Best Glue or Adhesive for tank stands (doubling up 2x lumber)

[Tuffloud1]

What is the best glue or construction adhesive to sister together 2x lumber for the top frame of a stand?

Locktite PL Premium, Titebond 2, 3 or epoxy?

I know Titebond states “not for load bearing or structural use” which is strange because of how strong it is and the way it bonds wood fibers.

 

[VB313]

What is the best glue or construction adhesive to sister together 2x lumber for the top frame of a stand?

Locktite PL Premium, Titebond 2, 3 or epoxy?

I know Titebond states “not for load bearing or structural use” which is strange because of how strong it is and the way it bonds wood fibers.

wood glue 100% you be surprised how strong it is when properly installed
construction adhesive is too thick and doesn’t compress or penetrate into the wood

 

[JoshH]

wood glue 100% you be surprised how strong it is when properly installed
construction adhesive is too thick and doesn’t compress or penetrate into the wood

+1 on this, good old fashioned wood glue is still the best IMO.

 

[Tuffloud1]

Even for limiting deflection?

Titebond says it’s not intended for structural or load bearing.

 

[VB313]

Deflection? What are you trying span a distance?

 

[Tuffloud1]

Deflection? What are you trying span a distance?

Check out post #28 on my build thread.

Large Build - Tuffloud1's 262 Gallon In-Wall Reef Build Thread

I got the Modular Marine overflow. I had him do teeth on the back of the weir as well in order to double the flow capability without having to double the length of the weir. Some like maximum length for surface skimming. I prefer as inconspicuous of an overflow as possible.

www.reef2reef.com

Trying to reduce deflection to already built in-wall stand.

Was going to sister a 1x8 to the back 2x8.

 

[sharpimage]

Wood to wood connection, wood glue. Hands down the best

 

[VB313]

Gotcha yeah I don’t think glue is gona help

 

[Tuffloud1]

Gotcha yeah I don’t think glue is gona help

What do you mean?

 

[VB313]

You may need to double up that 2x8 or go double 2x10 ..... or through bolt a steel C channel to the 2x8

 

[Tuffloud1]

Wood to wood connection, wood glue. Hands down the best

I'm trying to determine what is best for joining 2 boards together for load bearing and limiting deflection.

I realize wood glue has a good "bond" but want to know if it is better than construction adhesive for load bearing applications. \

 

[Tuffloud1]

You may need to double up that 2x8 or go double 2x10 ..... or through bolt a steel C channel to the 2x8

I've read in numerous forums that steel channel is worthless for limiting deflection.

I have space restraints so I can't go with another full 2x. I'm going to give the 1x a shot and if I'm still not comfortable, I'm going to just put a center brace in.

1/16" isn't an issue, it's more defection over time that I'm trying to avoid.

What is really strange is according to "RocketEngineer" from another reefing forum, the 2X8 is supposed to be sufficient for the span I'm using for a 260 gallon. Maybe 1/16" is within the acceptable range but I'm definitely going to keep an eye on it once it's filled.

 

[ca1ore]

Best way to avoiding deflection is to not use dimensional lumber at all. On my last two stands (a 265 and a 450) I cut strips of plywood on my table saw and glued (wood glue) and screwed them together to form DIY ‘micro lams’. For the 265 they were two thicknesses of 3/4” ply six inches wide. For my 450, same just eight inches wide. Essentially no deflection with just a single center leg (even though I ended up using more legs as mounting for the facia). Glue and screws simply holds the plywood together, they play no structural role.

 

[danoo]

The stand for my 350 is primarily held together with Titebond III, as is furniture that I sit on all day. I think "not for load bearing or structural use" is more of a liability thing. A proper glue joint should be stronger than the wood fibers themselves, and for something like a lamination where you'll have a ton of surface area, the wood glue is going to be plenty strong. My concern would be getting the surfaces prepared for a proper joint... wood glue is not good at gap filling, you'd want the boards to both have flat surfaces.

