Undercoat question...

[planovet]

Got my trailer last weekend and I'm planning on doing the floor this weekend. I'm leaning toward epoxy for the bottom over the black goo. I've read that some on this site have used the CPES from Rot Doctor. Is the only place to find that product is from their website? Can it be found in retail outlets? Is there a subsitute that works just as well that I can get at a big box store or the local hardware store? When I was picking up some Bondo I noticed that they make a fiberglass resin. I looked on the back and it stated that it could be used without the glass in thin coats for coating. Anyone use this? Also, while I was at the store I noticed an aluminum roof coating in a gallon can. I wonder it it would work like the black goo. Says it leaves a shiny coating.

Thanks in advance...

[Steve_Cox]

Well Doc,

The plastic roof coating is used for a couple of reasons. One being a traditional method used in the Kufflel Creek cubbie plans. The other reason is for the perceived impact resistance the thick goo provides. Some use epoxy, others CPES available from the Rot Doctor. So it is up to you how you want to proceed. There doesn't seem to be any empirical data to support any one method. I like the black roof coating rolled on with a foam roller. It gives an undercoated look without the expense of undercoating.

[madjack]

...do not put the epoxy over the black goo...with black goo, the epoxy is not needed, if you wish to use both, epoxy first to seal the wood and THEN the black goo to protect the epoxy!!!!!!!!!...CPES is a proprietery product of the RotDr and can only be had thru them...it is essentially an epoxy resin with a lot of volatiles added to make it thinner and penetrate better...ANY epoxy could be used and work just as well...the resin you found at the box store is a polyester resin...it is not as forgiving as epoxy and does not seal as good although multiple coats will work good enough...for epoxy, I would recommend the non-blushing product from www.raka.com ...I wouldn't recommend the polyester resin for much more than the occasional patch
madjack

p.s. the fiberglass cloth is only needed where strength is an issue...sealing the bottom is a "don't sweat it" area...ANYTHING that will seal the ply is fine...the bottom is to exposed to elements like the top is and is only exposed to moisture when driving in the rain(it does need to be sealed however)

[TPMcGinty]

I used this asphalt based paint I got at Tractor Supply for $9 a gallon:

http://www.tractorsupply.com/webapp/wcs/stores/servlet/ProductDisplay_10551_10001_43986_-1______?rFlag=true&cFlag=1

It dries hard, black, and shiny. I decided to use it because I didn't want to deal with the Goo and I figured if it's good for fence posts that you drive into the ground, it should work for the bottom of my tear. There are stores in Texas too.

[planovet]

Madjack, I didn't mean placing epoxy OVER the black goo. That would be really messy! I meant I was leaning toward the epoxy VERSUS the black goo. Bad choice of words on my part. Sorry..

[madjack]

...I added more to my response and the product that TP used is an excellent choice as well.......................................

[planovet]

Thanks Madjack for your advice. Maybe I'm overthinking things. Now I'm leaning back to the back goo or asphalt fence paint.

This forum is such a great resource!

[ArtMini]

years ago when customizing an old van I used drive way sealer to undercoat the entire underneath of the van. It was cheap and did a good job of covering everything. What do you think?

Art

[johnb]

I'm at the same stage as you planovet - I got some of the epoxy from the rot doctor and put it on the bottom - seems to be kerosene mixed in to help soak in. I did it outside in a reasonably windy spot and still got too many fumes.

I'm still terrified of getting the bottom plywood wet - I worry that the protection will not be tough enough - a few rocks could bounce up and scrape the bottom and a few puddles later the mold or rot will start. So I just got some ashphault emulsion (Henry 107) from home depot and will give a heavy coat on top.

Of course I'm overbuilding everything so this may not really be necessary but I figure it is a lot easier to overbuild than repair.

[looped]

i used zinzer oil based primer sealer then used a couple cans of rubberized automotive undercoating.. being aerosol it made clean up a breeze.

[Arne]

Any of the usual road stuff hitting roof coating on the tear under side will have no effect on it. Actually, after thousands of miles on all kind of roads, the bottom of my trailer, after 4 years, is like brand new. I used the roof coating from h/d... and just threw the brush away when I was done...

[johnb]

looped - I tried the rubber undercoating from automotive stores on the wheel wells, hoping this would be a bit tougher - seemed like good stuff, it dried really fast without a lot of stink as well. I found it hard to get full coverage, it took a couple tries and thick coats to get to the point of no metal showing through gaps. Probably the brand I used.

Anyway, looking to roll or paint on the bottom layer just to make sure it is all covered.

Anyone have thoughts on how long it will take for the roof stuff to be handle-able? I'm dodging rain here (usually not a problem here.

[Arne]

roof coating has some volatiles in it, meaning, it dries reasonable fast. I think mine only took a day or two before I could handle it... it will still take a thumb impression, but it has a skin on it by then.

I actually turned it at that point. I wanted it to seal to the frame without a gap. doing it while it was still a bit soft accomplished what I wanted.

[planovet]

Well, got the floor finished yesterday and went with the roof coating stuff from Lowes. I Bondo'ed all the seams and screw holes and then painted on a coat of the black goo. I was pleasently surprised on how easy it was to apply and how well it coated. Temps were in the high 90's yesterday so the part I started on was almost dry by the time I worked myself back around to it. I have half a can left so I think I will add another coat this evening.

I want to thank everyone for their help and sharing of their knowledge.

[jdaan]

Any one out there just use ext. paint? Roof tar just seems like overkill for the bottom of a tear. Any stories?

Justin