Silicone seal cleaning

[stevec176]

Just spent the day cleaning my Rapido and I'm generally happy with the results but I can't get the silicone sealing clean. I've tried using a toothbrush and black streak remover but it hasn't removed all the blacking, has anyone got a good tip please.

[Derek Uzzell]

My experience is that the ‘blackening’ takes place WITHIN the white adhesive/sealant Rapido uses, so cleaning the sealant’s surface won’t affect this. As the black discoloration is actually in and below the ‘skin’ of the sealant material, there’s no easy cure.

 

My 2015 Rapido 640F’s white sealant has become badly discolored at the joint between the metal cab and GRP over-cab moulding and (having tried your technique in the past without success) I’ve concluded that the only realistic ‘fixes’ would either be to cut away and replace the original sealant, or perhaps to paint the discolored sealant (assuming it would accept paint, of course).

 

(The sealant will be a SIKA product and almost certainly not ‘conventional’ silicone.)

[globebuster]

It's almost certainly a PU sealant - not silicone.

 

As Derek says, stain tends to leach into the surface.

 

There are ways to lift some of this out, but not all - and you do need to be careful to not weaken the sealant in the process.

 

I think you just need to live with it...

[John52]

After a leak I put bathroom sealant around my X2/50 windscreen - which discoloured after a few years.

Painted it with undiluted thick household bleach, left it to dry on for a couple of days.

Then washed it off with water

After a second application the seal looks like new.

Can't say it will work with yours because it might not be the same sealant.

But its certainly worked well with mine, took a few days but only a few minutes easy work, the bleach stains rinsing off easily with no damage.

PS - the paint is white though, don't know if bleach would whiten coloured paint?

[globebuster]

What !!!! - not Plumbers Mait……..I don't believe it!

[machra]

I use Mer polish on the whole of the van (minus windows and plastic bits) and find it cleans the sealant.

[John52]

machra - 2018-05-24 7:38 AM

 

I use Mer polish on the whole of the van (minus windows and plastic bits) and find it cleans the sealant.

 

When you have used polish regularly it will have kept a protective film over the sealant, so stains can't get a hold and are easy to remove.

Otherwise the sealant is slightly porous, so the stain gets below the surface, and needs something powerful (like bleach) to soak into the surface and deal with it. Putting polish over stains risks sealing them in.

[stevec176]

Thanks, think I'll just have to live with it for now.

[Den]

I’ve used a good quality T cut and it works followed by a decent polish.

[John52]

stevec176 - 2018-05-24 8:27 PM

 

Thanks, think I'll just have to live with it for now.

 

There must be a way because motorhome dealers get 10+ year old ones looking like new.

I suspect its something quick and easy like bleach, rather than time consuming hard work like T Cut and polish when they've got hundreds of vans to do.

[Derek Uzzell]

There is a good deal of discussion about this on-line (examples here)

 

https://tinyurl.com/y72ztwdu

 

If there is a magic product that motorhome dealers use, there’s no mention of it on-line even when people in the motorhome/caravan trade offer advice.

 

Once discoloration has entered the ’structure’ of the sealant material, merely treating the sealant’s surface using a solvent, polish or cutting-agent won’t address the interior blackening.

 

As globebuster has said, specialised products may reduce the discoloration, but may also damage the sealant itself. I’ve never successfully addressed this problem with mould-removal products (or bleach) when blackening has occurred in silicone sealant in domestic bathrooms. Such products have occasionally helped temporarily when the blackening has been minimal, but the only really effective fix has been to remove the discolored sealant and replace it.

[Derek Uzzell]

I’ve asked SIKA’s advice on this issue.

 

I was told that (as has been said above) if the discoloration is beneath the sealant’s ‘skin’, then using any agent that might pentrate the skin (eg. a strong acid or alkaline product) to try to reach and reduce/remove the discoloration would almost certainly damage the sealant’s composition. As far as SIKA was aware there was no ‘magic’ product to address this problem and the only effective cure would be to remove and replace the discolored sealant.

