Tub underside finish?

Getting about ready to put my tub back on the frame. I've read, researched and deliberated on the best way to finish the underside of the tub. I seriously considered U-Pol Raptor bedliner, but I'm wavering on that. For one, I don't think it's necessary, and it's heavy and is not fireproof, so I'm worried about hot exhaust. I will be shooting epoxy primer as the first layer, some of the underside is bare metal and some is still in the original factory primer. I understand epoxy primer is fully waterproof and wouldn't need to be topcoated. But should I topcoat it with a cheap urethane single stage for a little added protection? What about protection against stone chips? The Jeep was originally undercoated with a sticky tar-like rubberized undercoating, which certainly did protect it very well for 37 years, but I'm loathe to reapply that sticky crap after struggling so hard to remove it. What would you do? I see no need to paint the entire underside with body color urethane, as it will never be seen (unless I roll the Jeep, which I hope never happens!).

 

i have pondered the same idea. i also thought about "rhino lining" the whole cab. but i'm concerned about weight and looks. i didn't know that the liner wasn't fire proof. how much heavier do you think it is?? I'm definitely going to use a liner for the inside, just not sure about the rest. i just know i'm going to scratch the heck out it. That rustoleum looks like it will do the trick

 

I'm planning on using Herculiner...I think a one gallon can will do an 8 foot truck bed (don't quote me on that) so it'll be plenty for the underside of my Jeep....not sure about the heat resistance, but prolly they same as any regular paint. And a can only weighs a few pounds, and I don't think it gets heavier as it cures. Plus it'll help muffle rattles and such. There was one brand on Gearz they showed that has kevlar or something mixed in that's supposed to be super tough, too.

And you can paint over this stuff, so some hi-temp engine paint could be put where the exhaust is close.

 

Herculiner sucks. The PO used it on my Scrambler and I wouldn't wish it on my worst enemy. It has the texture of course grit sandpaper, doesn't stick worth a crap, and looks awful after about 6 months and is impossible to clean. In several places rust is bubbling up underneath the liner, so I don't trust its ability to seal the surface, either. The heat resistance is not the same as cured paint, these liners contain rubber, which will burn like an old tire if they catch fire. Fire isn't my primary concern, but why risk it by covering a Jeep completely in a flammable substance?

 

When you decide on an undercoating and ready to put the tub on give me a buzz. I'd love to help out.

 

Well that sucks if it doesn't seal worth crap......It seems to hold up well in all the work trucks I'm around and abusing.....I will hafta look into this, but either way I have a free can in the garage....somehow...

I definately need rust proofing, as I'll be damned if I hafta replace the floor and support again!!

But thanks for the 411, I thought this stuff was pretty great!

 

if you don't mind spending some money check this out

http://www.lizardskin.com/

 

I painted my whole tub with primer seal and acrylic enamel. I also seem sealed the seems before I top coated it.

 

Di you use just a regular automotive type sealer, like available at NAPA or whatnot?

I used chassis saver on my Flareside ford frame (3x fast) and that's held up to the calcium/salt/sand mix in the winter, the mud and dirt from the rest of the year, but that stuff cures with air, so once the can is open it'll harden up if it sets for a good while, unless you pour some thinner on top. But its a nice shiny black, unless you don't mix it good, then it'll be clear with a greenish tint...kinda weird.

But my Jeep won't see any of that stuff, only water will be from washes or if I'm caught in the rain, so I am gonna go with my Herculiner.......The coarse texture will help my welds look smoother I think with the proper prep it'll be fine....At least for my application....And its underneath, kinda hard to see going down the highway.

 

Prep is the key to making Herc stick. The places where mine has peeled up on my Scram are bare metal underneath. I think it sticks best to primer. I would either put it over epoxy primer or etching primer, or over well-stuck paint that has been scuffed for mechanical adhesion. I guess you can make it thicker, but it seems like the PO applied it extremely thin. It's like a layer of paint with chunks of rubber in it.

 

Thanks for the advice!!

 

I decided on U-Pol Gravitex over epoxy primer and seam sealer on every seam. Ordered the Gravitex today. http://www.autobodytoolmart.com/u-pol-gravitex-hs-stone-chip-protector-p-15137.aspx

I'll post some pics when I finish. It's a sort of crinkly, orange-peel finish that is supposed to be extremely hard and durable and protect against stone chips. It can be topcoated, so I will probably spray body color in the wheel wells rather than leave them black. Seems to be much more popular in the UK (and U-Pol is a British company, I think), but there are a few pics on the web of folks who have used it: http://1000fluffyclouds.co.uk/OurProjects/MorrisBlog/phpblogger.php?page=slideshow&id=1214259022

My hope is that it protects better than rubberized undercoating without the tarry mess and without the weight and expense of a bedliner type coating.

I believe Gravitex is similar to Lizard Skin only much less expensive: http://www.lizardskin.com/index.php