still have 5/8 . my suspension is slightly low after 112 K so I may go to 18mm.

Many thanks for your continued interest.

 

16mm thick but you also have the step up of about that again which is needed to locate the spring and centre it on the mount.
Major OD is 155mm, ID is 95mm and OD of step is 110mm.

 

Thanks for that but I think I need the item in my hand to get the full picture.