Ultrasonic thickness gauge for fiberglass

There are more things that need to have attention paid to than .1 of a mm of glass in a stack thats over 12 mm thick !! come on !!!

 

The Chinese approach...

His mat varies more than 10% in thickness, and if you want to reach 27mm, instead of 24mm, you need to be able to check it.

 

The 27mm is on the Double ups in the keel area !!talk about nit picking !!
no wonder you guys never got near the americas cup if you worry over such triviel matters !!

Here in china we use better quality glass and less of the other stuff . In the over all scheme of things its not even worth loosing a wink of sleep over . There will be other parts of the boat that need more attention paid to them i would say , Theres always a margin of era built into things !. Some times lighter is better than thick and ridged and unforgiving !! Its the laminating that is more important than worrying over virtually nothing !! .
You need to get into the real world and go live on a desert island for a year or two then you will understand what you are worried about is meaningless . Change you glass supplyer !!! How long do you have your glass instock before you use it ,a while !! why dont you do some small test panels if you are worried about it that much maybe your workers are rolling it out to hard Just roll a coat of resin over each laminate then at the end it shoud be the right thickness !! resin rich but your not worried about that just the thickness.
Man you going to have some fun and loose a lot of sleep when you start infusing your boats . Better book into a soft padded hotel room !

 

When we make test panels we need to weigh the CSM to unsure the amount of glass is correct so it can be compared to another laminate with a fair degree of accuracy. While some brands may be better than others, and things have gotten better over the years, but they can all still vary about 10%.

 

You think thats bad can you imagion what goes on if they had a chopper gun !! wow !!
The degree of inaccuracy would be in the milimeters not parts there of !!.
There used to be a small csm , woven roving and unimatt manufacture close by one place i worked in new zealand and he was really accurate with all his weights of glass and could make what ever weigth glass we wanted . once the machines were set all came out the same !! was the first time we could buy glass rolls in any width we wanted and with a csm on one side also any weight we wanted !!.

 

Supplying in any width, and accurate wovens is nothing new. It is just that the manufacturing process of CSM allows for a margin.

First of all most yarn suppliers have a 3% weight margin. (that is already 6% weight difference between low and high weight). Then there is the manufacturing process, which gives you a margin as well. 10% is nothing abnormal.

And if you want to non-destructively control the thickness of your part, which can vary 10%, ultrasonic measurement is quick and easy.

If you want to be more accurate than what the manufacturers give you, you need to set up more testing equipment than just counting number of plies. You cannot blame anyone for that.