Bulkhead rebuild

Topic: Bulkhead rebuild (Read 10399 times) previous topic - next topic

Re: Bulkhead rebuild

Reply #25 – June 09, 2025, 07:34:55 am

Quote from: stump – June 09, 2025, 04:29:14 am

How far forward is your bottom rotted out?

You can pretty well tell by how much rust is deposited on the filon.

And, using an awl, you can test the box beams for integrity.

Rust just forward of the rear bulkhead is common, as water from the wet bay as well as water thrown up by the tires rusts it.

Rust just aft of the forward bulkhead is a little less common as no wet bay.

The rust along the sides toward the middle of the coach is a little more surprising.

Re: Bulkhead rebuild

Reply #26 – June 09, 2025, 08:48:46 am

Quote from: oldguy – June 03, 2025, 09:27:03 pm

My son thinks we should make passage way from the fuel tank area...

If it will make your job easier, you should not be afraid to cut an access port through the bay wall. It will not compromise the strength of the wall, as long as you don't cut any steel frame members. You can locate the steel framework within the wall using a magnetic stud finder. Cut carefully around the framework and remove the section of wall material. When you are done with your project, simply glue the section of wall material back in place, or use a readily available access panel cover from Lowes or HD. Example from our coach linked below:

Behind the Water Heater Access Port

Re: Bulkhead rebuild

Reply #27 – June 09, 2025, 09:28:30 am

Thanks Chuck I guess we will go with way. I would like to replace the plastic sheets but I have no
idea where to get them.

Re: Bulkhead rebuild

Reply #28 – June 09, 2025, 10:07:02 am

As long as the filon is not damaged (or damage is in a small enough area that it could be patched (and waterproof), no reason not to clean up the old filon and reuse it.

Re: Bulkhead rebuild

Reply #29 – June 09, 2025, 10:18:20 am

Or, last resort, filon sheet material is available from online vendors in up to 8.5' wide by up to 40' long. Examples below:

https://cranecomposites.com/wp-content/uploads/7827.pdf

8.5' Wide Arctic White RV Fiberglass Siding and Roofing - RecPro

Re: Bulkhead rebuild

Reply #30 – June 09, 2025, 01:06:51 pm

Is the origial belly skin and basement bay walls Filon or custom laid up fiberglass sheets? Filon is 1/16" and designed to be laminated to lauan plywood, i thought the panels were thicker than that.

Re: Bulkhead rebuild

Reply #31 – June 09, 2025, 01:22:53 pm

Quote from: Geodmann – June 09, 2025, 01:06:51 pm

Is the origial belly skin and basement bay walls Filon or custom laid up fiberglass sheets? Filon is 1/16" and designed to be laminated to lauan plywood, i thought the panels were thicker than that.

When properly glued to the box beams (even better if vacuum bagged) filon is a very good, waterproof, light weight product for the application.

Re: Bulkhead rebuild

Reply #32 – June 09, 2025, 04:51:00 pm

Thanks everyone, now I know what it is and how to get it.

Re: Bulkhead rebuild

Reply #33 – June 09, 2025, 08:00:04 pm

Finally got it down, it was a fight all the way. It will pull out easily.

Re: Bulkhead rebuild

Reply #34 – June 09, 2025, 10:02:32 pm

Did you remove the foam insulation that is missing in places or did it melt due to diesel fluid getting to it or ??

Re: Bulkhead rebuild

Reply #35 – June 09, 2025, 10:34:05 pm

It was diesel fuel melt. I wander why they insulated under the diesel tank as most tanks are out
in the weather.

Re: Bulkhead rebuild

Reply #36 – June 10, 2025, 08:44:06 am

If that were mine, I'd probably just build a new floor rather than repair the old. No question then on how far to go in different spots and wondering if you went far enough. It would all be new. Might even be faster.

Re: Bulkhead rebuild

Reply #37 – June 10, 2025, 09:31:10 am

Quote from: wolfe10 – June 09, 2025, 01:22:53 pm

When properly glued to the box beams (even better if vacuum bagged) filon is a very good, waterproof, light weight product for the application.

