External water heater floor needs repainting

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External water heater floor needs repainting

February 15, 2020, 05:32:28 pm

I thought there was a thread about resurfacing floor of water heater (outside compartment) that peels and gets rusty from emptying . Just use a rustoleum type paint after cleaning as much as possible? Need to get a different drain system so water can exit beyond compartment. Thanks.
Robin

Re: External water heater floor needs repainting

Reply #1 – February 15, 2020, 06:39:18 pm

Robin, a drip will allow lime to accumulate, and will make that black paint peel and flake off. To do a repair, make sure the heater is off, then you will need to sand to remove all loose paint and calcium and to get the metal shiny. Mask off everything not being painted (a pain of a job), then clean the metal with a good degreaser such as acetone or lacquer thinner. Give it two coats of a good metal primer, then a top coat of a flat black automotive paint or flat black rustoleum or equivalent. You want to be sure the paint is for metal, for exterior use. With a little wax annually, the paint won't peel again.

As the drain plug releases water as soon as it is unscrewed, I know of no way to keep that area dry when draining and when flushing out the tank, which you should do at least twice a year.

Ken F in NM

Re: External water heater floor needs repainting

Reply #2 – February 16, 2020, 07:01:39 am

Thank you Ken for your information on water heater. I will following your instructions and hopefully never have to do this job again. Tedious job is in my future shortly.

Re: External water heater floor needs repainting

Reply #3 – February 16, 2020, 11:59:32 am

Hi Robin; The floor of that compartment is wood. It is coated with acrylic caulk, then painted black. The metal inside part, is part of the water heater. That used to be galvanized sheet steel. That can be de-rusted with what used to be called 'Naval Jelley', but just a thickened solution of phosphoric acid, with some hydroflouric acid. (dangerous stuff). You want to tape some plastic securely to the side of the motorhome just below the water heater, starting inside the water heater. These chemicals and other cleaners will permanently damage the paint and leave a stain. They will remove wax instantly also. I'd use a brush to repaint bare metal areas. If the rust isn't too bad, after cleaning, I would just paint over the rusted areas. If I remember correctly, Rustoleum, and similar products have zinc in them to help prevent more rust.
I put in drains and a small valve to empty the water heater easily. No plastic plug now. Pictures included. RonB

Re: External water heater floor needs repainting

Reply #4 – February 16, 2020, 02:01:02 pm

While checking the water heater compartment for rust, crawl under the rig and take look at the propane tank, it need paint too.
Many older propane tanks are found with extensive paint damage. The tanks have a Factory applied epoxy finish that is durable until it gets scratched or chipped, providing an entrance for water.
Once water gets under the paint, it will creep and slowly rust the bottom and sides of the tank, with the rusting hidden under what appears to be an intact coating of paint.
To deal with it, scrape all the loose paint off and use Naval Jelly to treat the rust and then paint. While this will not stop new rust from occurring , it will slow new rusting and will keep the existing rusted spots from continuing to rust.
I suggest an annual inspection of the propane tank for rust.

Larry

Re: External water heater floor needs repainting

Reply #5 – February 16, 2020, 03:20:58 pm

I think 'Older Fossil' Art posted pictures a few years back when he painted his. Looking at my tank then got me to repaint my tank. Not rusted too badly. While working on a friends MidBath (2001), that tank is right behind the front passenger side wheel. The tire had been kicking up rocks/sand right into the tank. Pits and rust spots took a few days to clean up, and 3 cans of spray paint, both primer and enamel overcoat! I ran out of time, but I should have applied a plastic shield of some sort over the front of the tank. My TK has a solid mud flap behind a rear tire pair, that is in front of my tank. A more protected spot. RonB.
Picture shows part of the painted 2001 red MB tank. The drips in the paint, well the more the better, don't show.

Re: External water heater floor needs repainting

Reply #6 – February 16, 2020, 09:57:30 pm

Thanks Ron for your input. Got a brass bushing to replace the plastic screw. Had to grind down the arms on handle a bit to clear tube in front of it. Sanded floor of compartment as Ken suggested . Metal under black peeling paint. It appears our 06' has a drain plug at a 45 degree angle pointing down. Yours looks like a maybe 10 degree slant. I like the pipe you added and were able to get it under the front pipe and away from the floor of compartment. You are probably able to shoot the water away. I am wondering if after I paint with floor with a metal paint if we should apply some type of acrylic caulking and if so will it be able to handle heat inside closed compartment? Really good pictures of your water heater compartment.

Re: External water heater floor needs repainting

Reply #7 – February 16, 2020, 11:12:39 pm

Excessive rust in the water heater compartment maybe the result of a seeping pressure relief valve, many times the valves will seep when the water heater is on. This can caused by either an old pressure relief valve or when the water heater's air gap has been lost and needs to be reestablished.

