Which Mastic ?

[pensioner]

We bought our van new but it looks as if it was parked outside the day it was completed and before the mastic sealing had time to develop a "skin" so now it is very dirty and looks messy.

I've tried cleaning a small area (successfully) but in doing so have removed some of the mastic.

Can I use a proprietary outdoor window mastic as sold by D.I.Y outlets or is there a specific one I need for my van

 

[Jaydug]

Window mastic tends to harden over time. With a caravan constantly being moved you need a mastic that stays soft and flexible. A good one is Sikaflex 512.

 

[pensioner]

Thanks Jaydug,,,is that readily available

 

[Jaydug]

Several companies selling it on ebay. Shop around prices vary a bit. Failing that any caravan accessory shop will have it.

 

[Gagakev]

Two things come to mind here.

If you are removing mastic as you are cleaning will it affect your warranty if it leaks in the future? I would be dubious about going down that road.

I thought I read on here a while ago New mastic doesnt bond/seal with the old it all needs to be cleaned off and started from scratch, another reason to leave alone.??

Only trying to help and not be negative.

 

[pensioner]

right,,,thanks for that info,,I'll make enquiries before I proceed any further,,mind you I haven't actually removed any completely,,just wiped off the surface crap,,

but if as you say new doesn't bond to old I'll have to think again,,,certainly don't want any leaks

 

[pmyo]

You shouldn't have any issues if you use Sikaflex - Its what many manufacturers use when building caravans. Also, I've stripped old awning rails off my previous van and used Sikaflex when putting them back on. I removed most of what I could of the old mastic / sealant, but not all would come off - stuck them back on with a decent amount of Sikaflex and I didn't have any issues in the 18months after refitting, its a great product. Also used it around a leaking window on the old van, sealed it even when wet.

Since purchasing a new van (5 years old) , I made a point of going over all the joints and windows with Sika - made the joints look like new, bonds like glue and remains flexible.

Watch out for the dates on the bottom of the tube - they have a short shelf life (6 months or so) so when you get it / its delivered, check that its in date before opening.

 

[Gagakev]

You shouldn't have any issues if you use Sikaflex - Its what many manufacturers use when building caravans. Also, I've stripped old awning rails off my previous van and used Sikaflex when putting them back on. I removed most of what I could of the old mastic / sealant, but not all would come off - stuck them back on with a decent amount of Sikaflex and I didn't have any issues in the 18months after refitting, its a great product. Also used it around a leaking window on the old van, sealed it even when wet.

Since purchasing a new van (5 years old) , I made a point of going over all the joints and windows with Sika - made the joints look like new, bonds like glue and remains flexible.

Watch out for the dates on the bottom of the tube - they have a short shelf life (6 months or so) so when you get it / its delivered, check that its in date before opening.

The OP stated he had a new van, hence the reason for my earlier post.
Indeed if the warranty has run out then fine, I have used sikaflex (and W4 Tape) to do my previous van awning rails and have the same job to do in the not so distant future on my current van.

Pensioner how old is the van?

 

[pensioner]

Gagakev, the van is 10 months old, and the mastic around all the seams has always looked scruffy, uneven,a few lumps as if it hadn't been smoothed out properly, above and below the guttering front and rear is black dirt. all around the wheel arches the same.
In short it's what we used to refer to as a Friday afternoon job, and not the standard I work to or expect. PLEASE don't suggest that as it's still under warranty I should go back and complain,,I did that with other issues and it always came out with a new problem,,,now I just do it myself. Certainly will think twice if we ever chance it about using the same manufacturer.

 

[pmyo]

Yep, he did - but the question was:

"I've tried cleaning a small area (successfully) but in doing so have removed some of the mastic.
Can I use a proprietary outdoor window mastic as sold by D.I.Y outlets or is there a specific one I need for my van"

Indicating that he had already removed the mastic, albeit by accident, and so a warranty would be invalid at that point. So the OP required advice on what mastic 'could' be used and if anyone had used a type of mastic before - to which the posts offered advice on personal experiences, which I think is what was required in this case.