What would the best adhesive be for gluing the filon/fiberglass in place and would it be best to glue the filon to the block foam as well? Agreed that vacuum bagging would be best but if one intended to peel back the belly skin and reuse it after doing a partial floor replacement that would be difficult to impossible. Plus the basement floor on a 42' coach is really large!

Re: Bulkhead rebuild

Reply #38 – June 10, 2025, 09:54:27 am

Dave I'm rebuilding the hole floor.

Re: Bulkhead rebuild

Reply #39 – June 10, 2025, 10:02:55 am

Quote from: Dave Larsen – June 10, 2025, 08:44:06 am

If that were mine, I'd probably just build a new floor rather than repair the old. No question then on how far to go in different spots and wondering if you went far enough. It would all be new. Might even be faster.

Yes rebuilding is a pain for sure. So many variables. Seems I recall FT using an odd thickness material seeking to save weight. With the new pour foams available I would fill rather than use block foam. FT failed IMO on all there proactive corrosion prevention, but they didnt seek to have there product live for extended life as we all seek. Easy to be a back seat designer. Building out of aluminum has been done before and would add to the CCC. Subtract from your bank account though. What a big job regardless. Peter I envy your ambition.

Re: Bulkhead rebuild

Reply #40 – June 10, 2025, 09:42:59 pm

I removed the filon/fiberglass today and started cleaning up the rusty surfaces on the coach. That is going
to be a lot of work. I was looking at the old frame and the way they built it looks like it could be built in a
way that would be easier.

Re: Bulkhead rebuild

Reply #41 – June 11, 2025, 08:16:51 pm

Yup definitely a lot of work ..

Re: Bulkhead rebuild

Reply #42 – June 11, 2025, 09:52:57 pm

I'm floored (sorry) at anyone being able to do this, Kudos to you

Keep up the great work!

Re: Bulkhead rebuild

Reply #43 – June 11, 2025, 10:50:43 pm

Quote from: Dave Larsen – June 10, 2025, 08:44:06 am

If that were mine, I'd probably just build a new floor rather than repair the old. No question then on how far to go in different spots and wondering if you went far enough. It would all be new. Might even be faster.

On mine (U300) there was no way to repair the steel tube structure. An all new tube matrix was assembled, treated with corrosion proofing and installed, along with all new Filon on the bottom.

Re: Bulkhead rebuild

Reply #44 – June 17, 2025, 09:28:34 pm

Starting to build the new frame. Drilled the bolt holes for the front and rear bulk head tubes.

Re: Bulkhead rebuild

Reply #45 – June 20, 2025, 10:39:41 pm

Welded the nuts to make easier install and started lining up.

Re: Bulkhead rebuild

Reply #46 – June 21, 2025, 08:02:04 am

For the connection to the bulkheads (i.e. the front and back of the assembly) better to make washers from steel that are as tall as the box beams and a little longer side to side.

This will help spread the tension load to the top and bottom of the box beams. Certainly not required, but a more robust design.

Re: Bulkhead rebuild

Reply #47 – June 21, 2025, 10:25:31 pm

I agree Brett, I was looking for bigger and heavier washers but I couldn't find them easily so I just used what I
could find easily. Got the frame welded all around and Monday I will go out and get more tubing. I'm going to
weld all the joints all around and grind all the top and bottom welds smooth. Foretravel only did the vertical
welds.

Re: Bulkhead rebuild

Reply #48 – June 22, 2025, 11:51:12 am

Brings back memories. If you haven't already, you might want to look at my writeup to see there's anything useful.
I wouldn't expect anyone to follow what I did as I went to the extreme on details.
Bulkhead Repair (Partial Floor Replacement)

Re: Bulkhead rebuild

Reply #49 – June 23, 2025, 09:34:12 am

Quote from: wolfe10 – June 21, 2025, 08:02:04 am

For the connection to the bulkheads (i.e. the front and back of the assembly) better to make washers from steel that are as tall as the box beams and a little longer side to side.

This will help spread the tension load to the top and bottom of the box beams. Certainly not required, but a more robust design.

1 1/2" flat steel cut into 2" or 3" pieces with a hole drilled in the middle would be easy to make and spread the load nicely.

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