{"id":3611,"date":"2014-03-23T21:10:03","date_gmt":"2014-03-24T05:10:03","guid":{"rendered":"http:\/\/www.corbinstreehouse.com\/blog\/2014\/03\/led-cyr-wheel-notes-casting\/"},"modified":"2018-11-03T13:36:24","modified_gmt":"2018-11-03T20:36:24","slug":"led-cyr-wheel-notes-casting","status":"publish","type":"post","link":"https:\/\/www.corbinstreehouse.com\/blog\/2014\/03\/led-cyr-wheel-notes-casting\/","title":{"rendered":"LED Cyr wheel notes: casting"},"content":{"rendered":"

\n

Here’s some notes on casting\u2026maying for myself when I go back to do this again and try to remember what I was doing.<\/p>\n

First, to get the curve, I would cut the LEDs every 6 and re-solder them together:<\/p>\n

\"IMG_0998.JPG\"<\/a><\/p>\n

All us techie programmer know a curve is an approximation of straight lines; and mine are 6-pixel straight lines.<\/p>\n

Next, casting: I had two materials to cast with (see Casting experiments<\/a>). Smooth-on EpoxaCast 690, and some Polyester casting Resin<\/a>. The resin is fairly cheap, and they sell it at my local Tap Plastics store (I discovered that after I ordered it on Amazon). I experimented with both, and they seemed about equal. However, the Resin was harder after it dried, while the smooth-on was sort of more plyable. I’m not sure if that is good or bad (yet).<\/p>\n

My first official wheel piece didn’t go so well. I used the EpoxaCast, and tried taping over the groove horizontally (in line with the wheel curve), but this was a mess. I kept getting a lot of bubbles and it was just not going well.<\/p>\n

\"IMG_0995.JPG\"<\/a><\/p>\n

In the above picture, you can see I bought a scale, as it is a two part epoxy measured by weight.<\/p>\n

Eventually, I realized it was better to spread the tape perpendicular to the wheel\u2026but even then, I got lots of air bubbles under it. Worse, the next day a bunch “drained” out, probably from capillary action:<\/p>\n

\"IMG_1002.JPG\"<\/a><\/p>\n

Hmm..not so great.<\/p>\n

So, I decided to try the Resin for the second casting. It went on really well, as I put the tape perpendicular to each piece and seemed good. But the next day, the resin (which dries MUCH faster than the Smooth-on Epoxy) was sort of “blotchy” under the tape. Grr. (Note: later I fixed this by putting some epoxy on top of it).<\/p>\n

So, I tried the smooth-on epoxy again, and with the horizontal technique it was working pretty well, despite some spots getting air bubbles and dripping out.<\/p>\n

One thing I would do is hot-glue fill in the edge to keep the epoxy running out:<\/p>\n

\"IMG_0996.JPG\"<\/a><\/p>\n

After I taped it, I discovered I could “cotterize” it with more hot-glue to keep it from dripping:<\/p>\n

\"IMG_1046.JPG\"<\/a><\/p>\n

The glue is fairly easy to cut off with an exacto knife.<\/p>\n

Next thing I learned: tape makes a difference. I was using Heavy Duty Scotch shipping tape to “cast” the LEDs in; it pulls off pretty easily and cleanly. I ran out, and used the weaker\/cheaper ACE tape.<\/p>\n

\n\"IMG_1047.JPG\"<\/a><\/p>\n

Bad idea. It reacted funny with the epoxy:<\/p>\n

\"IMG_1045.JPG\"<\/a><\/p>\n

Luckily most of the white opaque mess peeled off, but some I had to scrape off. Plus, this tape left a sticky residue. It was not the right tape to use.<\/p>\n

Other notes: the temperature should be warm..ideally 70F or higher. The stuff takes forever to cure when thin; it says 24 hours, but it seems much longer — at least 36, but probably 48 hours. And I think it takes a week before it is fully cured. Outside temps have been 50-60F (or up to 70F during the day).<\/p>\n","protected":false},"excerpt":{"rendered":"

Here’s some notes on casting\u2026maying for myself when I go back to do this again and try to remember what I was doing. First, to get the curve, I would cut the LEDs every 6… [read more]<\/a><\/p>\n","protected":false},"author":1,"featured_media":3595,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[13],"tags":[],"class_list":["post-3611","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-circus-and-silk"],"jetpack_featured_media_url":"https:\/\/www.corbinstreehouse.com\/blog\/wp-content\/uploads\/2014\/03\/IMG_09981.jpg","jetpack_shortlink":"https:\/\/wp.me\/p8zn47-Wf","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/posts\/3611","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/comments?post=3611"}],"version-history":[{"count":1,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/posts\/3611\/revisions"}],"predecessor-version":[{"id":5386,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/posts\/3611\/revisions\/5386"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/media\/3595"}],"wp:attachment":[{"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/media?parent=3611"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/categories?post=3611"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.corbinstreehouse.com\/blog\/wp-json\/wp\/v2\/tags?post=3611"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}