Can I just cut out this angle iron? Will it matter?

[robwok]

I have a 64 Overlander. I just built 2 custom gray tanks and a black tank out of 1/4" ABS. Saturday, I dropped my belly pan, and found I have a thin angle iron between every frame rail, running down the center of my floor. It is apparently there to stiffen up the floor. However, I can't get my gray tanks between frames with this 1x1 angle iron in the way. Can I just cut that out? It's only 2 of them.

The tank itself will be pushed up against the floor, and it's pretty thick plastic, with plastic walls. I can stand on my tank.

Thanks,

Rob.

[bwoodtx]

Can you not cut it out and weld a piece of flat bar in place of it. I think if it were mine I would do that. The floor might flex enough to rub on the tank. I probably would put something on the flat bar so it was not directly on the tank.

Just my thinkin'

[RickDavis]

If I am right picturing these as running parallel with the frame rails you probably would be alright. Possibly you coud just cut out the vertical leg of the angle. Of course with out seeing it this could be bad advise too

[Mixter]

Pics would be good. But my first thought is that there is no way I would do that. When I pulled the shell, and got down to bare frame, I could not believe how light duty these things are. You may be a little beefier in '64, but my '76 was very weak. The main frame rails on min are just 1/8" cold formed channel. The cross members and outriggers are 1/16". The entire thing flexed so much. I even found cracks where the cross members meet the frame rails. I understand the original intent of the design was lightweight, however that doesn't really apply to me, since I'm towing with an Excursion. I beefed up my frame in strategic places without going over board to add "unnecessary" weight. all my outriggers were replaced with heavier gauge, and I added 1" angle across the top to connect the main rails with the angle you are referring to in your project. The purpose was to reduce flex, which I felt was the cause of the failures I already found- (cracked metal, cracked welds, sagging outriggers, rear end sag). I have new 3500# axles, so I have more than compensated for the minimal amount of additional steel I put on- which i would guess is less than 50# differential.

Sooooo.... to address your situation, I'm afraid that although cutting those angle sections is totally doable, and your new tank would be supporting the floor just fine, the reduction in frame support will allow more flex and torque and ultimately lead to premature failure.

Maybe you can cut them out and weld back in some 1"-2" plate up against the floor to tie the frame rails together?

My thoughts are with the assumption that you want maintain the strength and integrity of the trailer for hauling. If your coach will be sitting more than it is used, then the flex is really a non-issue.

Hope that helps- keep us posted as to what you decide.
Mic

[putback]

If your cross members, plywood deck and elevator bolts are in good shape probably be OK. You may get a little give under foot walking down the ctr.isle. I'm really interested in how you build tanks from ABS. That sounds very usefull.

[robwok]

I talked to Colin Hyde as well about it. He says that in my case, to take an angle grinder and grind off the vertical piece as well as any bolts. Then, put some abrasion resistant strip on top of the metal between that and the tank.

In my case the tank is 1/4" ABS. There's no way a flat piece of metal will wear through that in my lifetime. The material itself is a bit of a lubricant in this case - like UHMW a little.

I plan on putting wide straps to hold it up to the floor. There will be the mylar bubble wrap stuff under that, wrapping the tank, so I'll get some heat transfer through the floor to the tanks. Not as much as the original system where the furnace warmed them, but unlike the original, my tanks are sloped to the center.

The ABS is first chemically tack welded with Weldon 16, then heat welded with a special heat gun and ABS welding rod. I then finish up all the seams with a thick coating of chemically dissolved ABS in Mek, which fills any gaps I may have missed with the other two methods. The tanks are tough as nails when done.

All the fittings are put on with the same method. Since I have a 64, rear bath, under floor tank, and I wanted gray water tanks, I shifted the tank just a tiny bit to the left. That allowed me 2 ABS gray water tanks above the axles. Kitchen flows in from the front, the bath comes in from the back of the trailer and the lines run parallel to the ones that will drain back to the black tank mix valve. I get about 25 gallons of gray, and about 22 gallons of black, and 40 gallon fresh water polyetheylene up top. The gray tanks both have to be vented, but I can do so by running lines into the bunk on the street side, and then tying into the original kitchen vent.

[StPierre]

Robwok
I cut mine to install a 26 gal gray tank in my 65 Safari without a problem .Howerever I also replaced the sub floor at the same time

[Mixter]

I like that idea... You keep the reinforcement that way, while still making room for the new tanks...

Nice job on those tanks- that is awesome! Got any pics of the welding process & materials? I'm about to tackle my cracked up end caps.... Just bought some weld-on fast cure, MEK, some ABS scraps from a friends junk end cap and some 3M reinforcement material.

Not sure exactly what I'm going to do yet and going to play around with it first, but thinking I'd use the precision applicator to drip the weld on into the crack, then mix up a MEK slurry to do what you did, and apply over the top of the crack, and also on the back side with some of the 3M reinforcement. Then I'm guessing I'll grind or sand down flush on the good side?

Got any tips working with that stuff?

