Sealant Adhesive Primer Question

[thompwil]

Howdy,

I’m replacing the crank open vent with a MaxxAir 7500K. It was difficult finding one in stock anywhere, but that’s another story. I already had the black silicone sealant for the roof flange but then noticed on the sealant call-out sheet Chemlok 459T Adhesive Primer in that location too. I called Winnebago Tech support and was advised to use it to get the silicone to stick to the plastic on the vent. Contacted the manufacturer of the 459T and was directed to two suppliers that would ship me a 4oz. bottle of it for 30+ bucks, $46 from Lichtsinn.

So I did a small test dab of sealant on the flange while on the work bench. One spot roughed up with sandpaper, one spot not. The silicone did not stick well in either spot.

So here’s the questions,,,

Does anyone know of a similar over-the-counter product that I could use in place of the 459T ?

Has anyone replaced their roof vent, used the recommended silicone sealant, not used the primer, and had, or not had problems?

Note: I cannot use Dicor, research has shown it will not stick to a roof surface that previously had silicone sealant on it.

I may end up having a bottle quick shipped to me, but was hoping for a suitable substitute. Thanks...

BT

[Winterbagoal]

Could you use something like the sealants, adhesives, or tape that some people use to repair their roofs or to mount solar panels? I think some of the products are 3M brand and are pretty close to permanent fixes.

[BobC]

I can't say if it will work or not, but have you tried acetone? If that doesn't work, try mineral spirits.

[Morich]

You might look at other materials to remove the silicone residue as silicone is used in sealing fish tanks and it will not stick to glass where there was old silicone. So that requires using a cleaner/primer and I think the preferred is acetone if I remember correctly but do some checking on that as I do not do tank reseal and lack real world experience with that part. Certainly would be cheaper than what you are talking!
Note: Do not take the first video as being correct as there is a ton of bad info on the internet so check carefully for other, conflicting info!

[Winterbagoal]

How to remove silicone sealant/caulk...
https://www.hunker.com/12623575/what...clean-silicone

[thompwil]

Howdy,

Thanks for the replies. I decided to just go ahead and order the 4oz bottle of adhesive primer and do the job right. The black self-leveling silicone used on our roof seams will not stick to the plastic roof flange on the new fan without the primer, my bench tests proved that beyond a shadow of a doubt. I eventually figured 40 bucks is a small price to insure the sealant will stick to the new fan flange as well as it did from the factory. Now all I need is a couple days without rain to get it installed.

Thanks Again
BT

[Sqwatchi]

Originally Posted by thompwil

Howdy,

I’m replacing the crank open vent with a MaxxAir 7500K. It was difficult finding one in stock anywhere, but that’s another story. I already had the black silicone sealant for the roof flange but then noticed on the sealant call-out sheet Chemlok 459T Adhesive Primer in that location too. I called Winnebago Tech support and was advised to use it to get the silicone to stick to the plastic on the vent. Contacted the manufacturer of the 459T and was directed to two suppliers that would ship me a 4oz. bottle of it for 30+ bucks, $46 from Lichtsinn.

So I did a small test dab of sealant on the flange while on the work bench. One spot roughed up with sandpaper, one spot not. The silicone did not stick well in either spot.

So here’s the questions,,,

Does anyone know of a similar over-the-counter product that I could use in place of the 459T ?

Has anyone replaced their roof vent, used the recommended silicone sealant, not used the primer, and had, or not had problems?

Note: I cannot use Dicor, research has shown it will not stick to a roof surface that previously had silicone sealant on it.

I may end up having a bottle quick shipped to me, but was hoping for a suitable substitute. Thanks...

BT

Was one bottle enough??
We are doing a sky light..two distributors Lords referred me to have no stock require me to buy 12 bottles...know I dont need that much!
Thanks!

[TravatoJohn]

BT, you might want to watch AZExpert on YouTube. He does a lot of Winnebago roofs. Good advice on last tube he did on a complete new roof where he prepped for silicone caulking. Travato John

[thompwil]

Originally Posted by Sqwatchi

Was one bottle enough??
We are doing a sky light..two distributors Lords referred me to have no stock require me to buy 12 bottles...know I dont need that much!
Thanks!

Howdy,
I could have done 50 Maxxair vents with one 4oz bottle. It doesn't take much at all, but the sealant sticks like crazy to the treated surface. I'm glad I purchased the primer. I'm trying to remember where I bought it, believe it was from a chemical distributor in New Jersey who sold me one bottle.

[Wyatt]

I’m sorry, do you have a fiberglass or rubber roof?
I’ve been following this thread and I’m just curious because a lot of it doesn’t seem to apply to mine.

[thompwil]

Originally Posted by Wyatt

I’m sorry, do you have a fiberglass or rubber roof?
I’ve been following this thread and I’m just curious because a lot of it doesn’t seem to apply to mine.

I have a fiberglass roof. There is a black colored sealant that the factory uses on the vents and roof openings, can't remember if it's silicone or what it is at the moment. The sealant would not stick at all to the flange on the new Maxxair vent, no exaggeration, not at all. The sealant call-out sheet specifies the primer, so a call to Wbgo tech support put me on the trail to get some. The sealant sticks like crazy after applying the primer.

[Ray,IN]

That's the problem with silicone, it does not adhere well, especially long-term. There's a reason RV mfgrs use silicon sealants, and there's a reason it's the cheapest sealant on the shelf at hardware stores, could they be connected?
Proflex, and Geocel make excellent sealants, to name a couple.

[thompwil]

Attachment 184739

Originally Posted by Ray,IN

That's the problem with silicone, it does not adhere well, especially long-term. There's a reason RV mfgrs use silicon sealants, and there's a reason it's the cheapest sealant on the shelf at hardware stores, could they be connected?
Proflex, and Geocel make excellent sealants, to name a couple.

For sure some silicones are not good and don’t last. The product used on our roof (NuFlex 311) is going into its sixth year. To date it looks as good as it did new, no cracks or shrinkage, no chalking, no flaking or discoloration. The edges are still firmly stuck to the roof and to the roof accessories like day one, maybe because of the primer..?.. The light colored stuff they used where the front and rear end caps meet the roof is another story though. I have to replace it every other year due to shrinking and cracking.

[Ray,IN]

I agree, surface preparation is key to a good job, whatever the product.