Utility Bay Sewer Notch Trim Metal

Topic: Utility Bay Sewer Notch Trim Metal (Read 905 times) previous topic - next topic

Utility Bay Sewer Notch Trim Metal

June 30, 2015, 02:29:10 pm

In working on replacing my tank valves and adding a third valve, I have learned a lot about the beast. This article addresses the THIN metal angle that is used as a trim piece around the sewer cutout notch. It was obvious before I started that it was badly deteriorated. Removing it revealed just how bad it was.

The first photo shows the trim piece after it had been removed. The two small squares show the pieces that were under the black edge flange. This metal angle was very thin; somewhere closer to tin foil than a tin can.

The second photo shows what was left after the trim piece was removed. Photos 3 and 4 are closeups of the left and right sides.

I removed the excess caulking and cleaned some of the rust off of the metal around the cutout. There were some obvious rust flakes under the box tubing, I removed what I could with my "cotter pin removal tool." I then applied some Corrossion X to the affected areas, including the gap between the box tubing and the lower fiberglass (?) bottom. The next photo shows what is left after some cleanup (I have not yet removed the large plug of yuck from the ends of the box tubing that make up the outside "framing" piece of the floor). The next three photos show closeups of the left, back, and right sides of the cutout.

Photo 9 shows a closeup of the utility bay cutout (thank you, Don). It is not shown for its accurate representation of my RV, but to show that the cutout is surrounded by box tubing.

My intentions are to replace the original trim with 1 1/2" aluminum angle stock that is about 1/16" thick. My game plan is to cut a piece about as long as the two sides plus the width. I would then make two cuts in the top half of the angle so that I could bend two right angles at the two cuts, to wind up with a shape similar to the original piece, but much stronger and thicker. I will have to trim it in a few places because of its additional width and thickness (no more sliding under the outside flange).

What I need some help with is what to do about the rust scale between the cutout box tubing frames and the bottom skin. I have already scraped it with a doodad and applied Corrosion X. It seems to need something much more serious about removing rust. What product would be best for removing the existing rust and preventing any further rusting?

The existing trim piece was attached with some sort of adhesive. For the new piece, I am thinking of using an adhesive product (possibly an epoxy) and maybe some recessed screws into the surrounding box tubing. Actually, the screws do not have to be recessed, since a sewer hose, a water hose, and electric wire will be going through the opening.

Well, that is enough for y'all to cogitate on for now. I will address the issue of fitment of the bottom of the new metal trim and the door (which is now broken -- thank you, gravel pad) in a separate message.

I hope that my journey has been helpful to some of you that might not have known the details of our utility bay cutout notch, and that the photos will help in your learning from my experiences.

For those of you who have "been there; done that" please add to this discussion so that we can learn how to address such problems in the future. I am eager to learn anything I can, especially before I start making some irreversible modifications.

Thanks,

Trent

Re: Utility Bay Sewer Notch Trim Metal

Reply #1 – June 30, 2015, 04:32:30 pm

That thin metal trim piece looks similar to the stuff they used to separate the two long pieces of steel that make up the often cussed and discussed bulkheads. You have to wonder what they were thinking! The engineers must have realized that any metal that fragile would quickly self destruct...especially in such a hostile environment.

Re: Utility Bay Sewer Notch Trim Metal

Reply #2 – July 01, 2015, 12:13:32 am

Trent, looks like that was needed to be cleaned up a long time ago!!
I did this job last year and also dug out of the box section on left and right side some paper that had been stuffed in when built so a caulk could be used to smooth off ends before putting that cheap s--t angle over it to look good. What I did was give it all a good clean up with wire brush and grinder then spray lots of Ospho into box section for as far as I could. I pumped at least a pint of it into tubes. let it dry overnight then sprayed cold zinc "paint into box section then let that dry before sealing the end of it. I then put an aluminum angle section around it and sprayed whole area with rubberized undercoat. I also extended the trap door in width and put a foam rubber strip around it so no water can get into that area from road. This area now is always clean and good.. All my bays are dry and clean as I check them weekly and do not allow any water or road dirt in them unlike some we see pictures of on Forum.
JohnH

