Talk Composites - The Forum for Advanced Composites

Second mold, new issues :-)

http://www.talkcomposites.com/Topic37677.aspx

By mporta71 - 8/14/2020 2:46:19 PM

Hi, after the first not successful mold and part (http://www.talkcomposites.com/Topic36543.aspx) I worked on the part to fix the issues in order to build a new mold.
This time the part popped from the mold almost by itself but... something has happened to the tooling gelcoat!
Please se pics. Last pic is the tooling gelcoat on the base glass, so I tend to exclude some interaction with the plug.
Any ideas?
By mporta71 - 8/16/2020 7:29:11 PM

 
beliblisk - 8/16/2020 7:25:39 PM
 
Massimiliano - 8/16/2020 7:19:15 PM
 
beliblisk - 8/16/2020 7:11:15 PM
 
Massimiliano - 8/16/2020 7:05:56 PM
 
beliblisk - 8/16/2020 6:59:44 PM
 
Massimiliano - 8/16/2020 6:54:06 PM
 
Massimiliano - 8/14/2020 4:31:52 PM
 
Warren (Staff) - 8/14/2020 4:28:41 PM
If you look at your second attached image, you can see the strands of fibreglass heavily printing through the flat gelcoat to the right.  That might be a side effect of the reaction you have had but looking to the left and edge of the mould it doesn't look much better.

It might be pre-release from the surface in some way as the edge looks a bit like the gel has distorted a bit but that doesn't account for all of it.

Thanks... hope my third mold would be better :-)

Do you have any suggestions on how to fix this mold?

Anyone has suggestion on how to fix this problem?
Just apply new gelcoat?
Is there any way to apply it the "flattest" possible?

I think the fastes way would be to redo whole mould from scratch. 1% catalysts seems way to low for gelcoat (i always go with 2%). Peehaps first layer didnt cure and then second layer pulled it a bit.

If you were to try and fix it there will be a lot of sanding:/
Apply gelocat with spatula and cover it with flash tape so you will get relatively flat surface..... sand and do one more step if any low spots remain.

Thank you... I will try on one damaged area and see how it will go... then decide to redo it for the third time..😒

You are welcome. I tend to take every failure as a learning process...... just keep it up and you will get there eventuallySmile 

Yes you are right, first mold plug did not release properly as there were some slight undercuts. Also while applying the tooling resin I mixed too much in one pot so it started to gel before finishing to apply the various layer of mat 🤦‍♂️

Gealcoat wont gel on you to fast opposed to coupling coat and tooling resin (with both of these i go just above lower limit for catalyst and mix amounts i can use in the next few minutes).

When making the plug and filling stuff with fileting wax always think how you will make cf part (either to help easy release of making your life easier laying carbon cloth). It may look straight forward but it actually sometimes takes a lot of forward thinkingSmile

Definitely yes!
Thank you!