Glue Types and Techniques

[dhdarren]

Of the couple towers I've tested in this season so far, I've only managed to get a score of just over 1000. I've followed a pretty basic design of a square ~16x16 base with a vertical portion on the top. Here's a pic of one I tested at invitational yesterday: https://goo.gl/photos/WTiRL1WLv1vUYHzM6 So far, it seems like my problems have arose from not the actual sticks breaking, but a glue joint breaking, followed by the rest of the tower. So, it leads me to the following questions:

1. What type of glue is most effective in making a solid joint? So far, I've been using the BSI CA glue in the purple bottle, which had served me pretty well in bridges in the past, but not so much now. I've also experimented with adding wood glue around the joint after gluing with CA glue, but I'm not really sure how effective it is. Perhaps the glue I am using IS effective, but I am just not gluing with the correct technique, but are there any glues that are better in terms of bonding strength? Is epoxy an effective adhesive to look into? If so, how do you clamp it (due to the long cure time) without damaging the wood?

2. Butt joints or lap joints? So far, I've used butt joints almost exclusively because 1. slightly less wood and 2. having joints only of the outside might be bad if the vertical beams end up twisting. Thinking about it now, having lap joints does make a lot more sense because you do not suffer from non-precise cuts and there is more surface area to glue, but it also brings up another question: if you have a tower that has 4 sides that are non-vertical (like the base part of the tower that I made), how do you make a lap joint? The surfaces of the main beams will NOT be flat on the same axis, but rather at a slight angle away from each other, so any trusses that are added will not be able to make a perfectly flat contact. Should you sand away the beams to make them on the same axis, or will simply gluing it on at that angle be enough?

Thank! I look forward to incorporating your responses into my next design.

[Unome]

Of the couple towers I've tested in this season so far, I've only managed to get a score of just over 1000. I've followed a pretty basic design of a square ~16x16 base with a vertical portion on the top. Here's a pic of one I tested at invitational yesterday: https://goo.gl/photos/WTiRL1WLv1vUYHzM6 So far, it seems like my problems have arose from not the actual sticks breaking, but a glue joint breaking, followed by the rest of the tower. So, it leads me to the following questions:

1. What type of glue is most effective in making a solid joint? So far, I've been using the BSI CA glue in the purple bottle, which had served me pretty well in bridges in the past, but not so much now. I've also experimented with adding wood glue around the joint after gluing with CA glue, but I'm not really sure how effective it is. Perhaps the glue I am using IS effective, but I am just not gluing with the correct technique, but are there any glues that are better in terms of bonding strength? Is epoxy an effective adhesive to look into? If so, how do you clamp it (due to the long cure time) without damaging the wood?

2. Butt joints or lap joints? So far, I've used butt joints almost exclusively because 1. slightly less wood and 2. having joints only of the outside might be bad if the vertical beams end up twisting. Thinking about it now, having lap joints does make a lot more sense because you do not suffer from non-precise cuts and there is more surface area to glue, but it also brings up another question: if you have a tower that has 4 sides that are non-vertical (like the base part of the tower that I made), how do you make a lap joint? The surfaces of the main beams will NOT be flat on the same axis, but rather at a slight angle away from each other, so any trusses that are added will not be able to make a perfectly flat contact. Should you sand away the beams to make them on the same axis, or will simply gluing it on at that angle be enough?

Thank! I look forward to incorporating your responses into my next design.

Your main problem is that you're building your tower as though we are still living under the 2012 rules; you don't need a separate base and chimney, a single pyramid is legal (and will do much better).

[dhdarren]

Got it, I'll definitely keep that in mind! Regardless, do you have any suggestions about the glue joints?

