What adhesive sealer to use?

Filsjag

Guest
Hi,

My '87 Pilote had a new water heater (before I bought it, so I can't go back and complain). It appears that the stainless steel chimney is not properly sealed to the roof and the water is really dripping through and damaging the woodwork.

I have determined that I shall remove the chimney and clean off what appears to be car body filler and refit with proper sealer.

But. What is proper sealer? Should it stay flexible? Will it need to stand much heat? Will it adhere to two different materials (I'm unsure if the roof is gellcoat GRP or aluminium?

Phil
 
Sikaflex - 552 Sticks like s**t to a blanket.
Best there is.
Should be no direct heat as chimney will be a balanced flue type (ie: two in one. Fresh air drawn in through the outer part, burnt exhaust expelled through inner part.)
Be careful to renew any gaskets found upon taking apart the flue, as if not you may find carbon dioxide leaking into the habitation part of your van. Better to just get sealent and clean the area well with a degreasent such as accetone and put sealent on. A well wetted finger can be used to smooth it out if neccessary.
 
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If you contemplate using any silicone based product remember to only use NEUTRAL cure, not ACID cure this will corrode steel and other metals. Most of the cheaper lines are usually acid based.
As previous post I reckon Sika products one of the best,a lot of professional convertors seem to use them
 
The only option is Sikaflex - costs more but is MUCH MUCH better than cheap sealants. I learnt the hard way!
 
I use sika 221 normally for all horsebox building stuff - but Glenseal sell something identical for 98p a tube - seriously. cheaper than sika, but identical. you have to buy 12 tubes though

PU sealant anyway....
 
Thanks for your responses. I rang my local dealer, Lowdham Caravans and spoke to the Parts Manager, he confirmed that the only adhesive to bond Stainless Steel with Gelcoat would be Sikaflex 552. Then he said "We don't stock it."
The only 552 to be found on Ebay is £22 plus postage. I will reflect on this price and it will be worth every penny when I am in torrential rain!!!
Thanks again, Phil
 
Filsjag said:
Thanks for your responses. I rang my local dealer, Lowdham Caravans and spoke to the Parts Manager, he confirmed that the only adhesive to bond Stainless Steel with Gelcoat would be Sikaflex 552. Then he said "We don't stock it."
The only 552 to be found on Ebay is £22 plus postage. I will reflect on this price and it will be worth every penny when I am in torrential rain!!!
Thanks again, Phil
Click to expand...

It's not just that, though obviously that's why you put it on. The good thing with this sealant is its ability to contract and expand across a vast temperature range, so where many other sealants would develop pinprick holes (-ie- leaks) this won't.
 
552??????????????????

thats a structural adhesive! Thats for sticking main structural bits together, not sealing a chimney!

the spec shows that it will take 140 C for 4 hours, vs 221 takes 120 for 1 hour (officially)

Someones trying to rip you off dude. How hot does the flue get? If it gets really hot - then the PU adhesives will fail - you need a silicone based adhesive - but silicone has a poor adhesive quality. Try looking for roof flue collars (look like a rubber cone set into lead - used on houses) - then seal the lead to the roof with 'cheap' 221 or similar. If it is double lined, and stays 'cool' (ie under 100 degrees C), then just seal it with 221!

the highest temp stuff I can find is SikaFireSil®-N which is 200C
 
Well! That's how the Sikaflex 552 worked. In fact Very well.

I appreciate that there are probably a number of adhesives that would do the job but I couldn't afford to try something and hope for it to work.

I asked on this forum because I was confident that I would get some help and I have had help.

It wasn't just a case of the roof leaking, it was dripping down a panel and soaking the chipboard. It swelled up so much that the plastic T shape edging strip came away.

Now here's a silver lining to the awful weather we are having - It has tested the join and my motorhome has stayed dry.

I am so relieved, I would have paid several times the £22 that the '552' cost me.

Please accept my grateful thanks for your advice, it's a good feeling to know there is help out there.

Phil
 
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