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[John W E]

Hi one and all

Here is a word of caution with regard to plastic we used in the 1990s.    I am renovating my Boston Blenheim trawler, which I built in the very early 1990s - for the bulwarks and fish-hold I used Plasticard of 2mm thickness and 1.5mm thickness.    I bought this from a model shop in Newcastle, the shop doesn't exist now though (sad that - was a good model shop that one was).   

Anyway, come to get the model out of the loft and I clipped one of the bulwarks and it shattered into many, many pieces!   I have now found all the of the Plasticard has turned extremely brittle - so much so - it shatters like glass.   What has caused this I have no idea, it may have been cos the model has been in the loft for 5-6 years or it may have been that the very early Plasticard isn't very good.

What does everyone think?

Thank you David Tait for your link - its very useful

aye

John

[Brian60]

Oddly enough I encountered a similar problem today. This morning in the garden I brushed against one of the solar lights on the driveway, the top shattered into fragments. I went along to the next one and when I took hold of it between finger and thumb a piece of the plastic just snapped off.

On inspection all the lights (15 in total) were the same. These were only put in last summer so just coming up for a year in situ. It seems plastic doesn't like to be exposed to hours and hours under tropical sun.

[Klunk]

Always check that plastic is uv stable!  Most solar lights are made on foreign shores and are not uv stable.

[Colin Bishop]

A lot of the earlier plasticard was chemically unstable. Dave Sambrook's award winning HMS Ashanti that used a lot of it virtually disintegrated after 15 years or so.

I think the modern stuff is more stable but still needs painting for UV protection. There is quite a lot about the longevity of plastic card online and a general feeling that it has a limited life as a petrochemical product which is why I prefer to use wood in my models - it worked for the ancient Egyptians!

Colin

[DavieTait]

John would a set of the plans for the Boston Blenheim help ?? I've got a set here I can post down ( you can post them back once you've finished with them ) if it'll help

Davie

[Capt Podge]

I had a somewhat similar experience when re-rigging the mast on my little SHG trawler "saucy sue" - the mast is a thin plastic tube which I had painted with thinned down Humbrol Enamel.
This model was completed about 15 years ago.
 
When I took a firm grip on the mast to release it from the tabernacle the mast shattered. I had put this down to a chemical reaction between the plastic and the paint - but now I'm not so sure .
 
The mast has now been replaced with a thin brass tube
 
Regards,
 
Ray.
 

[ballastanksian]

Plastics can react with other plastics to degrade, or often, the UV light will destabilise the volatiles in a plastic leaving the non volatile parts of the plastic that then are brittle, as the volatiles provide the springiness to the model. Most plastics suffer this even today though there are a few that while resiliant, are also hard to glue woith anything. These are the plastics that do not biodegrade that quickly:O/

It is nuisance ebnough when your lights fall apart, but so much worse when it is a model that took hours and hours of work.

[vnkiwi]

No surprises really, plastic modellers where made aware of all this back in the 70's and 80's
I's why, when commisions for models by Museums and the like, the museum had a list of materials that they would accept in the construction and finishing of said models. Plastis, where absent from said list, for all the reasons given in the above posts.
Don't know if that is still a requirement now though.
 

[John W E]

Hi all, this is an interesting topic and it doesn't half give ya food for thought.

What is sticking in my mind - is of all the models I have simulated hull plating with the plasticard - I wonder how long that will last.

what about the plastics that 3d printers use - how long will that last.

Dave you got a PM

aye

John

[vnkiwi]

Hi Bluebird,
I wonder how long that will last.
That's a question that I've asked myself over the years.
Back in the '60's and '70's, I built a lot of plastic kitset cars, and since then they have sat on shelves and window cills in my parents homes. Some in small glass cases, some not, some in the sun, some not. They are a mixture of UK, French and USA company products. The plastics do vary, some very hard to cut, some very soft to cut.
Most where painted using Humbrol enamel paints. a couple not painted at all.
Of them all, only one paint has failed, this was a metalic mid green, on an Airfix 1/32nd Capri. All the other paint has survived near as I can tell as it was painted.
Funnily enough, this was also the plastic body, which has failed, and I think because it has spent a good 50% of its life in direct sunlight on a window cill.
Also from that period, I had sheet and profiled plastic, of Plastruct and Evergreen brands. These have been always stored in a closed box, and stored in an uninsulated garage, exposed to summer heat and winter cold.  Only one sheet has gone brittle.
So, what does this tell me. I'd sy around 5% of the plastics I used back then have gone brittle, or have deformed possibly due to over exposure to New Zealand's very high uv.
So, over a period of 40 to 50 years, I have experienced upto a 5% failure rate, which is only a little higher than the wooden hulls of the boats I have built and part built in the same period. These have been always stored in the uninsulated and unheated garages.
A couple have dried out and the plywood, delaminated. and one had gust a tiny bit of rot, where the roof had leaked onto it.
Make from this what you will.
cheers