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A popular method to bridge gaps is to saturate baking soda with thin CA glue.
Fact: Baking soda dissolves readily into a solution when in contact with water.
The argument...
This cannot be a good thing for joints in a boat hull. What about the CA glue used to stiffen baking soda joint? Doesn’t it seal off the baking soda from contact with water?
I put the question on the internet. Here is the answer..
May 2, 2023 David Codillero, Starbond Glue
Once cured, our CA glues are definitely water-resistant, but if submerged and constantly exposed to water, the water will act as a solvent and degrade the CA glue.
For outdoor applications where exposure to a high level of humidity is expected, our KEG-500 Flexible Medium-Thick CA glue is recommended. This adhesive is four times stronger than our standard CA glue, and has a higher resistance to heat, humidity, and natural weathering.
Okay, CA is water-resistant. Still, not a satisfactory answer for a joint immersed in water.
Armed with this information, I prefer, whenever possible, to use a mixture of phenolic micro-balloons mixed into slow setting two-part epoxy. This is as waterproof as it gets. When I use the baking soda/CA glue method, I seal off the joint by painting over the joint with slow-set epoxy or, two-part epoxy paint. For soda/CA joints that will be seen on the finished model, I have painted the joint with slow-set epoxy thinned 60/40 with acetone with good results. Remember to coat both sides of the joint. Maybe this is overkill but, I am just anal enough to try and put the odds of long term joint integrity in my favor.
As gluing and adhesion is quite basic and vitally important to model building, please add your experience, observations and opinions to this thread.
Fact: Baking soda dissolves readily into a solution when in contact with water.
The argument...
This cannot be a good thing for joints in a boat hull. What about the CA glue used to stiffen baking soda joint? Doesn’t it seal off the baking soda from contact with water?
I put the question on the internet. Here is the answer..
May 2, 2023 David Codillero, Starbond Glue
Once cured, our CA glues are definitely water-resistant, but if submerged and constantly exposed to water, the water will act as a solvent and degrade the CA glue.
For outdoor applications where exposure to a high level of humidity is expected, our KEG-500 Flexible Medium-Thick CA glue is recommended. This adhesive is four times stronger than our standard CA glue, and has a higher resistance to heat, humidity, and natural weathering.
Okay, CA is water-resistant. Still, not a satisfactory answer for a joint immersed in water.
Armed with this information, I prefer, whenever possible, to use a mixture of phenolic micro-balloons mixed into slow setting two-part epoxy. This is as waterproof as it gets. When I use the baking soda/CA glue method, I seal off the joint by painting over the joint with slow-set epoxy or, two-part epoxy paint. For soda/CA joints that will be seen on the finished model, I have painted the joint with slow-set epoxy thinned 60/40 with acetone with good results. Remember to coat both sides of the joint. Maybe this is overkill but, I am just anal enough to try and put the odds of long term joint integrity in my favor.
As gluing and adhesion is quite basic and vitally important to model building, please add your experience, observations and opinions to this thread.