www.TK560.com Forum Index www.TK560.com
Vacuum Forming, Movie Prop, Sci-fi and GIjOE Forum
 
Log in to check your private messagesLog in to check your private messages

Log inLog in  RegisterRegister


Profile  Search  Memberlist  FAQ  Usergroups
Newby needs help making Molds

 
Post new topic   Reply to topic    www.TK560.com Forum Index -> Mold Making Tips
View previous topic :: View next topic  
Author Message
Qmavam
Newbie


Joined: 11 Aug 2009
Posts: 6
Location: Panama City Fl.

PostPosted: Tue Aug 11, 2009 12:28 pm    Post subject: Newby needs help making Molds Reply with quote

Hi all,
I'm a first timer and want to make bottom corners for coleman coolers.
I use them in my business and the corners wear through and the the insulation gets wet.
The first thing I want to know is how to make the mold. I suspect I'll need to us the mold about 32 times, maybe 16, depends on whether all four corners are symmetrical.
Ok, so I need to pour, lay, spray something on the corner of the cooler.
Let it solidify. Then I need to fill this piece to make the mold for use with the vacuum former.
Can you give me materials and some instruction on how to make these two pieces?
Thanks, Mike
Back to top
View user's profile Send private message
jdougn
Guru


Joined: 18 Mar 2009
Posts: 714
Location: Louisville KY area

PostPosted: Wed Aug 12, 2009 8:01 am    Post subject: cooler corners Reply with quote

Hey Mike, welcome.
You've got a great idea in making corner reinforcements for coolers! Do you have a vac former already or what equipment do you have available? There are a least a couple ways to do this depending upon the desired result. Vac forming is quick and the plastic is cheap but it requires more upfront expense in building the machine. Although, for a project this size you could possible heat the plastic in a regular oven. Liquid casting would work too but the product is more expensive.

A couple other thoughts. Do the corners need to be hard and slick so they'll slide easily or should they be softer and rubbery to help prevent sliding? Also, what method would you use to attach the corners to the coolers? My first thought would be epoxy but some plastics don't work well with epoxy. So, what material is used to make the coolers?

Sounds like an interesting project you're working on.
DougN
_________________
DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions.
Back to top
View user's profile Send private message Visit poster's website
Qmavam
Newbie


Joined: 11 Aug 2009
Posts: 6
Location: Panama City Fl.

PostPosted: Wed Aug 12, 2009 9:46 am    Post subject: Reply with quote

Hi DougN,
Thanks for the reply.
I don't have a vacformer yet, I expect to build one, just for this purpose.
I see plenty of plans on the net, the job is well within my capability.
I expect to use the oven to heat my plastic, we have one in the garage
so I will have work space to do the job.
The corners I expect to be hard, but they won't be slick long because it's a daily slide in the van, then on concrete then on wood. They wear through
over time, so an 1/8" corner cover would add a more than a year to the life of the cooler, maybe two or three. The thing I see that seems to stick to the
plastic that the coolers are made from is "Great Stuff" the foam insulation in a can. I thought, put a few spots of foam on corner piece and push it in place. I would try one and see how it holds up.
So what do you think would be the easiest way to make my mold?
Mike
PS, I found the quote button, next time I'll intersperse responses into your questions.
Back to top
View user's profile Send private message
jdougn
Guru


Joined: 18 Mar 2009
Posts: 714
Location: Louisville KY area

PostPosted: Wed Aug 12, 2009 11:37 am    Post subject: epoxy for corners Reply with quote

Qmavam wrote:
Hi DougN,
Thanks for the reply.
I don't have a vacformer yet, I expect to build one, just for this purpose.
I see plenty of plans on the net, the job is well within my capability.
I expect to use the oven to heat my plastic, we have one in the garage
so I will have work space to do the job.
The corners I expect to be hard, but they won't be slick long because it's a daily slide in the van, then on concrete then on wood. They wear through over time, so an 1/8" corner cover would add a more than a year to the life of the cooler, maybe two or three. The thing I see that seems to stick to the plastic that the coolers are made from is "Great Stuff" the foam insulation in a can. I thought, put a few spots of foam on corner piece and push it in place. I would try one and see how it holds up.
So what do you think would be the easiest way to make my mold?
Mike
PS, I found the quote button, next time I'll intersperse responses into your questions.


Hey Mike, let me start with a disclaimer. There are a number of people here that are much more knowledgable than I so take my opion with the proverbial grain of salt.

There are lots of good plans for vac formers. I would recommend the plans at http://www.build-stuff.com. There are a couple sizes available, well thought out, source information, tech help if needed.

For the corners, ABS plastic would be relatively cheap, hard, and slick. The disadvantage is that it might need more vacuum than a shop vac can produce to form which may mean buying a vac pump. Although, Harbor Freight has now started carrying inexpensive vac pumps.

I would not recommend Great Stuff since it will expand out and get all over. If the G.S. is sticking to the cooler then regular two part epoxy from Lowes or HomeDepot may also work. It'd be easier and without the mess.

