How thin of a panel can you resin cast?

[ChuckT]

I’m just thinking out loud here, but is it practical to resin cast a thin instrument panel master using a one piece mold?

 

I was thinking of mounting the instrument panel master onto a thin backing card (to close off the open instrument holes in the panel) and once cast, would then sand the thickness of the thin card off the back of the cast panel to open up the holes and free up the panel for use. The backing panel would not only close of the holes in the panel (making a one piece mold practical) but would also prevent warping of the resin casting. I want to overall casting to be as thin as possible while preventing warping.

 

If it is doable, what would be the thinnest combined thickness of panel casting (to include the actual panel and the back card) that I could realistically cast in resin? Would a total thickness of .01” (.25mm), .02” (.5mm) or something thicker cast vertically in a one piece mold work?

 

Thanks in advance, 

C.

 

 

 

 

 

 

Edited March 11, 2020 by ChuckT

[RLWP]

If you are sanding the 'thin' back off, it doesn't need to be thin

 

Or have I misunderstood what you are trying to achieve?

 

Richard

[ChuckT]

No, your right. I'm just wanting to save time and sand paper by not having the backing thicker than it needs to be.

[BiggTim]

I think that could work, if you cast it lying face down, so the piece you sand off is the "pour block", though in your case it wouldn't be much of a block. It might not even require using a pressure pot, as bubbles escape from small parts quickly. I'd suggest using a slow cure resin like Smooth Cast 310, which is clear when still in liquid form, so you can see any bubbles that form and work them loose from the mold with a toothpick. I've actually experimented with casting copies of an Ares panel just as practice, and had surprisingly good results, even with fast cure resin.  

 

Tim

[ChuckT]

I think that would work. I am able to vacuum degauss and pressure cast, so I was thinking of doing the part standing up with the backing plate to cut down on the amount of material I would need to remove/sand off the back of the panel as compared to doing it laying down.

[D.B. Andrus]

Chuck

 

How about this:

 

Horizontal Flat Mold, no pouring block

 

1. Place the part onto a piece of clear packing tape or Scotch tape (sticky side up).
2. Trim tape with 1/4 " relief around the edge of the panel.
3. Mount the master(panel/tape combo) face up to a flat surface, you can tape the part down along the edges of the panel tape.
4. Build pouring flask around the outer edge of the tape, be sure it's leak-proof.
5. Pour RTV mold material.
6. After curing remove master and pour P/U resin for parts with ultra thin backing.
7. Make sure you let resin cure longer than normal in order for the thinnest parts to harden as much as possible.
8. I've done this with PE frets and it works very well.

 

HTH,

 

D.B.

 

 

[ChuckT]

Very nice!

 

Thanks very much, 

Chuck.

[Bob MDC]

DB,s method looks great, on closed moulds it depends on the silicon a hard mould so no flex in the center then really a vacuum is the best and again don't demould to soon, we work to 0.5mm for one of our customers (who will remain nameless !!!!)

 

Bob

[ChuckT]

Thanks for the confirmation.

 

C.