[robwok]

Thanks. One of the hardest things to determine is what your end cap plastic is made of. People refer to it as "Thermoplastic" but that could cover tons of items. I would suggest to see if Mek disolves some of your end cap. If so, you could use it. Acetone may work as well.

If you could get some pieces of end cap from someone else, then break / nibble the pieces and put them in a mason jar, pour mek over and put the lid on. agitate it slowly for a day or so, then you should end with a slurry. I would then use fiberglass tape from lowes and apply that to the back of the end cap. Then, paint a thin layer the first time, to fill in the crack, then another layer to reinforce it. That should embed the open weave fiberglass in the back to hold it together.

I actually used all purpose pvc cement on mine, but my cracks were on the flange. I pulled the pieces together with a clamp to the outside, and the PVC glue welded together. I then used TYVEK tape all the way around both sides of the flange that's hidden in 2 layers to reinforce it and the screw holes. You can see a little bit of it when you're laying in the bed, but I'll clean that up some other day.

[robwok]

oh, and I've been taking youtube videos on the whole process, from cutting, to welding to tacking. I'll post a link when I'm done. Haven't totally finished the tanks yet.

[Mixter]

Good stuff- got any pics of your end cap fix?

[robwok]

sorry. It didn't seem like a big deal at the time.

[putback]

Originally Posted by robwok

oh, and I've been taking youtube videos on the whole process, from cutting, to welding to tacking. I'll post a link when I'm done. Haven't totally finished the tanks yet.

Great, you have a student here. I'm looking to have 30 gal of gray storage in our '62 w/in the 4" frame. All centered over the X's where the frame is re-enforced.

[cwf]

With all that skill in building, why can't you put notches in tank top? Or, let it hang that inch and add bottom pan of steel. Better than breaking your trailer spine.

[robwok]

Not quite breaking the spine. I could notch it, but. Then I'd have to vent both sides of a shallow tank. Hanging it below destroys an original belly pan. That little spine should have little effect, and the thickness of the tank should make up for the loss of a inch by 1/32 thick piece of steel.

[robwok]

So, an update. I have more pics I need to load, and maybe some video. To Channing's question, the notches would have created air pockets, at least on one side. Since the capacity on these was only 14 gallons, and less than that since I chose to drain out of the side instead of the bottom, and couldn't get the fitting low enough, I didn't want to jeopardize anything. I think the floor is actually siff enough. I only cut 2 of the ribs, and replaced it with a abs box, so I think it may be a net zero on the rigidity.

The tanks are connected to the lines with rubber couplings. That adds some flex, made it easy to drop the tanks, and the black rubber will never see the light of day, so it should last pretty long.

Here's a huge tip if you want to build your own tanks. Use lots of ABS cement. Glue all the flat pieces, then run the abs welds on them. I had no leaks where I joined the boxes with cement and ran a bead inside and out, then slathered on the cement. The problems were the tops actually. It was a heat weld, and then an abs slurry on the outside. It just didn't hold. Both tanks leaked when they were filled to capacity as the water pressure broke the weak bond. I think the heat bond is much weaker than the chemical bond.

So, I took both tanks down, and then I put rubber caps on the drain sections, and put my shop vac with a tapered nozzle into the top where the vent goes in and hooked it up to the blower side. It is a LOT of pressure, more so than the water. It ballooned the tank up quite a bit, possibly expanding the middle from 4 inches to 8 under pressure. I could feel the broken seams just blowing water at me. Then, I put it on suction, That collapsed the tank and opened up those broken seams. I then slathered those seams 3 or 4 times with the cement while on suction. that sucked the chemical inside the seam. I then turned off the vacuum, and the crack closed up. I let that cure, and rechecked, did it again. Then I reversed the vacuum to blower and did a soap bubble test. Found a couple pin hole leaks, and then finally, completely air tight at the highest sustained pressure.

As far as tank supports, I ran some hurricane banding under the tanks, holding it to the floor with elevator bolts that were epoxied in from the top, but recessed to hide under the new tile foor. Even full of water, supported at every 12 inches, the 1/4" black abs barely flexed.

rob.

[Aerowood]

Can't wait to see the pictures, looks like a job well done.

[robwok]

I updated a few things on my page here, page 8 I think: http://www.airforums.com/forums/f157...ml#post1577719

One thing I'll add, in the rear, the tank takes up a lot of room under the floor. As a result, there isn't a lot of floor support - technically it is missing a cross member underneath. I grabbed an idea from housing - the attic load bearing beam. You put a beam in the attic, then hang joist hangers off of it for the first floor ceiling - then you can have an opening to another room, load bearing, without having that beam in your face. Same thing here. Get a piece of angle iron, or even U channel, put it on top of the floor, then put elevator bolts under the floor from the belly pan side. Glue them in, and you'll have bolts sticking up into your living space. Slide the angle iron over them, and you now are "hanging" your floor from steel channel, because you can't put it underneath as the black tank is in the way. This only works if you have something that allows you to hide this steel - like a rear bench.