I'm also very surprised you can get away with no supports. My 96" long stand uses 2x8s for the top frame and has 2 center supports. I don't remember exactly what was required and I generally over-engineer everything, but if you are concerned with deflection than a single center support is going to help much more than sistering another board onto the horizontal beam.

 

[Tuffloud1]

Best way to avoiding deflection is to not use dimensional lumber at all. On my last two stands (a 265 and a 450) I cut strips of plywood on my table saw and glued (wood glue) and screwed them together to form DIY ‘micro lams’. For the 265 they were two thicknesses of 3/4” ply six inches wide. For my 450, same just eight inches wide. Essentially no deflection with just a single center leg (even though I ended up using more legs). Glue and screws simply holds the plywood together, they play no structural role.

I don't think you would have had any deflection no matter what you used because you have so many legs.

So are you saying that a 3/4 plywood is better than 1x dimensional lumber for my application of sistering a 2x8?

I think the long grain lumber is going to be stronger for this application than the same thickness plywood because with plywood, you have multiple layers, some of which the grain is going in the opposite direction you want it to go in.

 

[Tuffloud1]

The stand for my 350 is primarily held together with Titebond III, as is furniture that I sit on all day. I think "not for load bearing or structural use" is more of a liability thing. A proper glue joint should be stronger than the wood fibers themselves, and for something like a lamination where you'll have a ton of surface area, the wood glue is going to be plenty strong. My concern would be getting the surfaces prepared for a proper joint... wood glue is not good at gap filling, you'd want the boards to both have flat surfaces.

I'm also very surprised you can get away with no supports. My 96" long stand uses 2x8s for the top frame and has 2 center supports. I don't remember exactly what was required and I generally over-engineer everything, but if you are concerned with deflection than a single center support is going to help much more than sistering another board onto the horizontal beam.

I'm going to give the Titebond a shot. There really isn't any risk because I was going to fir out the area where my 1.5" overflow pipes are dropping down and anchor them. The 1x8 is the perfect depth to anchor the pipes down once installed.

 

[ca1ore]

I don't think you would have had any deflection no matter what you used because you have so many legs.

So are you saying that a 3/4 plywood is better than 1x dimensional lumber for my application of sistering a 2x8?

I think the long grain lumber is going to be stronger for this application than the same thickness plywood because with plywood, you have multiple layers, some of which the grain is going in the opposite direction you want it to go in.

Yeah, but that’s the entire point. That fibers go in multiple directions means it’s much stronger in the vertical dimension (though not in the horizontal dimension). Think of a dimensional lumber joist as a bunch of straws all running in the same direction; plywood as them reinforcing one another. Sistering two 2x8 joists is nominally 3” thick. Laminating three thicknesses of 3/4” ply would only be a little more than 2” thick and both stronger and dimensionally stable. It’s a no brainer to me ..... as long as you have access to the right tools.

 

[Tuffloud1]

Yeah, but that’s the entire point. That fibers go in multiple directions means it’s much stronger in the vertical dimension (though not in the horizontal dimension). Think of a dimensional lumber joist as a bunch of straws all running in the same direction; plywood as them reinforcing one another. Sistering two 2x8 joists is nominally 3” thick. Laminating three thicknesses of 3/4” ply would only be a little more than 2” thick and both stronger and dimensionally stable. It’s a no brainer to me ..... as long as you have access to the right tools.

So you think I'd get better resistance to deflection with the 3/4 plywood Titebonded to the 2x8 than a 1x8 Titebonded to the 2x8?

 

[danoo]

I'll note that I'm not on board with the idea that using plywood instead of dimensional lumber is better for the horizontal supports. There is nothing wrong with using plywood, but it is heavier, more expensive, requires more preparation and I don't think it offers a whole lot of advantages. There is a reason the joists in your house are dimensional lumber and not strips of plywood.

I think in theory the dimensional lumber should also be stronger, but that is just my gut feeling, and it might be that dimensional lumber is stronger on a per-pound basis but since plywood is quite a bit more dense that might offset it. I think I'm going to head into the garage and test this...

 

[zoo]

+1 on this, good old fashioned wood glue is still the best IMO.

I agree and iam a master carpenter and wood worker