Re: Utility Bay Sewer Notch Trim Metal

Reply #3 – July 01, 2015, 12:45:39 am

Trent,
I think you are on the right track. I decided not to close off the ends of the trim since I figure that water can get in, but it can also get out again. While I had everything exposed, I used POR-15 and coated all of the angle iron underneath the trim. I believe that it was unpainted when it came out of the factory. The 2000's and later used the rectangular trim that fit over a box beam, where as the 99's and before had an angle iron sill underneath the white, round bottomed trim. I cleaned all the rust off of the angle iron and welded in a full length piece of 1.25"X1.25"x1/8" angel iron to beef up the outside edges of the basement and then prepped and coated the exposed edges with POR-15. When I put the new style compartment trim (FOT calls it a batten), I had to add a 2" wide piece of ⅛" thick aluminum riveted to the trim to overlap the bottom skin so that I could use screws to secure it on the bottom. The last picture in your first post looks like it might be from my basement rebuild project, one with the white rounded trim like what used to be on our 99'. I would say that if the bottom and top fiberglass skin is still well adhered to the steel, then you can probably get by with doing a real good clean up of all exposed metal, paint it with some good rust preventative, and then some trim if you like. I still haven't added any trim around the notch on our coach, though I may do it when I make a new hatch for it. I will also make it over lap the opening like John described. I left the bottom compartment trim open on all the ends so that air can get through the entire length. Water had clearly been trapped in the void and the old trim showed a lot of galvanic corrosion on the inside. If I make trim for the notch, I will probably use stainless, but may opt for aluminum...
Don

Re: Utility Bay Sewer Notch Trim Metal

Reply #4 – July 01, 2015, 01:24:33 am

Quote from: Don & Tys (AKA acousticart) – July 01, 2015, 12:45:39 am

The last picture in your first post looks like it might be from my basement rebuild project

Don,

Good eye! The fact that it was different is why I phrased my description a little weirdly. I just wanted those who had not dug into their coaches, to understand the surrounding box framing. I did not know there was solid metal there until I had removed all of the gunk around and on it. Even though the metal has its problems, the box appears to be strong enough to adhere the trim piece to it, if necessary.

Thanks,

Trent

Re: Utility Bay Sewer Notch Trim Metal

Reply #5 – July 01, 2015, 01:39:13 am

Quote from: John Haygarth – July 01, 2015, 12:13:32 am

Trent, looks like that was needed to be cleaned up a long time ago!!

John, I do not recall how much info I shared about the original owner. He bought it new and retired (from the military). He was 86 years old and had been living in it as his only residence for many years. At first he was quite active and spent a lot of money on upgrades.

However, I think for several years, he had not driven it or performed the necessary maintenance. His daughter came and took him to Hawaii to live with her. She knew nothing about RV's (Hawaii, remember?) and turned it over to a wholesaler to get rid of it.

As we prepare for a more active Summer and Fall, I am busy taking care of many of those deferred items, but it is a very long list! Jean and I would really be in trouble without all you kind Fofummers, willing to share your knowledge and give advice. Since this is our first RV, many of the things that are second nature to most of you are things we are still learning about. Yes, it was the deep end, but we are enjoying *most* of it, and look forward to meeting many more of you in person.

Thanks,

Trent

Trent

Re: Utility Bay Sewer Notch Trim Metal

Reply #6 – July 01, 2015, 02:25:01 pm

I have now confirmed that my 1 1/2" aluminum angle is not wide enough to cover the sides of the cutout all the way. I do have some 1 3/8" aluminum angle stock. I could make two of the trim sections, and put them together, top and bottom. There would be enough overlap that I could put a screw through them in the center into the box tubing. This is beginning to sound like a better alternative and has several benefits.

I would have the top overlap the bottom, because any moisture from the sewer pipe would be dripping downward. The door would have the responsibility of protecting the cutout notch from the elements while driving.

the top layer to box frame appears to be intact . the real problem area is the bottom "skin" is not attached to the box frame except with rust flakes. After cleansing it out as much as I can, and applying a good rust preventive product, it should be good to go. I would install the bottom, then the top frame pieces and clamp the sandwich together. while clamped together I could drill the holes and install screws into the center of the box tubing. A total of six screws should make the "trim" secure and the cutout notch would be ready to go for many more years.

