Mold Setup and Resin Infusion Questions

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#1

Hello. I am getting close to setting up for my first mold. Here is a picture of the plug that I have made.

I have since covered those holes you see in the cover with aluminum. I am in the process of applying filler and sanding. My questions are these:

  1. Can MDF board be used as a Base for Molding? Can Wax be applied to MDF board so the mold will not stick? I am thinking yes, but I am asking also.

  2. This is a cover is a complex shape. Where do you think is a good place to put the infeed resin line and should there be more than one line? Does resin flow around very tight angles, like the point in the top of the cover?

I pretty much have most of the process figured out for molding and infusion. Just from time to time I have questions and need advice. If you all see anything else that could go wrong or needs to be addressed please advise.

#2

The thing looks like a B2 bomber!

I would seal the MDF with something first like bondo first but only because I know it’ll work. I’ve never tried using only wax but I do suspect the texture of the MDF will come through which would be undesirable.

I would extend the flanges a few inches, especially on the vacuum side. For a part like this you could feed from the front nose to the rear, just include a large resin break or use MTI hose from DDcompound.

Here’s a question of my own. What is that exactly?

#3

Hello,
if you want to make the mould in infusion I would not use a MDF plate, to many problems with porosity and resin absorption. Take a sheet of Plexi glass or makrolon. Metal works too but there can also be problems with the tightness.
If you want to make your mould by hand laminate you can take MDF, but than your mould might be not tight, thats why I make Infusion mold only by infusion or in special cases by prepreg and autoclave.
I would work with the MTI hose so you don’t need a brake zone and the complex contour does not matter. Also I would start the infusion at the xxxxpit top, the deepest point of the mould, that always the best point to start a infusion.

#4

Thanks for the info! If I used bondo or filler, I can wax or pva right over that stuff?? Or do I have to clear coat the plug before the wax and pva??

Where can I get MTI hose here in the USA?? I was just reading up on it yesterday.

I’ll be looking into a large piece of pelxi-glass.

#5

You can wax mdf and it will release a piece of cake. However you will get an undesired texture on the mould.

Keep posting pictures :wink:

#6

You can wax right over the bondo. A couple of coats of paint and some light sanding helps the finish immensely though.

#7

An option when you are applying the Bondo, pick up some transparencies or a small roll of mylar. We typically will apply the Bondo and lay a sheet of mylar over it, then run a bondo spreader on the mylar speading the Bondo around on the plug. Let it dry and lift the mylar…we do this to reduce the sanding time, you’ll like the finish you get and can save hours.

#8

Thanks!!

Ya, I will be searching for a piece of plexi or glass from Home Depot or Lowes or somewhere…

Interesting trick. Thanks alot. My plug needs additional work so this would be a great trick, though, I am almost done sanding and such.