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OT Removing Old Sealant From RV Top

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paul39

Titanium
Joined
Jul 12, 2008
Location
Asheville, NC
My daughter bought a 2001 RV and took it to the factory in CA for a check up before driving it home to NC. She was told the polyurethane sealant needed to be redone every 7 years and was told what to use and how. RV has original sealant which has slight leaks. Body is aluminum.

The below photo shows what she got done in 2 hours by hand. A multi tool with a sharp blade was recommended. Anyone have a suggestion? I don't know what she was using. My thought is a 1 inch wide stiff putty knife with a nice fat handle, sharpened to razor sharp at about a 50 to 60 degree angle.

Paul
 

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Spray on bedliner should stick to it, and eliminate all leaks.

I've been seeing 15 year old RV's go cheaply as they seem to get roof leaks, and
then it's all over.

Why did she travel so far to buy one with existing leaks ?
 
Its almost always water not time or miles that kills rvs.

I usually use citrus degreaser of some sort from dollar general -something cheap to loosen old sealant. I use a plastic putty knife, get several, they don't last. Sometimes,some gentle persuasion with a metal putty knife comes into play.

You are looking for cracked, loose, discolored sealant. Dirt under sealant is a dead givaway. So are cracks along a seam. Often dried sealant will simply pull off in long strings. Intact sealant is just that.

On the right side of the picture you sent, it look like there is some eterna-bond. Good stuff, but once it leaks, it's best to remove. Often used on rv endcaps cuz they frequently leak due to lack of firm attachment and resultant motion. I had an old safari that the dash moved several inches with bumps in road before some stiffeners welded/ drilled in....

To seal, DO NOT use silicone. New silicone won't stick to old silicone, so you are creating a problem down the road. Use a self-leveling sealer designed for RVs. I like dicor, but there others. about 10 bucks or more each tube.

See online how to apply -generous amounts to clean roof once loose stuff removed.

I have often found that the TV antenna and Fantastic brand fans will look sealed, but when removed will be wet underneath. Personally, I remove anything unused from RV roof when I redo one - TV antennas, radio antennas, etc. If there are soft spots on roof, these are damaged areas and there will be a leak nearby.

Now that roof is done, Non-sag sealant can be used on seams around window and endcaps.

Repeat every year, first year is always the worst.

Some folks have used with success house trailer roof paint, like Tropic-cool, but I haven't tried it.

Sometimes a whole new roof is needed, I did that once but used a scrap of industrial rubber roofing from a roofing company which was far cheaper than low volume RV parts suppliers. It was black and I painted white with latex to limit heating of rv.

Lastly, RVs last best when stored under a roof, not a tarp when not in use.
 
digger doug;Why did she travel so far to buy one with existing leaks ?[/QUOTE said:
I was not party to the selection process. Probably because it was the RV she wanted, at the price she wanted, and she had a cousin in Los Angeles who could check it out. It does not rain much in So. CA so the slight leak was discovered when they drove through the storm system that dropped 5.19 inches of rain on Asheville in 24 hours. She bought it in mid Dec. and they flew out and brought it home over Christmas break, stopping at Grand Canyon & other places.

They stopped here on the way to Raleigh. The RV is like new in and out. 51,000 miles, Ford 450 chassis, V-10 engine, almost 9 mpg on the level at 70 mph, 3.9 mpg going up hill. She claims drives and handles steady as a rock.

She said that buying it, flying the three of them to LA, and the trip, cost about 1/3 of what a new one would cost. They still make the same one, 2018 looks just like the 2001.

The Classic Ride: Lazy Daze 26.5 | MotorHome Magazine

Paul
Click to expand...
 
Hey, I've got one of those.
The roof is aluminum, not plastic. (As are the sides. Painted with catalyzed paint -- sorta like Imron, but not...)

Sealing consists of removing existing (a bear) and replacing with Eternabond tape. 6" wide or so. Some folks skip the removal part, and just overlay new. Removal is best, though.

I've not had to dig into mine, but I think a sharp caulk removal blade in an oscillating multi-tool (like a Fein Multimaster) lubricated with non-silicone citrus (Goo-gone?) will remove it without digging thru aluminum, but also keep goo from sticking to blade. Faster than manual putty knife, to be sure.

There's a great owner's group on-line:
Lazy Daze Owners' Forum
You need to register and be 'approved', but new owners of old coaches are welcome.

And it does drive great. Low CG, very few squeaks and rattles even on my 2000 machine. The fridges, microwaves, furnaces, etc. are the same that the rest of the industry uses, but fit and finish, construction techniques, and installation are what makes them better than average.

Love the machine, but not overly fond of the 'Lazy Daze' name...
 
A heat gun may work depending on the gunk.

Harbor freight sometimes sells a pneumatic gasket scraper which is just a vibrating device with a blade on it.

For this it would zip that stuff off like magic.

Also go over to irv2.com and search there as this is somewhat common so someone likely has figured out what does not work. .

