size problem :(

General Composites Discussions Composites Talk
#1

well i finished my first mold and pulled an excellent part from it but it doesnt fit :frowning:
thinking about it i know why it doesnt fit but i dont know how to make one that will fit… imade a female mold of the stock mirror and made the part from that mold so the part is obviously smaller than the mirror now,obvious when you actually think about it :oops: but how can i make a mold that will be the correct size??? do i make the mirror bigger with resin and then make a mold? is there anyway i can use the mold i have just made to make a new one? im confused.
its a bit annoying that it doesnt fit but ive learnt a huge amount from making the mold and am extremely happy with the part,even though it doesnt fit lol

#2

The part is the exact size of your stock mirror. If you were trying to put that part on top of the mirror then it obviously not going to work. How about taking out the back of the stock mirror and replace it with the new cool part you made. At least you were successful at making a part. Feel good doesn’t it?

#3

i know its obvious now lol but its a bit late now :lol: i could chop the mirror up but i want to able to sell these as covers so i need to sort a mold that will work,so how would you do that???
and yes,it feels great when you make your first good bit :smiley: (all thanks to you guys)

#4

You can get and use sheet bees wax (mill to spec’s) to place over the part to make the mold a little larger, next time…

#5

when you say ‘mill’ do you mean cnc mill it? im not sure what you mean sorry.

oh yeah,i just finished a 2 part mold for the ‘foot’ of the mirror,that is also not gonna fit lol,but hey ive learnt loads and now know how to do a 2 part mold so im not tooo disheartened…

#6

like this??
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=3089&item=8159396051&rd=1&ssPageName=WD1V&tc=photo

#7

:slight_smile: http://www.cstsales.com/Mold%20Making%20Supplies.htm

#8

:slight_smile: how is it used? and which thickness would i need?
thanks

#9

this should shed some light on it’s use.

http://www.freemansupply.com/video/surfacecasting/surfacecasting.htm

The thickness would be the same as you want your part to turn out.

#10

Hey, you guy’s invented this dumb metric system and forced it on us didn’t you?!?! :smiley:

Just kidding.

He’s referring to the measurement. Thickness is measured in mills.

#11

:slight_smile: ive ordered a pack of 10 sheets at 1mm thickness,the cover i made was a fraction over 1mm thick so that should be correct i think…hope it will go over the corners fairly easily. :?

#12

Mills are “Thousands of an Inch”…no metric there :wink:

#13

Well darn, I guess I should’ve paid attention in school.

#14

Actually it’s not “mills”. In engineering speak, it’s “mils” or thousandths of an inch. This is normally used in talking about thickness of a coating or film. “Mils” can also mean a completely different thing. With snipers and artillery people, “mils” refers to milliradians which is a measurement of angle.

#15

If you are wanting to make covers, why not just use the mirror as a male mold? Its just like overlaying a part, except you use pva on the mirror before you lay it up, so that it “pops off” after it cures. Better yet, you can use the part that you just popped out of your mold. Its a little more finishing work, but it’ll make a cover :slight_smile:

#16

hmm,i thought about trying to do a male mold but it seemed to difficult to predict the thickness required.ive got the 1mm wax now and had a go at applying it,its fairly easy to use although i may do it again before molding as there are a few too many fingerprints on it lol :slight_smile: