Another Bulkhead Separation Story Part II

Topic: Another Bulkhead Separation Story Part II (Read 2279 times) previous topic - next topic

Re: Another Bulkhead Separation Story Part II

Reply #25 – December 03, 2011, 08:46:49 pm

Quote from: Rudy – December 03, 2011, 08:07:12 pm

Pierce & Peter,

Linseed oil was noted as controlling corrosion as early as 1826 according to the referenced article.

CorrosionX is a invention of the 20th century. It is a fluid thin film that has polar bonding technology. This means it does not coat over existing corrosion but rather penetrates the corrosion. Each molecule of the surface of the metal item will have a molecule of CorrosionX polar bonded to it having penetrated and releasing the corrosion from the surface.

CorrosionX meets Mil-C-81309E for use on all aircraft including many military aircraft. It is available from the GSA for government use.

Although CorrosionX is superior for corrosion, there are other excellent uses for linseed oil for which CorrosionX would not be appropriate.

I want to thank Rudy for his response. While linseed oil is marvelous stuff, it's hard to argue with molecular polar bonding.

Re: Another Bulkhead Separation Story Part II

Reply #26 – December 03, 2011, 09:01:19 pm

I'm sure that CorrosionX does work well, especially where you don't want to have to wipe the linseed oil off your hands. I am also sure that Folker Aircraft also researched corrosion protection before they started with their synthetic substitute. While linseed oil was brought into use back in the 1800's, it is still the preferred choice for homebuilt/experimental aircraft today in the 21st century. The airworthiness directive (AD note) was a 21st century fix for a 20th century choice that proved inadequate.

Here is the Poly-Fiber website describing the properties and installation instructions of "Tubeseal", a linseed oil product (REF: MIL. SPEC. L-21260) from Consolidated Aircraft Coatings. Poly-Fiber Aircraft Coatings - Tubeseal Internal Tubing Corrosion Inhibitor

Whenever you go to an airshow and watch the experimental planes race or demonstrate aerobatic manuvers, you can be sure the majority are using linseed oil to protect their fuselage and engine mounts from rust and corrosion.

Re: Another Bulkhead Separation Story Part II

Reply #27 – December 03, 2011, 09:17:08 pm

Pierce,

Do you fly? I love planes and recently got to go to lunch in a Robertson R-44 copter. What a ride!

Linseed oil certainly is good for corrosion protection or it would have fallen out of use for that long ago.

But do remember the majority of RVers are not using Foretravels as their coach of choice. I do not plan to follow their lead here either.

Re: Another Bulkhead Separation Story Part II

Reply #28 – December 03, 2011, 09:34:07 pm

Art,

Grainger supply has the fiberglass sheets in a variety of sizes and thicknesses. Here's a tip that might help you if you want to just reuse your old panel and run a seam. The easy way to apply glass overhead without having to shave the resin hardened hair off your head later is to wet out your fiberglass-you can do multiple layers of mat at one time if you don't over catalyze-on a strip of saran wrap. Carefully pick up the saran wrap with glass on it and place it into position overhead. No muss, no fuss plus the plastic allows you to really smooth, compress and blend the new glass in. If you leave the saran wrap on until the resin kicks when you peel it off you will have a gloss finish.

Chuck

Re: Another Bulkhead Separation Story Part II

Reply #29 – December 04, 2011, 12:27:14 am

Thanks for the suggestion... it appears I am going to need a fair amount of this stuff. I pulled up the streetside floor of the fresh water tank compartment only see a discouraging level of rust present. I believe I will need to replace some, if not most of the square tubing down there. I hope that is the extent of it. Goung to sleep now, and maybe when I wake up it will all have been just a bad dream:(
Don

Quote from: Chuck Pearson – December 03, 2011, 09:34:07 pm

Art,

Grainger supply has the fiberglass sheets in a variety of sizes and thicknesses. Here's a tip that might help you if you want to just reuse your old panel and run a seam. The easy way to apply glass overhead without having to shave the resin hardened hair off your head later is to wet out your fiberglass-you can do multiple layers of mat at one time if you don't over catalyze-on a strip of saran wrap. Carefully pick up the saran wrap with glass on it and place it into position overhead. No muss, no fuss plus the plastic allows you to really smooth, compress and blend the new glass in. If you leave the saran wrap on until the resin kicks when you peel it off you will have a gloss finish.

Chuck

Re: Another Bulkhead Separation Story Part II

Reply #30 – December 04, 2011, 01:22:31 am

Don,

Your new rig really looked perfect in the photos. I there a chance it went through any kind of flood? Does not sound like a California vehicle. History?

Photo of the damage possible?

If you can wait, I've got a Miller 200 wire feed here.

Pierce

Re: Another Bulkhead Separation Story Part II

Reply #31 – December 04, 2011, 10:31:55 am

Quote

Thanks for the suggestion... it appears I am going to need a fair amount of this stuff. I pulled up the streetside floor of the fresh water tank compartment only see a discouraging level of rust present. I believe I will need to replace some, if not most of the square tubing down there. I hope that is the extent of it. Goung to sleep now, and maybe when I wake up it will all have been just a bad dream:(
Don

Well, shoot.

