Foam/paste that can be injected into a hole and when it hardens, it's as strong as hardwood?

Submitted by flying-benedictus t3_xxcupw in DIY

I don't know if such material exists in an affordable way today, or how to look for it. Most stuff I have found so far are either too brittle or soft when hard, or epoxys that are sold as such small quantities that would be very expensive at the amount I need (around two deciliters).

The situation I have is a hole in a plasterboard wall, to which the end of a staircase railing has to be attached. When people pull part of their weight using the railing, it generates quite some side force, and the hole in the plasterboard is already damaged from failed attempts at fastening the railing, and the hole is around one inch diameter. There's something metalic with a hole of around 0.8mm behind the plasterboard, but there's no way to put a nut behind it, and screws won't attack firmly around it, because it doesn't have a proper thread). But if I could inject some kind of putty between the plasterboard and the metal, that when it dries acts pretty much like a piece of moderately hard wood (beech) then I could just screw it to this.

I know there are screw plugs for plasterboard, including chemical ones that have something similar to what I say, but these assume the plasterboard is not ruined into a big gap like in this case. It's not an aesthetic issue because the end of the railing hides the gap, but these screw plugs don't have anything nearby to grab on. That's why I need something like two deciliters of a putty that extend way beyond the gap behind the plasterboard.

Edit: From my description it may sound like there's a safety issue, but there isn't. The rail just makes a 180 degree turn at the end of the stairs, and the gap down to the lower floor is just 5 cm wide.

Also, the problem is that I don't have access to a wood stud. What I have behind the plasterboard is metal, with a hole of around 8mm wide. The owner tried to use a screw into that hole, but there's no proper threading so it eventually gave in. Now it's loose for a screw of diameter 8, and way too small for the next size 10. I could try to make holes bigger to use a 10, but: it would push the limit of how big the hole in the handrail can be, and potentially ruin the very expensive welded handrail, and creating threading in the metal behind is very difficult and would probably get ruined like it did for the 8 screw.

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DriedChalk t1_irbd5fe wrote

I feel like the railing should really be attached to something more secure than the plasterboard

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bms42 t1_irbe2gz wrote

I think you're looking for the wrong type of solution here. The proper fix for a railing is to remove some of the plaster, add additional wood framing to create a strong anchor point, then repair the plaster.

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SchillMcGuffin t1_irbe7ry wrote

Replying to DriedChalk (#46,622)

I agree. I had a similar railing (in a house constructed in the mid-'70s, I guess anchoring railings in drywall was the style back then), and I cut a portion out of the dry wall to put a cross piece between the rafters behind it, then anchored the railing to the cross piece and restored the drywall.

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icosahedronics t1_irbgk90 wrote

sounds like you first need something for bulk. make a cement paste using epoxy and bits of another solid material, such as old bricks or stone.

for the other issue where you can't get a nut on the backside, there are commercial products which use a plastic screen to form a plug on the backside of the wall material, which you can also improvise. (example: https://www.strongtie.com/screentubes_adhesiveanchoringaccessories/optimesh_screentube/p/opti-mesh-adhesive-anchoring-screen-tubes)

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littleMAS t1_irbpflj wrote

If the properties of the 'fix' are stronger than the things being 'fixed,' the stress just moves outward, which might later be a bigger problem. I rely on strong railing, as it might need to support a lot of unsteady weight. Try to find studs to anchor, even if it means additional anchors.

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bananabreadvictory t1_irbtp6z wrote

You can't attach a handrail to drywall, you need to either find a stud in the wall or open it up and install bracing that spans the two studs.

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John5247 t1_irc0fyj wrote

Cotton wool soaked in super glue . Hard as hell can be drilled and tapped.

−4

SirGlenn t1_irc3enx wrote

I used to cut a piece of plywood slightly narrower than the hole; then cut the ply wood, or solid wood works too, to a length longer than the hole, put the ply behind the sheetrock, put a screw partway in the wood where the missing rock hole is, slide this behind the sheetrock, hold it by the screw in the hole tightly then screw through the surrounding rock board with enough screws to hold it all in place, it will be stronger than the original wallboard in that area. It works like a charm. And for homeowners who have a heavy picture to hang, they now have a place to hang a heavy picture as you now have a section of drywall with a backing of plywood.

