I enjoyed reading through this thread and it was the inspiration for repairing my RollerGames ramp as shown below. A few more details are on my RollerGames webpage at... http://www.jeff-z.com/pinball/rollergames/repair/repair.html
This was one of the worst ramps I've come across. The floor and both sides of the ramp entrance were blown out. The flap was attached to the ramp with some sort of stiff adhesive-backed plastic. The rivets were gone and all the ramp material beneath the flap was gone. The ramp sort of worked, but its flimsiness was absorbing too much ball energy. Aside from the entrance, the rest of the ramp was solid.
My starting point...
I made my repairs with sheets 0.060" PETG and SCIGRIP Weld-On 3. Both were had through Amazon. The PETG was by SIBE Automation and came in packages of 5" x 5" sheets. This was a popular size that had something to do with dentistry. Larger sizes were available, but the 5" x 5" pieces were handy to work with.
First I cut up some PETG and experimented with the Weld-On 3. Go to YouTube for some Weld-On instructional videos and note that the work has to sit for 24 to 48 hours to strengthen. Lap joints were fairly indestructible. Butt joints weren't so good. Corner joints were iffy. I tried Weld-On 16 thinking it would make more of a fillet at the corner joint. No such luck. My Weld-On 16 experiments were weak. All my ramp work was done with Weld-On 3.
A few of my PETG experiments...
Thinking I might need some corner reinforcement, I made some PETG angle stock. Using a heat gun, I gently warmed a piece of PETG and tightly formed it over the corner of a piece of aluminum angle stock. Once formed, it could be cut to any desired length and width. I also laminated three sheets of PETG and cut some strips of PETG "bar stock".
I used a band saw for most of my cuts. This might seem like overkill, but the saw was so powerful relative to the work that the work was super easy to control. I used a thin piece of plywood as a poor man's "zero clearance insert". A lot of tedious filing and sanding was needed to get some parts to their final shape. Emory board nail files worked well. The edges of each piece of PETG should be as smooth and square as possible. The more contact area, the better the joint. Weld-On 3 is a solvent (smells like Bondo) and has zero gap-filling ability.
One more preliminary experiment... I swept up some PETG "sawdust" and used Weld-On 3 to mix a batch of PETG paste. I used the paste as a fillet material for a corner joint test. My sawdust was contaminated with dirt and I wasn't careful with my application. Nevertheless, the joint was strong yet somewhat pliable. In the end I didn't use the paste or my bar stock for the ramp repair.
Okay, on to the ramp. First I discarded the plastic thing that was holding on the flap. I needed room to work so I used a razor blade to partition two of the ramp decals. Then I carefully removed the decal pieces with a heat gun. I used naphtha (lighter fluid) to clean the ramp and remove any decal adhesive. I used a razor saw to cut about a 3/8" strip of old material off the ramp floor. This gave me a straight edge to work with and ensured that my flap rivets wouldn't fall on the joint between the original ramp and a new piece of PETG.
Removed decal pieces...
Removed strip of original ramp floor...
Since lap joints worked best, I took a layered approach to this. My first piece of PETG was a sort of "sub-floor" to provide a lap for the main floor to be added later. This piece was also to support some hairline cracks in the old portion of the ramp. The piece was oversized, but trimmed later. The piece was positioned with lots of clothespins to conform the new piece to the shape of the old ramp. The Weld-On 3 came with an applicator. I touched the applicator to the edge of my piece of PETG and capillary action sucked the solvent into the lap joint. Then the hard part was to walk away for two days and let the joint strengthen.
Clamping the "sub-floor"...
Next I removed the clothespins, flipped over the ramp and applied more Weld-On to the opposite seam as well as to the aforementioned hairline cracks. There's a skill to using the Weld-On applicator which was explained in some of the Weld-On YouTube videos. Too much Weld-On may cloud the work, but I was more interested in strength than appearance. I also learned that too much clamping inhibits the capillary action. It's better to leave a bit of wiggle room and then firmly clamp after the Weld-On 3 has fully penetrated the work. Joints tack up pretty fast. Clamping was unnecessary unless a part had to be held to shape.
Shown below was a test fit of the sub-floor. I've marked for the flap so I could trim clearances for the rivet washers. The Sharpie marks could be removed with lighter fluid which was what I used to clean the parts before applying the Weld-On 3. A motor tool with cutting disks and drum sanders was good for rough trimming.
Sub-floor trimmed to clear the rivet washers...
Next I applied the new floor piece (and walked away for another two days). The new floor was a few thou thicker than the original floor, but not enough to create a hang-up or impact ball trajectory.
As can be seen in the picture above, there was a "pothole" on the right side of the ramp just above the new floor. The sub-floor covered the hole and I could have left it as it was. But I decided to fill in the hole. I made a pencil tracing of the hole. Using some spray adhesive, I applied the paper to a piece of PETG before cutting out the patch.
Pencil tracing of the pothole...
Rough cut of the patch. The PETG piece still had its protective film in place...
The picture below shows one of about a dozen test fittings for the new floor. I've already trimmed around the red post, finalized the shape of the leading edge and drilled for the playfield mounting screws. Next I marked and drilled for the rivet holes.
I used a motor tool with a drum sander to grind away all the jagged edges from the broken right sidewall. Then I riveted the flap back in place. I installed the flap at this stage of the repair because I wanted to see the final curve of the floor before I began fitting the new sidewall pieces. The sidewall pieces were shaped and applied with the ramp in the game.
Flap riveted to the new ramp floor...
I used a piece of cardboard to trace the opening in the right sidewall. I used the cardboard as a template to cut a PETG piece to fill the opening. This was the inner layer of PETG to be installed later. I used the inner layer as a guide to cut a larger outer layer of PETG to be applied outside the opening.
The sidewall opening traced onto a cardboard template...
Right sidewall inner layer...
Right sidewall outer layer...
The picture below shows the outer sidewall piece applied. The picture also shows why I left extra floor material. I had enough outside clearance to install some outside corner bracing using a sliver of my PETG angle stock. I trimmed all these layers to an even line after the joints solidified. This area was too tight to use the Weld-On applicator. Instead I used a small modeling brush which was (I assume) made from some sort of Nylon. There was no reaction at all between the Weld-On and Nylon
Right outside corner bracing...
Right sidewall inner layer applied...
Next up was the left sidewall. There was less clearance on this side of the ramp due to the Pit mechanism. I used more of my PETG angle stock with the angle stock lapped under the ramp floor. I beveled the bottom of the first piece to get it as close as possible to the ramp entrance. I added a scrap of parchment paper under the PETG piece to protect the playfield from the Weld-On 3. I used a stick to brace the curve of the wall while the joint set. Since this ramp corner was a compound curve, I used multiple short lengths of angle stock. I also hit that left sidewall rivet with a drop of Weld-On which was drawn into the cracks.
I applied a total of four angle stock segments to the corner...
The left sidewall was mostly intact. I only needed a small inner sliver of PETG to fill a narrow gap between the original sidewall and the new floor.
I believe these repairs will prove durable although I'd have to qualify them as "pretty ugly". On the other hand, I've seen worse looking epoxy jobs. A friend suggested I reapply the decal over instead of under the ramp. First I scanned the decal as a backup. Next I covered the top surface of the decal with a protective layer of Mylar. Then I applied the decal with 3M 467MP transfer tape.
The right sidewall repairs were largely concealed behind a RollerGames Cliffy Protector. The left sidewall repairs were mostly hidden by the Pit mechanism. In fact, the whole ramp entrance was conveniently tucked away behind the Pit and associated habitrail.