Christian S. Hansen
Post Number: 539
|Posted on Friday, 17 March, 2017 - 05:35 pm: |
In the not too distant past there was a discussion where David Gore (as I recall) suggested a product for topical application to rubber grommets and weatherstripping to soften and rejuvenate them. I have tried without any success to search for that reference, so simply ask if anyone remembers it? David, perhaps? Those on my Silver Cloud are all in need as they are hard and that product, while noted as being expensive, apparently did wonders and I would like to try. Thanks!
Post Number: 1757
|Posted on Friday, 17 March, 2017 - 05:41 pm: |
370608496774 on eBay is probably the stuff.?
Post Number: 2481
|Posted on Friday, 17 March, 2017 - 07:20 pm: |
The product is Dupont Krytox GPL105 liquid - this is a liquid polymer that restores hard UV degraded elastomer seals eliminating wind noise and water leaks as the seals regain their original soft and supple characteristics virtually immediately after the fluid is applied VERY sparingly as it is expensive but a little goes a very long way - I have used 2 50g bottles over 8 years at a cost of AUD200 for 16 to 18 applications [usually twice yearly].
My partner has a VW Eos hardtop convertible and the roof/door/boot seals are like new, the roof doesn't generate wind noise, creak, groan or leak like most convertibles of this vintage. Virtually all convertible manufacturers buy Krytox in bulk and repackage it for sale as their recommended seal lubricant.
You can buy Krytox on Ebay but price usually reflects quality as shifty sellers dilute the genuine product to offer a lower price but you use more with each application to get proper rejuvenation. You may encounter a German product on Amazon named Gummi Phleg which claims to be as effective as Krytox and cheaper however I have seen reports which dispute this claim as the amount required to give equivalent rejuvenation to Krytox is reported to be greater than the amount of genuine Krytox. One user also reported it did not retain is effectiveness as long as genuine Krytox GPL105.
The Ebay item quoted by Paul Yorke is genuine GPL105 repackaged but may have been diluted to lower the price as it is about 2/3rd the price I have paid in the past for undiluted GPL105 from an official Australian Dupont distributor. Only actual use or a viscosity test will confirm whether it has been diluted or not. The needle point applicator is a "must have" as it allows more accurate and controlled distribution of the liquid during use.
Here is a link to the original thread on this forum:
Post Number: 52
|Posted on Friday, 17 March, 2017 - 07:37 pm: |
A friend of mine used to soak rubber parts in glycerin to soften. The important thing is to not leave the parts in contact for too long or it can over-soften the rubber. Try some glycerin in a zip-lock bag with the rubber parts and seal. He left some in for weeks after forgetting and the rubber was so soft it was no longer useful. A pharmacy should have glycerin or maybe even eBay. I saw this on eBay:
Christian S. Hansen
Post Number: 540
|Posted on Friday, 17 March, 2017 - 07:55 pm: |
Paul and David G:
Wonderful. Thanks. That's the stuff, and although perhaps pricey, as the entire car needs to be done...actually, my entire fleet...it will be worth it. I will use the EBay link provided by Paul, even if repackaged as the product number matches. I did an EBay search for simply "Dupont Krytox" and apparently there are all sorts of different products with different Krytox numbers within that category and I assume that each number is a different product with a different purpose, even though called Krytox.
Your suggestion may come in handy as well someday under the right circumstances, but this event involves treatment of the weatherstripping, windscreen surrounds, door bumpers, etc, etc, while installed on the vehicle.
I will definately give my perspective on the product's effectiveness down the road as my rubbers are all as one would expect for 60 years of atmospheric exposure, even if not direct sunlight...except for those periods when driven.
Post Number: 2482
|Posted on Friday, 17 March, 2017 - 09:10 pm: |
You are correct, Krytox comes in liquid and grease forms. The numbers simply refer to viscosity for the oils and "stiffness" for the greases.
A tremendous product for ensuring elastomer seals exposed to harsh conditions are preserved and retain their original effectiveness. I am extremely happy with the seals on the Eos and they look and perform the same as they did when first installed during assembly of the car.
I have not used GPL105 on natural rubber seals likely to have been installed on pre-WW2 vehicles so careful testing on a non-visible location is required before applying it to visible seals. I have no hesitation in suggesting GPL105 for elastomers as I have been able to evaluate it long-term in our harsh environment with very impressive results. Old seals may need 5 or more treatments over a period of 3 to 6 months in summer ambient temperatures to get the necessary penetration and rejuvenation for very hard and UV degraded seals. Manual patient reshaping of the seals over time after they have softened is usually necessary to restore the original sealing of bodywork gaps in older cars. Leaving the car to warm up in direct sunlight is very effective in accelerating penetration and rejuvenation; in cold weather, the process will take a lot longer.
Degraded seals will have a grey colour and will feel hard to the touch; rejuvenated seals will be a matt black in colour and feel very supple when touched and "spring back" immediately if indented with a very firm finger push.
David B - under no circumstances would I use Glycerin for elastomer seals as it most likely permanently changes the properties of the elastomer leading to future irreversible reductions in the longevity and performance of the seals.
Post Number: 53
|Posted on Saturday, 18 March, 2017 - 12:37 am: |
David G. - My comments were not intended to be just anecdotal, as I have seen empirically how effective glycerin is for this purpose having used it myself as far back as 1986. I've never soaked parts in it though, just wiped it on. The guy that showed me originally, used to soak windscreen rubbers in it so that the glass was easier and thus safer to re-install after repainting the body shells on his many restorations. He once told me he forgot about one windscreen rubber and by the time he found it 6 months later, it was so soft it would no longer retain the glass. The main benefit is it is cheaply available, so is good for large sections of hardened rubber, and like Krytox, the rubber starts grey and hard and goes black and supple. I have never used it on my current car as window rubber has been right down the priority list, but I always keep a bottle for this purpose.