I’m currently building a DIY PCR machine using Peltier modules controlled by a microcontroller. Everything is working well except for constructing the aluminum block needed for uniform thermal conductivity. Since I don’t have access to metal molding facilities, I’m looking for alternative methods to craft or find a suitable aluminum block.
The block needs to hold PCR tubes securely while maintaining efficient heat transfer from the Peltier modules. Has anyone successfully built or sourced a similar block using basic tools or readily available materials? Any advice on dimensions, machining techniques, or sourcing pre-made blocks would be greatly appreciated.
ask around for people with old dead pcr machines and scavenge the block. Consider 3d printing
Dear Rutland, Thank you for your answer. I tried to find an old PCR machine. But yet it seems costly. The outer casing and enclosures I'm planning to 3D print. But still I couldn't find a suitable block. Any suggestions for a low cost alternative?
Ask folks in your molecular department if they have a broken machine gathering dust in a cupboard. Or see if your university has a "surplus" warehouse for old/no longer needed furniture & equipment. I'm sure you'll be able to find one!
If nobody has a dead machine to donate perhaps you could make a heat block by mixing a lot of carbon or aluminium dust with an epoxy resin in a plastic mould ( tobacco tin or similar greased on the inside). Grease the outside of a 96 well plate or a nummber of pcr tubes on the outside then embed the tubes in the liquid glue.Then hopefully when the block is set the tubes can be removed leaving holes of the right profile. You might even consider a liquid(oil/silicone) block with the tubes sypported by a plastic mesh
One possible option for your project could be to have an aluminum plate machined using CNC. This method might allow you to obtain a block with the precise dimensions and cavities needed to securely hold the PCR tubes while ensuring efficient thermal transfer from the Peltier modules. I’m considering this approach for a LAMP device I’m working on, which also involves 3D printing techniques.
Maybe if you ask at your university, they might have a CNC machine available in one of their workshops. If you want to keep costs low, I would suggest opting for a design with a smaller number of tubes. Personally, I work with a 96-well cycler, but unless you really need to run a large number of PCRs simultaneously, I never use a full plate. In Argentina, we typically opt for running several tests and different runs with fewer tubes to keep costs down. I do PCRs very often, and before, we used a 24-position cycler, and I never felt limited by that—it just took more time.
Regarding your question about recommended measurements and characteristics, you could check out https://openpcr.org/, where they have all the 3D files of the various components and necessary specifications, including the heatblock.
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