OK,I have one bar "mostly" installed but only 1 screw of each mount hit solid wood. We all know camper paneling is tissue thin... The second grab bar/towel bar is to go inside the shower unit, one layer of thin plastic over the same partition. The partition measures 3" thick or a tad less subtracting for the corner trim. I thought I'd just bolt on through, backing block & acorn nuts on the other side... but the grab bar base is countersunk for tiny (but long) screws #6 I think. I'm sure in a house, wall anchors would be used.The hardware stores seem to stop at 2" lengths... I was hoping for 3 1/2 to 4". I'm not finding them on line either. I know I could carve a big ___ hole in the partition & install a solid plank to screw to... but after 6 months of mouse combat & the resulting destruction/reconstruction, I'm not sure she'd speak to me again.So, I know there are lots of smart guys here... IDEAS Gentlemen?Thx, Russ

In instances thru the years we have had attach a board to the wall studs and then attach the grab bars to that. If you are putting one in the shower you need somthing that will work better than wood though. Maybe a piece of 1/4" aluminum flat stock. Drill and tap some holes for machine screws to attach the grab bar and then bolt the flat stock to the wall.

Sorry, Forgot to mention the shower wall has some ridges in it. I've found some on-line sources of bolts to 3". I'm going out with a dial caliper & a pad to do the math... to see it I can make it work. Too freaking close to call.

Like you said Luan panelling is very thin stuff. The big problem is this grab bar has to be capable of holding weight while fastened to Luan panelling. So to keep if the ripping apart I would either increase the size of the bases or carefully open up the wall and add a full length stud. But even on the increase size the bases you'll still be pulling hard on the upper fasteners almost like you need a good size backing plate on the other side of the wall. I'll keep thinkin'

The first bar is verticle on the partition against the edge of the shower splash & caught the framing of the partition on the edge but the other 2 are just in the paneling. I was hoping to bolt though & just put big fender washers on the other 2 on each verticle base.On the horitontal bar, I can find no framing. I figured to install bar #2 horizontal, cutting the bar to length to miss the ridges in the splash. My original idea was to bolt through and put a hardwood block on the sink side to spread the load across the whole partition. I took my dial caliper to the partion. The countersink in the base takes .165" The net thinkness of the partition is ~2.77"... with no allowance for the shower splash which I have NOT got a measure on. So I am darn near 3" with no allowance for a board or the nut. Reccessed nuts have entered my mind... I don't have any at hand... maybe I could find / hand make such nuts. I'd rather not make a big project out of simple nuts.

I needed a grab bar to help me jump down from the back door of our camper. It had machine thread studs. One on ea. end of the bar. The studs were too short so I just drilled the holes to fit snug to the fiberglass body and squirt about a fourth of a tube of Vulkem in ea. hole. Lots of caulking pressure squeezed in there using the tip. Next I stuck the grab studs in their holes and left it undisturbed for a month in warm weather. Been there for about 10 years now and use it all the time.I think it would be better to use a big glob of epoxy squirt in the holes instead. The builders supplies have epoxy in the big tubes for a caulking gun. You could let it set up before tapping for the wood screws rather than what I did, just sticking it into wet caulking.

I found some 3.25" SS machine screws for almost $4 each, with 10 required! Sheila rejected that plan.I can't believe that Sheila suggested cutting a hole in the partition to install a block of wood as a backer board. I had rejected that idea as too destructive. Oh, wait, she expects me to make the hole pretty! I can just see working a board into the partition & then DROPPING IT! I'm thinking, drill through (long drill) the partition to mark the area. Work a block of wood in & screw bar in place. Cut an over sized trim board to overlap the edges of the hole, screw in place. Back to the trailer to measure...

Dang I wish I could see what you wall looks like... What make and model of RV do you have again?

2001 28' Thor TranSport

Is this it?

Yes, that's it... the sofas & rear bed, were gone before we got it. There's a shallow cabinette behind the toilet that I opened up & added shelves/doors. I'm working on the tub side of the partition, backs up to the sink area as pictured. I have to go below the medicine cabinett.

That is a PITA... I was hoping you had a wall that you could say peel open and add a stud to. But with cabinets on one side and tub on the other just ain't happening easy. I heard of several people managing to peel open walls and adding studs for there new flatscreen TV's. Easy no... But it can be done...

I managed to separate the tub splash... but just a finished wall, smiling back at me. I drew a line from the bottom of the medicine cabinette around to the tub, leveled it & screwed the bar into the shower. Just the first 2 upper screws to hold it in place. When I pull on it, I can see the whole wall flex. I'm really inclined to just screw it in, fix it if it ever strips out. I know 6 screws into paneling... but 2 screws are stronger than the panel. The way to fix it might be to remove the tub surround, open the wall behind it & reinforce it. Reinstall the tub surround, covering the violence.A "quick & dirty" might be to spray foam into the wall through the screw holes & see if it sticks to the back of the panel enough to stiffen it. I have no idea if it would work. The nozzle won't go through the #6 screw hole, I'm sure.

If you know where the solid wood is can you run some unistrut or something to it then bolt the handles to that? Might look cheesy but maybe you can fancify it.

EDIT: I HAVE found 1 verticle "stud" I suppose in the middle of the wall section. No where near where the grab bar mounts. I suggested to the dear wife, that I just screw to the wall & pray I never need it. She said "No Way!" OK, after dinner, we go out to the camper to inspect (when I located the stud). I suggested removing the tub surround as it would conceal butchering the wall. She says "No Way!" She suggests bolting through the wall again & I remind her the (SS #6 x 3.25") machine screws were $4 each... and iffy if they would reach. She threw up her hands & said screw it (to the wall, I think she meant).