CATALYST CHART MEKP according to temp

[northrivergeek]

Several years ago I found a fiberglass repair site CaptDsboatshed.com, or Helendalepublishing.com but all his sites are gone, he was a very nice man . Dale C. Whiteman was his name .. apperantly he either retired or has passed away.

He had a CATALYST CHART on there that gave you not only the ratio, but by air temp as well or he had a link to it ? .. I did have it saved but after a HD crash .. it must have not made to the backups I had made.

Does anyone have a chart for Poly and MEKP that gives the ratio according to air temp ?

And If I lay glass above 75 degress say at 4pm.. but at 7:30 the sun sets and the temps drop into the 50s or below over night will it still fully cure in the 24 hr period because not at 70 or above for the full 24hrs ?

Thanx in Advance
Sean aka Da Fish

 

[ondarvr]

Re: CATALYST CHART MEKP according to temp

I do have a chart that gives the amount of increase or decrease for temp.

For the most part though catalyst charts are generic recommendations, each type or brand will react a little different to catalyst levels and an amount that works well with one, is too fast for another. If you stay between 1% and 2.4% you should be OK. 1% when it's hot out and 2.4% when its colder. Resins are tested at 77F at around 1.25%, For every dergree above that drop the level by .07, below 77F increase it by .07 up to 2.4%.

For the second part of the question.

Yes, but only on Tuesdays during a full moon in the second half of the year.

It will get hard, but depending on how thick the laminate is it may not fully cure.

 

[northrivergeek]

Re: CATALYST CHART MEKP according to temp

I do have a chart that gives the amount of increase or decrease for temp.

For the most part though catalyst charts are generic recommendations, each type or brand will react a little different to catalyst levels and an amount that works well with one, is too fast for another. If you stay between 1% and 2.4% you should be OK. 1% when it's hot out and 2.4% when its colder. Resins are tested at 77F at around 1.25%, For every dergree above that drop the level by .07, below 77F increase it by .07 up to 2.4%.

For the second part of the question.

Yes, but only on Tuesdays during a full moon in the second half of the year.

It will get hard, but depending on how thick the laminate is it may not fully cure.

Would I have the same issues with epoxy ? Im doing a transom, stringers and floor in a boat .. would the air temp fluctuation affect the cure as it does with poly and mekp ?

 

[ondarvr]

Re: CATALYST CHART MEKP according to temp

Temperature will have an effect on both products, at 50* though don't stress over it. You're doing the work at much higher temps and most of the cure is taking place in first hour or two and if you think it's going to be too cold out just use a heat lamp. You can put a light near the area and it will keep the temps up enough so it will cure well, just don't get it too close.

 

[northrivergeek]

Re: CATALYST CHART MEKP according to temp

Temperature will have an effect on both products, at 50* though don't stress over it. You're doing the work at much higher temps and most of the cure is taking place in first hour or two and if you think it's going to be too cold out just use a heat lamp. You can put a light near the area and it will keep the temps up enough so it it cure well, just don't get it too close.

Oh thank you, Thank You , thank you, thats what I wanted to hear!
Ive done a good bit of glass work, but was in late spring or summer.. Im trying to get this done before it gets cold and stays that way

 

[oops!]

Re: CATALYST CHART MEKP according to temp

For the second part of the question.

Yes, but only on Tuesdays during a full moon in the second half of the year.

rofl

 

[109jb]

Re: CATALYST CHART MEKP according to temp

Would I have the same issues with epoxy ? Im doing a transom, stringers and floor in a boat .. would the air temp fluctuation affect the cure as it does with poly and mekp ?

Epoxy MUST be mixed in the ratio given in the directions or else you will not get full crosslinking. The mix ratio needs to be measured accurately either with a pump that delivers a set volume, or other means to accurately measure the correct ratio. Poly resin has a range of catalyst ratios that will get you a full cure. Epoxy does not have this luxury. If the epoxy ratio is wrong, it may seem cured and hard, but the full strength is not realized.

 

[wca_tim]

Re: CATALYST CHART MEKP according to temp

as above, epoxy is gonna need to be mixed at a constant ratio to get good results - temp will just determine how fast it cures.

for poly resin, free radical initiators are used. As a general rule, you'll get similar results if you use double / half the catalyst for every 10 degrees celsius down or up from the ratio that you do have. (that's about 18 F).

Note that although for epoxy you need to keep the ratio constant, but can get an idea ofhow fast it will cure based on the same relationship. will double for every 18 degrees up, etc...

note that that is more for the kick off - since most generate their own heat, it's going to get a little hotter than that as it cures if your doing if relatively fast.

note that a huge amount of variability comes from the age and storage conditions of various catalysts. they degrade over time and faster at higher temps, etc...