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Post by Scott on Sept 14, 2021 3:24:00 GMT -8
I wouldn't use plywood at all. I don't specifically know how long plywood outgasses (technically, off-gasses) formaldehyde, but I believe it's months at a minimum, if not years. Further, the adhesive itself is always there, so if (when) the gerbils gnaw the platform they'll be getting it in their mouths.
I don't recall where PipSqueak is located; I think the EU has lower maximum VOC standards for plywood than the US does, but that doesn't affect the chewing issue.
IIRC, I used poplar.
BTW, I'm not a big fan of putting screws into endgrain. Probably not a big issue with a low-stress item like this, but it's a very weak joint.
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Post by Markpd on Sept 14, 2021 3:48:31 GMT -8
Re screwing into end grain, yea I see what you're saying, I guess it could be prone to splitting? But like you say these platforms are low stressed items.
They would have to have a heavy weight on them and then dragged sidewards before splitting was an issue, which isn't going to happen in a gerbils cage. Also I pre-drilled the legs so the screws aren't trying to wedge open the wood .
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Post by Scott on Sept 14, 2021 4:34:47 GMT -8
Splitting, yes, but it also holds weakly. The screw is parallel to the grain, so the fibers do a poor job gripping and thus making it relatively easy to pull out. If you screw into the side, it's perpendicular to the grain and grips across the wood fibers, which is a far stronger hold.
Consider, in comparison, a pair of pliers: if you pull with the teeth perpendicular to the thing you're gripping, it holds much better than if you have it sideways, with the teeth parallel to the item and so easily slipping.
I'd be more concerned with the screw working its way out after repeated rotational movement of the leg (i.e., sideways force).
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Post by PipSqueak on Sept 14, 2021 9:01:44 GMT -8
Yes I am located in the US, I will try to see where I can find safe wood that’s not plywood. I might try to make the platforms again without any screws, or do you think that the screws in my platform are fine? Should I be taking the platforms out now? Also if there any seal or something I could put onto the wood that would protect anything toxic coming through?
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Post by Scott on Sept 14, 2021 11:33:16 GMT -8
Personally, I would not have plywood in there, period. The problem with using a sealant is that even if the sealant itself is gerbil-safe and prevents outgassing, it won't protect your gerbils if they gnaw on the plywood, since they'll be chewing through the sealant and into the adhesive.
Use a hardwood like poplar or oak; there are others, like apple, but you're not likely to find them in places like Home Depot. The screws are OK so long as they don't work their way out, so if you've driven them through an endgrain, check every time you clean the tanks they haven't worked their way loose. I used the screw-less method so that I never have to worry about that.
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Post by LilyandDaisy on Sept 14, 2021 11:59:23 GMT -8
I use kiln-dried pine for shelves. Solid pine is widely accepted as safe even if pine shavings are debated.
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Post by PipSqueak on Sept 14, 2021 12:38:03 GMT -8
I will take them out for now. Is there a possibility that this could be pressed wood and not plywood? I don’t know much about woods, is pressed wood even safe or does it still contain the same glue as plywood?
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Post by Scott on Sept 14, 2021 14:55:17 GMT -8
Pressed wood is just wood chips held together by a resin, so it's basically the same issue. FWIW, from your photo it looks like plywood--you can see the alternating layers, and that's what plywood is (the layers are called "plies").
Anything other than solid wood is going to have the same adhesive issue regardless of the specifics of how it's constructed--engineered woods are basically made from sawmill waste that's glued together.
Side note: if you hadn't heard it, people were sickened in the FEMA temporary housing provided to Hurricane Katrina victims; the issue was traced to high levels of formaldehyde in the Chinese-manufactured plywood.
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Post by PipSqueak on Sept 14, 2021 15:15:49 GMT -8
Ok, thanks. I will see if I can find any solid wood that’s made from a safe wood. Do you think I will be able to get the screws out of the dowels while still being able to use the dowels when I remake the platforms?
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Post by Scott on Sept 14, 2021 15:43:03 GMT -8
Probably, especially if you pre-drilled like Markpd did, though it might not hold as tightly. If they're loose, depending on the size screws you used, you might get away with using the next-largest diameter screw of the same length. As I posted above I'm not the biggest fan of this sort of configuration and it's harder still to answer without knowing precisely how you did it--and by that I mean how centered and vertical the holes are and the screw diameter compared to dowel thickness, etc.
