Carbon= FAIL

You can see how it pullet out of line here





You can see here where I had to cut the "pleat" off to lay somewhat flat in front



Twill FAIL



Ill be buying some faster resin because I fell asleep waiting for it to "tack up" and it went mostly hard.

Plus the resin would not stick to the mold. It looked like oil on wax paper. Should I have not waxed the mold first?

I think you will struggle to get the weave looking perfect using one piece of carbon as the shape is complicated.  Perhaps a few thought out cut lines??

if it were me, perhaps try some profinish carbon and accept you will have visible (but neat and planned) cut lines.

Hi,

One thought about when you say "Resin would not stick to the mold" : from my experience, I think it would be because of tensions in your fabric. Too many forms for the fabric to take withtout any help from vacuum force. Then a few cuts would help here.

 



 


    A $1000 electronic device will always protect a 10 cents fuse

I did use pro-finish and I still sucked at it.

 I have a plan of attack for my next try (don't want to use cuts). I'm going to fold the carbon in 1/2 and do the "valleys" first working up to the openings, cut the holes and wrap inside, then over the tops on to the flat part. Ill also use a bigger piece of carbon this one was kinda tight.

If the base coat of resin dried too much will this still come out or did I just ruin my mold too?

Thanks for the help

Chris

Your mold is not screwed, you can scratch your resin on your mold with a plastic tool. Like bondo spreader or anything like that. Plastic would help not to ruin your mold surface finish.

Hope i helped, and good luck for your next try.

 



 


    A $1000 electronic device will always protect a 10 cents fuse

Can I modify this mold to use a vacuum bag? I think that may be my only real shot at visually perfect parts

For something like that I'd prefer resin infusion. You've got very complex curved shapes in there and you'd be much better off laying the fabric in dry and tacking in place with a spray adhesive. You can always adjust the lay of the cloth as you pull vacuum. Then once it's all happy pull resin through Resin infusion won't cost any more than vac bagging, unless you're planning on pulling a vacuum with a hoover or sommat

There's no reason you can't use that mold with vac bagging, as long as there aren't any sharp projections. Only trouble being you don't have a flange to tape materials to I'm not sure if anyone has any reccs for that, the only thing I can think of is using an epoxy putty to build an edge up on the mold and then coating it in tooling gel, but that sounds a bit bodged. Maybe someone else has a better idea?

Thats exactly what I was thinking of doing. Will resin pull around the whole mold even with extra flanges around the outside? Or do I tape the bag onto the flanges and pull resin over the top? Anyone have a video or pictures on how this can be done? I'm new to composites so I need some help.

As an example of my inexperience....

As an alternative to whats Mr Rooty Tooty said,

I would try the "vacuum bagging" method, without the infusion side of it.

To wet my fabric on the mold then wrap the whole thing with perforated release film, then wrap the whole thing with breather cloth, then wrap it all in a bag, then pull vacuum.

Perforated release film would prevent breather to stick to the part.

Breather is meant to distribute pressure all over the part evenly, and soak up excess resin thru the perforated release film holes.

Using that method would skip the "Add a flange" process.

If you want to add a flange as Mr Rooty Tooty suggests, that can be done too. I made some test with some mold making putty: adding a coat of putty on an already cured coat of putty. It will stick together, however I did not make a real mechanical test (aka smashing it on the ground and see what happens, or using a lever to tear the two layers apart). Maybe the EC guys would tell you if it can be done in a reliable way.

I hope I helped.

 



 


    A $1000 electronic device will always protect a 10 cents fuse

Ideally you want a flange all the way round.

However you might get away with a flange at each end, one flange for the resin feed, one for the vacuum connection.

Then envelope bag it.

Ive done envelope bagging on a couple of moulds and you get virtually zero resin underneath the mould. Remember the vacuum pump is drawing a force through one axis so the resin has no reason to under the mould when the forces applied are sucking it in the part and out other side.

Only bit you will get some resin weepage is due to gravity at the sides due to your zero flanges.

What i did on one of my moulds was sand the putty smooth as it has glass strands that could puncture the bag, then coat it with a thin layer of old resin i have.  I then gave it a quick coat of easylease just in case. (Matt and Paul think i have a drinking problem with easylease but i just throw it everywhere and do loads of layers just to be oversafe).