# EPDM adhesive



## Sembob (Feb 27, 2014)

Hi Jaredline, I have a fair bit of experience with EPDM. We use it in flat roof applications and it seems to me to be pretty durable stuff. I am not sure the chemical name of the glue we use but it is a Gen-Flex product. All the EPDM we use is a very heavy 90 mil. We use two different glues. One is for glueing to the wood sheeting and another for seams or laps. I think you would want the latter. It comes in one gallon cans. Also clean your boat and the new rubber with unleaded gasoline. After that it is pretty much like any rubber patch work, roll it on both sides then wait for good tack and starting from one end lay it on and roll it towards the edges to get a full adhesion. I bet most roofing supply warehouses will have the Gen-Flex adhesive. Good luck.


Jim


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## B4otter (Apr 20, 2009)

Any hypalon glue (Shore or others) will work, the EPDM is impregnated in the fabric and toluene (toluol - my spelling is bad pre-coffee...) is the thinner you want to use for cleaning and prep. I sure wouldn't put any petroleum-based product on ANY fabric used in boats - try it on a small patch and watch the results if you want to see for yourself. 
As for glue, the roofing glues are designed to be mopped or brushed on and some then are heat-activated (Sarnafil recommends this procedure, using a propane torch). It's just not as high quality a glue as the boating products, but it probably would adhere for wear patches - I don't know although I've thought about it with a Sarnafil distributor across street from where I used to work. Given what you're applying, might be worth a try depending on cost of a gallon of the Gen-flex versus a pint of Shore or any of the two-part glues. A gallon of glue will build an entire boat!
Whatever you use, pay attention to temperature and two or three thin coats way better than one sloppy one. Light sanding - not through to threads - using 100 or 120 sandpaper on both the boat bottom and the side of the patch to be applied. Clean all surfaces well, apply glue, let dry, apply glue, etc. When you have nice even coverage and both sides are just past tacky (you can touch and feel sticky but glue doesn't adhere) it's time to carefully lay down patch and roll flat, starting from middle/inside to outer edges. Roll with any rounded edge, try to work any bubbles out but if you've done a good job of layout and application there shouldn't be any - this is easy with small patches, extremely difficult with big ones like the ones you're wanting. But good news is that a bubble in a wear patch isn't fatal, while it likely is with any patch over a leak. 
Go slow, take your time, and don't apply the patch until you have everything like you want it. Best temps are 60-80 F, low humidity better than high, but we seldom get to pick those conditions. And stay out of the sun - UV or something can cause problems in addition to the heat. 
Good luck!


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## Sembob (Feb 27, 2014)

The glues we use we just use paint rollers and make damn sure to do very even thin coats. On the seams we use mini rollers. If it was mopped on it would fail. Never use a torch. That is all for some other roof system. Maybe hot mop? Not the EPDM we do. I just thought the roofing supply would have the same glues as the raft shops only a far better price. The gas probably works well for us because of how thick our rubber is and gas has toluene added to it. I actually think it is a by product of crude that is added back in after refining. Anyway straight up toluene is probably better. My only experience with EPDM is in the roofing biz. I have done lots of raft repair and other similar glueing jobs such as laminates and such and the glues we use now are not inferior. I bet they are the same thing. 


Jim


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