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Index > Body Exterior > Thread: those %#&!%@& channels under the bed
Thread: those %#&!%@& channels under the bed [' This thread is 2 pages long: (1) 2 ']
rotormunky


Redlining
Orlando, Florida
Posts: 424
posted December 09, 2003 04:58 AM

those %#&!%@& channels under the bed

Hey I was just sitting here trying to figure out the best way to deal with the balsted channels that support the underside of the bed. My concern is sealing them up so that moisture can't build up and start rotting them from the inside (after I rust treat them of course).

A work buddy mentioned (half-jokingly) filling them with expanding/hardening foam and then just sealing them up completely with undercoat when I do the rest of the bottom of the bed. I was dismissive at first, but then I got to thinking that the idea might have some merit.

Anyone got any thoughts on the subject?

Also do you think its better to seal up the undercarriage with rubberized undercoating or with spray-on bed-liner?


____________
-Martin
Orlando, Florida

http://www.themonkeyhouse.org/REPU

'77 REPU (Some assembly required :)
'91 Cabrio (Battered and bruised, but she's still my baby.)

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nwaco


Redlining
Posts: 407
posted December 09, 2003 08:42 AM

Yea, DON'T DO IT......

IF you do, you will see your bed disappear before your eyes.

The reason is that you can't seal the moisture out. It will penetrate the seams and wick in and once in, now it will never dry out. The trapped moisture will rust it's way out.

The best method I can think of is use a pressure washer/blower/bottle-type brush to clean debris out and spray it with a corrosion preventative. You will not get rust through for a very very long time if you avoid dirt or debris buildup. If it can drain freely and dry, it will not rust (or at the least, it will be surface rust). Rust starts where moisture is constant. That is between seems and under debris and dirt piles.

Also, if you were to use a foam, if it is polyurethane, it could bulge the channels to the point of distortion. Trapped expanding poly can be very devastating to structure as it will not stop until the pressure is relieved.

Do yourself a favor, never seal it up. I am not wrong or misinformed on this. These are facts as this is the business I do for a living.

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nwaco


Redlining
Posts: 407
posted December 09, 2003 06:03 PM
Edited By: nwaco on 18 Dec 2003 17:48

I guess I might as well address the bedliner-on-the-bottom issue...

to get it out of the way. I see it and several other "versions" repeated here and other forums often, so here I go.

These coatings are designed to withstand impact and abrasion. They are not designed to function as a corrosion or rust protective barrier.

Now don't get me wrong, they can perform that function, they just won't necessarily buy you any "value". The problem is they are heavy, thick, expensive and require absolute cleanliness to adhere properly. None of which are characteristics that are ideal under a 30 year old bed or in the cab for that matter.

Here is another problem, the surfaces under your bed are complex layers of weathered and dirty metal with a host of "faying surfaces" (surfaces of overlapping metal). The coating you put on the open and accessible areas (those that you can reach) will do little to protect your truck. Think of it, it is 30 years old, and where is your rust? It usually starts between two surfaces of metal and consumes more metal outward of that point. It does start working under paint from a scratch or nick in the painted surface in the open as well, but it is the covered part under the paint that incubates the rust, not the open nick in the paint itself.

Try as you might, you "WILL NOT" be able to coat the under side of you bed good enough to protect it from moisture with paintand especially not a thick "bedlliner material". IT WON"T WORK, PERIOD.

You must use a combination of cleaning, sealing (certain) seams, painting all that you can reach with a good quality polyeurethane or epoxy paint, and most important of all, coat it liberally with a good quality penetrating corrosion inhibiter (CIC)like LPS, Corban, Dinitrol, Boeshield T-9, etc.

Remember, the insides of the closed channels were most likely painted at the factory, and that paint with the underlining phosphorous coating LEFT UNDISTURBED is better cleaned and coated with a CIC then removed and some half complete coating system. Remember the golden rule, "if it ain't broke, Don't fix it"

A key point is you want your surfaces to be able to drain freely and dry out. Sealing or coatings improperly applied can severely impede that function.

These coatings (CIC's)will wick into every last seam, displace what moisture is there, inhibit any corrosion, and cure in the void eliminating any further water penetrating within the cavity because there is no longer air to facilitate capillary action to bring in moisture.

1 can of corrosion inhibiting compound can literally do your whole truck for like less than $15.00.