Art, you may be privy to this info, but I have never read a good explanation of the structural design of the bulkheads/lower square tube frame. I would encourage you to do this before assuming the worst. While the sight of rust is discouraging, it's not necessarily a death sentence for the steel. I'd for sure want to know just what the structural function of the various components is before starting to repair/replace.

Many of the industrial grade conversion coatings and inhibitors require a heavy coat of rust and/or scale to work properly. Wire brushing/sanding limits your options for repair to paint or oil type coatings. Most designs are so overbuilt that they work exactly the same with half the structure removed. The goal here is probably not to build a new Foretravel.....

Chuck

Re: Another Bulkhead Separation Story Part II

Reply #32 – December 04, 2011, 11:33:29 am

It would be great to find some engineering drawings of the Travelride chassis. If we had that, it'd be a lot easier imagining the loads on the lower bulkhead. I'm sure there are plenty of engineers on this board willing to offer some insight into loadings and deflections. You might start with imagining the stresses on components in all the bending and torsional modes. Six degrees of freedom, bending moments on three axis and torsional moments on 3 axis. Something like the lower bulkhead might offer quite a bit of stiffness in torsion about the x-axis, x being along the length of the coach (front to back), y being transverse to the length (left side to right side) and z being thru the roof. Imagine holding the front axle and twisting the rear. I have hunch that this is the kind of motion the lower bulkhead helps resist, but it's just a hunch with a heap of speculation added in!

Re: Another Bulkhead Separation Story Part II

Reply #33 – December 04, 2011, 04:21:52 pm

I've come to the conclusion that the discussion in connection with bulkhead repairs is not centered around a design flaw in the semi-monocoque chassis but rather a selection of materials and the fact that proper drainage from inside the utility bays was not incorporated into the design. In addition, a routine inspection/maintenance procedure was never coming from the factory in a timely manner as in a technical bulletin to owners/repair shops so that 100% of the possible coaches out there could be well informed. With some coaxing from valuable members of this forum, Foretravel put out a white paper a few years ago, and it is availble to all on this forum.

In conclusion, the bulkhead issue is not a deal breaker for anyone. It just needs to be taken into consideration and well inspected and maintained on an annual basis to ensure the original design functions as intended.

Re: Another Bulkhead Separation Story Part II

Reply #34 – December 04, 2011, 04:25:46 pm

Pierce,

I am pretty sure flooding wasn't involved... It seems to be only in the rear and I suspect the cause was similar to what Barry showed pictures of on the second page in this thread Making sure the fresh water tank is completely full. So in short, I believe it is likely from the freshwater tank area, possibly leaky overflow connection or the like. My next move is to pull the water heater, pump, etc. out, disconnect and pull the freshwater tank out and inspect from above after removing the rest of the compartment floor under the those parts. Hopefully, some of that steel is intact and I can reinforce the area where the angle iron attaches, bolt it up from above after drilling from below, reinsulate and cover with fiberglass sheeting or the like. But that could change in light of what else I find. I need to know the truth of it, and then we can decide how to proceed. My son has welding skills and a wirefeed welder, but that is an awesome offer and I thank you for it! If we get up in your neck of the woods when you happen to be there, I would love to meet up in person and see your shop set up when you finish (if you don't mind playing tour guide). I hope to finish in time to make a trip to quartzite, but I will have to see how that goes. You going this year?
Don

Quote from: Pierce & Gaylie Stewart – December 04, 2011, 01:22:31 am

Don,

Your new rig really looked perfect in the photos. I there a chance it went through any kind of flood? Does not sound like a California vehicle. History?

Photo of the damage possible?

If you can wait, I've got a Miller 200 wire feed here.

Pierce

Re: Another Bulkhead Separation Story Part II

Reply #35 – December 04, 2011, 04:37:09 pm

I am with you on that goal! I don't wish to replace every part of this coach one piece at a time! I just want it to be structurally sound and to stop the rust form doing more damage. Once I get a more complete look, I will have to decide how to proceed. In the mean time, I am researching the rust converter options. Seems like it is somewhat controversial just how effective they are. Anyone with personal experience or just informed opinion on the subject, feel free to chime in!

Don

Quote from: Chuck Pearson – December 04, 2011, 10:31:55 am

Most designs are so overbuilt that they work exactly the same with half the structure removed. The goal here is probably not to build a new Foretravel.....

Re: Another Bulkhead Separation Story Part II

Reply #36 – December 04, 2011, 04:42:11 pm

I would love to see this! I would also love to know if there are more substantial framing members under the floor. Anybody know?
Don

Quote from: travelite – December 04, 2011, 11:33:29 am

It would be great to find some engineering drawings of the Travelride chassis...

Re: Another Bulkhead Separation Story Part II

Reply #37 – December 04, 2011, 04:58:05 pm

Don,

Unless there is another family emergency, we will be there. Have not heard the dates yet.

Pierce

Re: Another Bulkhead Separation Story Part II

Reply #38 – December 04, 2011, 05:12:36 pm

Quote from: acousticart – December 04, 2011, 04:42:11 pm

I would love to see this! I would also love to know if there are more substantial framing members under the floor. Anybody know?
Don
Quote from: travelite – December 04, 2011, 11:33:29 am
It would be great to find some engineering drawings of the Travelride chassis...

