I used to carve foam with a product called Dragon Skin. Kind of a metallic sandpaper or flat grate. I can’t find that on Amazon but I do need to carve some curves into a piece of foam that needs to mate with my hull in order to serve as a hip pad. Does anyone have a source for this product, or ideas for how else to carve curves into thick pieces of minicell? Thanks.
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https://www.harborfreight.com/10-inch-two-way-combination-rasp-plane-66620.html
https://www.harborfreight.com/5-1-2-half-inch-multirasp-pocket-plane-94551.html
This might work.
DEWALT DWAM4321 80 Grit Mesh Sheet (5 Sheets), 1/4" https://www.amazon.com/dp/B01GW48U86/ref=cm_sw_r_apan_i_K09W51BRFS55AFPWAJPT?_encoding=UTF8&psc=1
I’m not a fan of dragon skin, as it tends to tear the foam and it’s hard to handle. What I prefer is a small Surform tool like this one:
If you want a smoother surface, you can use 80 grit sandpaper - or even finer if you like - after doing the rough work with the Surform tool.
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That’s what I use too. I have a collection of small sure form rasps. Sometimes when shaping foam I start out doing the rough cutting and shaping with a bendable serrated steak knife.
Dragon Skin is pretty rare right now. I don’t know if it will be back or not. I was looking for some recently and couldn’t find it anywhere. I didn’t look on eBay, though.
Like others here I have a selection of rasps but unlike many I vastly prefer working with Dragon Skin. It does tear a bit but gets the job done in a predictable manner that suits me. I use the DeWalt Mesh Sheets (or similar) for finishing but find it unacceptably slow for serious shaping. Personally, I find that rasps do not achieve desired results for concave surfaces but I’m sure that it is just because I lack the skillset.
I use a power drill with a very aggressive wire brush for creating concaves with a piece of Dragon Skin shaped around a tennis ball for smoothing and the abrasive sheets (drywall abrasive) for finishing wrapped around shaped pieces of minicell. A clean and rasp for shaping straight lines and a separate (clean) precurved piece of Dragon Skin wrapped around a Nalgene bottle for smoothing.
Works for me and I know that many folks have experienced problems controlling the wire brush. Somehow that is a skillset that I developed working with over-powered sewing machines and production ski repairs.
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Dragonskin was a Red Devil product and they ceased production of it quite a few years ago now. The only thing you will be able to possibly find is new, old stock and that is probably now very rare.
I have generally been able to substitute surform tools of various types and 3M Sandblaster sand paper but there were some times when shaping foam along a tight curve where Dragonskin worked better than anything else.
I have a Stanley #297 Surform-style rasp that’s ~5/8" in diameter, essentially like a tubular rat-tail file. I haven’t tried it on Minicel, but I don’t see why it wouldn’t work.
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Looks like it ought to work.
You can get dragon skin by spending too much time in the sun.
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FWI, after shaping the minicell, the material will be rough. If you run a heat gun over it, it will smooth it out to look like a factory-made saddle. Move the heat gun quickly and keep a good distance.
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Thanks. Sounds like a great tip.
Just picked one up at ACE hardware. Once my foam arrives I’ll see how it does. Thanks for the suggestion.
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I also use a fine-toothed Japanese style saw to shape the foam. A regular crosscut saw also works. Even an electric jig saw works well. The surform round file is good for making foam blocks for roof racks.
I have been lucky to find after flooding on a local river three large 3" thick sheets of Minicel foam about 30" by 48" that I have used for various projects. They were a bit beat up by their time in the flood waters until being caught high up in log jams.
Some photos. you can see how smooth the saw cuts are. The grove for my round Yakima racks I used the surform round file.
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Wow! That is a golden hoard of mini cell. What a fortunate find.
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I often cut Minicel foam on a bandsaw. Actually, that’s how manufacturers cut it, using special blades that are either knife-edged or serrated. I found a place where I can order them in whatever length I need, but I have done so yet.
Holding the Surform tool at an angle - like skewing a plane - helps it cut better.