Adhesive Recommendations for Running Board Mat?

[Guest]

Which adhesive works best for bonding rubber running board mat to flat, new running boards? I'm thinking about spray on 3M Super Trim Adhesive. It is used for vinyl tops among other things. Your experience appreciated.

[jpage]

When I worked for Restoration Specialties we always recommended using a good water proof contact cement used in construction with laminates. You must first clean the rubber well with a cleaner like xylene, lacquer thinner or similar to get off all traces of mold release.The back of the mat must be roughed up with a heavy grit sandpaper for optimum adhesion. Also, the board itself must be thoroughly cleaned and roughed as well. If the mat has a silicone rubber composition it may not stick well with any adhesive. After applying the adhesive, according to the manufacture's instructions, roll out the mat with a hard roller like a rolling pin to make sure the adhesive makes good contact and clamp down any curved areas that may want to pull away. 

Edited June 20, 2016 by jpage (see edit history)

[Guest]

5 minutes ago, jpage said:

When I worked for Restoration Specialties we always recommended using a good water proof contact cement used in construction with laminates. You must first clean the rubber well with a cleaner like xylene, lacquer thinner or similar to get off all traces of mold release.The back of the mat must be roughed up with a heavy grit sandpaper for optimum adhesion. Also, the board itself must be thoroughly cleaned and roughed as well. If the mat has a silicone rubber composition it may not stick well with any adhesive. After applying the adhesive, according to the manufacture's instructions, roll out the mat with a hard roller like a rolling pin to make sure the adhesive makes good contact and clamp down any curved areas that may want to pull away. 

 

Great tips! Thanks.

[Friartuck]

How about asking the source where you purchased the rubber mating?? I would investigate a thicker type of adhesive, one where it can be troweled or rolled onto the surfaces. Perhaps a mastic adhesive?? Keep in mind, this will get hot in the sun. The above surface prep sound reasonable.

[ckowner]

I tried a good contact cement but it did not seem to do the job. A floor layer recommended a 2 part epoxy glue from a floor supply store. It worked great!

[jpage]

With rubber, especially a silicone based rubber which is used in much of the products out there today, proper prep is a must. All real rubber  products have a mold release agent present that must be removed. Usually you won't find that true in foam extrusions. Also, no adhesive will adhere well to a shiny smooth surface, rubber or paint. Actually, you'll get the best  adhesion to raw steel rather that painted metal.  You might also try an  adhesive like Liquid Nails, only make sure that it's waterproof.

[Guest]

I appreciate the input. One thing I have strong reservations about is the idea of not painting the running board tops. They would certainly rust under the mat, causing blistering and lack of adhesion, not to mention the damage to the running boards themselves.

[Spinneyhill]

If you paint the running board tops, the mat is stuck to the paint. That is usually a good way to get lifting. If the glue is waterproof and the mat is non-porous, there should be no rusting. You might even put a metal prep on it to provide some resistance.

[trimacar]

The running board tops should be bead or sand blasted, then painted with an epoxy paint such as DP-90.  Once epoxy paint is on clean metal, you can glue to it all day long.  Contact cement will work in this application, but you have to make sure the cement is fairly dry.  If you leave any "wet" under the rubber, it will vaporize and cause a bubble, which is virtually impossible to get out without ripping rubber off again.

[Guest]

2 hours ago, trimacar said:

The running board tops should be bead or sand blasted, then painted with an epoxy paint such as DP-90.  Once epoxy paint is on clean metal, you can glue to it all day long.  Contact cement will work in this application, but you have to make sure the cement is fairly dry.  If you leave any "wet" under the rubber, it will vaporize and cause a bubble, which is virtually impossible to get out without ripping rubber off again.

 

This is where I'm at now. They've got DP90 on them. Waiting for the mat to arrive...... These running boards have many holes drilled in them - the originals were duplicated exactly. I/m thinking perhaps this was to allow adhesive to lock into these holes much like plaster and lath forms a "key."

[Spinneyhill]

I always thought they were originally cast directly onto the metal and the holes were to provide a key?

[jpage]

You say that your boards have many holes in them. You didn't say what year or make you're working on .Many board mats, especially in the '30's were moulded around a steel core with fastening tabs. The tabs fit into the holes and were twisted to lock the mat down so the mat could be easily replaced if need be. If you are just going to glue an ordinary replacement mat down you may have to fill the holes so you won't end up with a bunch of dimples, which will happen later. Some mats, usually the plain, straight mats would have been glued or vulcanized to the steel board. I really don't know if many mats were actually moulded to the boards from the factory. Most of the new repro mats are now simply moulded over the entire board.

[Guest]

 The task is completed, and I felt that I should follow up. I appreciate all who took time to post and share their ideas/experiences. These running boards are for a 1931 Cadillac 355A. I had to have them made, and the fabricator did an excellent job. They are exact copies of the originals, minus the rusted out areas.   They are flat. After a thorough cleaning with wax and grease remover they were sprayed with PPG black epoxy primer. The tops were sanded with 320 grit paper to provide some bite without removing the primer down to bare metal. The bottoms of the rubber mats were cleaned with lacquer thinner. The adhesive used was 3M Super Trim Adhesive spray. It is for use on heavier type materials such as vinyl tops. Instructions call for two crisscrossed coats on both parts, and then wait at least 5 minutes before bonding. You will not be able to slide or easily remove the mat once contact is made - this stuff is strong. I had a helper who helped me locate the mats properly. We held them almost on edge and initially just stuck them along the straight outside edge of the running boards and then rolled them towards the inside edge. Two clamps were used and then bricks were laid on top of the mats overnight. The mats seem to be bonded very securely. These particular running boards are finished off by 4 stainless steel trim strips around each of the outside edges that overlap the mat by about 1/4 inch. The thing I liked best, was no mess, lol. The spray glue ( at least to me), is much easier to work with than something that is rolled or brushed on, and I had no problems with any kind of lumps forming. I am fortunate that these are simple, flat running boards as opposed to those that have rubber mats that are formed.

Edited July 27, 2016 by Guest (see edit history)