Our LD's water heater is flushed once or twice year and has a plastic drain that cannot damage the threads when being installed if cross threaded. A spare plug is always carried, just in case.
When reinstalling the drain plug, it's at a difficult spot and angle to get to and it's easy to cross thread it. A cross threaded brass fitting will damage the tank's aluminum threads.

To properly clean and flush the water heater requires removing the drain plug and filling and draining the tank a few times while physically scrapping the tank's interior with a flexible plastic cleaning tool. The tool is soft and will not damage the tank, it help break up the mineral build up that insulates the tank and reduces its heating efficiency.
A significantly calcified tank will benefit from an overnight soak in vinegar, plus a good cleaning.
When done, you driveway should look as if it has hailed hundreds of small white pellets . Be prepared to get wet, a job best done on a warm, sunny day.
The floor of the water heater will get wet doing this process, but since it happens only once or twice a year, it will dry without damage, it's long term exposure to moisture that causes problems.
Amazon.com: Camco Water Heater Tank Rinser-Cleanses and Removes Sediment...

Youtube has many videos showing how to clean the water heater.

Larry

As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.

Re: External water heater floor needs repainting

Reply #8 – February 19, 2020, 08:50:40 pm

Well Ken and Larry, I spent last two days prepping, priming and painting my water heater compartment floor. Ken mentioned putting on a wax also. I saw this anti-rust wax in a spray can called Cosmoline RP-342 "Heavy" rust preventative treament that these auto gurus use to protect rust parts of vehicles. Have you heard of this or used it? It also comes with a little straw like
like WD. I pause at use being close to propane fuel of water heater. It says the only way to remove it is using something like solvent like gasoline. BYW, instead of taping and covering everything before primer and paint I used one of those small sponge disposable paint sponges and sprayed the primer and paint on sponge and appied it to areas. Worked well and not a drop of black primer or paint got anywhere where it was not intended. Thanks again for your expertise and replies.
Robin

Re: External water heater floor needs repainting

Reply #9 – February 19, 2020, 11:37:33 pm

Quote from: Robin B - February 19, 2020, 08:50:40 pm

Well Ken and Larry, I spent last two days prepping, priming and painting my water heater compartment floor. Ken mentioned putting on a wax also. I saw this anti-rust wax in a spray can called Cosmoline RP-342 "Heavy" rust preventative treament that these auto gurus use to protect rust parts of vehicles. Have you heard of this or used it? It also comes with a little straw like
like WD. I pause at use being close to propane fuel of water heater. It says the only way to remove it is using something like solvent like gasoline. BYW, instead of taping and covering everything before primer and paint I used one of those small sponge disposable paint sponges and sprayed the primer and paint on sponge and appied it to areas. Worked well and not a drop of black primer or paint got anywhere where it was not intended. Thanks again for your expertise and replies.
Robin

Do you have before and after photos for us, Robin?

Chris

Re: External water heater floor needs repainting

Reply #10 – February 20, 2020, 12:17:09 am

Quote from: Robin B - February 19, 2020, 08:50:40 pm

I saw this anti-rust wax in a spray can called Cosmoline RP-342 "Heavy" rust preventative treament that these auto gurus use to protect rust parts of vehicles. Have you heard of this or used it?

It's an old school preservative used to protect metal parts while in storage or during shipping.
It isn't for use on active equipment, it is sticky, attracts dirt and will soil your clothes.
I occasionally see machine parts, coated with cosmoline to prevent rusting.

Once the water heater floor is done, keep an eye on it to make sure the relief valve isn't seeping.

Larry

Re: External water heater floor needs repainting

Reply #11 – February 20, 2020, 08:57:21 am

Robin, the type of "wax" I meant was the type you use on the rig's paint. What it does is to penetrate and seal any pores or scratches in the paint so the surface is protected. If you are going to apply any wax, make sure you have given the paint a LOT of dry time, like weeks. If the paint job is good, the wax is probably unnecessary, but rubbing the paint on, the way you described, while a great idea, might not have resulted in a fully sealed surface. In your shoes, I would use wax once a year.

You want a clean, dry surface that will not hold dirt. That means oils and greases, while rust preventing, should not be used. That includes things like vaseline and cosmoline.

By all means, follow Larry's recommendation to clean the heater. After cleaning, periodically look for signs of leaking and, if found, address the leak promptly so your efforts are not wasted.

Ken F in NM

Re: External water heater floor needs repainting

Reply #12 – February 20, 2020, 09:51:32 am

Thanks again Ken and Larry, I have plenty of rig wax around here. Good news to know about the Cosmoline product Larry. Waiting a very long time before applying wax is also good info. As always, go to those that know.
Robin

Re: External water heater floor needs repainting

Reply #13 – February 20, 2020, 10:16:34 am

"I occasionally see machine parts, coated with cosmoline to prevent rusting."

If you were in the Military and were issued a new rifle it no doubt came covered in cosmoline!
In that case you know what a terrible job it is to clean that gunk off... especially if there is an inspection the next morning!

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