|
Group: Forum Members
Posts: 34,
Visits: 413
|
Preface: This is the first time I've ever touched fiberglass, resin or even CF Excuses: I'm a noob  Working outdoors (under cover though) It's winter here so temps and conditions (very windy) aren't ideal. Etc...  Products: Vinylester tooling gel coat, polyester resin + 198 cloth, wax + PVA Attempt #1: Mixed up tooling coat + hardener using incorrect ratios. Scrapped first attempt and started over. Attempt #2: I'm attempting to make a mold of my engine cover as it seems like a fairly simple part to start with. As you can see from the pic, I raised the part off my polycarbonate sheet slightly and then plugged up the bolt holes with filleting wax as well as smoothly extending/blending the sides of the part onto the base with some more wax.  I then applied 6 layers of mold release wax to the part as per the manufacturers instructions. Followed by a single layer of PVA applied by brush, again, as per manufacturer instructions. I do not currently have access to any spray equipment. Stupidly I didn't apply any wax or PVA to the polycabonate sheet underneath as I though nothing would stick to it. Doh! Next, I mixed up the tooling coat (@1.5%) and applied it to the part and base as pictured.   I left it overnight (perhaps a little too long) till it was tacky. I mixed up the polyester resin (again @ 1.5%) and applied it to the tooling coat. I then started off with one layer of 198 FG cloth. However, I could see issues starting to develop already so at that stage I made the decision that I wasn't going waste any more product and I was going to finish off the mold "as is" and use it as a learning experience.  I had pre-cut the cloth as one large piece in the hope that it would drape over the part easily and conform. However, because of the indentations for the bolt holes, every time I tried to push it into place it would pull and lift elsewhere creating air voids. I tried to roll the air out but to no avail. Next time I will pre-cut the cloth differently, or alternatively, I plan on using CSM instead of cloth which looks like it might be more conformable.  So, I only applied 2 layers of cloth as best as I could, knowing full well that it was not going to cut it, and left it at that to cure for the next few days. Today I pulled the mold apart and as could be expected, it wasn't pretty      However, once I had the mold separated from the base, my part almost fell out of the mold without any effort so it seems that at the very least my waxing and PVA efforts worked. In any case, I have some observations and some questions I'm hoping you guys could help me with. Looking at the below pic, does my tooling coat look thick enough?  Should I have applied a second tooling coat once the first coat went tacky? I probably let the tooling coat set too much (it was still very slightly tacky but not what I expected) before applying the FG cloth as it looks like the bond between the tooling coat and FG isn't very good. Would I be correct in my assumption? Generally, how long should I wait for a tooling coat to start to set? I'm also not happy with the finish of the mold surface from the PVA. I've tried finding Frekote/EasyLease/Chemlease locally but it's like hens teeth over here  Would applying the PVA in multiple coats and or with a sponge give a better result/finish? |
|
Group: Forum Members
Posts: 14,
Visits: 592
|
Good effort for trying The toolcoat is thick enough, I use two coats, usually leave an hour or so between. Usually because of my job I leave the laminating until the next morning, never been any problem First layer I would of used csm and second third mat As for the release I personally just tape on the barrier. Wouldn't bother with PVA. To remove the lettering I would dremmel it out and spot fill it and wet flat it out
|