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maize4dinner t1_irc3xbd wrote

There's cans of spray foam for filling cracks and stuff. No it's not as hard as hardwood but that's kind of asking alot. It is pretty firm though. Probably not good for the application you want it for though

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deeperest t1_irc753i wrote

Replying to Hey_look_new (#47,650)

> if it seems like it's too much work and too costly, it's probably the correct renovation

This is especially if true if THIS renovation will require three others to be performed at a later date.

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seventh_skyline t1_ircfrd5 wrote

Milliliters. 200 milliliters. It's not that much volume.

0.8mm? so less than 1mm? or do you mean 8mm?

Aside from the random metric measurements - the others are onto it with doing it the right way.

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SaverioJames t1_ircgg80 wrote

I had this same issue for a single point on a longer railing, so I used a toggle bolt. They have wings that are spring loaded and expand once they get past the wall board, then you can tighten as needed. They’re basically like trying to put a cat in a carrying crate. However, I only did this because it was one of many points on the railing. If the whole thing wobbles, I wouldn’t bet my life on it.

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Kraymur t1_irckgdv wrote

You want to attach the railing (that people put weight on) to plasterboard? put some wood up and anchor it properly.

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fangelo2 t1_irclf3p wrote

The only thing worse than no railing is a railing that is not securely anchored. You must find a stud to screw it to or cut out the drywall or plaster and secure some wood backing between 2 studs.

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madmax_br5 t1_ircn0f5 wrote

Sounds like you may have metal studs. Try a self-tapping screw first and see if that grabs. Then patch the hole with high strength patch. If the self-tapping screw doesn't work, drill a larger hole and use a plywood backing piece as others have suggested, then patch the hole.

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RogerRabbit1234 t1_ircp2v3 wrote

You have to attached railings to studs. Don’t bother with anchors or toggles, it just won’t hold up to the wear and tear that railings are subject too. And I’m not the guy who tells people they must hang a TV in 2 studs (one is plenty). But not true with railings, if not in a stud, it will come lose, no anchor or toggle is secure enough in plaster to suffice.

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PositiveNegitive t1_ird5son wrote

Replying to AlienDelarge (#49,092)

While it's not right I don't understand OP's epoxy problem, you can buy 1L of epoxy at any old hardware store right, you don't need to squeeze out 100 that you bought from the super market....

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John_B_Clarke t1_irdca8q wrote

You can get epoxy and milled glass by the gallon. Total Boat is a popular supplier but they seem to be out of the milled glass--Aircraft Spruce seems to have stock on the milled glass.

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ChefbotBarksdale t1_irdhtzt wrote

None of these guys are right, you need a 2 part polyester resin, its used for industrial applications like the railways and oil rigs in the UK. you can set a threaded bar or bolt plug into the unset resin and once its hardened it is structural

−4

U_oOkay-Buddy t1_irdkyiq wrote

Option 1: Cheap fix, toggle bolt the railing in.

Option 2: Cheap fix. Since the hole is 1”. Slide a piece of 1” lumber in and you can screw directly to that which will sandwich the plasterboard between the railing and 1” wide lumber.

Option 3: Move the railing completely to where it screws into studs.

Option 4: Cut out a section of wall and put a wooden brace in between the studs. Then repair the cut out section and screw railing into the brace.

Options 3 and 4 will last the longest.

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SinfulCrown6 t1_irdvhf6 wrote

Just wait til he sees what they do with the ramen…

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bitchprophet t1_irdww7k wrote

The other way is to remove railing, fix a piece of dressed timber on top of the plasterboard securely into studs then fix railing to this. Saves you opening up wall for blocking and the dressed timber covers up holes that would have needed to be patched.

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yeteee t1_irdydb8 wrote

Replying to SchillMcGuffin (#46,671)

Rafters are usually the pieces of wood in a roof. I think you meant studs. Outside of that, that's exactly what OP should do, proper and safer way than anything else. It is just a week end project too.

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CaptainPolaroid t1_ire0kf7 wrote

Filling it with a harder material wil just result in ripping a large hole because the rest of the wall is still soft AF.

I'm going to be blunt. Anyone that says anything else than put in some proper bracing should be banned from ever installing a hand railing. People hang on these with their full weight pulling themselves up stairs. If you fall. What do you grab? The railing! That's a dynamic load that can exceed your body weight. Even though there is "no safety issue"with falling down a 5cm gap. You can still fall down the stairs when the handrail gives and you lose your grip.