C'mon Guys, once and for all, lets be done with this "Rhino-liner" theory and get back to reality.

There, now I said it. Sorry for the lecture.

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rotormunky


Redlining
Orlando, Florida
Posts: 424
posted December 09, 2003 08:57 PM

quote:


The best method I can think of is use a pressure washer/blower/bottle-type brush to clean debris out and spray it with a corrosion preventative. You will not get rust through for a very very long time if you avoid dirt or debris buildup. If it can drain freely and dry, it will not rust (or at the least, it will be surface rust). Rust starts where moisture is constant. That is between seems and under debris and dirt piles.



Hmm. As you can see from the pics I posted I did my best to blast/sand to the bare metal and then hit it with the PPG/Omni two-part cleaner/conditioner which etches/rusts then converts to iron phosphate sort of like using ospho.

The cleaaner/conditioner was wicked into every seam I could find and heat and air dried before I laid down the sealing primer.

I'm doing all this just to arrest the advance of surface rust while I cut/grind and replace holes and big rust patches.

Maybe I'll just do the rag on a wire pull-three thing with some por-15 or something for the insides of the channels.


quote:

Do yourself a favor, never seal it up. I am not wrong or misinformed on this. These are facts as this is the business I do for a living.


I wish I knew that before I started or I would have picked your brain. Now that I know I'll have to pester you throughout the rest of the bodywork phase of my rebuild.


So leave the channels open, check. You think its alright to try to hit the inside surfaces with a POR-15 type product? Something to convert/seal?


____________
-Martin
Orlando, Florida

http://www.themonkeyhouse.org/REPU

'77 REPU (Some assembly required :)
'91 Cabrio (Battered and bruised, but she's still my baby.)

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rotormunky


Redlining
Orlando, Florida
Posts: 424
posted December 09, 2003 09:17 PM
Edited By: rotormunky on 9 Dec 2003 21:20

quote:

These coatings are designed to withstand impact and abrasion. They are not designed to function as a corrosion or rust protective barrier.



Gotcha. I was sort of thinking more in terms of:

1) strip to metal
2) treat with rust converter product of some sort to kill rust chemically and in the nooks and crannies
3) prime it with an epoxy sealing primer (PPG/Omni)
4) Undercoat the sanded/treated/sealed/primed surface

Is it undercoating in general that's a bad idea or the idea of just spraying gobs of it over panels without prepping them?


quote:

Now don't get me wrong, they can perform that function, they just won't necessarily buy you any "value". The problem is they are heavy, thick, expensive and require absolute cleanliness to adhere properly. None of which are characteristics that are ideal under a 30 year old bed or in the cab for that matter.



How clean are we talking here? I'm pretty much taking everything down to bare steel and starting from there.

Pics are here:
http://themonkeyhouse.org/REPU/2003-11-27_Derusting_Bed-web/index.html

Am I dreaming here or do you think this process might work? Every piece is coming off the truck, disassembled, sanded, cleaned and repainted. That will include hte frame and suspension components, etc. I figure it'll take about 100 years but right now anyway its about the process for me more than the eventual result.


quote:

Here is another problem, the surfaces under your bed are complex layers of weathered and dirty metal with a host of "faying surfaces" (surfaces of overlapping metal). The coating you put on the open and accessible areas (those that you can reach) will do little to protect your truck. Think of it, it is 30 years old, and where is your rust? It usually starts between two surfaces of metal and consumes more metal outward of that point. It does start working under paint from a scratch or nick in the painted surface in the open as well, but it is the covered part under the paint that incubates the rust, not the open nick in the paint itself.




Yeah that's what I figured too. There are definitely seams that I might be missing but I'm doing my best to hit every seam with a wicking rust converter of some sort.



quote:

You must use a combination of cleaning, sealing (certain) seams, painting all that you can reach with a good quality polyeurethane or epoxy paint, and most important of all, coat it liberally with a good quality penetrating corrosion inhibiter (CIC)like LPS, Corban, Dinitrol, Boeshield T-9, etc.



Ah, yes, that's what I'm shooting for in this process. I'll look into those products, thanks.



quote:

C'mon Guys, once and for all, lets be done with this "Rhino-liner" theory and get back to reality.
There, now I said it. Sorry for the lecture.




Not at all, I'm all for learning from someone else's mistakes/experience.