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
it's not necessary to remove that sealant. there is another, thin, penetrating, self leveling sealant that goes on top using a chip brush. comes in qt cans
 
I've been to this rodeo a couple times with the one piece aluminum roof on my race trailer. It is a nasty job. What is it they say? "It builds character!" I know it sure builds cramps in your hands.

I find a small concrete trowel, with a nice round wood handle, works better than a scraper. The geometry on your hand and wrist is much better, and your knuckles are much better protected if the blade slips. Also the handle doesn't get hot if you heat the blade with a torch. Radiusing the sharp corners helps prevent slicing the roof open.

I've used a propane torch and the trowel to scrape. In that case it helps if the ambient temps are as hot as possible. You can heat the trowel and push at the same time. It works okay. A heat gun might be another option, but I did not try that. Even outdoors the fumes are probably pretty dangerous.

An angle grinder with a wire cup brush also works. I use a router speed control to reduce the rpm to something more controllable. In some spots I used an electric die grinder with a smaller brush, slowed down. In this case very cold temps may work better by making the material tear apart rather than turn to mush. Again, the fumes from this are bad, but also the rubber dust is probably very toxic.

For the flat smooth parts, heated scraping may be best. And then a powered wire brush for the odd shapes and nooks. If you need to get residual off, mineral spirits or laquer thinner (I can't recall which I had to use).

Ladder safety is another thing. Ideally you would rig some kind of a scaffold..

I need to do this project again, hopefully with a longer lasting sealant - with some consideration how it can be touched up in the future, rather than completely stripped.

This time there will be aluminum tape of some kind to UV shield the sealant. I think it was a mistake to not do that.

Good luck. Let us know how it goes and what you figure out.
 
Having done that a couple times now on different motorhomes.
Some of the gunk Mineral Sprites works wonders.
Anywhere it is metal with sealant on it a wire wheel is the king.

Once you get done Eternabond tape is a great , but not cheap way to get a great seal.

Heck the Coachman we drove from Phoenix to Lewiston Idaho had a Ford V10. We got 9 plus MPG towing a Ford Escape.
 
Tony Quiring said:
The blade does not move like an air chisel.

The whole thing vibrates and as such it is safe unless you aim a corner into the material

Sent from my SAMSUNG-SM-G930A using Tapatalk
Click to expand...

I OWN said tool, and have used it.

I stand by my comments.
 
You need a caulk cutting blade for a Fein or similar oscillating tool.
Fein ‘Multimaster’ tools were originally deglazing tools for building and auto industry- they work.
They make the blades for this but I usually am in a rush and just make one up.

Take a normal paddle type blade (not the circular ones), grind off the teeth and grind in a bevel, break the corners and round off, hone the whole edge and all around corners to 600 or so, finally- polish right over the sharp edge with 600.

That all sound like a lot but it takes five minutes- the key is that you want to be able to bear down with the flex of the blade and scoop off the old caulk without scratching or digging into surface.
I use the tools routinely on polished gel coat and leave no marks.

So- scoop off the bulk of caulk, scuff the surface then solvent wash and you are ready to re-caulk or tape etc.

Don’t get any silicone products anywhere near the work and do not use silicone caulk to seal.

Edit- a simple palette knife works.
For small work like a single hatch I just scrape off by hand.
The palette knife is dressed as above.
For odd jobs with radius work or the like I make up acrylic scrapers from a stick of 3/8” acrylic scrap- these are handy as they reduce further any chance of digging into surface and can be handed to a helper with less chance that they will wreck the work.

Edit edit...

Reading your op:
“sharpened to razor sharp at about a 50 to 60 degree angle.”

The key to this sort of work is how the tool is dressed and used.

“Razor sharp” is not the goal as this type of edge can dig into surface if angle of attack is not carefully controlled.
You want a very fine polished edge which is NOT razor sharp- you can’t cut yourself with the correctly dressed blade but it is sufficient fine so as to part the caulk from surface without just pushing it along.
A bevel can be used to rock to angle for best work but is not needed.
Make SURE to break, radius and polish the corners of tool- a slip will then just skip off surface and not lay in a deep scratch.

This is the “trust me” moment of internet advice..
I have lifted miles of caulk debris from surfaces in the course of service work.
This is often on million $ plus yachts where screw ups are not good for business..
 
Trboatworks said:
You need a caulk cutting blade for a Fein or similar oscillating tool. ...
That all sound like a lot but it takes five minutes- the key is that you want to be able to bear down with the flex of the blade and scoop off the old caulk without scratching or digging into surface.
I use the tools routinely on polished gel coat and leave no marks.
Click to expand...

Thanks. I am going to try that.

It reminds me of the magic of the air chisel. The short high frequency hits can accomplish what heavy pounding cannot.
 
Any straight edge fairly sharp tool will work. Remove the old sealant, clean and wash the RV roof’s surface to remover dirt, debris and any residues and then apply new sealant e.g., RV Roof Magic. This will allow the new sealant to achieve a smooth finish and adhere properly to the RV roof surface.
 
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