Foam pucks

I've cut at least a half dozen foam pucks for thru-hull transducer installations and I've always hated trying to cut it to follow the compound curve of the hull.

I'm about to make a new puck.  Does anyone have a simple way to cut foam to the proper contour?  Am I doomed to cussing and starting over a lot?

Having never done it, I don't understand the challenge.  What type of foam are you using?

It doesn't matter.  The challenge is to cut it to conform with the shape of the hull.  In an Ocean Kayak T13, the bottom of the hull isn't flat.  There's a narrow flat area above the keel line that isn't uniformly shaped - it becomes more narrow towards the bow - and the bottom slopes upwards along the sides towards the gunwales.

Use an assload of goop.

It doesn't matter.  The challenge is to cut it to conform with the shape of the hull.  In an Ocean Kayak T13, the bottom of the hull isn't flat.  There's a narrow flat area above the keel line that isn't uniformly shaped - it becomes more narrow towards the bow - and the bottom slopes upwards along the sides towards the gunwales.

It would seem that a soft foam would be easier to press/glue/conform to fit vs. something like polystyrene. 

Use a contour gauge...

https://en.m.wikipedia.org/wiki/Profile_gauge

...and an assload of goop.

Any reason you wouldn't want to use duct seal? This is a much easier method to mount the transducer inside the hull. I used it on my first kayak, and never had a problem with it during the eight years ownership. I continue to use duct seal today on my fourth kayak.

My tranducer is outside, so not speaking from experience. But I wonder if you  taped down some cling wrap where you wanted to mount the puck, then sprayed some high expansion foam, hopefully in a controlled manner, then let the foam conform to the hull rather than conforming the foam with a knife. Then your trimming would all be around the sides and top, which should be relatively easy. You could also make some sort of containment for the foam as it expands maybe?

My tranducer is outside, so not speaking from experience. But I wonder if you  taped down some cling wrap where you wanted to mount the puck, then sprayed some high expansion foam, hopefully in a controlled manner, then let the foam conform to the hull rather than conforming the foam with a knife. Then your trimming would all be around the sides and top, which should be relatively easy. You could also make some sort of containment for the foam as it expands maybe?

Oops. Probably should have looked at the thread dates on this one. Once the wheels start turning, those things can get lost in the smoke...

Well, at least you didn't say anything about an assload of Goop...

Any reason you wouldn't want to use duct seal? This is a much easier method to mount the transducer inside the hull. I used it on my first kayak, and never had a problem with it during the eight years ownership. I continue to use duct seal today on my fourth kayak.

My personal prejudice?  I know folks like to use duct seal and I've seen it in use.  I've done foam carving and tried Gooping (three times).  If my current attampt at carving doesn't move along I may turn to duct seal.   

Use an assload of goop.

Ha, ha.

Use a contour gauge...

Got one, tried it.  Didn't help much.

...and an assload of goop.

[SIGH]   


I guess it's back to trial and error, a fair amount of cussing... and an assload of Goop. 

Thanks, all.

Any reason you wouldn't want to use duct seal? This is a much easier method to mount the transducer inside the hull. I used it on my first kayak, and never had a problem with it during the eight years ownership. I continue to use duct seal today on my fourth kayak.

My personal prejudice?  I know folks like to use duct seal and I've seen it in use.  I've done foam carving and tried Gooping (three times).  If my current attampt at carving doesn't move along I may turn to duct seal.

I'll endorse duct seal as well. I had a transducer attached to the bottom of my hull for four years without issue.

Any reason you wouldn't want to use duct seal? This is a much easier method to mount the transducer inside the hull. I used it on my first kayak, and never had a problem with it during the eight years ownership. I continue to use duct seal today on my fourth kayak.

My personal prejudice?  I know folks like to use duct seal and I've seen it in use.  I've done foam carving and tried Gooping (three times).  If my current attampt at carving doesn't move along I may turn to duct seal.

I'll endorse duct seal as well. I had a transducer attached to the bottom of my hull for four years without issue.

Likewise, duct seal works great. Initially, I used to create a rim of duct seal around the transducer in the inside bottom of my kayaks and each time I went out I would add a little water under the transducer. However, that is not necessary, if you make sure you get no bubbles between the duct seal and the hull and transducer surfaces it works great, no need to add liquid.

Back in my RC airplane days I almost got into cutting wings out of foam w/ a heated wire cutter - folks have figured it out to the point that you can make intricate designs that are easily repeated.