www.TK560.com

ANH trooper · Master Joined: 20 Oct 2005 Posts: 305 Location: UK

If you can fill the void in the mould where the hole is popping it will sort out the problem.

If you need to have some kind of undercut then try tapering the undercut rather than having a void. Mould removal will be harder but at least you will have a perfect pull and you can cast a new mould.[/img]

jdougn · Posted: Wed Feb 08, 2012 8:32 am Post subject:

MDR · Novice Joined: 22 Nov 2011 Posts: 49 Location: Missouri

It's very close, just didn't form properly on the front grill area. This is the piece that sucked the hole and lost some of it's shape. I sent this photo to some dealers and they are very interested, maybe everything will work out!

MDR · Novice Joined: 22 Nov 2011 Posts: 49 Location: Missouri

Man I tried a sheet of petg, and man what a big difference form hips. I can heat hips for about 2 min, I let that petg sit in there for about 7 min and still not real soft in the corners.

MDR · Novice Joined: 22 Nov 2011 Posts: 49 Location: Missouri

Do you have to preheat PETG, I tried a piece with hundred of small bubbles.

IMMark · Posted: Sun Feb 12, 2012 1:11 pm Post subject:

When I have used PETG, I did not preheat and it worked fine. However, I do not have a lot of experience with it. Perhaps Scott or others will chime in.
I would say, it either has moister content (which heating is suppose to help with, although for my acrylic that has not worked yet) or you are heating it too much with breaks down the plastic? Again that was something Scott had mentioned to me. You could try to heat it low and slow?
Mark

MDR · Novice Joined: 22 Nov 2011 Posts: 49 Location: Missouri

I did form a piece of acrylic with perfect results, but when I tried to pull the form off it cracked along the bottom. The center section of my oven is wide open right now, last week one of my switches fried, and I had a guy solider around the bad spot to get by for now, but I'm gonna have to order a new one ASAP now. I'm tring to sell these and the clear is the one everyone wants. Thanks for the info, and maybe Scoot will crime in and help me out.

spektr · Master Joined: 07 Jan 2008 Posts: 425

Ck The Inbox....

MDR · Novice Joined: 22 Nov 2011 Posts: 49 Location: Missouri

Well, I got ahold of Scott and he gave me some every good information. I'm very thankful for all this great advise, there is know way I could have accomplished this project with out the great leaders on this site. Were getting orders in and will be filling these orders with quick turn arounds.
Thanks again
MDR Plastic

MDR · Novice Joined: 22 Nov 2011 Posts: 49 Location: Missouri

I finally got to order my bc8009, it will hold only 5 gallons. I had to make a bigger piece to go into my mold as a backfill, the first one didn't take up enough room, it was going to hold 7 gallon. I made a Mdf box the same shape as the mold only 1"sq smaller and then filled the box with rocks. Golfballs where to large and marbles are extinct I guess, I looked everywhere. Maybe ill get this new mold made, it's getting old having to repair my old mold after every pull.

spektr · Master Joined: 07 Jan 2008 Posts: 425

then look for pea gravel and landscape lava rock ....

jdougn · Posted: Fri Feb 17, 2012 4:37 pm Post subject:

Remember that BC8009 does not like humidity or moisture. It won't set up correctly if the filler is too humid. Even the MDF gets coated with shellac before it's used as a filler when casting BC8009. Also, follow the directions when mixing. Mix part A & part B in their own cans with a power mixer until the liquid is perfectly smooth. It is not uncommon to have heavy sediment in the bottom of the can that has to be gouged out by hand. After the two have been poured into a 5 glln bucket and thoroughly mixed then pour them into another bucket to make sure the corners are mixed.

I've had to deal with both issues. The humid filler leaves the BC8009 sort of gooey and sticky. Unblended mix is a catastrophe.
_________________
DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions.

MDR · Novice Joined: 22 Nov 2011 Posts: 49 Location: Missouri

Yea I used small river rocks, thanks for all the great info. I should be getting in my new switch any day now, I'm ready to get that petg another try, that's what everybody is asking for.does anybody know if you can get transparent colors in petg, like they use for sunglasses lenses?

jdougn · Posted: Fri Feb 17, 2012 4:58 pm Post subject:

MDR · Novice Joined: 22 Nov 2011 Posts: 49 Location: Missouri

I havent cast my mold yet, I just now got it ordered. My first order of PETG was made by makolon, but after some research I think vivak is a better choice, they say this is available in transparent colors and mirrored, but can't find a color chart.