Friday, April 24, 2009

emails 20/4/09

20/4/09

From: Corrie Wright [mailto:she16@bigpond.com]
Sent: Monday, 20 April 2009 5:53 PM
To: Brendan Morse
Cc: struth arts
Subject: drop by drop
Hi Brendan your email was good news bad news!! Have answered your thoughts beside them (below) not very positively sorry hope the engineer has better news!! Can you tell me who does Perspex work for you I would like to get another quote for the Perspex We do really like the guy I use but would be good to see the differences if any in quote we will talk soon Corrie
Hi Corrie & Tamara,
Thanks for that.
Yes, it was good to hear more about the project and what you are trying to achieve.
The information you’ve sent is perfect for the moment. Great
We have our engineer here this afternoon and we will see what he can do.
After some discussion here we have some concerns about the structure that may need a left-field solution.
In short, the frame should not be a problem to build and clamp to the caravan. Our main concern is that however that is approached that there will be a very well defined stress region along the bolting line
And that thickness of Perspex is very prone to cracking through there (again, we will review it with the engineer).would 12mm thickness be better? Will talk with Peter from ASAP Plastics to see if he has any thoughts/suggestions about this

For the moment I can see 2 plausible solutions. Please think again!
1. To double the thickness of the sheet. think this option maybe cost prohibited
2. To create a more box-like structure by using 2 sheets joined with a 50-100mm cavity in-between them think this may also be cost prohibited
3. To include a line of supporting compression springs (sketch attached) as a part of the frame that will for the most part keep the caravan upright but allow movement with wave action or strong wind.
The other minor concern is that the ‘raindrops’ that you will be adding (partly that the gluing technique may not being reliable), but mostly that they will add considerable weight that to the structure which will mean even more risk of breakage. My suggested solution to this would be that you may save a lot of time and effort (and possibly even cost) by having the raindrops done as cut-outs on the sheet. This will not only save you the work, and weight of, the glue, resins and the risk of glue failure, but may go a long way to reducing the surface area and therefore the wind load and risk of cracking. We have talked about this option but would really like 3d look (will look into the weight thing)
Please let me know what response to these ideas is,
Thanks
Brendan.

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