REFLECTOR: epoxy pump ratio

[Douglas Holub]

How do you adjust it?

----- Original Message ----- 
From: "Tony Babb" <tonybabb at alejandra.net>
To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
Sent: Saturday, September 16, 2006 4:01 PM
Subject: Re: REFLECTOR: epoxy pump ratio


> 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) _______________________________________________
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