cobalt naphthenate

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Yes you should still use the catalyst. It is what causes the chain reaction and the PR to eventually cure. The gel promoter will only thicken the PR, not cure it.

I have tried a gel promoter (vs gelling agent) and have found little use for it in casting blanks. But, if you want to give it a shot, do keep in mind that a very of the gel promoter little goes a very long way. And there is not much open time with this, so be prepared for a fast reaction.

BTW, if you think that PR reeks..you should get a whiff of the gel promoter!:eek:
 
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When I was a kid, my dad used the cobalt and MEK to cure his resins.
(synthetic marble trophy bases) We (kids) got a kick out of putting a few drops of
MEK in a coffee can and then a drop of the cobalt. The reaction was quick
and created a nice smoke mushroom that went right up to the ceiling.

.. and I wondered why they wouldn't let me play with scissors... :confused:
 
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Many moons ago I used cobalt napthate (I'm pretty sure that's what we called it)with resin in a commercial application and wonder if it's the same as cobalt napthanate?

It was purple in color and we had to mix it with the resin well prior to adding the mekp else we could start a fire due to the chemical reaction.

If it's the same stuff I would be very cautious using it if I used it at all.
 
Polyester resin cross-links with oxygen, which is provided by the peroxide in MEKP (the hardener). A promoter, such as cobalt napthenate, accelerates the reaction, but does not catalyze it. You still need the hardener.

As others have noted, cobalt napthenate can react violently with MEKP, so the two need to be stored separately. Ideally, the resin should be pre-promoted, so you won't have to deal with handling and storing potentially explosive chemicals.

Regards,
Eric
 
mostangrypirate said:
I bought some gelling agent with my last order of PR. my question is, how much do I use and do I still use the catylist?
Click to expand...

Yes you still use the catalyst.

If memory serves the instructions for use are on the label of Gelling Agent from Delvies Plastics, or from Eager Plastics. Regardless, they usually tell one to use 2 or 3 drops per ounce. However, promoted PR's that are cobalt promoted are usually done in the 3 parts per million range. So 2 or 3 drops per ounce of resin is TOO much.

If you must use it, use a .5cc/ml syringe, and dispense .01cc/ml of gelling agent for resin volumes greater than 180ml(6oz). Be aware that using it with white liquid/paste pigments that are made with Titanium DiOxide, the resin will gel just about instantly.

You don't have to listen me, most don't.
 
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