Any problems with this concept?

Thanks,

Trent

Re: Utility Bay Sewer Notch Trim Metal

Reply #7 – July 01, 2015, 04:18:38 pm

If you have any of the skin that is not adhered and the area is clean enough, you could squeeze in some 3M 5200, clamp with cauls, which would probably do a very good job of sealing the metal that you can't see. The trim idea sounds feasible, if you counter sink the screw heads and use stainless screws. I use machine screws in these situations, because two often the sheet metal screws will strip if you remove them and reinstall. You could actually use the 5200 behind the sheet metal which will fill the tiny void underneath the top one. It would also be adequate to hold on the trim...but it would be very difficult to remove. I red somewhere that is used to adhere keels on sailboats...

I take it that you are going to attach the hinge though the bottom trim piece?
Don

Re: Utility Bay Sewer Notch Trim Metal

Reply #8 – July 03, 2015, 05:46:30 pm

I use Rust Bullet. http://www.theruststore.com/Rust-Preventative-Paint-C112.aspx The original stuff (it's silver). You can wirebrush and paint right over paint with it, but the preparer works really well (it's like a phosphoric acid) to clean and etch the rust: http://www.theruststore.com/Rust-Bullet-Metal-Blast-P376.aspx

You can find the stuff from other retailers too, like amazon. DON'T GET THE PAINT ON YOUR SKIN or HAIR. It took weeks for it to get off my arm hair, lol

Re: Utility Bay Sewer Notch Trim Metal

Reply #9 – July 04, 2015, 09:01:25 am

Here is another paint option that I have had very good success with, and of course surface prep is the most important detail.
SPRA-GALVÂ® - ZINC RICH Weld-thru primer - Seymour of Sycamore

Available at Amazon;
Seymour 16-845 Spray Weld Through Primer - Spray Paints - Amazon.com

Good luck,

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Utility Bay Sewer Notch Trim Metal

Reply #10 – July 04, 2015, 09:31:56 am

3M 5200 is pretty tough to remove. We used it to glue the boards on our deck to the joists. 15 years later, through summer and winter in MN they are still holding. A few places have come loose mostly along one joist. The one applying the 5200 must have been stingy on that one.

I have a tube of 3M 4200 UV resistant. That should hold those trim pieces on OK. Even if you use screws, seal it up well. But it seems like there needs to be a way for any moisture in those tubes to escape or they will just rust.

Roger

Re: Utility Bay Sewer Notch Trim Metal

Reply #11 – July 04, 2015, 09:39:54 am

Quote from: Rick – July 04, 2015, 09:01:25 am

Here is another paint option that I have had very good success with, and of course surface prep is the most important detail.
SPRA-GALV® - ZINC RICH Weld-thru primer - Seymour of Sycamore

I have used this to coat the back side of welding projects, but never considered it as rust protection. I don't think that it would work for that unless you clean all rust off, and then use some sort of metal cleaner/etcher before application. POR-15 and others bond to the iron oxide to seal the surface against future oxidation. The preparation is quite meticulous for this stuff is labor intensive if you follow the directions to the letter, but it is very effective. OTH, you can also just wire brush the rusty metal to remove flakes, wash with an etching cleaner, and rinse with water. I did that with a few scrap pieces and then left them laying in the yard exposed to weather. two years later, no new rust on the coated parts. The surface oxidation actually promotes adhesion. The ospho type stuff is easier to apply, but I don't have any experience with it. And of course, there is Rustoleum etc. that also claims to able to apply over rust.
Different options...
Don

Re: Utility Bay Sewer Notch Trim Metal

Reply #12 – July 04, 2015, 04:27:24 pm

Quote from: Don & Tys (AKA acousticart) – July 04, 2015, 09:39:54 am

I have used this to coat the back side of welding projects, but never considered it as rust protection. I don't think that it would work for that unless you clean all rust off, and then use some sort of metal cleaner/etcher before application.
Don

Which is why I said "....surface prep is the most important detail." POR-15 won't work either if you don't do all of the surface prep.

