Anything that floats 2022

So it’s raft race time again and the lowrider is busy cutting away… it’s fun to watch the machine fly through foam at 50mm/s at 30mm depth of cut

This year we are doing a 1 sheet build out of a lightly used piece of foam board.

His opinion… … isn’t there something better than all these dumb holders (tabs).


Oh that is looking interesting already. Can’t wait!

Was trying to figure out why lr was struggling to cut the last few parts…

Turn down the router speed to as low as possible? I have had a few cuts like that with foam.

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Yup that’s all the way down. It’s weird it made 90% without hooping up I guess it’s a cumulative thing. No big deal it was an old bit.

Just had fun with a can of spray foam


Oh that had to be fun!

Yep sanding is going to be … unfun

Could Hot Wire Foam Cutter be used, would that be easier than sanding? Or just go at it with a serrated bread knife, usually used for cutting insulation batts, e.g. “Grip-Rite Stone Wool Insulation Knife”

Looks like a cool sturdy project. Makes me wonder if 'm just a few foam boards and spray foam cans away from that yacht I’ve always wanted.

Not sure if a hot wire will cut expanding foam.

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I would start with a hack saw.

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Or that electric carving knife you got as a wedding gift that never gets used.


I am kinda old. Coping saw may work great

I did an initial pass with an angle grinder with a flapper wheel will follow up with some 60 grit sandpaper.

Thanks Barry for the heads up about the hot knife and spray foam.

Spending far too much time on this but if it comes out good it may have a life beyond this one race.


old bit: you can heat gun it and get the purple plug to fall off and keep going…


Acetone does wonders on this kind of foams, it eats it up righ away.


I’ve used foam acetone slurry to build out props for theater class. Build out armor in cardboard then paint it with the slurry. The acetone flashes off and you’re left with a fairly durable part. Little sanding and paint and it looks great on stage, and might last through more than one production.


I’ve used foam acetone slurry to build out props

i took a note for future use! (Shrek will be our next musical, so lots to build)

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Do it outside or a well ventalated space with fans blowing outside. Lots of fumes until the acetone evaporates.

First time trying pmf (poor man’s fiberglass)

Basically paint a layer of glue and lay a cloth tarp on the wet glue. Then multiple layers of paint over the cloth.

Not super impressed compared to real fiberglass cloth but I think it will work ok.