[dhdarren]

Of the couple towers I've tested in this season so far, I've only managed to get a score of just over 1000. I've followed a pretty basic design of a square ~16x16 base with a vertical portion on the top. Here's a pic of one I tested at invitational yesterday: https://goo.gl/photos/WTiRL1WLv1vUYHzM6 So far, it seems like my problems have arose from not the actual sticks breaking, but a glue joint breaking, followed by the rest of the tower. So, it leads me to the following questions:

1. What type of glue is most effective in making a solid joint? So far, I've been using the BSI CA glue in the purple bottle, which had served me pretty well in bridges in the past, but not so much now. I've also experimented with adding wood glue around the joint after gluing with CA glue, but I'm not really sure how effective it is. Perhaps the glue I am using IS effective, but I am just not gluing with the correct technique, but are there any glues that are better in terms of bonding strength? Is epoxy an effective adhesive to look into? If so, how do you clamp it (due to the long cure time) without damaging the wood?

2. Butt joints or lap joints? So far, I've used butt joints almost exclusively because 1. slightly less wood and 2. having joints only of the outside might be bad if the vertical beams end up twisting. Thinking about it now, having lap joints does make a lot more sense because you do not suffer from non-precise cuts and there is more surface area to glue, but it also brings up another question: if you have a tower that has 4 sides that are non-vertical (like the base part of the tower that I made), how do you make a lap joint? The surfaces of the main beams will NOT be flat on the same axis, but rather at a slight angle away from each other, so any trusses that are added will not be able to make a perfectly flat contact. Should you sand away the beams to make them on the same axis, or will simply gluing it on at that angle be enough?

Thank! I look forward to incorporating your responses into my next design.

Your main problem is that you're building your tower as though we are still living under the 2012 rules; you don't need a separate base and chimney, a single pyramid is legal (and will do much better).

Got it, I'll definitely keep that in mind. Regardless, do you have any suggestions about making the glue joints?

[bernard]

If you're using a butt joint, the members better not be in tension and use gussets to reinforce. Your tower is beautiful. Take videos in slow motion and watch for buckling and point(s) of failure.

[dhdarren]

If you're using a butt joint, the members better not be in tension and use gussets to reinforce. Your tower is beautiful. Take videos in slow motion and watch for buckling and point(s) of failure.

Thank you so much! Butt joints in compression and lap joints in tension makes sense, and I'll be sure to incorporate that next. But, if there's a member in compression against a butt joint, what is the need for a gusset? Won't that member just be pushing towards the joint, and not be prone to slipping off at the joint?

[bernard]

If you're using a butt joint, the members better not be in tension and use gussets to reinforce. Your tower is beautiful. Take videos in slow motion and watch for buckling and point(s) of failure.

Thank you so much! Butt joints in compression and lap joints in tension makes sense, and I'll be sure to incorporate that next. But, if there's a member in compression against a butt joint, what is the need for a gusset? Won't that member just be pushing towards the joint, and not be prone to slipping off at the joint?

If it is only compression, gussets are not necessary. If you have angled joints, expect shear stress; gussets help hold those joints together.

[Random Human]

Of the couple towers I've tested in this season so far, I've only managed to get a score of just over 1000. I've followed a pretty basic design of a square ~16x16 base with a vertical portion on the top. Here's a pic of one I tested at invitational yesterday: https://goo.gl/photos/WTiRL1WLv1vUYHzM6 So far, it seems like my problems have arose from not the actual sticks breaking, but a glue joint breaking, followed by the rest of the tower. So, it leads me to the following questions:

1. What type of glue is most effective in making a solid joint? So far, I've been using the BSI CA glue in the purple bottle, which had served me pretty well in bridges in the past, but not so much now. I've also experimented with adding wood glue around the joint after gluing with CA glue, but I'm not really sure how effective it is. Perhaps the glue I am using IS effective, but I am just not gluing with the correct technique, but are there any glues that are better in terms of bonding strength? Is epoxy an effective adhesive to look into? If so, how do you clamp it (due to the long cure time) without damaging the wood?

2. Butt joints or lap joints? So far, I've used butt joints almost exclusively because 1. slightly less wood and 2. having joints only of the outside might be bad if the vertical beams end up twisting. Thinking about it now, having lap joints does make a lot more sense because you do not suffer from non-precise cuts and there is more surface area to glue, but it also brings up another question: if you have a tower that has 4 sides that are non-vertical (like the base part of the tower that I made), how do you make a lap joint? The surfaces of the main beams will NOT be flat on the same axis, but rather at a slight angle away from each other, so any trusses that are added will not be able to make a perfectly flat contact. Should you sand away the beams to make them on the same axis, or will simply gluing it on at that angle be enough?

