Shaping foam with an angle grinder

[marko69]

I watched a youtube video where the guy cut out a bad section of a car seat bolster and then glued in a piece of open cell foam.  He then rough cut the shape with a turkey knife then fine tuned it with an angle grinder.  What king of pad or disc would you use to grind the foam?  How about on closed cell foam? Thanks.

[JuneC]

I've done it numerous times on boat seats with 60 grit on an angle grinder - old and used is better.  Never tried it on closed cell, but works like a champ on standard or dri-fast foam.  Wear a dust mask - the bits get EVERYWHERE.

June

[Mike]

ive used a disk sander or grinder as my dad always called them.as you heavy grit .

[Darren Henry]

Ditto; I've got a 5" pneumatic that is about the size of a 3/8 angle drill and a bulkier 6" electric that I normally use for fibreglassing. 50 grit works best, but I have used 80 rather than running into town. As said; it's one messy job. I go outside with safety glasses and a smock on.

As Mike pointed out --- this a a disc of "sand paper",not a stone as in "grinder".

I can post pics if we are unclear.

[marko69]

Ok great!! I'll give it a shot...
I've been trying (for years) to make a mold of the seat cushions then filling it with pour foam, but it's expensive and very time consuming.  I think it's time to learn how to repair the old ones.

[MinUph]

Ok great!! I'll give it a shot...
I've been trying (for years) to make a mold of the seat cushions then filling it with pour foam, but it's expensive and very time consuming.  I think it's time to learn how to repair the old ones.

Or shape a new one with this method. A gentile hand its easy.

[JuneC]

Another technique for getting flawless rounded surfaces if you're making a new cushion from scratch, is to cut your basic shape as best you can with a foam saw/turkey carver.  Make it smaller than necessary by about an inch or so.  With 1" soft foam make a cover and glue to your carved block. 

Here's some pics of a bolstered sunbed I did years ago.





June

[Mojo]

June, your a master. I marvel at your work just wished you posted more pics of the work you do.

Awesome. :)

Chris

[fragged8]

If June does it that way, thats what i'm going to do ..

I don't do that many cushions but from what I have done I never see the point in sanding foam ?
if its the right shape the cover tends to pull the foam into the required shape .

[MinUph]

Shaping foam is mostly for bike seats, contours that are originally molded.

[marko69]

I would love to shape out a new seat cushion, but I think the curves, angles, and slits are just too difficult for me.  I can image going thru 10 blocks of foam before I got one that was even close.

http://www.youtube.com/watch?v=5kbqPg9doQE

By the way, here is the video I mentioned before.  Skip up to about 4 min to see the shaping section.  I also work on this particular seat cushion that he's doing.  They are from the 70's and early 80's and they are almost always trashed at the spot he's working on.

[Darren Henry]

Here are the two I use. I use 2.2 lb seat cushion foam 'cause I always have it on hand and the denser grey foam he is showing is alot more money than the cheap people that want an old seat refurbed would pay for.