Search found 78 matches

by Jones
Wed May 14, 2008 6:18 am
Forum: Miscellaneous
Topic: Is there an engineer in the house?
Replies: 23
Views: 5958

Here's the steel spreader:

Image
by Jones
Wed May 14, 2008 6:01 am
Forum: Miscellaneous
Topic: Is there an engineer in the house?
Replies: 23
Views: 5958

P is you lifting force at the center. P/2 on each end. The distance from the end to the lift point is L/2. M= force x distance or P/2 x L/2 = PL/4 It's hard to believe that I made a living for almost 34 years on variations of one equation. Stress = P/A -+ MC/I. Bill Bill & FDMSIV, Not to make this ...
by Jones
Tue May 13, 2008 8:29 pm
Forum: Miscellaneous
Topic: Is there an engineer in the house?
Replies: 23
Views: 5958

I used it today to lift the BoJest from a flatbed and place it on the 3800 trailer I'm building. Now I can get proper bunk angles since there's quite a bit of twist to get a good supporting fit.

Thanks for the help on the calculation!

MJ
by Jones
Mon May 12, 2008 12:55 pm
Forum: Miscellaneous
Topic: Is there an engineer in the house?
Replies: 23
Views: 5958

Thanks much for the responses. I also was curious about the yield/ultimate strength because my manual (typical) gives the lowest carbon grade. It's A36, which used to be rated at 36K but is now rated @ 48K yield, 70K ultimate. I'm not sure how that has happened, but several searches on google under ...
by Jones
Mon May 12, 2008 9:15 am
Forum: Miscellaneous
Topic: Is there an engineer in the house?
Replies: 23
Views: 5958

The section modulus for C4x5.4 is 1.93 Back to back would be 3.86. At 10 ksi x 3.86 =38.6 "k Moment is PL/4 = 38.6 P= 4x38.6/96 = 1.6k or 1600# Bill Bill, thanks :!: Questions... PL/4? I don't understand the formula, had I known what to "plug" in I could have done it. I'm guessing distance x moment...
by Jones
Mon May 12, 2008 9:11 am
Forum: Miscellaneous
Topic: Is there an engineer in the house?
Replies: 23
Views: 5958

FDMSIV wrote:
If you could post a sketch of what you are trying to do I could help you with more details.
Sure:

Image
by Jones
Mon May 12, 2008 8:28 am
Forum: Miscellaneous
Topic: Is there an engineer in the house?
Replies: 23
Views: 5958

Is there an engineer in the house?

If so, please help me with a calculation of moment, simple bending stress: Purpose: Spreader Bar (mild steel) Design: Two 4" x 5.4(lb/ft) C-channel facing opposite: ]-[ Gap: 1.5" (bolts regarded as shear property) 1" G5 bolts (3) located center and ends, housed in 1" i.d. pipe (spacers). No cable/ch...
by Jones
Mon May 12, 2008 7:54 am
Forum: Power Boats
Topic: If Only This Boat Was In Wood
Replies: 5
Views: 2349

You know Jones, welding... Might not be a bad thing to know (if you don't already, I mean) What the heck, if you love the boat, build it out of popsicle sticks if that's what it takes. :P I can't mig weld, yet. But there's a boat out there I'd be willing to learn it for. JMHO. :roll: Gregg I like t...
by Jones
Wed May 07, 2008 7:32 pm
Forum: Epoxy
Topic: Epoxy - A batch gone off
Replies: 31
Views: 9390

My understanding is that "Cured is Cured". There are not degrees. I happen to trust scales, nothing I said implied that your work was less than satisfactory. Here is the reasoning behind getting an accurate ratio: 1. All glues, in order to be received by the host wood for a good bond, require a red...
by Jones
Wed May 07, 2008 12:31 pm
Forum: Epoxy
Topic: Epoxy - A batch gone off
Replies: 31
Views: 9390

The West System pumps are calibrated at 5:1 and work fine. (except for the West System "Special" Hardener which is 3:1 - be careful to use the right pump) Sorry, not trying to split hairs, but "work fine" because the product went on ok or "work fine" because you've compared the pumps to a reliable ...
by Jones
Wed May 07, 2008 9:53 am
Forum: Epoxy
Topic: Epoxy - A batch gone off
Replies: 31
Views: 9390

I suspect those who are having success with pumps are using brands of epoxy that have a ratio more forgiving than the glen-l brand? At 5:1 it's much more critical.
by Jones
Wed May 07, 2008 6:05 am
Forum: Epoxy
Topic: saturation before filling or after?
Replies: 4
Views: 2168

Re: saturation before filling or after?

Hi Gents I am building a Zip. I have read that you should saturate the hull with epoxy before you fill in screw holes etc. with hard setting putty. I have also read that you fill in first, then saturate with epoxy. I have also read that you should never sand bare plywood. Can someone please tell me...
by Jones
Wed May 07, 2008 5:52 am
Forum: Epoxy
Topic: Epoxy - A batch gone off
Replies: 31
Views: 9390

Hi Mr Jones, Thanks for your advice. West Epoxy kits come with "mini pump" dispensers which they say gives the correct ratio. See page 8 of their manual - http://www.wessex-resins.com/pdf/English.pdf You're welcome :D I visited the site you provided and yes, that looks like the same pump. Glen L al...
by Jones
Tue May 06, 2008 9:13 pm
Forum: Epoxy
Topic: Epoxy - A batch gone off
Replies: 31
Views: 9390

4 squirts?

It sounds like you are relying upon a dispenser system for accurate ratios of hardener:resin? I think you'll be much better off purchasing an inexpensive mail scale that reads in grams... a decisively more reliable method of determining mix ratios with epoxy!
by Jones
Tue May 06, 2008 3:01 am
Forum: Epoxy
Topic: Epoxy - A batch gone off
Replies: 31
Views: 9390

Placing the mix in a nearby freezer (if convenient) will arrest the catalyst w/o damaging the product. Some builders use an iced cup under the mix cup to retard the catalyst. Narrow/tall cups produce the highest amount of heat.

Go to advanced search