Thank! I look forward to incorporating your responses into my next design.

Your main problem is that you're building your tower as though we are still living under the 2012 rules; you don't need a separate base and chimney, a single pyramid is legal (and will do much better).

I don't want to argue with you, but I have a lot of perspective why a 2 part design (chimney base) is better. Tell me if I'm wrong. Yes, 2 part design adds more leg stick length, but it does allow the chimney leg sticks to be closer togheter, saving bracing sticks, and making it stronger, and you can use less heavy sticks on the top, distrubuting the weight to the weaker bottom, where u can use bracing at lower intervals incrasing the strength. Any thoughts, maybe why im wrong, and why pyramids are better than mine?

[Unome]

Of the couple towers I've tested in this season so far, I've only managed to get a score of just over 1000. I've followed a pretty basic design of a square ~16x16 base with a vertical portion on the top. Here's a pic of one I tested at invitational yesterday: https://goo.gl/photos/WTiRL1WLv1vUYHzM6 So far, it seems like my problems have arose from not the actual sticks breaking, but a glue joint breaking, followed by the rest of the tower. So, it leads me to the following questions:

1. What type of glue is most effective in making a solid joint? So far, I've been using the BSI CA glue in the purple bottle, which had served me pretty well in bridges in the past, but not so much now. I've also experimented with adding wood glue around the joint after gluing with CA glue, but I'm not really sure how effective it is. Perhaps the glue I am using IS effective, but I am just not gluing with the correct technique, but are there any glues that are better in terms of bonding strength? Is epoxy an effective adhesive to look into? If so, how do you clamp it (due to the long cure time) without damaging the wood?

2. Butt joints or lap joints? So far, I've used butt joints almost exclusively because 1. slightly less wood and 2. having joints only of the outside might be bad if the vertical beams end up twisting. Thinking about it now, having lap joints does make a lot more sense because you do not suffer from non-precise cuts and there is more surface area to glue, but it also brings up another question: if you have a tower that has 4 sides that are non-vertical (like the base part of the tower that I made), how do you make a lap joint? The surfaces of the main beams will NOT be flat on the same axis, but rather at a slight angle away from each other, so any trusses that are added will not be able to make a perfectly flat contact. Should you sand away the beams to make them on the same axis, or will simply gluing it on at that angle be enough?

Thank! I look forward to incorporating your responses into my next design.

Your main problem is that you're building your tower as though we are still living under the 2012 rules; you don't need a separate base and chimney, a single pyramid is legal (and will do much better).

I don't want to argue with you, but I have a lot of perspective why a 2 part design (chimney base) is better. Tell me if I'm wrong. Yes, 2 part design adds more leg stick length, but it does allow the chimney leg sticks to be closer togheter, saving bracing sticks, and making it stronger, and you can use less heavy sticks on the top, distrubuting the weight to the weaker bottom, where u can use bracing at lower intervals incrasing the strength. Any thoughts, maybe why im wrong, and why pyramids are better than mine?

I'm not particularly skilled at Towers, I mostly just regurgitate what more experienced people say. I tend to see mostly pyramidal towers doing well, similar to how by midway through the season in 2015 pretty much everyone was using triangular bridges rather than "traditional" trusses because of the point load.

[dhdarren]

If you're using a butt joint, the members better not be in tension and use gussets to reinforce. Your tower is beautiful. Take videos in slow motion and watch for buckling and point(s) of failure.

Thank you so much! Butt joints in compression and lap joints in tension makes sense, and I'll be sure to incorporate that next. But, if there's a member in compression against a butt joint, what is the need for a gusset? Won't that member just be pushing towards the joint, and not be prone to slipping off at the joint?

If it is only compression, gussets are not necessary. If you have angled joints, expect shear stress; gussets help hold those joints together.

Got it, I could definitely have benefited from having gussets on my last tower design.