Iam still having trouble with the amount of resin that is used by the size and the weight of fibre.\
I find sq. ft. #x#= total
how many layers
total weight of fabric
I either get to much resin or to little
I am useing a scale that reads Oz. and grams
Ive read that you should have 2 to 3 times more resin then fabric weight?
ive been reading aroung, havent seen any questions on this
any help or point me to some topics…thanx
A good ratio would be 40% resin - 60% reinforcement for laying up parts. For making molds, you can have as much as 70% resin - 30% reinforcement since you’re not really looking to achieve maximum strength to weight ratio. Almost all of the different reinforcements in the industry besides fiberglass mat is rated at oz per square yard. Fiberglass mat, however, is rated at oz per square feet.
I would use grams to weigh out your resin and fabric. If you are just planning on a regular wet layup I would shoot for 49-50% resin ratio. If you go below 50/50 you might start getting dry spots which might not be good for cosmetics. Of course for stiffness the more fiber the better. I know you can get down to 40/60 resin to fiber ratio with infusion. I would just weigh out your fabric and mix up an equal amount of resin and try that.
I allways try to add allittle bit extra for the stuff that doens;t come out to the contaner.
also I don’t know the oz of some plain weave glass, it s stuff that has been around for a while, is there any way of to find out the oz per sq.ft.
If you call the place you bought it from they should be able to give you the materials GSM (grams square meter) but just chop off a piece and weigh it on a scale. Mixing up slightly more is a good idea though.
besides fiberglass mat is rated at oz per square yard. Fiberglass mat, however, is rated at oz per square feet.
Evan, I do not want to correct you, but…you got those backwards: mat is rated by the square foot (in oz. as the glass manufacturers do it this way) and Cloth is rated by the square yard (as this is the way textile mills do it as they have to weave it).
On the % deal, you are being a little too worry for no reason, just lay it up and watch for if you have the back finish too glossy, if there’s too much resin (wipe some off). You want to see some of the reinforcement texture on the back.
Keep a record for each part and once you have a formula, so you only mix that much resin up for each new part / step.
JM,
Isn’t that what I said? You need glasses? :8)
:lol:
I’ll be in this week so if you want to stop by.