[John52]

Derek Uzzell - 2018-05-25 6:32 PM

 

I’ve asked SIKA’s advice on this issue.

 

I was told that (as has been said above) if the discoloration is beneath the sealant’s ‘skin’, then using any agent that might pentrate the skin (eg. a strong acid or alkaline product) to try to reach and reduce/remove the discoloration would almost certainly damage the sealant’s composition. As far as SIKA was aware there was no ‘magic’ product to address this problem and the only effective cure would be to remove and replace the discolored sealant.

 

Yes I can understand that.

Bleach may have damaged the sealants composition on the surface.

But doesn't seem to have penetrated very far because its still looks and feels fine

It took a couple of days to penetrate into the surface to whiten it.

Then I rinsed it off.

I can't think how else dealers get 10+ year old vans looking like new.

[Derek Uzzell]

You could always contact some dealers and ask them.

 

I can’t see them using the thick-bleach treatment you’ve employed (too laborious), but if they have some miraculous ploy that can remove discoloration from white Sikaflex without damaging the sealant (and that SIKA are not aware of), lots of motorcaravanners would be interested.

[John52]

Derek Uzzell - 2018-05-26 8:44 AM

I can’t see them using the thick-bleach treatment you’ve employed (too laborious),.

laborious? It took about 2 minutes to brush on and the same to rinse off with my hose brush

Doubt if dealers want to reveal their trade tricks

And I don't need to know since I found an easy way thats worked for me. :-D

[Derek Uzzell]

Yes, but you have employed bleach to treat bathroom sealant and that won’t be what motorhome manufacturers use. As was said earlier, the normal adhesive/sealant will be a PU product (Rapido uses SIKA products) and what works with bathroom silicone sealant won’t necessarily work with SIKAflex.

 

If you can’t be bothered to make the effort to to give credence to your suggestion that motorhome dealerships have some sort of cleaning trick, then so be it...

[Den]

To those who suggest bleach. Don’t do it.

It takes minutes with a good quality T cut.

Of course an easy way is probably bleach and pay the consequences a little later.

[gordonaldson]

Silicone Sealer Eater anyone...Does it work, don't know but its sold at I think Screwfix and Toolstation...

[John52]

Derek Uzzell - 2018-05-26 3:35 PM

If you can’t be bothered to make the effort to to give credence to your suggestion that motorhome dealerships have some sort of cleaning trick, then so be it...

 

 

If you can't be bothered to look at the old motorhomes on their forecourts, then so be it (lol)

I'm not the one looking for a way to clean sealant. (lol)

[Derek Uzzell]

“Silicone Eater” is (as it says on the following link)

 

https://www.everbuild.co.uk/product/silicone-eater/

 

intended to remove all types of silicone sealant by digesting and breaking it up but - as I’ve emphasised above - the sealant used by Rapido and (presumably) by other reputable motorhome manufacturers is not the silicone material generally employed for domestic sealing purposes in bathrooms, kitchens, etc. And, in any case, the objective is to address the black discoloration in the sealant , not to ‘digest’ the sealant itself.

 

This recent MHFun discussion

 

https://www.motorhomefun.co.uk/forum/threads/cleaning-black-marks-from-sealant.150625/

 

repeats this thread’s original enquiry. The attached photo shows the black discoloration in the sealant where an Elddis motorhome’s cab joins the overcab section and is similar to the ‘blackening’ of that joint on my Rapido.

 

It should be straightforward to remove dirt that is just adhering to the sealant’s upper surface by using a suitable solvent, but if the discoloration is in the sealant itself, it should be plain that any agent or technique employed to remove the discoloration will need to penetrate the sealant’s outer skin or remove the damaged skin (ie. by using a cutting compound like T-Cut). T-Cut would definitely not be effective on my Rapido as the surface of the sealant in the cab-to-overcab joint is ‘bumpy’ not smooth.

