How do you shape pour foam?

[NickMDal]

Hi. I have a kayak with a DIY storage area in the bow. Just added a trap door.

Inside I created a mold and filled it with light weight 2 lb. pour foam. I then pushed a flat cardboard box (the shape of a lithium battery) onto the foam to create a seat/shelf. The idea was to create a flat secure shelf for the battery.

It worked, except, well after it dried (and I removed the box), the foam continued to expand. This ruined the flatness of the shelf for the battery. The battery goes in but is not at all secure. It works but is ugly.

I'd like to shape the cutout in the now fully cured foam to a rectangle again. The floor of the foam that the battery sits on has bowed up and rounded. The access door is 10" wide by 7" tall. Also, I cannot remove the foam without grinding it to bits. So I have to work through the DIY access door.

So how can I work this lower surface of the foam to flatten it? Would a wood planer work?

I can see how to do the vertical sides using a hacksaw blade. I'm thinking the rear wall of the battery insert space would be flattened with a dremel since the rotary blade would be perpendicular to the floor.

Any thoughts?

 

[23vc]

You can sand (with a block and a bit of sandpaper) some types of foam to a degree

 

[noseall]

Hi. I have a kayak with a DIY storage area in the bow. Just added a trap door.

Inside I created a mold and filled it with light weight 2 lb. pour foam. I then pushed a flat cardboard box (the shape of a lithium battery) onto the foam to create a seat/shelf. The idea was to create a flat secure shelf for the battery.

It worked, except, well after it dried (and I removed the box), the foam continued to expand. This ruined the flatness of the shelf for the battery. The battery goes in but is not at all secure. It works but is ugly.

I'd like to shape the cutout in the now fully cured foam to a rectangle again. The floor of the foam that the battery sits on has bowed up and rounded. The access door is 10" wide by 7" tall. Also, I cannot remove the foam without grinding it to bits. So I have to work through the DIY access door.

So how can I work this lower surface of the foam to flatten it? Would a wood planer work?

I can see how to do the vertical sides using a hacksaw blade. I'm thinking the rear wall of the battery insert space would be flattened with a dremel since the rotary blade would be perpendicular to the floor.

Any thoughts?

multi tool.

 

[NickMDal]

multi tool.

 

[NickMDal]

You can sand (with a block and a bit of sandpaper) some types of foam to a degree

I guess I could buy a wood planer and just try. That and sandpaper on a block should do it. Thanks!

 

[JohnD]

It's what we call this sort of thing. Small hand held tool with replaceable oscillating blades. They may have a different name in your country.

DRAPER MULTI TOOL FUNCTION OSCILLATING SANDER GRINDER CUTTER MULTI TOOL 58288 5010559582884 | eBay

2 Year Warranty Included FEATURES: Constant electronics, Variable speed control, Supplied with offset combination bi - metal saw blade, hook and loop base with 3 x sanding sheets, offset scraper blade and 2M cable with BS plug Power Supply 240V Power Output 300W No Load Speed 15,000-22,000rpm...

www.ebay.co.uk

 

[NickMDal]

It's what we call this sort of thing. Small hand held tool with replaceable oscillating blades. They may have a different name in your country.

DRAPER MULTI TOOL FUNCTION OSCILLATING SANDER GRINDER CUTTER MULTI TOOL 58288 5010559582884 | eBay

2 Year Warranty Included FEATURES: Constant electronics, Variable speed control, Supplied with offset combination bi - metal saw blade, hook and loop base with 3 x sanding sheets, offset scraper blade and 2M cable with BS plug Power Supply 240V Power Output 300W No Load Speed 15,000-22,000rpm...

www.ebay.co.uk

Ohhh... I thought you were joking! You know like one of those pliers multitools? I like this suggestion! Thanks so much

 

[noseall]

Ohhh... I thought you were joking! You know like one of those pliers multitools? I like this suggestion! Thanks so much

A multi tool will cut the foam keenly and quickly. There is also a sanding attachment so you can sand accurately too. Be careful, it cuts real quick.

 

[SFK]

I was considering suggesting the "Dremel type multi tool" (too many multi tools).
And using the router tool and even the flexible shaft.
This link is randomly selected.

https://www.amazon.co.uk/GOXAWEE-Accessories-Creations-Engraving-Polishing/dp/B07GXBTDJ5/