All that said I realise I should have been a little clearer about my question. Is a Rhino-liner application a good/bad/ugly idea over a properly cleaned/treated/sealed/primed/painted surface? I just look at my '91 vert and the entire bottom is undercoated and there isn't a softspot or sign of rust anywhere in the floor pans (from the inside or on the bottom). Its 12 years old now and there isn't a spec of rust on the car, I'm just trying to duplicate as much of the more modern rust-prevention techniques as possible.

Thanks again for the input.


____________
-Martin
Orlando, Florida

http://www.themonkeyhouse.org/REPU

'77 REPU (Some assembly required :)
'91 Cabrio (Battered and bruised, but she's still my baby.)

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nwaco


Redlining
Posts: 407
posted December 09, 2003 09:20 PM

Relax, Rotor, Your doing fine.......

Everything you've done, you've done good. Sand blasting is OK, just don't try to entomb everything with a sealant because you will never win. Seal works good from the top, shedding water, or to separate dissimiliar metals to prevent against galvanic corrosion, but never from the bottom only.

Take a chimney type brush, clean out the dirt and surface corrosion inside the channels, wash it good, let her dry thoroughly, and swab with a conversion coating. That will be fine. That stuff works good. Then don't bother to paint inside, cause you will only get the edges anyway.Then after paint, spray the shit out of it with good CIC, wipe up the puddles, and let it cure. Just make sure it wicks good in the cracks.

Don't try to seal up anything with seal or foam, or anything else, because even the slightest pin-hole will wick in water and fill it up. If water can get in, then it's best to it drain out.

Think about how your roof is done, they shingle from the top to shed water, if you put the roof on from underneith, it would fill with water. The bedliners do their job best from the TOP only.

You'v done everything fine, skip the bedliner on the bottom, give it a coat of spray paint, brush the missed areas and nooks, spray a CIC, cure and your good less the repair panels.

Take a breath, your doing fine.

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nwaco


Redlining
Posts: 407
posted December 09, 2003 09:27 PM
Edited By: nwaco on 9 Dec 2003 21:51

As for the bedliner on the bottom issue....

My concern is that it is a very thick coating and it will seal up the seams from the bottom, creating a whole bunch of mini-water-traps. This will incubate rust.

A thinner coating that allows a sacrificial corrosion inhibiting compound to penetrate the seams and displace the water is much better. These coatings must be periodically replaced as they wear off from the enviromental conditions of the bottom of your truck. But they are designed to be of the right viscosity to penetrate. Bedliners coat. Big difference.

As for "undercoating", my only question to all of you is why is it that the manufacturers don't undercoat cars? Only dealers do.....Hhmmmm? Millions in research and they don't do it. None of them? Why?

I myself, would never "undercoat" a car. Ever.

Newer cars don't rust because of 30 years of evolution with metal alloys, sealants, primers, paints, application techniques, drainage, etc. Doors have drain holes, low points have leveling compounds and water channels, hinges have sealants, panels and parts are specifically shaped and assembled to shed water, etc.

Look at the subtle differences in auto assembly between and old car and a newer car. That is why they (in general)last longer.

And....If you take the old parts off and completely clean, prime, paint and protect them and then install them...That is the best you can ask for.




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Klaus43


Rotorhead
Posts: 1259
posted December 10, 2003 03:55 PM
Edited By: klaus42 on 10 Dec 2003 15:58

Thanks for the education, guys!

I didn't know a thing about those CIC's... sounds like the way to go! I will say I've seen a really, really nice 'Armacoatings' spray-on over-the-rails bedliner job on a local friend's '77 REPU... but I have to assume the bed was in near-flawless factory paint prior to application. (Yes, the rest of the truck is comparably original and clean!)
Certainly makes sense about the moisture-trapping vs. seam sealing/corrosion inhibiting...
Glad to be learning now, rather than after I've screwed up!
If it's good enough for the Boeing factory's products, it's good enough for a restored REPU. :)
If it was me, I wouldn't apply anything directly on top of any primer, no matter how good... I'd want a top coat of paint, or several, over the primer, regardless of what else I was applying after...

       
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Fd3BOOST


Hauling
Posts: 114
posted December 16, 2003 10:14 PM

Thanks for the lesson.
I dont know much about preventing and trying to elliminate existing rust. (Sorry I was a 3rd gen guy till i got this repu. These old vehicles are new to me)
Anyway, would someone ellaborate on the specific products mentioned and where to purchase them.

