Biopowered - vegetable oil and biodiesel forum
Biodiesel => Biodiesel equipment => Topic started by: nigelb on May 31, 2013, 08:54:58 PM
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Today I've been mostly replacing seals in my wash tank.
When I rebuilt the system 18 months ago I used cork as a replacement material for the rubber washers on the tank connectors. Over the past few months I've noticed a deterioration of the seals. They've not been leaking but they had begun to breakdown, so I bought some viton sheet from the bay. It's a tad expensive but I'm now much happier that the seals are bio proof.
I bought some 3mm thick stuff for about £15 delivered...200mm square. :o
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as you probably already know be very careful with viton. if it catches fire the sticky mess left behind contains hydroflouric acid. very nasty stuff. the lower the concentration the worse it is. thinking if you were disposing of small offcuts in the wood burner or something like that. easily done. clear out the ashes and get the residue on your fingers bye bye fingers.
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While I'm aware of its chemical composition ie VINYLIDENE FLUORIDE HEXAFLUROPROPYLENE but I was not aware of it's properties when burnt.
I am aware of the dangers of HF but feel enlightened now that you've shared that knowledge of burnt viton. The small off cuts were disposed of in my general waste bin
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i first became aware of the danger while sitting in a grotty garage office waiting for an MOT. got bored with the magazines and was looking at the notices on the wall, when i came across one from the fire service warning about the dangers of viton hoses in cars that have had engine fires. warned against touching any burnt viton hoses as they contain HF when burnt. discovered not many mechanics know this, whereas the scrapyard guys tend to. suppose it depends on how proactive your local fire service is in letting people know about the danger.
http://knowledgeweb.afac.com.au/research/hazmat/documents/HAZMAT_Articles_Fluoroelastomers_and_vehicle_fires.pdf
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That is partly why when a car goes on fire, it is sometimes made a category A write off, no parts to be salvaged.
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From Wikipedia:
Aqueous hydrofluoric acid is a contact-poison with the potential for deep, initially painless burns and ensuing tissue death. By interfering with body calcium metabolism, the concentrated acid may also cause systemic toxicity and eventual cardiac arrest and fatality, after contact with as little as 160 cm 2 (25 square inches) of skin.
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I was not aware of how serious it is, untill I look it up as a result of this thread I thought it was just another H&S scare! Perhaps a warning should go on the wiki?
Dick
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I was not aware of how serious it is, untill I look it up as a result of this thread I thought it was just another H&S scare! Perhaps a warning should go on the wiki?
Dick
..about HF or the burning of viton?
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While I don't doubt the danger of burned viton, it has to be said, I don't know anyone who has suffered as a result of exposure to it. I don't know anyone who knows anyone, or anyone who met a bloke in the pub who knew someone either. So I guess it doesn't happen very often.
I do know someone who knows someone that had medical test carried out on them by extra terrestrials, so that seems more of a risk. Then maybe that's got more to do with me.............
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While I don't doubt the danger of burned viton, it has to be said, I don't know anyone who has suffered as a result of exposure to it. I don't know anyone who knows anyone, or anyone who met a bloke in the pub who knew someone either. So I guess it doesn't happen very often.
I do know someone who knows someone that had medical test carried out on them by extra terrestrials, so that seems more of a risk. Then maybe that's got more to do with me.............
;D
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I do know someone who knows someone that had medical test carried out on them by extra terrestrials, so that seems more of a risk. Then maybe that's got more to do with me.............
Likewise. In my friends case, it was this one to blame -
(http://upload.wikimedia.org/wikipedia/commons/thumb/8/88/DMT.svg/200px-DMT.svg.png)
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I'm sure I'm not hallucinating how far off topic this thread just got. ;)
Yes we should put a warning on the wiki. I think we have a page about materials in there somewhere.
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i think the reason no one knows of anyone suffering from HF poisoning from burnt viton is, i suspect because HF poisoning is likely it be rarely encountered in the average A and E dept. if you don't know the dangers you are unlikely to go to A and E with specific symptoms. given the amount of different nasty chemicals the average mechanic gets in cuts every day it could well be missed. i would say if you don't know anyone who has suffered from HF burns they have been very lucky. if course since viton is fairly new in its use in cars it could be that mechanics seem to wear gloves a lot more than they did in my day.( 1960s) it was unheard of to wear gloves back then even if you could get them.
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I was not aware of how serious it is, untill I look it up as a result of this thread I thought it was just another H&S scare! Perhaps a warning should go on the wiki?
Dick
..about HF or the burning of viton?
I was thinking of the Viton. As more peeps up rate processors etc and are looking for "the best"materials more are going to use Viton for seals etc and may burn the residue or even accidentally burn seals when soldering.
Dick
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hmmm interesting...
stick with nylon and nylon washers it is then
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I has to reach a very high temperature for a sustained period of time, form what I've been told, to produce the acid. It's not going to happen with a soldering iron, more like the inside of a car engine, after its been burned out in a multi car pile up.