Starlit Rose
Member
Hi all,
Today I come with a question about safe surfaces for bucks when vacuum forming with PETG sheets.
Quick run down of the situation - I made my own vacuum form table and gave it a whirl a few weeks ago using the oven-and-hollow-box method. As far as I can tell, the table is fine, the vacuum suction is fine, but I did run into a couple of major problems - one of which I already know the solution to (at least, I hope I'm understanding it right), the other, I am now paranoid of getting wrong again.
The first issue was that I don't think I was able to get the plastic soft enough. I had the frame propped up in the oven on some long screws, but I had to take the sheet out of the oven too early because the plastic was going to sag and hit the platform it was sitting on. Because of this, the plastic was too solid and the vacuum sucked it down onto the buck and caused it to collapse. The buck should have been fine because it was very solid, but I think the semi-solidish plastic was too rigid and gave me that result. So I think this could be solved with longer screws so that the plastic has more room to sag. (The reason I'm even mentioning this part is because I want to make sure no one sees this and thinks it could have been a different factor. In which case, I would love to know what else might have caused this.)
The other problem that I'm not sure about is that my buck not only got crushed, but it got stuck to the plastic. I had to literally rip it out of the plastic, and entire layer of paperclay remained attached to the plastic. What I SUSPECT is the cause of this is because I coated the buck with a layer of Mod Podge. Ironically, the reason I did this was because I thought Mod Podge would give it a sleeker surface and make it easier to remove from the plastic, but I think it actually got sticky when the hot plastic touched it and caused it to adhere to the plastic. Usually Mod Podge makes a surface sleek and fills in pores, so it seemed like a good idea at the time. But now I am not sure what to do to prevent this from happening. I have another buck that I made with Pepakura (so it's cardstock that I resin'd, fiberglass'd, resin'd again, covered with Bondo, sanded, and then added a layer of paperclay to get it extra smooth), but I don't want the same thing to happen to it. I put Mod Podge on that too, but I am definitely going to sand it off.
Will it be safe to vacuum form with just the paperclay surface? Or will that possibly get stuck too? What can I do to the surface of my buck to ensure it won't have the same thing happen? Would a coat of resin over it be a good solution or would that stick too? :T
Thanks!
Today I come with a question about safe surfaces for bucks when vacuum forming with PETG sheets.
Quick run down of the situation - I made my own vacuum form table and gave it a whirl a few weeks ago using the oven-and-hollow-box method. As far as I can tell, the table is fine, the vacuum suction is fine, but I did run into a couple of major problems - one of which I already know the solution to (at least, I hope I'm understanding it right), the other, I am now paranoid of getting wrong again.
The first issue was that I don't think I was able to get the plastic soft enough. I had the frame propped up in the oven on some long screws, but I had to take the sheet out of the oven too early because the plastic was going to sag and hit the platform it was sitting on. Because of this, the plastic was too solid and the vacuum sucked it down onto the buck and caused it to collapse. The buck should have been fine because it was very solid, but I think the semi-solidish plastic was too rigid and gave me that result. So I think this could be solved with longer screws so that the plastic has more room to sag. (The reason I'm even mentioning this part is because I want to make sure no one sees this and thinks it could have been a different factor. In which case, I would love to know what else might have caused this.)
The other problem that I'm not sure about is that my buck not only got crushed, but it got stuck to the plastic. I had to literally rip it out of the plastic, and entire layer of paperclay remained attached to the plastic. What I SUSPECT is the cause of this is because I coated the buck with a layer of Mod Podge. Ironically, the reason I did this was because I thought Mod Podge would give it a sleeker surface and make it easier to remove from the plastic, but I think it actually got sticky when the hot plastic touched it and caused it to adhere to the plastic. Usually Mod Podge makes a surface sleek and fills in pores, so it seemed like a good idea at the time. But now I am not sure what to do to prevent this from happening. I have another buck that I made with Pepakura (so it's cardstock that I resin'd, fiberglass'd, resin'd again, covered with Bondo, sanded, and then added a layer of paperclay to get it extra smooth), but I don't want the same thing to happen to it. I put Mod Podge on that too, but I am definitely going to sand it off.
Will it be safe to vacuum form with just the paperclay surface? Or will that possibly get stuck too? What can I do to the surface of my buck to ensure it won't have the same thing happen? Would a coat of resin over it be a good solution or would that stick too? :T
Thanks!
