Re: Confused on Mats, cloths etc
A few notes on different clothes,
First kevlar is woven into certian types of cloth for building racing hulls with polyester resins, they can be used with great success without haveing to do and entire epoxy layup, same with carbon fibre ( which is black so take extra care rolling the air out).
ALL repairs and laminates need to have a bonding layer of mat applied if the cloth being used is not a combo cloth if not used your laminate will peal off. By this i mean you should never apply just a woven cloth by itself unless you have pu a layer of at least .5 oz down first wet. (this is why combo products are used) no need to put the mat layer down beacuase the cloth manufacturer as already stitched it to the cloth.
Epoxy resins are not a 50/50 mix for all epoxyies, west system is a 1 to 1 pump ratio, one can generally being 1 gal resin the other is 1 quart of hardner. 1 pump of each is the correct mixture and it is critical that it is right.
On polyester catylasts, you can go as low as 1% depending on how many layers and the conditions you are working in. the more layers you pu on the more heat you will generate, the more shrinkage you will get. and yes you can get it to hot as well. There are also two main types of layup resins used depending on your geographical are and its based on ambient temperature. In the north east we us "summer resin" and when it gets colder we use "winter resin" the basic difference is the amount of promoter used to activate it with the catalyst. the winter resin has more of it. Back in the 50's and 60's the promoter was added by the boat builder in the form of cobalt. They also built the boats in a contiuos laminate in one session which created the need for the self control during layups. IE the more promoter added the quicker the kick off......
In todays world the "single shot" layup has been replaced by the "Scrimp system" which is basically a vacuum process. the cloth is laid in the boat with spray adheasive to hold it in place, the core is added like balsa or foam, more cloth, stingers and their cloth then the peal ply and vacuum bag are added, sealed, resin is pumped in while vacuum is going. presto instant boat in single layup, ( there is a little more to it than that but you get the idea)
When installing stringers i recommend a tri ax cloth over a bi-ax its easier to bend and shape and it adds strength in another direction the bi-ax doesnt.
And i dont mean to stomp on anyones toes here, if i have i apologize