       
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nwaco


Redlining
Posts: 407
posted December 16, 2003 10:28 PM
Edited By: nwaco on 16 Dec 2003 23:07

Corrosion Inhibiting products.....

are usually and readily available at either marine supply outlets and if you are a glutton for financial punishment, at aircraft supply outlets. The latter being substantially more expensive. A can or two will cover most of a single truck. CorBan, LPS, Dinitrol, Boeshield T-9, etc.... are brands most available.

Just remember, complete your rust removal, conversion, prime and paint first because these products do not come off easily. You can solvent wipe all you want, but they are still there.

Oh, two more things, 1. Spray-on bedliner(s) are FANTASTIC...even if applied properly over less than perfect, but clean TOP surfaces, NEVER underneith, NEVER.

And 2. Epoxy and polyurethane primers are perfectly suited to be the final surface coat. The two-part catalyzed coatings that chemically bond and are pretty much impervious to environmental conditions. It is the spray can versions or one part, air cure coatings that break down. The aircraft industry quit using colored topcoats on surfaces not visible years ago. The paint industry has a host of primer products that are vastly superior to most any topcoats of the past. They are perfectly suited to be left exposed if one so chose.

The key is if you are inclined to put a finish color coat on epoxy or polyurethane primers, you have 48 hours to do so or the paint will become too hard to bond to itself, and 100% sanding is the only way to get them to bond. You don't want to resand a frame, under a bed or cab. Watch the clock and be careful when you embark upon a spray job using those products.

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Klaus43


Rotorhead
Posts: 1259
posted December 17, 2003 10:13 AM

When can we all get together...

...and have a massive REPU restoration effort in a nice, well-equipped shop, where we can learn from, and help out one another? I know I'm dreaming, but it's a pleasant dream in which I get to ditch everything else and become an apprentice to learn and apply restoration techniques... and end up with a beautifully restored REPU!
Sounds like a number of us would have much to offer in terms of knowledge and experience...

       
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Fd3BOOST


Hauling
Posts: 114
posted December 17, 2003 02:07 PM

Thanks.
BTW,,, JESUS CHRIST!!! You have nine repus nwaco??

       
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nwaco


Redlining
Posts: 407
posted December 17, 2003 04:10 PM

Yea, why do you have one for sale?

...Like I need another. I know I have a problem, but in reality, I find it becomes easier to work on them.

By buying in "bulk", I can move parts around from truck to truck, I can remove, restore, fix, paint or fiddle with parts and then swap them out when I am done. I have three I drive to get my Yah, Yah's to keep me motivated and get to know the performance and handling while I work on the others. By disassembling several, I learn the differences between the model years and the basics of how they are built and assembled. I have a couple of clearly parts trucks, and I have three trucks that are under various stages of construction in two different shops.

I am rebuilding three 4 port engines now, I work them simultaneously so I save supplies and work processes. I rip them apart together, I bead blast the parts together, I buy the supplies at once, and I rebuild them together. I find it is easier and cheaper to do like processes at the same time.

I learned this process with all my sevens over the years. I have restored and rebuilt 36 of them now. As I collected the vehicles, I scooped the best parts for my chosen rides, and used the less than perfect parts for my sellers. As I got too many of the good ones, I trimmed the herd and since all I had left were nice ones, I got a premium for the ones I let go last. I find that on average, that I get a vehicle free for every 4 I process. I have only been into the REPU's for a little over a year now, and yes, technically I have 9, but two are serious shells now, pretty decent shells, but less than the rest.

All in all, I hope to end up with at least 6 very nice, not perfect or mint, but very nice drivable trucks. Believe it or not, final paint is always my last priority. As sick as it is, and especially being in my business, when I put a lot into a paint job to early, I take worse care of it, but those that are ugly, run like champs because I am all over them, and yank engines in and out because I never risk "scratching" my "precious" paint. Plus I get a kick out of taking my "beaters" up the freeway and tearing up the little ricer boys with coffee can tailpipes. They never know what hit them.

My present plan calls for 2 basic 4 ports, 2 street ported motors and a standard turbo II and one ported Turbo models.

How many I end up keeping? Who knows.....


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Fd3BOOST


Hauling
Posts: 114
posted December 17, 2003 08:34 PM

Thats pretty impressive.
I think my wife would divorce me first.
I got away with three rx7s and now this repu.
I would see FC's all the time around here that I would love to pick up but like I said my wife wouldnt be thrilled about that.


