Re: [DIYbio] Cheaper OpenPCR

Hey, solid points; getting some silver and making a miniature heatblock
by casting is certainly a good possibility for PCR block manufacture.

For a while, you could get sintered silver models from shapeways. Should
have made the most of it while it lasted! But, costly. Probably more
than double its value due to the tech requirements and margins alone.

On 02/10/12 02:38, Simon Quellen Field wrote:
> Suppose you took your PCR tubes (that you want to fit into a homebrew
> heatblock) and make a mold of them in plaster or one of the rubber mold
> making products. Then make a positive of it in plaster.
>
> Now melt a bunch of tin in a cup, and insert your plaster images of the
> PCR tubes. Let the tin cool, and then etch out the plaster with some
> hydrochloric
> acid.
>
> No machining, and you now have a big tin heat block. Make as many holes as
> you like for tubes, and make as many shapes as there are types of tubes you
> might want to use.
>
> At $23 per pound <http://stellartechnical.com/puretinbar.aspx>, tin is
> cheap. It melts at 232 Celsius, so it is easy to melt on the
> kitchen stove, but won't melt in the PCR device.
>
> You can insert fins made from tin plate from a 'tin' can while the metal is
> liquid
> if you want to make cooling fins.
>
> Copper has a thermal conductivity of 400 w/(m.K) compared to tin's 67, so
> you
> might prefer zinc at 116. But Silver is even better at 429, and is also
> something
> you can melt in your kitchen easily. It's $20 a pound, but you won't need
> more
> than about $30 worth.
>
> Of course, as someone who used to do bronze casting as a hobby, I know it is
> easy to melt copper and pour it into a mold as well, should you want to go
> that
> way. Skip the chrome plating -- just paint it with lead-free solder while
> it is still
> hot.
>
> But I'd go with zinc. It's cheap ($20 per pound, or just melt U.S.
> pennies), very
> easy to melt and work with, needs no plating to resist oxidation, and even
> if
> copper is four times better at heat conductivity, the zinc should work just
> fine.
>
>
> -----
> Get a free science project every week! "http://scitoys.com/newsletter.html"
>
>
>
>
> On Mon, Oct 1, 2012 at 2:00 PM, Cathal Garvey <cathalgarvey@gmail.com>wrote:
>
>> I suspect a cheaper heatsink and PSU are low-hanging fruit, here.
>> I would stick with a standard Arduino; as someone pointed out earlier,
>> in the €600 pricetag, €20 for an extremely well-supported and
>> easy-to-use chip isn't a big priority.
>>
>> Removing the display on the front and relying entirely on faux serial
>> output would save some money, too. It's a nice feature, and I like being
>> able to plug out my laptop and have the program run regardless, but it's
>> still non-essential.
>>
>> Heat block is probably not disposable. To get the right bores for PCR
>> tubes you practically have to get special drillbits machined. I recall
>> Josh or Tito wrote a blogpost on the OpenPCR.org blog about how you
>> don't screw around with your machinists, because heatblocks etc. are the
>> kind of component that you can't just knock together at home if you want
>> decent results.
>>
>> That's especially true of the OpenPCR heatblock, which is (I think)
>> chrome-plated copper; that's pretty much as good as it reasonably gets.
>>
>> Unless you want to use your own non-standard but
>> more-convenient-to-design-for tubes, I think that'll remain true;
>> heatblocks will have to be machined, and that'll cost moneys. Unless you
>> go with heated fluid/gas chambers, that is. I think that's still the aim
>> for the Amplino team?
>>
>> On 01/10/12 16:41, Jeswin wrote:
>>> OpenPCR is a cool thing. The only thing is, it's still quiet expensive
>>> for a kit. Looking at the BOM Josh posted:
>>>
>> https://docs.google.com/spreadsheet/ccc?key=0AiaWH3PL_9CndG1GbmtSZ1I3aGdkQkE4YVhwZ3o5c1E#gid=0
>>>
>>> I see that there are lots of parts. Can we build a simpler version,
>>> just like we have simpler Arduinos available? I assume the most
>>> expensive parts are the heat-block, PSU, microcontroller.
>>>
>>> Any ideas for simpler lid unit, cheaper heat-block, PSU, and MCU?
>>>
>>
>> --
>> www.indiebiotech.com
>> twitter.com/onetruecathal
>> joindiaspora.com/u/cathalgarvey
>> PGP Public Key: http://bit.ly/CathalGKey
>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "DIYbio" group.
>> To post to this group, send email to diybio@googlegroups.com.
>> To unsubscribe from this group, send email to
>> diybio+unsubscribe@googlegroups.com.
>> For more options, visit https://groups.google.com/groups/opt_out.
>>
>>
>>
>

--
www.indiebiotech.com
twitter.com/onetruecathal
joindiaspora.com/u/cathalgarvey
PGP Public Key: http://bit.ly/CathalGKey

--
You received this message because you are subscribed to the Google Groups "DIYbio" group.
To post to this group, send email to diybio@googlegroups.com.
To unsubscribe from this group, send email to diybio+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.