Myth or Fact: Porthole Gaskets and Mineral Spirits/Vaseline
- Thread starter Brian D
- Start date
I made covers for my ports. Originally to protect the screens from polish splatter but I will leave them on while the boat is not in use to keep dust and LAX airport grime out,
I made them from 1/4" corrugated plastic sign material. It cuts easily with a pair of scissors. I made them so that they are a snug fit on each end.
I made them from 1/4" corrugated plastic sign material. It cuts easily with a pair of scissors. I made them so that they are a snug fit on each end.
Re: Myth or Fact: Porthole Gaskets and Mineral Spirits/Vasel
Beckson has this posted at their website.
Over-Tightened Gaskets
If someone has over-tightened the knobs on a port and left it for a long period, the new style grooved gasket can take a compression set; effectively it becomes a solid piece of rubber and loses most of its resiliency and ability to repel water. Wiping the gasket with a very light coating of petroleum jelly and leaving the port open for a few days will rejuvenate the gasket. Over-tightening should not occur in ports using cam latches.
Older Gaskets
You may have an old design smooth gasket. A smooth surface can allow capillary action to draw water across though tightly sealed. It should be replaced with a newer design that has parallel ridges that stop capillary leaks. Wiping an old style gasket with a very light coating of petroleum jelly will rejuvenate the gasket and its water repellent nature will help resist capillary action. This is a temporary solution to stop the leak until the gasket is replaced. Do not use silicone grease as it attracts and holds dirt like a magnet. Other lubricants may adversely affect the gasket or lens material.
Beckson has this posted at their website.
Over-Tightened Gaskets
If someone has over-tightened the knobs on a port and left it for a long period, the new style grooved gasket can take a compression set; effectively it becomes a solid piece of rubber and loses most of its resiliency and ability to repel water. Wiping the gasket with a very light coating of petroleum jelly and leaving the port open for a few days will rejuvenate the gasket. Over-tightening should not occur in ports using cam latches.
Older Gaskets
You may have an old design smooth gasket. A smooth surface can allow capillary action to draw water across though tightly sealed. It should be replaced with a newer design that has parallel ridges that stop capillary leaks. Wiping an old style gasket with a very light coating of petroleum jelly will rejuvenate the gasket and its water repellent nature will help resist capillary action. This is a temporary solution to stop the leak until the gasket is replaced. Do not use silicone grease as it attracts and holds dirt like a magnet. Other lubricants may adversely affect the gasket or lens material.
I didn't say anything because I am at odds with using petroleum products on rubber. It eats rubber. That's why there is a difference in heater hoses, and fuel/hydraulic hoses. This will not happen fast, but in the long run will turn rubber into a ghastly goo. If grease, I'm onboard as well with Superlube. I like Teflon grease. It's all I use. That and the putty....
Re: Myth or Fact: Porthole Gaskets and Mineral Spirits/Vasel
Thinwater is correct .... chemical compatibility is the key here.
Most portlight etc. gaskets are either BUNA (Nitrile) or Neoprene and are 'resistant' to most common 'petroleum' products although for VERY long exposure may begin to soften and swell ... but after a VERY long exposure.
The problem with such 'synthetic rubbers' however, is long term attack by oxygen and especially ozone which 'hardens' and then allows cracking of the BUNA/Neoprene/Silicone, and 'whatever' these synthetics are 'filled' with - carbon powder, wood flower, floor sweepings, or whatever happens to fall into the vat when during the blending process, etc.
So, once you have functional failure of any 'rubber' gasket you really dont know the failure mode ... and the failure is most probably oxidation/ozone attack; and, smearing on some petroleum based 'goo' really isnt going to restore resiliency, softness, etc. of that oxidation. Best is always replace with new ... or new & improved (such as with improved UV and oxidation stabilizers .... and if you can find them but more expensive: "non-filled" {virtually transparent/clear} polymers such as food grade or pharmaceutical grade 'rubbers').
Here's probably one of best 'chemical compatibility guide' for 'rubbers and plastics' for gaskets, seals, and O-rings on the internet: http://www.coleparmer.com/Chemical-Resistance
Thinwater is correct .... chemical compatibility is the key here.
Most portlight etc. gaskets are either BUNA (Nitrile) or Neoprene and are 'resistant' to most common 'petroleum' products although for VERY long exposure may begin to soften and swell ... but after a VERY long exposure.
The problem with such 'synthetic rubbers' however, is long term attack by oxygen and especially ozone which 'hardens' and then allows cracking of the BUNA/Neoprene/Silicone, and 'whatever' these synthetics are 'filled' with - carbon powder, wood flower, floor sweepings, or whatever happens to fall into the vat when during the blending process, etc.
So, once you have functional failure of any 'rubber' gasket you really dont know the failure mode ... and the failure is most probably oxidation/ozone attack; and, smearing on some petroleum based 'goo' really isnt going to restore resiliency, softness, etc. of that oxidation. Best is always replace with new ... or new & improved (such as with improved UV and oxidation stabilizers .... and if you can find them but more expensive: "non-filled" {virtually transparent/clear} polymers such as food grade or pharmaceutical grade 'rubbers').
Here's probably one of best 'chemical compatibility guide' for 'rubbers and plastics' for gaskets, seals, and O-rings on the internet: http://www.coleparmer.com/Chemical-Resistance
Re: Myth or Fact: Porthole Gaskets and Mineral Spirits/Vasel
Rich: Thats a handy chart to use. One of my college degree minors is plastics and I have a nice reference book that has all kinds of info in it. Thanks, Chief
Rich: Thats a handy chart to use. One of my college degree minors is plastics and I have a nice reference book that has all kinds of info in it. Thanks, Chief
The problem is with such 'charts' is that polymer blends and fillers are always changing; and so too are 'petroleum based' products ... so such charts are only a 'rough guide' and for surety one now has to 'test' to be sure.
This is especially the case with cheap 'imported' stuff and especially any petroleum products that are co-blended with so called 'bio' stuff.
This is especially the case with cheap 'imported' stuff and especially any petroleum products that are co-blended with so called 'bio' stuff.
Re: Myth or Fact: Porthole Gaskets and Mineral Spirits/Vasel
Given enough time motor oil will eat through rubber. Petroleum jelly (Vaseline) is a crude oil derivative that will soften rubber seals. I would not use it in an airplane "O" ring seals, but to recondition porthole seals in a boat it should is fine.
Given enough time motor oil will eat through rubber. Petroleum jelly (Vaseline) is a crude oil derivative that will soften rubber seals. I would not use it in an airplane "O" ring seals, but to recondition porthole seals in a boat it should is fine.