What is 16 multiplied by 7?

amcardon

amcardon

Joined
Jun 29, 2009
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It's not 56, that's for damn sure! While helping my scouts make some homemade denim "micarta" (yes, using the term very loosely) it somehow made sense in my head that there are 8 tablespoons in a cup, right? Wrong. There are 16. I was thinking about a cube of friggin butter and I'm an idiot! Needless to say we added half the amount of hardener that we were supposed to (should have been 112 drops of hardener per cup of resin, I added 56) so we'll see if I get to redo the 7 sets of scales we clamped up. I did them yesterday, realized my mistake as I was laying in bed last night (for some reason it popped into my head... totally pissed me off) and today they seem rock solid but it was cool outside so I brought them in to warm up a bit.

So, I do have a question with all this - I am as new to this addiction as you can get, only in it to make some hopefully decent knives for some friends and family members, and know nothing of epoxies and resins and whatnot... Will these work or do I need to chuck them? I used bondo polyester resin just because I couldn't ask my boys to come up with the money for something like West System and I don't have the money to spot them...

Anyway, that's my frustration for the day; I should really stick to a calculator when it comes to math. That's one reason why I'm going to Chiropractic school: no math!
 
I hope I never have to learn the volume portion of the Imperial system...
 
Can't help you with your question, but...

A calculator wouldn't have helped you if you had your unit quantities wrong. Unless, you used the calculator to do the conversion of cups to tablespoons.

Hey, won't you have to count vertebrae and whatnot?!
 
Farmer Phil said:
Can't help you with your question, but...

A calculator wouldn't have helped you if you had your unit quantities wrong. Unless, you used the calculator to do the conversion of cups to tablespoons.

Hey, won't you have to count vertebrae and whatnot?!
Click to expand...

Yes but the highest number I'll have to count to is 12! I can do that with only 1 shoe off! And yes, I would have done the conversion on the calculator...

...Or I could have asked my wife! Don't tell her I said that, she'd never let me live it down!
 
sometimes not knowing can be beneficial.....for example, I don't cook so I don't know what the hell amount a tablespoon would be, forcing me to look it up and probably get it right. :p
 
It should still fully harden just take longer. When using polyester resins you control the speed of setup by the amount of hardener. If in doubt take and make 2 identical shaped and sized disks in the bottom of Dixie cups using the correct amount of hardener in one and 1/2 the amount in the other and wait a couple days and then compare how they break.


Yes, the imperial measurement system sucks. I see costly mistakes all the time with people making piping systems and steel fabrication. A good part of it is due to many peoples poor math skills and a lot to our system. What makes me laugh is many buy inch-foot conversion calculators that will handle fractions and then they blow it by pushing the wrong buttons while entering back and forth. I personally use paper and pencil. First I convert to everything to inches and fractions. I do most of the conversion in my head as I use the fractions in 1/8 to 7/8 all the time and am very familiar with them as I am with converting ft/inches to straight inches. Then I do the math and do it twice using different routes both times to the answer. If the answers match I built. If not redo math. I do have a calculator in my tool box and use it for sq roots and when using trig tables to work angles. The metric system would be so much easier and effective. But the logistics of converting all the bolt, pipe and structural steel sizes that already exist and then keeping an inventory for the old components that will be operating for many years in industry and an inventory for the new metric pieces, would be a major nightmare. For example, while running a structural steel shop, I had to use metric prints to make a huge trailer to mount a rock crushing system. The crusher was built in Australia and was metric and that is where the trailer prints came from. Converting the metric dimensions to ft/inches was easy. But, when it came to replacing all the metric structural components with standard, it sucked. The metric frame rails came out to about 22 1/2" and the closest standard where 24". So I had to adjust all the attachments to those. Then, when replacing all the rest of the pieces that attached with similar type differences each had to be adjusted to make up for their difference and the original frame rail difference. So on and so on. It all came out fine, but what a nightmare. The finished project weight 124,000 lb when it rolled out the door. I think you could do this now with Autocad, but, it was still in its infancy when I did this project.
 
amcardon,
I've made some homemade micarta using Bondo brand fibergass resin and here are some thoughts about my experiences.

If your slabs cured hard and dry without being tacky or gooey at all your fine.

After using the full amount of hardener and having it cure too fast to get all my layers done I made one with half hardener and had a slab that came out half cured. The top half of the slab stayed gooey just like it was soaked with resin and no hardener added.
I suspect when using less resin that getting full mixing of the resin and hardener to be the determining factor of the end result.

After going through this trial and error I found a recommendation somewhere online to use the recipe of 1 cup resin and 1 teaspoon hardener. I've only used this formula once but it did give plenty of work time and cured fully and completely.

It sounds to me like you and the Scouts are fine though. Cutting your slabs will tell the full story.

Thought I'd share my experience with the Bondo

-Josh
 
You'll note the warning on the can not to put any unused resin back in the can because it will harden all of the resin over time. As others suggested, it will just take longer.
 
ib2v4u said:
It should still fully harden just take longer. When using polyester resins you control the speed of setup by the amount of hardener. If in doubt take and make 2 identical shaped and sized disks in the bottom of Dixie cups using the correct amount of hardener in one and 1/2 the amount in the other and wait a couple days and then compare how they break.
Click to expand...

Given a couple of years most poly resins will harden with nothing added. If you're short on hardener, you can also speed the process up with more heat.
 
Time is the issue here, just wait it out. As far as measurements go I'm still trying to get past the concept that it takes 2.5 dimes to weigh the same as a quarter. :confused: Who'd a thunk it?
 
I learned the metric system back in the 50's in grade school because the US was going to switch. The plan was derailed by political pressure from industry and today the US joins with the Republic if Tonga as the only countries in the world still on the obsolete system. Even in the US, scientists all use the metric system. only when we have to talk to engineers do we revert to the old units
 
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