Pro Roofers-question about EPDM-Not OT

I want to recover a set of running boards on my '37 Buick. I've searched the HAMB and posted on the subject a couple of times looking for ways people have recovered their running boards. Pretty much everything I've found is about using running board matting found at the restorations suppliers or rubber floor mats. I want something with a more pronounced ribbing than the running board matting being offered. I also want something a little thicker.

I have checked out pickup bed mats. Some have wider ribbing and are thicker but their ribbing is continuous and would ride up the side of the running boards, the part that goes under the body of the car and still would be seen. I think it would look like I used a pickup box mat if I used one.

I also know there are a couple of places that will vulcanize rubber onto the boards like they were originally done. The problem there is the price, about $1000 plus shipping two ways. Not in my budget. I also would like to find a way of doing them myself.

Here is my question for professional roofers. I know there must be a couple that frequent this board. I was surfing the net and found a page on Bob Drakes web site talking about their running board matting and they said they made them of EPDM Rubber. I search some more and found EPDM rubber is used for flat roofs, both in sheet form and in a liquid form. The stuff seems to be pretty rugged and might be able to be used for coating running boards.

This is the finished look I want to achieve:



I am thinking of one of two ways to do it. First, just rolling it on and letting it dry. I thought I might be able to achieve the ribs by masking off the low spots with thin wood pieces wrapped in duct tape or some other material that EPDM won't stick to, applying a few coats of rubber to build depth, letting them dry, remove the wood and then recoating the entire board to achieve the ribs.

The second way would be to make a form out of MDF particle board with grooves routered for the ribs and then pouring the EPDM liquid rubber into the form, letting dry and peeling the covering out and gluing it to the running board.

My big question to the roofers that have used EPDM liquid rubber is how long does it take to cure completely? It's a two part product with a catalyst. Does it become relatively firm, will it take being stepped on repeatedly? Does it stay soft and plyable? From what I've read it fairly chemical resistant and can take UV rays. I figure it has to be pretty good stuff if it can stand being on a roof night and day, below freezing and desert heat.

 

I work in the roofing trade so let me see if I can shed some light on your situation. A EPDM system is generally used on a motorhome, rv or commercial application. It's supposed to be more enviromentally friendly than the standard built up roof system (asphalt, base, ply and cap sheet) and still meet current energy star codes.. Even when applied in these applications it's not considered a walkable deck. Meaning it' will always have some tackyness to it and not form a solid bond. The roof it's applied will expand and contract during the day from the heat and cooling cycling. It has to remain somewhat tacky or it would eventually just crack up.

So my first thought would be that if you're actually going to use that step to get in or out thats not the way to go. You would be better off spraying it with a Rhino liner bed seal process. It has all the UV properties and will completey harden. If scuffed up you can apply a color matched paint right over it and you're like new again.

 

Thanks, that's exactly what I wanted to know.

 

Make a female mold from fibre glas, spray in a heavy coat of bed liner. When it sets pull it out an bold it to your running boards.