100% Silicone vs Dicor

[egarant]

Hi Everyone,

I've always stayed away from using silicone on my RV's for the many reasons stated on this forum, BUT when I was at my local RV shop yesterday the tech was admiring my rig when he noticed some missing caulk on a vertical seam ( I am in the process of removing some old caulk an re-applying).

He asked what I was going to use, I told him I had used Geocel ProFlexRV sealant and did not like it at all and was removing it where I had applied it. He told me to use 100% silicone to caulk the outside vertical seams. It is what they use at the shop all the time on all the RV's. He just said make sure it is 100% silicone and not a blend of any kind.

What do you think?

[theczar]

trail-explorer wrote:
The clear winner for sealing roofs is Dicor, end of story.

I Agree, but my question does not pertain to roofs. I am looking to reseal a horizontal seam on a slide.

Thanks.

[trail-explorer]

The clear winner for sealing roofs is Dicor, end of story.

[theczar]

It looks like everyone has their opinion on what is best to use. I will keep my eye on this thread to see if something clearly is the winner.

While I am doing that, I need to reseal the horizontal seam at the bottom of a slide. It has Proflex on it now. What is the best way to remove it and prep for resealing? Scrape it (I am thinking a plastic scraper), some sort of removing compounnd?, something else?

I am assuming that all the prior material needs to be removed. Any help is appreciated. Thanks.

[covered_wagon]

joeshmoe wrote:

covered wagon wrote:
I have tested using no sealant around the outside, only applying the bytle tape between the mating or mounting surfaces. However, I go to the professional heating and air conditioning supply house to get the stickiest stuff on the planet. It has not leaked yet. When it oozes out thats a good sign, meaning its properly applied. only need a plastic scraper and a rag to clean it, not a mountain of elbow grease'

Can you name this most "stickiest" stuff so readers can look into it for themselves? And do you use it on the roof, too or just the sides/mouldings?

I use it on the sides only. My new water fill door was put on about 5 yrs ago and so far so good w/o perimeter caulking. It sits out all winter in the PNW.

The sticky stuff I get at Johnson Air Products in Portland, Oregon. Stocked up front so the Heating and Air contractors can remember to grab it when needed, it is wider and stickier than the standard hardware store grade.

[joeshmoe]

covered wagon wrote:
I have tested using no sealant around the outside, only applying the bytle tape between the mating or mounting surfaces. However, I go to the professional heating and air conditioning supply house to get the stickiest stuff on the planet. It has not leaked yet. When it oozes out thats a good sign, meaning its properly applied. only need a plastic scraper and a rag to clean it, not a mountain of elbow grease'

Can you name this most "stickiest" stuff so readers can look into it for themselves? And do you use it on the roof, too or just the sides/mouldings?

[covered_wagon]

I have tested using no sealant around the outside, only applying the bytle tape between the mating or mounting surfaces. However, I go to the professional heating and air conditioning supply house to get the stickiest stuff on the planet. It has not leaked yet. When it oozes out thats a good sign, meaning its properly applied. only need a plastic scraper and a rag to clean it, not a mountain of elbow grease'

[egarant]

egarant wrote:
I am removing the ProFlex as it got hard and did not stick, so I will not be using that product again. I just ordered some Manus-Bond 75AM from Amazon and will give that a go.

The Manus-Bond 75AM went on like a champ and looks great.

I like to tape off the area that I am caulking with painters tape, apply the caulk, then smooth with a finger dipped in soapy water or a finger sprayed with Windex. Pull away the painters tape and you have a professional looking job.

[ItsyRV]

trail-explorer wrote:
I only use Dicor on the roof.

By the comments in this thread it sounds like people are using it elsewhere.

Dicor comes in two different versions, the self leveling lap sealant and the non-sag version. The self leveling is what most people are familiar with and often is the only product they assume is what's in the tubes. The confusion is they both use the descriptor of "lap sealant" but they are two different products for use under two different conditions. So, when a person says they are using Dicor on their windows or side seams, it may not be the self leveling version but the non-sag.

[joeshmoe]

SidecarFlip wrote:
Silicone only belongs in breast implants. not on an RV. I use Sikaflex myself.

Once again, you speak and nothing but the truth comes out. :B

trail-explorer wrote:
I only use Dicor on the roof.

By the comments in this thread it sounds like people are using it elsewhere.

Yeah, lap sealant belongs on the roof, not the sides in my experience. Not that it won't work, but there are better things to use like Geocel or Sika. I prefer Sika. It's cheaper and available at my local hardware store.

Also, I have found that many people seem to be incorrectly using leveling/non-leveling. According to Dicor, the self-leveling type is strictly for flat, non-raised seams. Non-leveling is for applying over screw/bolt heads and in general, uneven, raised surfaces. And of course, transitions from horizontal to vertical and vertical itself.

I just used a bunch of self-leveling on the bath sky light, even over the screw heads (It's what I had on hand). The issue is it levels out thinly, so you have to lop, or "lap" it rather heavily whereas the non-sag doesn't sag off. It goes on thick and stays there.

[trail-explorer]

I only use Dicor on the roof.

By the comments in this thread it sounds like people are using it elsewhere.

[HMS_Beagle]

The Bigfoot clearance lights come from the manufacturer with butyl tape on them, and it isn't quite the same stuff as Bigfoot puts on the windows. I'm not a huge fan of butyl tape either (because it continues to squish out for many years), but it is far better than silicone smeared around the outside which is unsightly, useless for sealing, and actually detrimental in many cases. There are products made to remove it from fiberglass without damage, but it takes time and labor to do. I wish Bigfoot would quit the practice.

Silicone may have come a ways over the years, but even the manufacturers of it will not recommend it for critical sealing applications. There are better products.

[d3500ram]

SidecarFlip wrote:
Silicone only belongs in breast implants. not on an RV.... .

In my opinion, it is wrong for all 3 of those locations.

[stevenal]

I Sealteched my new 'foot while still under warranty. No roof leaks, but one of the clearance lights blew some bubbles. I removed the light and found the butyl tape under it had not been compressed evenly, and the bit of silicone around the edge didn't do much to help except to cover up some shoddy work. And the silicone could not be removed completely without risk of scratching the fiberglass. The windows all have the butyl squishing out under the flanges, and I don't see why the lights weren't done the same way. The light went back in with new butyl tape only. I will not be using silicone.

[bighatnohorse]

Consider that when Silicone sealant first came on the market and the number of slob-it-on jobs done by amateurs - it's not a surprise that silicone got a bad rep.

Technology moves on while some remain unaware.