Injectadeck

[Oeanda]

A couple experiments. I made a three-quarter inch deep box/sandwich with plywood top and bottom and crammed in some rotten wet plywood before screwing the lid down.




First try was with PL Premium which as I mentioned is a polyurethane construction adhesive.




Results were a bit underwhelming. It may or may not have filled the void decently if the small tube I bought hadn’t run out first. But there was not much expansion. You cannot dent the cured glue with a hammer but you can gouge chunks out with the hammer claw if you try hard enough. Tough stuff though.


Much more promising was today’s experiment.


The gorilla glue was amazing at expanding to fill the void- a perfect fill. Not quite cured yet I think but at this point it’s almost as hard as the PL.

I had ‘void filling’ in mind and didn’t really consider how well it would adhere to the actual box, or make any particular attempt to get it to stick. ( I wanted to open it again after all...)

Neither glue adhered fully to the box. Which is to say the box was definitely stuck to the glue mass in both cases, but when I pried it apart with a crowbar it made a fairly clean separation, with minimal wood tearing.

I might mess around with it more and try a more dirty soft/mulchy material inside. But so far the gorilla glue looks perfect for what I have in mind.

[rslifkin]

Out of curiosity, how does the cured gorilla glue / wood gunk sample compare to a similar size piece of dry wood (plywood or balsa) in weight?

[kayakerChuck]

I have used it for small areas.

1- The area around the top of the rudder post of my 30 O'Day had been previously repaired. The surveyor identified the area as "a little wet, repaired".) In drilling a mounting hole for something, um, we have a top skin and a bottom skin. NOTHING in between. The wood core used for the repair was rotted away to nothing. Of course, I found this a handful of days before my long scheduled launch date. It's an area about 1'x2', with defined boundaries from the previous repair. I drilled a handful of holes, carefully dried the area, and used the Injectadeck as an emergency repair. It's working surprisingly well. There is no noticeable movement of the rudderpost or the skins of the seat where it mounts. I'll still fix the area properly with balsa core the next she's out of the water.

2- One of my dorade boxes was leaking, which led to an area of core rot about 12"x12", mostly directly under the dorade. This area was full of punky/rotten balsa. I dug out the bad with a bent wire & vacuum, dried the area, and used the Injectadeck.

I'm sure I could have bought the same foam resins and loaded the cartridges myself and saved a few $. I was in a HURRY, and am happy with the price & the results. I have no experience with larger area repairs. Sometime during the off season, I'm going to try it in a large area of deck rot in our race committee boat. We'll see....

[Oeanda]

Originally Posted by rslifkin

Out of curiosity, how does the cured gorilla glue / wood gunk sample compare to a similar size piece of dry wood (plywood or balsa) in weight?

It’s light in the hand. In the name of some incredibly unscientific science i weighed a piece of fir plywood of the same size. The g-glue foam rectangle with the wet plywood inside was close to 150 grams and the dry plywood was about 200 grams.


The foam chunk seems to still be hardening. Most of it is too hard to dent at all with a fingernail but there are a couple softer spots which may or may not still be curing I’m not sure.
I used (most of) a 59 ml bottle of the glue to fill the 4.5” x 7” x 3/4” test void.

(We use the Imperialmetric measuring system around here...)

[rslifkin]

Originally Posted by Oeanda

It’s light in the hand. In the name of some incredibly unscientific science i weighed a piece of fir plywood of the same size. The g-glue foam rectangle with the wet plywood inside was close to 150 grams and the dry plywood was about 200 grams.


The foam chunk seems to still be hardening. Most of it is too hard to dent at all with a fingernail but there are a couple softer spots which may or may not still be curing I’m not sure.
I used (most of) a 59 ml bottle of the glue to fill the 4.5” x 7” x 3/4” test void.

(We use the Imperialmetric measuring system around here...)

Interesting. I dug into the SDS and did the math, the contents of a bottle that size should weigh about 67 grams / 2.37 oz. So the stuff isn't as heavy as I feared it might be as a core replacement. Seems like it's lighter than plywood, but maybe still heavier than balsa.