REFLECTOR: epoxy pump ratio

[Tony Babb]

Steve,

I also have a Michaels pump. As I recall the initial calibration was
slightly off (maybe 47:100?) from what I needed (44:100). Not surprising
since they sell these things to lots of different people doing different
things with them. I bought mine several years ago and I don't recall them
providing any measurements, I just adjusted it until I got 44:100. Are you
remembering to subtract the weight of the empty container from the total
weight of the container with harder or resin in them before you do the ratio
calculation? I usually do about 10 pumps to get a reasonable sample size and
minimize errors. I also recheck every now and again, such as before I do
anything structural or if I haven't used it in a while. 

Here's what mine looks like
http://www.alejandra.net/velocity/images/heated%20box%202.JPG

Good luck,

Tony
SEFG 62% done, 78% to go
www.alejandra.net/velocity

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Steve Goldman
Sent: Saturday, September 16, 2006 11:44 AM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: epoxy pump ratio


Well I've finally was ready to actually start mixing epoxy to attach the
wing foam cores. First thing I do though is check the ratio I get from my
Michael Eng. pump. It's wrong. When I calculate the wt. ratio I have .537
very consistently. I used two scales and they both agree. I've checked the
distance of the hardener setting and it's correct (2.25 in.) The slide is
directly under the hardener piston like it is supposed to be. I've tried
pumping very slow (waiting 15+ sec. at the bottom of the stroke) to be sure
cavitation shouldn't be an issue. No matter I get the same ratio.

Since the pump is brand new I wouldn't expect a problem with the check
valves but unless the calibration of these things is normally this far off
I'm not sure what to do. (If the calibration is commonly off this far I
can't see the point of the table for all the ratios.)


-- 
Steve Goldman
'77 Tiger N28531
Velocity XL5-RG (T-3485hrs)
Pittsboro, NC (9NC8) _______________________________________________
To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html