I have a recoil sensitive shooter in the household and am in the process of trying to make the recoil more manageable by adding a Limbsaver pad to a FAB stock.  The challenge is that the FAB stock uses a unique, proprietary attachment system that does not allow direct attachment of the Limbsaver.  What I have to do is glue the Limbsaver to the FAB pad.

I was able to track down another FAB recoil pad that I could use to experiment on.  I have also ordered a Limbsaver 1" thick, grind-to-fit, medium +, Speed Mount pad.  My objective is to glue the Limbsaver to the FAB pad.  My problem is I don't know what glue will permanently adhere the plastic at the rear of the Limbsaver to the rubber of the FAB.  If anyone knows for certain which adhesive will provide a permanent solution, please let me know.

The pictures below show the OEM pad to the left of the pad that has been modified to eliminate the "treads" to provide a flat surface to which the Limbsaver can be glued.




Here's the Limbsaver pad.  Note that the rubber pad is glued to a substantial plastic backing.  When I suggested to the folks at Limbsaver that I wanted to separate the rubber from the plastic and just glue the rubber pad to the flattened surface of the FAB rubber pad they strongly advised against it because the soft Limbsaver pad needed the reinforcement of the plastic to maintain its shape.  That's why finding the right glue to join the plastic of the Limbsaver to the rubber of the FAB is critical.




Unfortunately, I cannot directly screw the Limbsaver to the stock.  The picture below of the rear of the stock shows why.

"I know a guy who is recoil sensitive and winces when he he pulls the trigger on his 10/22"

It's ok to say you're recoil-sensitive.

Just messing with you. Anyway, if you're bonding rubber to a hard surface, I would suggest good old cyanoacrylate (Super Glue). If you're bonding rubber to rubber, maybe Shoe Goo, since it adheres, but retains the flexible properties necessary.

I wince just thinking about pulling the trigger.  That's because I'm extra sensitive and totally woke  Truth be told it's my wife.  She's no wimp, regularly competes in local Steel Man races, and has completed a full Iron Man race.  She used to shoot IDPA matches with me.  Somewhere along the way she injured her shoulder and it's uncomfortable for her to shoot any rifle with more oomph than a 10-22.

Super glue has the draw back of drying too quickly.  I need some time to be able to spread the adhesive evenly across a 5" x 1.5" surface and position it on the other surface.  One surface is rubber and the other surface is plastic.

I'm currently chasing down leads on 3M and Loctite adhesives.

It seems to me that the ground-down FAB pad would perform the same function as the hard plastic base of the Limbsaver once both were glued together. Gluing two like materials together is always easier and generally more successful than gluing disparate materials.
I understand Limbsaver warned you off, but their lawyers would become apoplectic if they were to say anything other than "don't do it".
I wouldn't hesitate to cut the base off the Limbsaver, grind it smooth (after freezing overnight, of course), and glue away. Worst case, it fails and you're out the cost of a Limbsaver. It's not like anyone's going to get hurt or the rifle destroyed.

I agree.

Can you use one of the LimbSaver slip on recoil pads on it?  That's what I did with my Beowulf.  It just slips on over the rubber pad on the Magpul MOE stock.  I couldn't find anything that really worked until that and it does a great job at taking the bite out of the recoil.

Unfortunately, the FAB stock and the Magpul stock don't share the same dimensions.  Your Beowulf is a beast.

I've had very good results with Gorilla Epoxy.  It comes in a big syringe that mixes the two parts as you squeeze.  

It works on all plastics except PVC, polyethylene and polypropylene.

If your pieces are ABC, PVC or CPVC then JB Plastic Weld is a great choice.  

I'd try the Gorilla Epoxy first.  That stuff works great.

Came here to suggest trying a slip-on Limbsaver.  I use one on a .45-70 single shot that has a curved metal buttplate, when shooting heavy 405 grain loads at 2100.fps.  That is elephant gun recoil level.  The pad really helps without permanently altering the stock.

They come in a variety of sizes.

Could 3d print a plate that will have the raised contours of that stock on one end and flat on the other, then screw limbsaver to that.

I would use 3M Black Super Weatherstrip Adhesive.

It's strong and flexible for gluing rubber to metal or plastic. Most Wal-Mart's have it for under $5 in the automotive/RV section.

If you have a napa auto parts near you go in and ask for some trim cement, the good kind in the red box. The adhesive should be yellow and it really works. Had a piece on dad's car kept coming off put this on and never had a issue after.

Thanks to everyone for all of your suggestions.

FWIW- For people who are severely recoil adverse, I have found the problem is usually NOT resolved with the addition of a recoil pad. I have found the solution is more often found with a proper fitting stock, change in hold or stance.

Adding another recoil pad is also going to increase the LOP which may make the situation worse.

Just something to consider.

looks like the same limbsaver pad Remington used on some of its rifles maybe a decade ago...   they are soft, too soft and start to tear with only moderate handling.  Plus I had a gun in a silicone sock and it reacted with the pad and started to melt it.

You take off that backing and I wouldn't be surprised if the turned into a blob one step above silly putty...

THE CONCLUSION

I finally had enough of researching every adhesive known to man and grabbed a tube of E6000.  I figured in the event of the worst case scenario (things didn't stick together) I could remove it easier than anything else.  I smeared a layer of the stuff on the plastic plate of the Limbsaver and on the rubber surface of the OEM pad.  Then I clamped them together and left the assembly alone for three full days at the end of which I set about shaping the Limbsaver to match the outline of the OEM pad using a bench belt sander.  I didn't do a terrible job and comfort myself knowing that there was no good way to attach the assembly to my Miles Gilbert Recoil Pad Installation Fixture.

Bottom line.  The E6000 worked.  The Limbsaver is very soft and pliable.  Launching 12oz projectiles no longer feels like a 3" Magnum 12 gauge.

Here's a pic showing how it turned out.  You can see the glue line between the plastic plate of the Limbsaver and the rubber of the OEM pad.  I may get after that with some sandpaper.  The fit between the two is actually very close.  The glue is just what slopped over onto the exterior of the OEM pad.



Many thanks to everyone who offered their suggestions.