Well … if I were a ‘Glass Half-Empty’ type I would call my first attempt at making a Two-Part RTV mold and then casting something in resin .. a FAIL! Since I’m basically a ‘Glass Half-Full’ type I will say .. *ahem* .. “It was a learning experience” …
Lessons learned –
- *Pressure Chamber* – and say that again .. Press-urrre Chammm-berrr. It is obvious that I need this for both making the RTV mold and casting the parts. The RTV failed to fill the voids in the parts. The reason in part at least is the viscosity of the RTV I am using. This OOMOO 25 is rather thick stuff. I have been using it since it is for use WITHOUT a vacuum chamber etc.
- Brush the RTV first: Ok. One thing I COULD have done is use a disposable brush and ‘paint’ the RTV into the recesses. This would force out the air that gets trapped simply from pouring RTV (and without using a PRESSURE CHAMBER)
- The mold release I used wasn’t the best – which I found when separating the RTV halves. GET NEW MOLD RELEASE!
- I printed the parts (Bridge Shoes) in WSF. MAKE THE SPRUES/RUNNERS LARGER!! reduce the size where they join to the part but make those suckers larger .. at least 2mm dia
- Flat/Open Face molds: Try doing that using the piece of plexiglass to flatten the open side
Thee may be .. heck .. will be more items but that’s all I can come up with at this minute
|Casting Resin With a Pressure Pot|
|Some good basic info here. He shows the HF paint pot – shows where he runs a diverter to a second pot via a male quick-release.
Note: He says you should “never go past 80 psi. The manual states a Maximum Pressure of 80 PSI – Paint Pressure Pot. Some other applicable info there: Air consumption is 4.0 CFM @ 40 PSI – need that to select a compressor. Required Pressure: 30-60 PSI (that’s for a paint gun).
I think that 50 psi maximum pressure would be an excellent idea.
He also covers some other things such as venting the mold. Good info.
|Pressure Casting Tutorial – Part 1|
|EXCELLENT video. He covers a little bit of everything. He makes a point in using a bolt on the inside of the outlet (no second paint pot). He also covers molds including venting.|
|Home Made Plastic|
|Ran up on this video totally by accident.I may try it just for fun .. I mean .. the cost is nothing. A Bioplastic is a form of plastic derived from biomass sources – such as the corn starch in this video (called thermo-plastic starch). I was thinking .. it might be useful for scenic items such as tires. Just a .. hmmmm .. moment.|
|Pressure casting resin with Cindy at resinobsession.com|
|Cidy covers vacuum chamber to de-gas the resin, pressure chamber. Excellent way she sets the chamber up with shelves.|