How to make a mould for this?

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#1

Hey

A friend of mine ordered a boot lid spoiler for his bmw and now I want one too :o So I thought I would make a copy of his for myself.

But I am not sure how to make a mould for this, the part he is getting is closed off at the bottom. I would prefer to infuse. Any ideas?


Regards
Jacques

#2

Looking at picture the visable shape you see flange off then bottom side can be made,a two part mold,make each part separately then cut sand and Bon together.

#3

Or make a 2 part mould, laminate a layer of glass in both moulds, pour in epoxy foam, then bolt the 2 molds together. After cure you can demould, and finish product.

#4

I’ll post a pic tonight of a similar spoiler I make. Youll see how I did the mold.

#5

I thought about this, but the rear edge is quite sharp, I’m not sure how I would get the cloth in there wihout some distortion. Is there a trick to it?

I’m guessing the foam would give enough pressure to give a good finish, or do you mean the carbon should cure first?

I would appreciate it.

Thanks for all the ideas so far.

#6

mmm…I will do something similar in a near future, I was thinking about foam and overlay.

#7

Stabilised cloth. One with a binder. Or use 2 pieces:
Make templates, one witch goes exactly in to the edge, the other with a small overlap. Layup and cut on a piece of backing paper, or vacbag or something. Transfer to the part, place in the mould(the flush one first), and remove backing paper.
Second pieces the same, pay attention to fibre orientation, placement can be a bit less precise. In the edge you don’t see a cut that well, and this way you prevent distortion and bridging.

The foam presses the seams together, so no need for glueing. rudders and foils are made that way.

#8

To make a fabric that will not distort you can spray tack two layers of carbon together. 1 layer on 0/90 and the other on +/-45. You can then cut this stack with a template. The template cut piece will not fray or distort. This stake can then be tacked into the mold for infusion. If you don’t need two layers then you can use really light glass as one of the layers.

#9

Make sure you post pictures, with all this good advice some of us guys can learn as well!

#10

That is an interesting technique I will have to try sometime.

Watching this thread so please keep it going.

#11

Could someone please further elaborate on the expanding foam use? I am having trouble grasping it’s purpose?

Thanks.

#12

The purpose is to glue the top laminate and the bottom laminate together, without the need for complicated overlaps. It also makes the spoiler sturdy enough while using only 1 or 2 layers of cloth. (without you being able to flex the laminate when pressing on it.

#13

Hey there, let me show you how I do it. Keeping in mind that this example was just a quickie that I only needed two spoilers out of it.
http://imgur.com/a/NuueU
For some reason imgur duplicated two pics, idgaf :confused:
First, split split it along the edges, I attached corrugated plastic sheeting with hot glue and then clayed along the seam were divider meets part.

Tooling gelcoat, rolled out 1.5 oz mat, then 2 layers of 3oz mat once thats half off. Remove plastics, wax, pva, do the other side. Dont forget keys (halved clay balls) and bolt holes :wink: ! Normally I would re-enforce and go thicker, but like I said, small run, not production, don’t care.

Ta-da, new part made with primer gelcoat and 3oz.s of mat, glued together with silica 1/8" chopp putty. Hope that help. BTW, the spoiler was for a Merc 63 if you wondered.

#14

worthless without pics of the final part :smiley:

I too have decided to go with some corrugated plastic, an 8 foot sheet bent in half has been sitting in my car for many weeks now:D