Catalyst Questions

General Discussion
1

I have done a search on the forum and found more or less what im after but i just wanted to double check this.

I have shaped me a 5’11 shortboard and was wondering how much catalyst i need to add in to the laminating resin. The air temp is around 65-70F here. Every where i have looked doesnt give an estimated drying time so any help regarding this would be great.

Thanks

2

You might want to have a look at ( and save as a general reference ) http://www.fiberglasssupply.com/pdf/miscellaneous/MEKPChart.pdf

and http://www.fiberglasssupply.com/pdf/polyester/S249.pdf

The latter gives a gel time of ~13 minutes at 75°F, so at 60 it’d be a fair amount less, at 70 pretty close to that 13 minutes. Figure a little more than that from ‘gel’ to ‘as hard as it’s gonna get’ . That’s, presumably, with about 1.5% catalyst.

Working outdoors in the sun will speed that up, of course. And my own experience is that whatever gel time the stuff has, ‘the damn stuff is starting to go gooey and dammit, I’m nowhere’s near finished’ So maybe using the minimum amount of catalyst is a good idea… oh, and preferably on a cool day.

Hope that’s of use

doc…

3

Thanks for the links. I knew glassing was gonna be the one to give me headaches and nightmares. Only 4 boards to do :slight_smile: - probably should have shaped thn glassed instead shaping 4 on the trot DOH!!

4

When you don’t have experience, it’s easy to get your cat’ wrong. Whenever I’m not sure because I’ve got a different source of resin, or the whether is different, or I’m working a large area and don’t want to get caught with a hot batch, I do a test batch while I’m getting ready. It doesn’t take much to do a 1 oz. littel batch to use as an indicator in your cat is in the ballpark.

Attached is a little conversion sheet I use to go from drops/oz to larger quantities.

As they say in the lab busines, “One test is worth a thousand expert opinions”.

5

Thanks for everyones help really was valuable :slight_smile:

Just to inform i have done the first side of glassing went a lot better than i thought also learnt a whole lot during the process. It gelled a lot quicker than i anticipated but fortunatly i had moved at rapid pace i think next time ill use less MEKP :slight_smile:

6

Shanti

you may want to consider using UV catalyst

7

11cc of mekp, to a Qt. of lam will kick in 20-30min. at 68 degrees.