sealant for bus caps on mci

[artglass]

I am getting ready to re seal the front cap on the front of my mci 8 , was wandering whats the latest and greatest sealant to use these days , its been about 15 years since ive  done it, thanx in advance for any advice any one has want something clear and paintable.

[MrCrowley]

I would say find what you used before 15 years is pretty good


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[Dave5Cs]

3M 5200 Marine adhesive and sealant or sikaflex

[windtrader]

I've heard good stuff about both. If they work the same, the 3M stuff is way expensive.

[Iceni John]

I recaulked my entire roof with Loctite PL S40  -  it's a moisture-curing polyurethane adhesive/sealant, so it can be painted over.   However, it's white when cured.   So far, so good.   I did use 3M 5200 to attach sheets of aluminum to my front cap and where I blanked off two windows on each side, and it was a lot less than $20 a tube from my local lumber yard.   It's good stuff, but it takes seven days to fully cure.

John  

[Oonrahnjay]

I recaulked my entire roof with Loctite PL S40  -  it's a moisture-curing polyurethane adhesive/sealant, so it can be painted over.   ...   I did use 3M 5200 to attach sheets of aluminum to my front cap ... 

       John, is the 3M sealant a silicone/ non-paintable-type?  And how long does a partially-used tube of the Loctite last in storage?  I ask because I have a number of places on the upstairs portion of my vertical sides and end caps that are going to need to be taken apart and sealed.  It's not going to be a quick task so I'll need a sealer that I can apply some today, some tomorrow, some next week when I take on that job. 
       Many thanks.   BH  NC

[Dave5Cs]

Bruce the 3M is not a Silicon and yes it can be painted. It can be cleaned up with Lacquer thinner or acetone and re sealed and it will keep a long time. You can use it on wet stuff too as they do in the water for boats. Use gloves because it can be messy if you get it on your hands.

[Oonrahnjay]

Bruce the 3M is not a Silicon and yes it can be painted. It can be cleaned up with Lacquer thinner or acetone and re sealed and it will keep a long time. You can use it on wet stuff too as they do in the water for boats. Use gloves because it can be messy if you get it on your hands. 

      Thanks.  I think most of my leaks are at flat aluminum panels and where they overlap so I was thinking butyl tape -- maybe the 3M or Loctite is overkill -- but I really have to seal these area up.  This info help - thanks, Dave.

[TomC]

When my truck box was made, the manufacturer used Polyurethane sealant. The roof leaked a caused damage to the interior wall. I went and grind out all that polyurethane and replaced with exterior sun rated silicone sealer. Now 8 years later-it still is water tight. Good Luck, TomC

[eagle19952]

Commercial roofers (as in flat roof malls and residential, etc) use this..no need to paint.
my SIL is a union roofer in MN. he gave me a case of it. i sealed the destination window in my eagle in 2008....still sealed.
rather than remove the side windows to reseal them...caulked...not leaking any more.
great stuff, imo.

http://www.ositough.com/en/colored-caulk.html

[brmax]

I thought this guy that runs a business relating to some serious sealant needs offers a great insight to particular applications. For the parts i need to use in the marine area the 400 sealant is where im at. But again the refferences in the boatwrights video are most important imo.
https://youtu.be/GnQG7eUyHxU
I am pretty sure if one looks at nationwide mfg's. for these other sealants mentioned a lot, well they all produce lots of great sealers or adhesive sealers for applications. Just take a good look at their offerings in example; tremco, loctite, sika.
Really in this post if i consider what the roof on mine has for the build i think a thin alluminum over another and or a fiberglass layer overlaying the aluminum. This has no real surface, rather a .080" thick edge. This seems to be very difficult unless overlaping the top edge. If this the case i may or could consider the rivets themselves as they might be the real area of concern.

Good day
Floyd

[windtrader]

No matter what you choose, and I'd venture to say may will do the job, the most critical aspect to durability is prepping the surface really well. I suspect most folks could do more to prepare an optimal surface for the sealant to adhere to. When I get around to sealing I'll sand with 400 and use lacquer thinner to remove all grease and other traces of stuff that will diminish the bonding. Much like prepping for auto paint.

[RichardEntrekin]

This is a great site for educating yourself on the different types of sealants available today.

https://www.jamestowndistributors.com/userportal/search_subCategory.do?categoryName=Caulking&category=32&refine=1&page=GRID