A materials question

[chrisvine]

Does anyone know what material or process is use to make the air plenum, steering column bulkhead cover and heater air intake? I think it's a type of glassfibre but it is mounded (pressed?) on both sides. Rather than typical laying of sheets of glassfibre and resin. The material is a lighting grey colour. Could it be a SMC/BMC moulding?

[Heuer]

I always thought the plenum was a glass fibre moulding. After the very early cars it was modified with a narrower rim edge and had the three strengthening ribs added, which were then filled in before painting on the 3.8 cars. The ribs were left exposed on the 4.2 cars. The other parts were made by the same method I believe.

[66an]

This is an old thread I know. But I started to sand my heater air intake before respray yesterday. I saw the light grey easy sanding material coming up and I stopped quickly when asbestos came up in my mind. Am I wrong with my thoughts?

[christopher storey]

Very unlikely that there is any asbestos there. As far as I know, the filler used on fibreglass mouldings etc is a resin substance, possibly also with an inert powder added, and mixed with a chemical hardener . When cured, if it is sanded it produces white powder

[cactusman]

Not asbestos. As Christopher says it is a resin....probably an epoxy resin. Common sense to avoid breathing it in if you are sanding but not asbestos.
As far as I know the only places asbestos would have been present when new would be the brake and clutch friction surfaces....almost certain to have been replaced by non asbestos containing alternatives by now - AND possibly heat shield materials between the exhaust manifolds and reservoirs. These may still be present. Wise not to disturb it.

[PeterCrespin]

There was asbestos in exhaust downpipe fire rings, albeit encased in metal and rope seal too. Neither apply today.

So no asbestos/mesothelioma risk, but chopped strand glassfibre 'may' still be a silicosis hazard once turned into breathable powder in the same way as mineral/silicate dust is for sandblasters?

The bonnet air duct looks moulded, and chopped strands are mostly just filler. unlike layered glass mat construction which may apply to the plenum. Chopped Kevlar strands in hoses is a waste of time, whereas a Kevlar textile layer like the original cotton, could make a hose 'bulletproof'.

[chrisfell]

Am I the only one who always sand stuff like this wet? And I mean drenched.

[PeterCrespin]

Am I the only one who always sand stuff like this wet? And I mean drenched.

Option A: Avoid dust but risk collapse from not breathing for a while (which is self-correcting when you faint).

Option B: Risk not breathing permanently by taking your Black & Decker into the shower (which might take your rescuer too, if the mains fuse doesn’t blow)?

Decisions, decisions! It probably boils down to whether you want company on your road to Hades or you prefer riding solo :-)

[tonyabacus]

Chris
You may recall some time ago you were going to lend your air intake as I was looking to perhaps get some made as my own was not present when I purchased the car.
At the time I eventually obtained one to have a look at and took it to a local injection moulding company where we investigated how it was made and of what material. We came to the conclusion that the only way you could successfully make them and produce the small finned area inside the intake itself would be to make it in two halves, otherwise there was no other way we concluded that it could be done.

We also came to the conclusion that the Jaguar moulding I had, showed a definite ridge around its waistline where in manufacture the two halves had a step so one half neatly fitted into the other and was then bonded with resin to obtain a reasonably neat overall look to the component. The injection moulder although stating they could possibly manufacture for me, thought it would be better to make it with fibreglass both from a practical as well as cost perspective.

As with all good intent, having finally obtained my missing part, the thoughts of manufacture slowly reseeded into the background. However I will always remember your kind offer to allow me to borrow yours to investigate possible manufacture, so again my thanks.

I hope that throws a little more light on the material as per your original enquiry.
Tony

[PeterCrespin]

Chris
You may recall some time ago …..a local injection moulding company... investigated how it was made and of what material.

What, if anything, did they say about material Tony?

[tonyabacus]

Hi Peter

They thought it was definitely glass fibre, certainly not any of the newer compounds that we see like Kevlar etc. Whilst awkward to see properly, inside there are some small fins, which they suggested had the hallmarks of glass fibre due in part to the poor quality finish around those fins. As we have a lot of boat building in Cornwall, I afterwards went to one of these guys and he too was of a similar opinion.
Tony

[Freerthy]

Usually they are made of sheet metal, but other rigid heatproof materials such as glass fiber or insulated plastic may be used.

[christopher storey]

Not another spammer ? Freethy's assertion that these were sheet metal is entirely wrong

[tonyabacus]

Chris
I got to thinking some more about the material that the air duct is made from and wondered what the factory had used by way of a colouring agent, added to get the black finish. When sanded, the combination of the white mat and the coloured gel, may have created a powder that rather than being black, came off as a darkish grey as was alluded to earlier in the topic.

Bearing in mind that these were being produced in the earlier days of fibreglass work, I just wonder what they used to colour the gel and if they also used the fine matting as the bond. The coarse mat usually starts to show when sanded, whereas the fine mat makes more of a powder and does not show through in the same way.
Any thoughts?
Tony