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2 Part expanding Foam question?

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AfterBurners

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First off I love this stuff. Just used some tonight on the nose cone for my Jayhawk. I didn't want it to expand above the nose cone because I need some room for the bulkhead plate and eyebolt.

Anyway the first pour was good and came up about half from where I wanted. When it cured the foam was hard like Styrofoam, which is what I want. So I mix up the second batch and again it expands nicely, but when it dries its not quite that hard. I guess the best way to describe it is its like a sponge texture, It has a little "give" which I really don't mind, because the threaded end of the eyebolt will push it a lot easier.

My questions:

What would cause the foam to have different types of densities? I used 5 drops of water in each batch, but the second batch probably didn't have as much mixture.

It the instructions it says to add the drop to part "A" before mixing. I did that on the first batch, but on the second batch I think I added the water to "B" or maybe it was after both were combine. Does this really make a difference?

At first I thought it was because of the shelf life of the product and maybe it was bad, but the first batch raised perfectly.

Thanks guys!!:) Much appreciated


Anyway the build is coming along well. I have a friend who has a lathe that can cut down the bulk head plate to get it to fit, which will save me a lot of sanding time.
 

jimzcatz

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I had the same problem recently. I mixed properly with no water, but it never really set up. Is there a shelf life on this stuff?
 

AfterBurners

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I had the same problem recently. I mixed properly with no water, but it never really set up. Is there a shelf life on this stuff?
I read the instructions and it say mix water with part "A" I think maybe I might have added too much water or not enough to the second batch. If you go on PML's website they have a PDF on how to mix it properly and what results you can expect. Could have something to do with weather as well.
 

TheTellurian

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I had the same problem recently. I mixed properly with no water, but it never really set up. Is there a shelf life on this stuff?
AFAIK all 2 part polyurethanes have a shelf life usually 6 months to a year. Thats because once opened moisture in the air starts to kick it over even when tightly closed. Drier climes just take a little longer. Some squirt dry nitrogen into the container before closing to add life span. Likely the OP's problem was adding it to part B since the first batch kicked off ok.


Richard
 

TheTellurian

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From Polytek:

STORAGE LIFE:
At least six months in unopened containers
stored at room temperature (60-90°F). Once containers of Parts A
and B are opened, they should be used or resealed tightly as
atmospheric moisture contamination may degrade product
integrity causing excess foaming, pressure build up and poor cure
properties.



Richard
 

AfterBurners

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From Polytek:

STORAGE LIFE:
At least six months in unopened containers
stored at room temperature (60-90°F). Once containers of Parts A
and B are opened, they should be used or resealed tightly as
atmospheric moisture contamination may degrade product
integrity causing excess foaming, pressure build up and poor cure
properties.



Richard
Mine had a crusted around the cap on Part "A" and I probably had them over a year
 

jimzcatz

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From Polytek:

STORAGE LIFE:
At least six months in unopened containers
stored at room temperature (60-90°F). Once containers of Parts A
and B are opened, they should be used or resealed tightly as
atmospheric moisture contamination may degrade product
integrity causing excess foaming, pressure build up and poor cure
properties.



Richard

That splains it!
 

blackjack2564

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If you have plastic bottles, after use,squeeze bottle till all air is out and liquid close to opening. Replace cap.

Removing air from open bottle will extend shelf life. I had of PML foam close to 3 years that still worked just fine.

Do same by the way, when using Gorilla glue, for locking grains in liners. It will last months rather than weeks.
 

rstaff3

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I do that with all my glues...including wood and CA. At least while the bottles are full-ish.
 
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