My Catastrophy.....................the saga of learning.

General Composites Discussions Composites Talk
#1

I have been a busy lil b@stard these days. Building molds like an idiot…I can only devote a few hours each night so it sucks to have so much in front of me to get done.

Anyways, I had about a gallon of tooling gelcoat left from my previous 5 gallon pail.

I tested it before using it by adding MEKP and making sure it got hard…it worked fine.

I have my 8 plugs out and I start spreadin’ the love so to speak…applying thick brushed coats of it to the plugs. This stuff was a bit older (9 months maybe?) and man did it cover well on a first coat.

I figure by the time Im on the last one the first one will be B staged enough to start the next coat.

Well…I ran out…so I open up my brand new 5 of CCP tooling gelcoat and mix the catalyst in it and start to brush it over the first coat…

wanna guess what happened?

First, after about 10 minutes I look back at the first mold and see that its now starting to bubble up…convienantly right where my modeling clay is from the part to the flange transition.

I start cussing up a storm. I think…"Maybe, just maybe I can razor blade it out and rebrush it.

10 minutes later…the thing has bubbles everywhere.

So I wait for about an hour and end up peeling it off. Thankfully it was cured enough to be peelable but not so much that it was hard.

I didnt have to reflange the plugs or wax or anything…but its a lesson learned in time.

Im not sure why it had that reaction, could have been that the old stuff was kind of bad…or it just wasnt compatible with the CCP.

Whats the lesson? Dont try to mix two brands of anything together even if it is the “same” system.

It cost me 10 hours of time if you add up everything from when it could have gone smoothly.

#2

That is what is called alligatoring or the top layer has shrunk the bottom layer (could be too thin to in those areas too), by curing faster and pulling on the soft first layer.

It is always better to use up the older material as filler or part making.

With the molds needing to be as perfect as possible and you have your choice between an old batch or new batch of tooling gel coat…use the new.

Learn the lesson and remember it the next time…you can do this!

#3

Oh I know…I been making so many great molds that I just thought Id go ahead and try it…

Now I know Ill never mix the two brands on top of one another. If anything Ill use all the old on a mold and use new on the other.

thats how we learn though…through experience.

#4

When we have a batch of older stuff to use up before opening a new container, we just mix it in.
Also, try not to do more than 1 application of gelcoat. Brush, or preferably spray it on thick and that’s it.

#5

it was brushed on…but the new tooling gelcoat is thin…it litteraly needs to be gobb’d on or it will go almost thin enough to be transparent.

I need to talk to my rep about this stuff.