I already thought of something like extending the mould with a lip but I do not yet understand how to use the sheet wax in this context. When I use wax, I will not be able to use prepreg on it.

If you've already made both top and bottom parts of the mould, then you could use a narrow strip of sheet wax all the way around the lip of one half of the mould, assuming that there is enough vertical depth to do this? 

If so, the wider the wax strip the better, as this will give you the recessed lip in the part to bond the other half to and a thickness of 1mm should be about right, or as close to the expected part thickness as possible. 

This should work as a 'one-off' solution to getting a joining surface, but it will depend upon the part's depth being sufficient to allow for the joggled edge.

No more ideas?

Do you have an idea how to make such a lip in the mould? You Said make it careful which is a good advice, but I am not sure how to do that...

+x

 

Hanaldo - 8/5/2019 12:46:50 PM

I agree it is a splitter with end plates, not a front wing. But it's small size makes me wonder what it is off - it honestly doesn't look very functional to me.

Regardless, I do think this has to be done as two pieces with a joggle joint as Warren suggests. Trying to do it as one piece is a lot of work/cost for very little gain. 

Yes it is a splitter, sorry wrong wording. I think it has a function because it splits the air to two channels - but thats not why I am trying to make a carbon part out of it

So I come back to your idea to make it as one piece. I would think that your idea above would be a problem to do here because the ends are not flat!?

I agree it is a splitter with end plates, not a front wing. But it's small size makes me wonder what it is off - it honestly doesn't look very functional to me.

Regardless, I do think this has to be done as two pieces with a joggle joint as Warren suggests. Trying to do it as one piece is a lot of work/cost for very little gain. 

That looks more of a splitter than conventional aerofoil.  If the detail is important on both sides, then in effect take a mould of each side and lay it up in 2 halves and bond together.  If you are careful in the moulding, you may be able to create a bonding lip or joggle on one half to give a nice bonding surface area.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

That is a great tip, thanks a lot! Unfortunately I think this will not work on my part. I add some photos...!

Leave the end plates out when making the mould so that it is just the upper and lower aerofoil surfaces. The ends will be open when the piece is finished, like so:



Lay up each half, do the bottom half with an overlap. Before closing the mould, lay tube style vacuum bag on the bottom half of the mould with plenty of excess out each end, fold the overlap carbon inwards so that it sits slightly over the vacuum bag and wont get pinched in the mould, then close the mould being careful not to pinch the vacuum bag or the overlap carbon especially on the trailing edge.

Then simply place the entire mould inside another tube style vacuum bag, and seal the ends of the inner vac bag to the ends of the outer vac bag. When you pull a vacuum, the outer bag will pull down on the outside of the mould, and the inner bag will pull outwards against the inside of the mould.

After curing, simply trim it up and bond in your end plates.

The part is about 60cm x 30 cm so not very small. But I cannot imagine how to make it in one piece because it has gloss surface all around!?