1929 Chevrolet International - 4 Door Sedan Project by BearsFan315

5 minute(s) of a 636 minute read

not sure if i noted it before but there is a scribe line in the mold and it shows clearly in the finished part. this shows clearly where to cut the rubber to go around the shaft. without this it would be a guessing game. 

you can see the scribe line on the right side of the urethane part, right at the quadrant of the cut out.

close up of the scribe line. 

well decided to go into production this morning and build complete finalized urethane parts !!

set up my four molds to pour, then applied sealed/release to each mold. this is a 45 minute process at minimum. then onto mixing urethane 3 parts, because adding in dye. mixed everything up, then combined and mixed, then on to pour...  well i learned that dues to a short pot life approx 4-5 minutes i can only really pour 2.5 molds in that time frame, pours have to be slow and steady stream to ensure air is out !!  once i his the third one it started to thicken and slow down... not to mention the cup was mighty warm, love chemical reactions !!

at least i got 2 poured, when i get home will break them open, and clean up the half pour, and prep for another pour. moving forward i will set up 4 molds.  then mix and pour 2 molds then mix and pour the other 2. only gonna mix urethane for 2 pours at a time so i have plenty of time to pour and set. then start on the next batch of 2.

this is all a learning experience. learning as i go !! frustrating & fun all at the same time

4 molds all set up and ready for pour

urethane for 4 mold pour

ok so got home and busted open the molds, well 3 anyways, 2 were complete and whole and i knew the third was a partial since the material was hot and solidifying as i poured. but it turned out pretty cool... i will strip off the urethane and then clean up the inset and reuse it on another set. but allows me to see how opaque the mix is and if i need to adjust it, but look pitch black through, no light transition! it takes 48 hours for the urethane to cure, so it is semi pliable and easily removed at this stage. once it cures, lol have fun !! they were not joking when they said urethane will stick to about anything. but the release compound i have is working great !!

mold split in half, and pedal seal ready to be removed

pedal seal removed, straight from mold, no cleaning

mold 3 where material began to solidify, you can see where material never made it all the way to the bottom. 

set up and did pour two... mixed up enough batch for 2 seals (1 set) poured that then mixed another batch and poured that. worked great, the time it takes works perfect with the material mix !!

set up and did pour two... mixed up enough batch for 2 seals (1 set) poured that then mixed another batch and poured that. worked great, the time it takes works perfect with the material mix !!

here is batch 2, plus a spare mold for a test i am doing... that is Mold 5 (back-up) top right next to minion cup

prepped all the parts for molding...

each inset is sanded and roughed up to help urethane stick and adhere to it, even though it really does not need it. then they are cleaned rubbing alcohol/brake clean to remove any and all contaminants. i only tough them with gloves on to install them and handle them from the container i store them in now.

i mark my mixing cups, A, and B as to NOT mix them up. also you only add dye to part B, then mix B to A, a specific process and i follow the instructions. each cup is cleaned out with rubbing alcohol to remove any contaminants. also it is mixed 1:1 so i mark the cups at 15ml for quick reference when pouring. as time is essential. 

use popsicle sticks for stirring, and mark them A & B so i can mix up and stir parts, and NOT contaminate bt them. one use and toss em. got plenty around. i cut one end off so it is flat to allow me to scrape hte bottom of hte cups which is flat, and to scrape the walls to ensure thorough mixing and pouring. 

it is a tedious process and i am following it thoroughly. it works so i keep on moving as directed...