How long is the normal cure time??

[hombre]

I'm putting a different HSF on my vid card, with Arctic Silver Adhesive, but I'm weakening the bond with some A/S Compound cause later I want to change it for a cosmetically better one.
I have followed the instructions from A/S's website, but I'm wondering how long it should take for it to dry enough to install?
It's been approx. 1.5 hours and it doesn't seem any more set then when it was first put on. I didn't use but maybe 1/3 compound to adhesive, so I thought it wouldn't take but an hour or so to dry, but then again I haven't used the adhesive and compound together.

Anyone got an idea?

[TruckChase!]

I usually wait at least overnight before mounting anything to be safe.

[Colin]

When I use AS epoxy, I let it cure for several hours but if it has not reached a set in 1.5 hours, something is wrong. Adding Arcitc Silver II will increase the cure time. A cold room will do the same. For every 10 F drop in temperature, the cure time doubles. You did use equal parts of A (translucent cap) and part B (black cap) and then mix in 1/3 Arctic Silver II, correct?

[Silversinksam]

(Keep in Mind Arctic Alumina adhesive sets much faster than ASTA)


Heres info from ASTA:

General Information
1. Cure Stages
Mixing the resin and the curing agent begins a chemical reaction that transforms the combined liquid ingredients to a solid. The time it takes for this transformation is the cure time. As it cures the adhesive passes from the liquid state, through a gel state, before it reaches a solid state.

Liquid-Open

Liquid-Open time (also "working time") is the portion of the cure time, after mixing, that the resin/curing agent mixture remains a liquid and is workable and suitable for application. All assembly and clamping should take place during the open time to assure a dependable bond.

Gel-Initial Cure

The mixture passes into an initial cure phase (also called the green stage) when it begins to gel, or "kick-off. The adhesive is no longer workable and will no longer feel tacky. During this stage it progresses from a soft gel consistency to the firmness of hard rubber, You will be able to dent it with your thumbnail

Solid-Final Cure

The adhesive mixture has cured to a solid. You should not be able to dent it with your thumbnail. At this point the adhesive has reached about 90% of its ultimate strength, so clamps or other retention aids can be removed. It will continue to cure over the next several hours at room temperature.


2. Understanding and Controlling Cure Time
Pot Life

Pot life is a term used to compare the usable life of different hardeners. It is the amount of time 100 grams at 72 F remains a liquid. Because pot life is a measure of the cure speed of a specific contained mass (volume) of adhesive rather than a thin film, a hardener's pot life is much shorter than its open time.

Curing Temperature

The warmer the temperature, the faster the adhesive will cure. The cure temperature is determined by the ambient temperature plus the exothermic heat generated during cure. Ambient temperature is the temperature of the air or material in contact with the adhesive. Air temperature is most often the ambient temperature unless the adhesive is applied to a surface with a different temperature. Generally, the adhesive cures faster when it is warmer. Exothermic heat is produced by the chemical reaction during cure. The amount of heat produced depends on the thickness and surface area of mixed adhesive. In a thicker mass, more heat is retained, causing a faster reaction and more heat. A contained mass of curing adhesive can quickly generate enough heat raise its temperature significantly above the ambient level and increase the curing rate. However, if the same quantity is-spread into a thin layer, exothermic heat is dissipated, and the ambient temperature determines the adhesive’s cure time. The thinner the layer of curing adhesive, the less it is affected by exothermic heat, and the slower it cures.

Controlling Cure Time

In warm conditions mix smaller batches that can be used up quickly, or keep the mixture in a thin layer thereby allowing exothermic heat to dissipate and extending open time. The sooner the mixture is transferred or applied (after thorough mixing), the more of the mixture's useful open time will be available for assembly. In cool conditions use supplemental heat to raise the adhesive temperature above the curing agents minimum recommended application temperature. Use a hot air gun, heat lamp or other heat source to warm the resin and curing agent before mixing or after the adhesive is applied. At room temperature, supplemental heat is useful when a quicker cure is desired.

CAUTION!

Heating adhesive that has not gelled will lower its viscosity, allowing the adhesive to run or sag more easily on vertical surfaces. Never heat mixed adhesive in a liquid state over 120F(49C). Regardless of what steps are taken to control the cure time, thorough planning of the application and assembly will allow you to make maximum use of the adhesive’s open time and cure time.

[hombre]

You did use equal parts of A (translucent cap) and part B (black cap) and then mix in 1/3 Arctic Silver II, correct?

Yeah, just like that...the second time. :rolleyes:

I started this little project last night and couldn't find my instructions for weakening the bond. Since I had already remove my card and the fan, (DAM=dumb ass move) I made the mistake of adding all 3 at the same time. This morning it hadn't set up at all, so I started over. This time with my instructions.

I would use it straight, but the HSF is old and since this is a new card, I wanted to replace it with a nicer one when I can get something ordered. And to, this is an experiment (for me), cause I don't know for sure how it's going to work; in theory, it should be fine.

I've put a 80mm fan on a 50mm aluminum heatsink, cause Gainward's HSF is like a High School Prom Queen, she's pretty but not worth much when it comes to a B/J. :eek: (at least not at my old school) :D

Now the logical thing to do would have been wait until a new HSF had arrived, but this is modification for overclocking, and when has "logic" played a part in that? LoL!

I've set the card under a desk lamp to warm it a bit, and I think I had better set back and give the A/S time to do it's thing, I just started wondering, due to my screw up last night, if it was normal for it to take hours to set up, and hoped someone had some experience with the diluted cure time.

Thank you all for your help, I do appreciate it!

[stymee]

I used the Arctic Alumina adhesive (mixed with about 1/3 Alumina grease) to stick an Antec Socket 370 cooler on my Ti200. I think it set enough to stop sliding around in less than 15 minutes. I was up and running in a couple hours (probably shoulda waited a little longer, but I haven't had any trouble out of it).

Something definitely went wrong with the first attempt...

[ButcherUK]

re: removal, I used some AS adhesive cut 50:50 with AS2 and after letting it cure I had to freeze the card to get the bond to snap. The stuff set very solid.

[hombre]

$#@$ !
It's been 24 hours now and the second mixture has not cured.

I wish I know what I was doing wrong.

I don't understand, I used the same tubes (I have 2 sets) to put a copper HSF on my GTS card and it's fine.
However, I did not dilute it with the A/S Compound.

I guess I'll wait until I get a new HSF, and then just use the adhesive straight. :mad:

Thanks everyone

PS:
I was noticing that one of the "B" tubes looks different from the other, could the one I'm using be bad?

It did seem to take quite a while for the other HSF to set up, which didn't have any compound added.