Don't muck about with this stuff. Broken bones can be the least of your worries after a good tumble down the stairs..

Find the studs and screw your rail holders there. Reposition all of the rail holders to studs. You can then fix the hole normally with putty, filler or whatever.

Another solution would be to rip out a section of drywall and get some wood or plywood behind / in-between fastened to the studs. After replacing the drywall, you can then safely use bolts or plenty screws to secure the handrail in the same spot.

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flying-benedictus OP t1_ire9q58 wrote

Replying to CaptainPolaroid (#50,788)

English is my L2 language, I looked up stud and it seems it's usually referring to wood. There's no wood behind, only metal. There's already a hole in the metal, but how can I attach something to it? Making a hole at the other side to place a nut is an option, but really, is there no option that doesn't require ripping off my wall from the other side?

I've thought about rivets, since it allows to create a widening behind the hole without having to place a nut or similar. But afaik most rivets are made of aluminium and the hole is 8mm, so it may not be very strong.

I am trying with this https://webshopresources.silvan.dk/resources%2fimages%2f1807876_large.jpg?id=1570697940000&width=1230&height=1230 but I am having trouble closing it, because the plug turns with the screw, since the two little spikes skid over the metal stud.

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CaptainPolaroid t1_iree0l2 wrote

Replying to flying-benedictus (#51,136)

What is your native language?

If there is metal behind the wall, this means it's a 'metal stud' wall. As a whole, the wall has a lot of sturdiness because of all the connecting components. But I have no experience mounting something as important as a handrail to it.

Personally, I would opt to get backing in there: https://www.google.com/search?q=metal+stud+backing&tbm=isch&ved=2ahUKEwij5oyUlM76AhXjgv0HHQE8AqQQ2-cCegQIABAA&oq=metal+stud+backing&gs_lcp=CgNpbWcQAzIFCAAQgAQyBQgAEIAEOgQIIxAnUNIGWOIKYNgLaABwAHgAgAFEiAGcApIBATaYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=qyBAY-PkJ-OF9u8PgfiIoAo&bih=937&biw=1920&rlz=1C1VDKB_nlNL982NL982

But this requires ripping out a section of wall.

I think as an alternative you could mount a backboard to the front of the wall that follows the handrail (example). That way you can secure to the studs where possible and get more screws in there. This will spread the load. But since I have no experience with metal stud, I would prefer it if someone corroborates this.

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PoopsExcellence t1_irh78pa wrote

Replying to madmax_br5 (#48,975)

Watch out though, often a thin metal panel is used to prevent you from drilling into plumbing or electrical wires behind that portion of the wall. Make sure it's 100% a metal stud, and not just a metal protective panel over a wood stud near something sensitive.

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flying-benedictus OP t1_irho8w6 wrote

Replying to CaptainPolaroid (#51,311)

Spanish.

The handrail is made of welded metal and connects only to the stairs, which are floating, so the fastening to the wall is preventing the rail from wobbling. Perhaps something could bend badly if a lot of sideways force were applied and the fastening to the wall is nonexistent, but at least among fit adults you would need a quite reckless behaviour for this, since once one notices it's loose, one can just stop using it when walking up the stairs (it just takes a bit more load on the legs when doing it so many times a day). But it's never gonna fall or anything like that, since the other points are very firmly attached to the metal frame that holds the floating stairs. So the setting in the image is not possible, but I have considered attaching a vertical wooden panel to the wall to grab from different points to the wall, and then the end of the rail to that.

But for the moment I managed to make it quite secure with that metal dowel I mentioned in the last post. If it gets loose again I may consider the plank, or making a hole at the other side.

As for whether the metal behind is just a stud for the plasterboard or something stronger, I don't know. It's a 250-year-old-house renovated 40 years ago, and has a combination of old wooden and newer metal structure inside. Could be a bit more structural than just the metal studs used to hold the plasterboard in place, especially since it's a corner of sorts, but it's very difficult to know.

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Hot_Bluebird_860 t1_iribcyw wrote

Minwax has a 2 part epoxy product, comes in a tin. (High performance) I use often for rotten window sills. Sets up very hard & stable. Marine epoxy like pc11 is more expensive, but is made to be able to put a new cleat in after they've rotted out.

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