2 piece mold contruction ??

[msm04]

hi guys. I just joined the sight and have found a wealth of info on here already. I have been in the marine business for over 10 years as a mechanic.

I am trying to build a 2 piece mold to make a carbon fiber induction system for my snowmobile. I am in the process of building the plug. The plug consist of a 4" tube that splits into two smaller tubes.

I am not sure of the best way to make the mold with the flange were it splits. I was thinking of building the mold as one piece and then cut in half and then install the flange. but I am sure there is a better way.

any help would be appreciated
thanks

[Herman]

Best way is to install a temparay flange, made of nice flat and smooth material (can be anything, but think of aluminium, melamine covered particle board, etc, and make it to fit exactly onto the product. Any gap that is still there can be filled with modelling clay. This clay can also be used to keep the temp. flange in place. Install locating pins if neccesary.

Now apply your favourite mold release, and carefully make your first mold halve.

Remove the temp. flange, and DO NOT REMOVE the first mold halve. Apply mold release to the second halve, and make your second halve of the mould. Drill some holes through the flanges, then demould the halves. The holes can be used for thru-bolts.

[susho]

build a sacrifice piece on the mould, can be made out of cardboard or something. you can laminate a flange on it, together with the first piece. get the sacrifice peace out of the way, and laminate the other piece against it. without moving the first piece, that way you have two pieces wich will fit perfectly.

[msm04]

thanks for the help.. I will you keep you guys posted thru the build

[ahender]

Hi:

I am currently building a mold for a 12' whitewater canoe.

This is my second attempt at building a canoe mold. The first failed for a variety of reasons.

Years ago, I had bought a lot of carbon fiber fabric at a great price ($6 per yard -- 50" 5.9 oz.), so most of the mold is made with carbon and Divinycell foam, which I got as a sample. I used epoxy and graphite powder as my gel coat.

Below are the steps I performed to make a flange for my male mold.

I bought a couple of water noodles -- those round foam play toys for the pool. I cut them in half and laid the flat part on the flange line with a little epoxy.

After they cured, I then cut a thin line down the middle and inserted a piece of poster board about 4 inches high the length of the spine. I then sprayed some 3M glue on that and applied a layer of release film on each side, all the way down to the actual mold. That gives me everything I need to separate the flange and the boat mold.

My reinforcement and additional strengthening via some core material and 1/2" plywood have been applied to the spine. I will have 5 primary bolt sections and some smaller alignment holes. I have also established 4 areas where I can insert a small wedge to assist in separating the part.

Once I finish with the spine reinforcement, I will cut my bolt holes, add the bolts, then cut the mold in half with a jig saw. The purpose of the foam noodle was to allow me to cut through the hull and not encounter any blade resistance.

One thing I have tried to judge correctly is the amount of thickness I have between the two sandwiched layers on the spine. I planned it so that it is approximately the same width as my jig saw blade.

That should leave me with a very small seam to fill once I start actually making my boat. Never having done this before, I assume I can use something like paraffin wax to fill this seem.

Pretty much everything I have learned during this project was taken from this website. It has been a 4-year, on and off again project.

I have about 6 hours left on the spine. Then I am done, well maybe, if all goes as planned. All in all, I expect I have several hundred hours in this project and probably $2,500 dollars out-of-pocket.

Could have probably saved a lot on resin, but after every gallon purchased, I thought that was the last gallon. There really was no last gallon!

I saved quite a bit by asking the various composite companies for samples of their products. With the core materials I used, all of it was received at no charge. I also got a sample 5-gallon pale of SP Systems gel coat that was out of date. That alone was worth about $600.

All-in-all, about $1,000 worth of free materials.

The mold I am finishing is actually the last of three molds it took to get what I needed. I started out with a discarded boat that a friend gave me. The bottom was pretty much rotted out. I made quite a bit of modifications to the length and width, as well as height.

I finished that female mold, made a male mold of that, then made the current female mold from that male mold.

Even with such a small boat, it has been quite a journey.

I cannot contemplate something on a much larger scale.

alan