 

This video-clip

 

 

shows the ‘bleaching’ method John52 apparently employed to clean the discolored bathroom sealant around his X250’s windscreen. It’s clearly effective on SILICONE sealant, but the method requires that the bleach remain in contact with the silicone sealant for several hours.

 

John52 said above "Painted it with undiluted thick household bleach, left it to dry on for a couple of days. Then washed it off with water. After a second application the seal looks like new.” and "It took a couple of days to penetrate into the surface to whiten it.”

 

As John52’s method (and the ploy shown in the YouTube clip) seemed to need the bleach to be left to act on the sealant for a prolonged period, that’s why I felt that the method was likely to be too laborious for motorhome dealerships to use - though “too time-consuming” would have been more apt.

[Geeco]

My solution is to use a product sold here called "exit mould". It may be available in UK not sure. It is a general purpose chlorine (I think) based bathroom/ kitchen cleaner. I spray it on and leave for a few minutes then hose off. As Derek has said it will not remove the mould under the skin but certainly makes it look more attractive. Deteriation of the plastic hatch surrounds surfaces is just as much of an issue for me due to high UV. Cheers,

[Guest pelmetman]

Cleaned mine yesterday with white spirit ;-) ........worked a treat B-) ........

 

 

[John52]

Derek Uzzell - 2018-05-27 8:11 AM

 

“Silicone Eater” is (as it says on the following link)

 

https://www.everbuild.co.uk/product/silicone-eater/

 

intended to remove all types of silicone sealant by digesting and breaking it up but - as I’ve emphasised above - the sealant used by Rapido and (presumably) by other reputable motorhome manufacturers is not the silicone material generally employed for domestic sealing purposes in bathrooms, kitchens, etc. And, in any case, the objective is to address the black discoloration in the sealant , not to ‘digest’ the sealant itself.

 

This recent MHFun discussion

 

https://www.motorhomefun.co.uk/forum/threads/cleaning-black-marks-from-sealant.150625/

 

repeats this thread’s original enquiry. The attached photo shows the black discoloration in the sealant where an Elddis motorhome’s cab joins the overcab section and is similar to the ‘blackening’ of that joint on my Rapido.

 

It should be straightforward to remove dirt that is just adhering to the sealant’s upper surface by using a suitable solvent, but if the discoloration is in the sealant itself, it should be plain that any agent or technique employed to remove the discoloration will need to penetrate the sealant’s outer skin or remove the damaged skin (ie. by using a cutting compound like T-Cut). T-Cut would definitely not be effective on my Rapido as the surface of the sealant in the cab-to-overcab joint is ‘bumpy’ not smooth.

 

This video-clip

 

 

shows the ‘bleaching’ method John52 apparently employed to clean the discolored bathroom sealant around his X250’s windscreen. It’s clearly effective on SILICONE sealant, but the method requires that the bleach remain in contact with the silicone sealant for several hours.

 

John52 said above "Painted it with undiluted thick household bleach, left it to dry on for a couple of days. Then washed it off with water. After a second application the seal looks like new.” and "It took a couple of days to penetrate into the surface to whiten it.”

 

As John52’s method (and the ploy shown in the YouTube clip) seemed to need the bleach to be left to act on the sealant for a prolonged period, that’s why I felt that the method was likely to be too laborious for motorhome dealerships to use - though “too time-consuming” would have been more apt.

Well, as you say, I didn't faff about with bits of toilet paper - just painted it on with a paint brush in a couple of minutes. I've done shower cubicles with thin bleach (28p for 2 litres Morrisons/Sainsbury's) in a spray bottle. Takes several applications,over esveral days but each one only takes a few seconds.

[John52]

Derek Uzzell - 2018-05-27 8:11 AM

“too time-consuming” would have been more apt.

Wouldn't have thought it too time consuming for a valeter to walk round the vans with a jar of bleach and paint brush and dab a bit on any mould?

[skaman]

Fenwicks multi surface cleaner , brilliant stuff.