Daan Terstegge asked:

>What are users of Alpha Metals flux 615/16 or 615/25 using as
>thinner ?
>The official Alpha 443 thinner is a lot more expensive than a good
>grade isopropylalcohol, and upto now Alpha didn't gave me a real good
>reason for not using isopropylalcohol. I recently switched to the
>Alpha 443 thinner because of explicit recommendations from Alpha,as
>soons as they're running in delivery-problems the supplier tells
>us that this is due to the fact that we are their only customer for
>this thinner and they have to import it especially for us ! Sounds
>like other companies are using isopropylalcohol, but I'd like to hear
>this from actual users of the flux.

I'm unfamiliar with the 615/16 but we have used technical grade IPA as flux
thinners for several types of liquid flux both here and at other firms.

There is a document required by US OSHA regulations called the "Material
Safety Data Sheet" (MSDS). Casual review of this document may reveal what
the solvent carrier is, especially the flash point or the vapor pressure.
I'm sure they would provide the MSDS to you on request.

Some fluxes used denatured ethanol, or blends of ethanol and isopropanol. I
believe the TLV of ethanol is actually higher, its vapor being somewhat
less toxic. Ethanol is sold as "denatured alcohol" in the US, referring to
the additions of ingredients to make it "undrinkable". Note that some types
of denatured alcohol include things like kerosene, benzene, or castor oil.
One type sold in the US is 95% ethanol and 5% methanol, which would be
suitable. Methanol might also be suitable, but it is a more agressive
solvent, which could be detrimental to the product coming into contact.

If you use an alcohol or alcohol blend as a vehicle, be aware that the
amount of miscible water is a potential problem, they absorb water rapidly
from the air. "Dry" or anhydrous alcohol being what you need. Try to
identify how much water is present and minimize it, as it will affect the
rate of evaporation and the "spattering" you may see in wave soldering
operations.

At the moment, we are using 99% IPA purchased locally in 5 gallon
containers (about $6 per gallon here) as thinner for our no-clean Lonco
flux. It is much cheaper than the Alpha thinner and seems to work just fine.

I would recommend that you measure the acid number of the resultant blend
rather than thinning based on density.

FYI:

                ethanol         methanol        isopropanol
flash point     13°C          12°C          11.7°C
BP              78.5°C                64.7°C                82.5°C
density         0.789           0.792           0.786

Any cost savings you achieve based on these recommendations should be
shared with the international "send Cupples' son to college fund". I've
only got a few years to go. Please email for details.


regards,





Jerry Cupples
Interphase Corporation
Dallas, TX USA
http://www.iphase.com

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################