If you have a Home Depot or Lowes nearby that's where I got the wood for my platforms. I used a hardwood (poplar) because I thought it would hold up better to gnawing, and apparently there's some grey area with pine sold in the US unless you're sure about the sourcing.
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Post by PipSqueak on Sept 14, 2021 18:06:13 GMT -8
I will make sure that the screws hold in well. I don’t think that the platforms will be thick enough for the way that you did it without the screws. I did find some cheap poplar wood at Home Depot and I am going to be getting it sometime this weekend.
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Post by Markpd on Sept 15, 2021 2:58:14 GMT -8
I think screws will hold just fine as long a you use long enough screws, if the screws were only to go 1/4" into the legs, then yea they'll likely work loose. I went overkill on my platform, IIRC I used 3" long screws so about 2+" went into the legs. Not sure what the minimum length screw penetration should be though, as far as the platforms we're talking about, I suppose 1"?? Splitting, yes, but it also holds weakly. The screw is parallel to the grain, so the fibers do a poor job gripping and thus making it relatively easy to pull out. If you screw into the side, it's perpendicular to the grain and grips across the wood fibers, which is a far stronger hold. Consider, in comparison, a pair of pliers: if you pull with the teeth perpendicular to the thing you're gripping, it holds much better than if you have it sideways, with the teeth parallel to the item and so easily slipping. I'd be more concerned with the screw working its way out after repeated rotational movement of the leg (i.e., sideways force). Yea I see what you're saying, but in the case of using it as a platform in a gerbils cage their is no significant sidewards forces, mostly it's downwards. Sure the gerbils jumping on it will put a small sidewards force on it, but apart from it being a small force, the platforms legs will also be largely buried in the bedding, adding support. (I suppose it might still be an issue if using very thin legs, but as I mentioned the legs on mine are 3cm square (nearly 1.25"), also I used very long screws (3" long! IIRC), and finally as I mentioned earlier too I put a bit of wood glue around the ctr of the legs, almost certainly overkill, lol, and if I ever have to replace the legs I think I'm going to regret putting the glue there! . I seriously doubt my platform's legs would work loose without the glue, but of course I can't know that now. Anyway, as it is, they haven't worked loose in the 1yr I've had it. Btw, although I haven't looked into it myself, I saw one article (posted on a forum) mention that Oak shouldn't be used as it contains a lot of tannins which could be toxic. No idea about the veracity of that article.
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shab
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Post by shab on Sept 20, 2021 19:57:11 GMT -8
Cool, although I've just realised that we didn't warn you about using plywood , IIRC the fumes from the glue used to bond the layers are the problem. Although I can't remember if that applies to just new plywood or indefinitely, perhaps Scott could pitch in on this?
I used solid pine for mine, and I think Scott used solid Birch? (although I can't find where he said that now).
Modern plywood is luckily no longer an issue. In the past, it was for good reason, and those concerns persist as an (outdated) rule. Safety standards have changed over the years though with construction supply requirements and it's no longer an issue to use plywood for small animal habitats. The US was the first to crack down on off gassing laws, the EU followed some years later. These days, you can even get low toxin plywood in the US.
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shab
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Post by shab on Sept 20, 2021 20:42:45 GMT -8
I use kiln-dried pine for shelves. Solid pine is widely accepted as safe even if pine shavings are debated. I also use pine in building. Somewhere along the line the danger was blown out of proportion. Unless they are chewing it on a regular basis, solid pine (aged to have no sap!) is safe.
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Post by Scott on Sept 21, 2021 9:01:45 GMT -8
Modern plywood is luckily no longer an issue. In the past, it was for good reason, and those concerns persist as an (outdated) rule. Safety standards have changed over the years though with construction supply requirements and it's no longer an issue to use plywood for small animal habitats. The US was the first to crack down on off gassing laws, the EU followed some years later. These days, you can even get low toxin plywood in the US. If nothing else, plywood is still made using adhesives--that's what what plywood is. And unless we can be certain that gerbils won't chew the wood (hah!) it's not safe to have in their tanks. Columbia Forest Products' PureBond plywoods--which is not what you get if you go to Home Depot or Lowest--claim to use soy-based adhesive and formaldehyde-free, but their SDS doesn't address what happens if you ingest it--it simply says "not applicable under normal use," so at the minimum there's no data on the health effects if chewed on.
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