Re: Utility Bay Sewer Notch Trim Metal

Reply #13 – July 04, 2015, 05:19:34 pm

I guess I should have said that I never thought of using the weld through primer as rust protection, not that it wouldn't work. When it came to the bulkhead rebuild project where most of the work would be hidden from site with no inspection possible later on (under the top and bottom skin of the basement floor), I researched as best I could and came up with POR-15 as my best bet to never, ever, have to look at it again. I am sure there are other good options. When It came to POR-15, I experimented with two different ways of using it. One was to grind off all the rust to clean metal, and then follow the directions exactly with great attention to detail. The other was to just quickly wire brush the worst of the rust off, use a the "Marine Cleaner" degreaser, skipping the etching step, rinsing with water, and then coating with POR-15. Although I opted to go with the more labor first option, I found that the piece that I did with the second option actually faired pretty well after laying in the grass/weeds for almost tow years. Part of it was coated with POR-15, and part of it was not. The part that wasn't was perforated in places while the coated part looked as good as when I laid it there, except for the UV fading. The "POR" stands for paint over rust, and if you have bare metal that is rusted, you can use that pretty easily. However, when the rusty metal is painted, the POR-15 won't adhere as well. This I got from talking to their tech support. Since the basement metal had been primed (except the angel iron portion), I decide I needed to strip the rust and paint off. There were parts where the rust was spotty, and parts where there was no rust. Since I wanted to coat it all the same way, I stripped all of it and did the whole enchilada POR-15 treatment on it.
Don

Quote from: Rick – July 04, 2015, 04:27:24 pm

Which is why I said "....surface prep is the most important detail." POR-15 won't work either if you don't do all of the surface prep.

Re: Utility Bay Sewer Notch Trim Metal

Reply #14 – July 04, 2015, 06:45:18 pm

I am sure many of the other options work fine. I agree with Don, POR-15 seems to really work well. It is a moisture cure paint. Humidity helps. I repainted one of my mirror mounts on the Jeep in Parker, AZ in March. Extremely dry there. Took a whole day to cure up. It looks great and is holding up very well. This was on a cast aluminum mount that had a lot of corosion and most of the paint was gone. Followed the directions. I would use it again. Roger

Re: Utility Bay Sewer Notch Trim Metal

Reply #15 – July 04, 2015, 10:18:07 pm

rust bullet is a competitor to por15. The prep instructions for rust bullet are not as arduous. That's why ibwent with it. Both seem like good produxts.

Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 14, 2025 ...

Utility Bay Sewer Notch Trim Metal

June 30, 2015, 02:29:10 pm

Re: Utility Bay Sewer Notch Trim Metal

Reply #1 – June 30, 2015, 04:32:30 pm

Re: Utility Bay Sewer Notch Trim Metal

Reply #2 – July 01, 2015, 12:13:32 am

Re: Utility Bay Sewer Notch Trim Metal

Reply #3 – July 01, 2015, 12:45:39 am

Re: Utility Bay Sewer Notch Trim Metal

Reply #4 – July 01, 2015, 01:24:33 am

Re: Utility Bay Sewer Notch Trim Metal

Reply #5 – July 01, 2015, 01:39:13 am

Re: Utility Bay Sewer Notch Trim Metal

Reply #6 – July 01, 2015, 02:25:01 pm

Re: Utility Bay Sewer Notch Trim Metal

Reply #7 – July 01, 2015, 04:18:38 pm

Re: Utility Bay Sewer Notch Trim Metal

Reply #8 – July 03, 2015, 05:46:30 pm

Re: Utility Bay Sewer Notch Trim Metal

Reply #9 – July 04, 2015, 09:01:25 am

Re: Utility Bay Sewer Notch Trim Metal

Reply #10 – July 04, 2015, 09:31:56 am

Re: Utility Bay Sewer Notch Trim Metal

Reply #11 – July 04, 2015, 09:39:54 am

Re: Utility Bay Sewer Notch Trim Metal

Reply #12 – July 04, 2015, 04:27:24 pm

Re: Utility Bay Sewer Notch Trim Metal

Reply #13 – July 04, 2015, 05:19:34 pm

Re: Utility Bay Sewer Notch Trim Metal

Reply #14 – July 04, 2015, 06:45:18 pm

Re: Utility Bay Sewer Notch Trim Metal

Reply #15 – July 04, 2015, 10:18:07 pm

Affiliate Notice