"substantial framing members under the floor" No - Think air frame construction and that is basically what you have between the two axles.

Re: Another Bulkhead Separation Story Part II

Reply #39 – December 04, 2011, 05:21:24 pm

Quote from: acousticart – December 04, 2011, 04:42:11 pm

I would love to see this! I would also love to know if there are more substantial framing members under the floor. Anybody know?
Don
Quote from: travelite – December 04, 2011, 11:33:29 am
It would be great to find some engineering drawings of the Travelride chassis...

Here are a few pictures of what rust can do under there

Re: Another Bulkhead Separation Story Part II

Reply #40 – December 04, 2011, 05:25:22 pm

Quote from: acousticart – December 04, 2011, 04:42:11 pm

I would love to see this! I would also love to know if there are more substantial framing members under the floor. Anybody know?
Don
Quote from: travelite – December 04, 2011, 11:33:29 am
It would be great to find some engineering drawings of the Travelride chassis...

A couple of photos after replacing all the tubular framing in that section.

Re: Another Bulkhead Separation Story Part II

Reply #41 – December 04, 2011, 06:57:11 pm

If the primary cause of the rust is overflow while filling the fresh water tank, assuming the overflow isn't thoroughly directed outside the coach, then maybe folks should consider some sort of automatic freshwater fill shutoff. Wanderlodge has been using a system like this for many years, and I suspect Prevost and Newell too. It's basically an electrically operated sporlan valve that takes an input form the tank level sensor. When the tank level reaches full the sporlan valve is automatically turned off interrupting shore water supply. Because of this system, I have never experienced an over flow from my fresh water tank while filling the fresh water.

David Brady
'02 Blue Bird, Wanderlodge LXi
NC

Re: Another Bulkhead Separation Story Part II

Reply #42 – December 04, 2011, 06:59:13 pm

When I worked at Country Coach in the chassis group I remember seeing a FEA analysis report on one of their designs. The maximum stress point was right where the bulkhead joint is on a Foretravel in front of the rear axle. Worst case condition is a fully loaded basement under full braking force. Eventhough the CC was less of a monocoque design (4 slides with two large longitude beams) than a Unihome/Unicoach it still had the maximum stress in the same place. Here's my thoughts on it: think of the whole coach as being a beam. When it flexes down due to a load being applied the maximum stress occurs at the very top (roof in compression) and very bottom (belly floor in tension). You can think of stress as being like water - it doesn't like changing directions. Changing directions is exactly what it has to do when it encounters the wheel wells and has to travel around them. The stress at the very top (the roof) doesn't have any obstacles to go around. Like I said - just my own way of think about it and I can't help but think this is true of other manufacturers as well. If one wanted to take some of the stress out of the bulkhead area joint you could run a couple of tension rods between the front and rear suspension frames. Probably right where the lower parallel arms attach to the large "L" beam and run the rods on the exterior next to the fiberglass belly skin. I don't think I would ever do it because I just don't think it's necessary but I thought the idea might help illustrate the stresses. Of coarse there is also "rust jacking" going on if water is getting in that joint routinely in addition to the loads wanting to separate that joint.

Re: Another Bulkhead Separation Story Part II

Reply #43 – December 04, 2011, 07:19:05 pm

John, Thanks for the very informative description. Here's a view of the underside of my Wanderlodge. This is an example of the longitudinal beams that you describe.

David Brady
'02 Blue Bird, Wanderlodge, LXi
NC

Re: Another Bulkhead Separation Story Part II

Reply #44 – December 04, 2011, 08:02:35 pm

A few years ago I was at FT having service work done when they replaced the floor on a coach. It seems the owner failed to notice a cracked coach battery. Electrolyte flowed freely until the batteries dropped to the pavement. I was shocked when I saw that bottom framework removed the same day the work started. I didn't see the coach finished, but it could have been the next day!

Re: Another Bulkhead Separation Story Part II, removing fresh H2O tank... help!

Reply #45 – December 12, 2011, 09:30:35 pm

Well I thought I was about ten minutes away from sliding the freshwater tank out the passenger side of our 99' U270... three hours later, no joy and I had to give up because of darkness, threat of rain, and general discouragement:( I took off the trim that holds the compartment door latch, strut support (drilled out the rivets), and the weatherstripping. That trim is screwed into a piece of angle iron about. 1/8" thick and both the trim piece for the right side of the utility bay door and the forward vertical part of the passenger side wheel well covering (fender) is anchored to it. Problem is, the fresh water tank will not make it past the lip of the angle iron, yet I can't seem to see how the angle iron is held in place. It seems that it may just be held by caulking yet, somehow it seems too firmly anchored to be just caulking adhesion. The FW tank itself has bulging sides and it may be just applying some pig grease (or a liberal dose of WD40) and the application of enough force from behind (water heater side) might do the trick, but it is so tight! I don't want to damage the tank, but it has to come out! Help!!! Anybody who has done this or knows something about it, I am all EARS!

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