There was a post awhile back about repairing bulkheads so I took a look at mine and noticed that the fiberglass was separating from the aft area that abuts to the angle iron.
When we bought the coach, one of the first things I did was inspect both the fwd and aft bulkheads and found them to be in very good shape so I sprayed the Rollkocks and edges with a rubberized under body spray which held up very well.
After peeling back the fiberglass (FG) to the first row of bolts ( 27' ) I was happy to NOT to see any rust other than the box beam that's bolted to the angle iron and a few other areas. There was no heavy rust and no rust jacking between the box beam and angle iron. I then wire brushed and scraped what rust I could see then painted all exposed metal with Corroseal rust converter. After that dried I replaced all 13 Rollocks with 3/8 x 18 grade 8 flange bolts and flange nuts, after drilling to proper size. There was 4 3/8 bolts already bolted thru the bulkhead which I replaced also.
Then I painted all metal with Rust Bullet high gloss black paint, then caulked all joints and seams.
I would say , the hardest part of this job was in removing whatever glue FOT used to adhere the FG to the underside of coach!
I used 2 cans of 3M super 90 spray glue to reattach the FG to the underside.i held it up with a piece of plywood and 2x4s using 5 bottle jacks to keep pressure on everything.
Once that was dried I screwed 3 pieces of 1/8x1 1/2 flat stock from the edge of the angle iron and over the end of the FG to cover the edge. Used #10x3/4 s/s self tapping bolts and caulking to seal it with.
Am very happy with the outcome. Oh! And since I still had over half a can of paint left, I cleaned and painted the under carriage as far up as I could reach till I ran out of paint.
One more picture
Great documentation and photos, Richard. Your work appears to be every bit as good as what you would pay several thousand dollars for in Nacogdoches. Nice job.
jor
Thanks Jor. Just glad I didn't have any welding to do or we would of gone to Texas for the work! I think the bill for supplies was around $500.00. I feel very lucky😁
Richard,
Good work. By catching and correcting it before the rust when any further, you saved the real expense of cutting out "diseased" box beams and welding in new ones.
Big difference is that your box beams are still structurally sound. But, I have seen some that you could push a nail through the side wall. OK, I have inspected a few where I could stick my FINGER through the box beam sidewall. No amount of rust remediation/coating will fix "not structural".
So, the moral of the story is: if there are bulkhead issues, it is less $$/less work to address it NOW. Waiting only allows rust to do more damage.
Richard, I am so impressed by your work. When you first posted it caused me to crawl under Orchid to inspect. It does not appear that there is any damage but I may not know what to look for,. The many pictures on the Forum and Beam Alarm gave me a good idea for how to inspect.. There is no bulging and I cannot see any signs of anything but surface rust. I will look for an opportunity for an inspection by someone who knows what they are doing. Whew!
KUDOS for using Rust Bullet,looks good,only thing I would also do is spray some ACF-50 corrosion spray inside the beams thru the holes.
Brett, I agree with all of that! I felt after seeing how many threads there were when I removed the Rollocks, plus the lack of heavy rust, that the box beam still had some meat left.
Thanks to David S for bringing this post up again. He got me to look at my bulkhead. I was a little concerned when I saw the fiberglass separating from the bottom, but after pulling it down I felt confident I could do this job.
Thank you Ken. Next time we are togeather I could give you my two cents worth!
John44, thanks for that tip! Will look into that product and do that. I've also heard that Boiled Linseed Oil works well also.
Any thoughts on that?
Tim got me to use the ACF-50,is an aircraft product,they did have more products on their site,never heard of the oil,think some
older mercedes used some kind of wax.
Cosmoline - Wikipedia (https://en.wikipedia.org/wiki/Cosmoline)
I have to rebuild the battery compartment and will take care of a few areas on the bulkhead while I'm in there. The battery florr is sagging pretty bad and the previous owner tried using a poor patch job that just hid the issue.
I had to do mine also. You will probably find a lot more than you want to see when you get into it But you can make that decision when you see how bad it actually is .
Yes, Mercedes injected wax. Most all aircraft use the tried and true, boiled linseed oil or raw linseed oil inside all their tubing. Some claim that the raw linseed oil does a better job plugging small holes, etc. Read Oiling the Inside of the Fuselage Tubes – www.stearman.net (http://www.stearman.net/index.php/oiling-the-inside-of-the-fusdlage-tubes/)
One of the major aircraft suppliers sells Tubeseal for interior corrosion protection. See it or order it at: POLY-FIBER TUBE SEAL LINE OIL from Aircraft Spruce (https://www.aircraftspruce.com/catalog/cspages/tubeseal.php)
Pierce
Pierce, I ended up using the boiled linseed oil. Time will tell. Thanks for the tip.
Good write up on this. Like the pictures. My coach had the basement redone last year by the PO at Berdnts. Hard to know exactly what they did but new fiberglass sheets and foam was done. Interesting because Paul Smith, the owner before my seller had the basement checked out and was told it was ok. When they did the repair, they did not bond the fiberglass to the foam, which is strange to me. Would make a better structure if they had. I might have to redo portions of their work (again) ! They used some kind of thick pastey stuff between the fiberglass and the metal parts that I see. Also al lot of silicone which I hate. They didn't appear to seal the screws that hold the bottom part to the beams. I have to do that at some point.
I wonder why it costs so much (30K) and took so long to do, but then when your charging north of $100/hour I guess it adds up.