Wednesday, May 29, 2013

Nano review: bicycle tire patches

I've been using some very cheap patches from Harbor Freight, and they work just fine, but they're pretty ugly, and with the new narrower tires I've got now (23mm slicks), they seem like they're too clunky.

So I bought some nicer patches and cement from Amazon.  < $20 for the whole thing, a big can of cement and 100 patches. About the cost of 3 or 4 tubes, and I've already used two in the last month, so the payoff is very quick on these.

Here's the new patch (round) versus the old Harbor Freight patch (square).  As you can see, the new patch has tapered edges and blends right down to the tire so it should inflate better without getting caught.
FWIW, the cement I bought is here on Amazon, and the patches are here.

If you have never patched before, or if you've had bad luck in the past, here's a quick and easy guide.  A properly done patch is very strong and will never leak - I've ripped tubes when experimentally seeing if a patch could come off before.

BTW I'm not a believer in self-adhesive patches, except as an emergency side-of-the-road measure to be replaced by a REAL patch when you get home again.  I've never had a proper patch leak, but every self adhesive patch I've put on has failed eventually.

  1. Locate the hole by inflating the tube - mark somehow if necessary to find it again (marker or whatever).  Deflate the tube most of the way.
  2. Scuff the area to remove any powder or dirt and to give the cement some 'bite' into the material.  You can use sandpaper or a scuffing tool if your patch kit has one.  I improvise with pushing it hard against carpet and rubbing or even scuffing against pavement while pushing with my thumb.
  3. Apply a small amount of rubber cement.  I usually just put on a dob then smear it with a fingertip.  Be sure to cover an area LARGER than the patch - be generous here.  You don't want a corner to not be stuck down.
  4. Set the tube aside and let the glue dry for 5 minutes or so.  It should be very tacky, almost set before you put the patch on.
  5. Finally, remove the backing from the patch and stick it down.  Start in the center and SMASH that sucker in with your thumb, working from the inside out to push out any bubbles.
  6. Ideally let it sit for an hour or so before reusing, but if you're on the side of the road without a spare tube, you can just chuck it right back into service - the air pressure will smash it into the tire and help it cure.

Tuesday, May 14, 2013

Replacement parts keep on coming

Saved from buying another $25 pump for want of a 25 cent replacement part.

I had a flat tire on the way to work today.  No problem.  Set to fixing, a few minutes later, discovered that the compression cap has gone missing from the pump.  Topeak will probably replace it but I decided to see if I can print threaded parts - I have had trouble in the past but my printer is now much better tuned.

To my surprise it worked great.  The threads are 14mm x 1mm, printed at 0.1mm layer height.  It just screwed right on and works fine.


http://www.thingiverse.com/thing:89041

Monday, May 13, 2013

Tried new plastic source

I got some 3mm PLA from an eBay vendor called globel_egrow.  The spools are labelled "reprapper.com" and are 1.18KG each (about 2.5 pounds) and $34 each from the US including shipping.  This is a very good price.

I just tried printing with the "natural" PLA yesterday - it works very well on my i3 with a 0.5mm nozzle - it's very nearly clear, moreso than the previous translucent stuff that I had, which was natural ABS.  I have need for some translucent things and this will work well.

I need to print something with the other spool, which is fluorescent green, and assuming that's good, I'll probably get a few other colors - they have a glow-in-the-dark blue that's still only $34.  Too bad they don't have any gold, I could use some.

Thursday, May 2, 2013

I don't need it, but it's free, so I'll take ten!

I sometimes wonder about the downloads of some of the stuff I post on Thingiverse.  I mean, I'm not posting the useless crap that a lot of people do - like 52,325 different pen holders, each with a different word on it.  That's just downright pollution.

A lot of my stuff is pretty useful, I think - generic cable tie holders, improved printer parts, etc, but I have to wonder if there are really 69 people who needed a replacement bio-wheel bearing for a Penguin fish tank filter, or 91 people who needed a replacement ATX I/O port panel for a Dell Inspiron 531 mainboard.  This seems unlikely.

I think it's more likely that there are people who have bots that just download everything from Thingiverse.  I'll admit that in the past I fell prey to being a data hoarder, before curing myself (mostly) and throwing away many terabytes of crap that I was never going to use anyway.