Making the mold will be interesting. I've only done one female mold to date. The rest of my stuff is all formed from MDF board. You'd probably want a male mold for accuracy. That means making a female mold of the existing corner then using that to create a male mold. For the female mold you might use fiberglass & resin. Then fill that with a product like Durhams Rockhard Water Putty to create the actual mold that you'll use to form the plastic. Keep in mind that you'll need some extra spacing around the base of the mold to allow for trimming the plastic. Well this may get you started in a general direction for your research.

Hope this helps, DougN
_________________
DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions.
Back to top
View user's profile Send private message Visit poster's website
Qmavam
Newbie


Joined: 11 Aug 2009
Posts: 6
Location: Panama City Fl.

PostPosted: Wed Aug 12, 2009 12:05 pm    Post subject: Re: epoxy for corners Reply with quote

Quote:
There are lots of good plans for vac formers. I would recommend the plans at http://www.build-stuff.com.

For the corners, ABS plastic would be relatively cheap, hard, and slick. The disadvantage is that it might need more vacuum than a shop vac can produce to form which may mean buying a vac pump. Although, Harbor Freight has now started carrying inexpensive vac pumps.

I'll check out that site and note that ABS might be a little harder to pull.

Quote:

I would not recommend Great Stuff since it will expand out and get all over. If the G.S. is sticking to the cooler then regular two part epoxy from Lowes or HomeDepot may also work. It'd be easier and without the mess.

I new about the mess, but figured I could wipe it away before it hardened,
but I wasn't thinking about the expansion!
Quote:

You'd probably want a male mold for accuracy. That means making a female mold of the existing corner then using that to create a male mold.

That's what I was thinking.
Quote:

For the female mold you might use fiberglass & resin. Then fill that with a product like Durhams Rockhard Water Putty to create the actual mold that you'll use to form the plastic. Keep in mind that you'll need some extra spacing around the base of the mold to allow for trimming the plastic. Well this may get you started in a general direction for your research.

I'd thought about fiberglas, but I don't like working with fiberglas!
How about Bondo to make the female and then the water putty to create the male? Maybe outline the corner with some clay to give me some lines to work to.
Mike
Back to top
View user's profile Send private message
verdatum
Newbie


Joined: 06 Aug 2009
Posts: 9

PostPosted: Wed Aug 12, 2009 10:51 pm    Post subject: Reply with quote

Bondo works. If applied too thick, it can deform, and regardless, it will shrink a bit, but probably not enough to matter for this application. Wait 24 hours minimum before removing it, and use plenty of release agent.

Plaster would also work. Plaster can be reinforced by soaking pieces of damp burlap in wet plaster. Obviously, do this for the outer layers only.
Back to top
View user's profile Send private message
crashmann
Guru


Joined: 27 Sep 2005
Posts: 501

PostPosted: Thu Aug 13, 2009 1:21 pm    Post subject: Reply with quote

To make the mold, a somewhat cheap and easy method would be to use plaster to cast the existing corner on a 45° angle. This will make a female cavity. Apply a light layer of vaseline then pour plaster into the cavity. Repeat until you have 4 corners. Cut risers out of 3/4" MDF and you are ready to form.

What size coolers are you using? Got a picture?

But why just make the corners? Wouldn't it be more rugged to just vac form the whole rectangular bottom?

I would also recommend using ABS since it handles the abuse much better than HIPS.

Charlie
Back to top
View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger
Qmavam
Newbie


Joined: 11 Aug 2009
Posts: 6
Location: Panama City Fl.

PostPosted: Sun Aug 16, 2009 9:08 am    Post subject: Reply with quote

crashmann wrote:
To make the mold, a somewhat cheap and easy method would be to use plaster to cast the existing corner on a 45° angle. This will make a female cavity. Apply a light layer of vaseline then pour plaster into the cavity. Repeat until you have 4 corners. Cut risers out of 3/4" MDF and you are ready to form.

I set the cooler so the corner pointed straight up, then formed clay around
the corner section to form a bowl. I had a floor leveling compound in my shed that said "doesn't shrink' so I used it for female mold. I took it off
after a night, Has one crack but it's not critical. I'll let it cure a little more
and clean it up, then figure out what to pour into it for the final mold.
Quote:

What size coolers are you using? Got a picture?


The coolers 28" x 14" Coleman 68 quart.
I also use another size 24 x 12 " Coleman 48 quart.
No pictures now.
Quote:

But why just make the corners? Wouldn't it be more rugged to just vac form the whole rectangular bottom?


I like the idea, that way the edges wouldn't catch when we slide them
across a surface. I would need a very large vacformer though.
And oven! Maybe I could make it in two sections.
Quote:

I would also recommend using ABS since it handles the abuse much better than HIPS.


Ok, ABS. What is HIPS?
Mike
Back to top
View user's profile Send private message
jdougn
Guru


Joined: 18 Mar 2009
Posts: 714
Location: Louisville KY area

PostPosted: Sun Aug 16, 2009 1:25 pm    Post subject: Reply with quote

Mike, if catching edges is a concern you might consider making the individual corner guards bulge out slightly around the point of the corner. This img gives a general idea although your design would probably be simpler.

_________________
DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions.
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    www.TK560.com Forum Index -> Mold Making Tips All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

phpBB "skin" by DewChugr


Powered by phpBB © 2001, 2005 phpBB Group