       
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Klaus43


Rotorhead
Posts: 1259
posted December 19, 2003 11:03 AM

Ken...

Might there be any chance you'd ever be available to do some REPU restoration, either in whole or in part, perhaps in exchange for another REPU...?
The pace at which you've gone from REPU-newbie to where you're at now is quite impressive! I've been too much the dreamer for too long... Your dedication and motivation is an inspiration!
Wanna start a REPU-resto biz together?

       
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Fd3BOOST


Hauling
Posts: 114
posted December 19, 2003 01:21 PM

LOL, Ken has a fan club. :)


       
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nwaco


Redlining
Posts: 407
posted December 19, 2003 03:19 PM

Yea, thanks guys, but....

I am up to my ears in work. I would love to have a resto shop and work on the trucks full time, but alas like most people, I got bills and family to deal with.

I've got to admit though, the wife gives me way more time on my projects than any of my friends can even dream about. In fact, my shop time has caused some neighbor friends some spats. They and the wife drive by and see me in the shop, with cars re-arranged daily, they trot out in their garage, and when the wife knocks them for not paying attention to the family issues, they pull out the "but Ken gets to do it" bit, and the shit hits the fan. I've told them never to say anything like that, because you know how wives talk. They could blow my gig.

She figures that as long as I am home, she knows where to find me. I don't go out, don't watch TV, don't give a hoot about sports, I'm just a shop guy who likes beer and tinkering.

In reality though, I'm not so sure REPU's could make a decent return. It seems the very nice ones go for 2 - 3K, and maybe an occasional 4K or so. With all the work they take, there is no room for profit. I make a decent return on sevens, but after so many, their not nearly as fun and interesting. I still work them to pay the bills and offset the trucks. (That's another thing, I buy the REPU's with seven profits, so as long as I don't spend the family money, she is good.)

Anyway, I chalk them up to a labor of love....and don't expect a profit.

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Klaus43


Rotorhead
Posts: 1259
posted December 20, 2003 02:56 PM

You nailed it!

It IS a labor of love... But then, would we be happier with a pile of money, or a fully-restored, super-nice hotrod REPU and a tank of gas? IMHO, BTW, I think that a totally completed, brand-new, fresh resto should bring around 5K... trouble being, it'd be very easy to spend twice that on it's completion.
Guess ya gotta love it!

       
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rotormunky


Redlining
Orlando, Florida
Posts: 424
posted December 20, 2003 05:17 PM

quote:
IMHO, BTW, I think that a totally completed, brand-new, fresh resto should bring around 5K... trouble being, it'd be very easy to spend twice that on it's completion.
Guess ya gotta love it!



My estimation is that I'll wind up with nearly 15k into mine all said and done. That's bearing in mind that I'm doing all the body work myself. It might be 1-2k less if I paint it myself, but we'll see how confident I feel about that after I shoot the primer coats :)

Figure a fresh engine is going to run you about what you can buy a really nice one for.

Then there's all the other little expenses that add up, PLUS the comsumables which most fail to factor in. I'll have spent nearly $100 just in sand, faceplates and blasting tips just doing my bed. Then there's the cab.

I'll try to tally my costs up to this point (including tools needed) and keep it up to date on my site.


____________
-Martin
Orlando, Florida

http://www.themonkeyhouse.org/REPU

'77 REPU (Some assembly required :)
'91 Cabrio (Battered and bruised, but she's still my baby.)

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nwaco


Redlining
Posts: 407
posted December 20, 2003 07:45 PM

It's not the money or "fair market value".....

that interests me. Sure I know a nice REPU is worth a few shillings, but it is the combination of obscurity, rareness, uniqueness, and downright coolness of the "rotary truck' that I enjoy. They are a collectors item of the future in my book.

I have acquaintences who in their macho-ism, proclaim that my REPU "isn't a truck" from the towering bench of their F350. But I always respond that "I'll bet them their truck, that I can return in an hour with an identical F350 "truck"", and they can't return within a week with a comparable REPU.

To make money, I have a job, and rebuild/sell sevens. To go really fast, I have my TII. For fun, amongst other things, I collect and tinker on REPU's. I won't make any money on them, but I will spend my time on something that is enjoyable and produces a product that in the end is nice, fairly rare, eye turning, and not easily replaceable.


It's just plain fun dammit.

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