Hi,

hi adrian,

if your only getting to -20hg you must have a leak somewhere, while its under partial vacuum around -10hg or so switch off the pump and ease the cloth into the shape then pull full vac and isolate the mould to check for leaks, if all ok continue with the fun.

neil in sunny melb

Hi Neil,

It makes a world of difference mate you will see! The last 10 is where it really compacts it and essentially the only way it works.

Hi Adrian,

Sorry for the delay in getting back to you on this forum and thanks for the order you've just placed, you're right, that's a whole lot of gear; I'm sure great results are just round the corner.

I'll get back to you with some answers but could you be more descriptive about what this is? - 3" long in the shape of a dug-out canoe, that's tiny! What sort of reifnorcement have you been using (what weight?) and how have you been laying it in? You'll want to be working with some very light reinforcement on something so small.

I think your bridging problems are probably coming from a combination of the low vacuum pressur eyou've been working with (20" is really not that high) and also, probably, from bad bagging technique.

Next question is do you have a product that can be used like gel coat on small parts to get a good finish, currently using 3/4 fglass as the first layer but still get some pin holes.  Just don't want to go to all the effort to setup a dump gun for a 3" part.

Yes, GC50, it can be brush applied too. Remember though that anything that goes into a mould first, unless it's totally flat, will leave some  sort of a whitness on the reinforcement. If you're not doing cosmetic carbon then this won't be a problem at all though and brush application of the GC50 is the easiest thing. Your pin holes problem will dissapear.

Talk soon, Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

[quote]al010964 (18/10/2012)

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Hi All,

Sorry part is about 6" not 3"'s as it is mirrored.

The part is for an RC Plane.

I have put a screen capture, note this is an ealy drawing - don't have the current one available, the only difference is that all the edges have a 0.1 radius in the final one.

I have tried a variety of fabric's CF and GF in e.g.

1x 3/4 oz GF & say 2 x layers of 2.9 oz CF (2 twill) @45 degrees.

Matt I suspect this you may be correct abut poor bagging technique / vaccuum.

I also am starting to suspect this part my be on the limits and need an A & B mould ???? not sure until I try again.

Happy to hear everyone thoughts.

NeilB - No dry season is long gone we are starting to get an early wet.

Cheers,

Adrian

You should contact a guy called wyowindworks on the composites central forum, i think he builds these things professionally. Quite switched on for sure. 

Something like this?

http://www.carboncopyuk.com/acatalog/info_267.html

Hi All,