Help Me Fill in this dead space before i mold

General Composites Discussions Composites Talk
#1

Im sure some of you have seen my post and this part before. I need to think of a way to fill in the gaps when i place this part onto a flat piece of sheetmetal (which will act as a flange).

Here’s a side view:

you can see the gap between the inner radius of the part and the blue carpet.

Here is the largest area that needs to be filled:

Some people recommended using cardboard some have said sheet metal. I said maybe i should make a foam part and attach it to the inside of the part
:
this is the underside

this is the top side

What i was thinking: Build framing in the shape of a rectangle, use cardboard around the round corners of the part to make a type of bowl.
Then pour plaster or some type of liquid that would hardened inside. This would make a solid, thick piece that fills the gaps. Then i can sand or machine the plaster to make is smooth. place this entire chunk on a piece of sheet metal and make a FEMALE mold off of this male plug.

I know it seems like a lot of work, but i haven’t seen any good recommendations from people. If more pictures are needed tell me what angle i need to take them at.

What are your thoughts of opinions?

#2

You really don’t need to go to all that trouble really. Look up the undertail mold how to by perfeng702. It will tell you all you need to know.

#3

youre making this way more complicated than it ever had to be.

Aluminum flashing from Lowes and some modeling clay is all you need.

#4

I will search for that writeup that was recommended above.

But, What in the hell is aluminum flashing? Where the hell do i put the clay? This is too dry of a statement. I am asking a specific question, and getting such open ended answers.

I have explained this before that i am will have to use heavy molding fabric (not sure what yet) with heavy tooling resin, so i need a very strong and sturdy flange.

This part has had a mold made 4 times, NOT one has been perfect and all have used similar recommendations for flanges, molds e.t.c. that i have been told so far.

I am trying to figure out specific and precise issues to over come.

SUCH AS:
If i use the “aluminum flashing” do i put that on the inside of the panel pointing upward (perpedicular to the panel surface, parallel to the lip)? What is the clay used for at this point? To fill the gap between the Aluminum and my panels outter edge?

I was going to use clay to roll a edge so that releasing the par form the mold would be easy.

I AM NOT TRYING TO BE RUDE, i am trying to be clear.

#5




Here are some shots i took with a piece of mdf pressed against the panel. I know this would take alot of plaster to fill and be wasteful, but think about how strong this plug will be. The plaster is easy to sand but difficult to surface coat.

I am not doing this method, just investigating and gathering info form others

#6

http://www.racingcomposites.net/unt?id=332

Learn it, live it, love it. It’s much simpler than you are making it out to be.

#7




here are some shots that i took with some foam hotglued to the inside of the panel. This was just a test. My plan was to put this all around the inside of the panel then put this onto a piece of sheetmetal. the sheet metal would actually be the flange. And the foam wouldn’t be cut so high.
Just an idea. this took 10 mins totally.

Ill read the link that was posted above and get back to everyone

#8

WOW that is a great writeup! That is one of the best i have seen on the entire net.

One problem with this method. He used the orange stuff (assuming clay) to build height for his part.

Look at how much of a gap i would have to fill using clay. I have at the greatest amount 1" tall and 28inches wide. I need something stronger. thats why i kept shutting everyones ideas down.

By the way. where can i buy some of that orange stuff?

#9

How much experience do you have using composites? You will find that those who are experienced will often have very different ways of achieving the same end result, and what might work very well for one person wont work for another.

If you are new to working with composites, you might find it easier to get hold of a copy of the Forbes Aird book, which provides a lot of very helpful info, and may well answer your questions.

#10

The undertail in that write up has quite a bit of curvature also. The gap that was filled was approximately 1/8" in some places. The gap would have been much larger if the undertail was just placed on the posterboard. The playing cards help match the curvature of the undertail. There are many ways to build a flange. Because your part is relatively flat, I would just use a piece of sheet metal or similar and put a slight curvature in it to match the plug. Then I would fill the gap with clay. The orange stuff is just standard modeling clay.

I would even go as far as to use some screws on the backside of the plug to help pull the flange in as close as possible before claying up. Take a look at the “solo seat cowl” tutorial on that racing composites website to get an idea of what I man.

#11

Could you please ellaborate on this statement? I am trying to understand how the playing card help Absorb some of the curvature?
I like the idea to mount the panel directly to some sheet metal. That would cause the flange to have the same curvature at the panel(more or less).

Do you mean that since you have the cards tapes to the plug they have absorbed the contour because of their length allowing the cards to relax from the contoured shape to a flat plane?

In the first few pictures of the undertail writeup, we do not see any clay. is that so that u can demonstrate how the cards mount to the plug? then you went back and added the clay to build thickness on the part, then taped the card to the clay?

So after reading your undertial part tutorial i want to ask. Did you use clay to add thickness to this part? It seems like the factory undertail was directly mounted to your poster board. I think i can use a very similar method to fill the gap for my plug and make my flange.

I am very curious about the clay and when it is applied. referring to my questions above. I see that you use the clay to fill some points but are you using the clay to build thickness in the part? I keep asking this b/c if your part is the same height as the mold height by the time you cut the excess material from the c/f part i would imagine a smaller part.

thanks for the help. i am headed to buy a piece of aluminum sheetmetal to avoid the aluminum tape. What do you think about this?
What is the aluminum tape you are using?
Almost time for me to get to work!!

#12

Could you please ellaborate on this statement? I am trying to understand how the playing card help Absorb some of the curvature?

I like the idea to mount the panel directly to some sheet metal. That would cause the flange to have the same curvature at the panel(more or less).

Do you mean that since you have the cards tapes to the plug they have absorbed the contour because of their length allowing the cards to relax from the contoured shape to a flat plane?

The foam board he’s using doesn’t bend very well. The playing cards are used because they conform to the curve of the part.

In the first few pictures of the undertail writeup, we do not see any clay. is that so that u can demonstrate how the cards mount to the plug? then you went back and added the clay to build thickness on the part, then taped the card to the clay?

So after reading your undertial part tutorial i want to ask. Did you use clay to add thickness to this part? It seems like the factory undertail was directly mounted to your poster board. I think i can use a very similar method to fill the gap for my plug and make my flange.

I am very curious about the clay and when it is applied. referring to my questions above. I see that you use the clay to fill some points but are you using the clay to build thickness in the part? I keep asking this b/c if your part is the same height as the mold height by the time you cut the excess material from the c/f part i would imagine a smaller part.

thanks for the help. i am headed to buy a piece of aluminum sheetmetal to avoid the aluminum tape. What do you think about this?
What is the aluminum tape you are using?
Almost time for me to get to work!!

The clay is used to fill the gaps and holes. Nothing more, nothing less. If he didn’t use the clay then the resin and milled fibers he used around the sharp areas would run under the part and he’d never be able to release the part from the mold.

I think it would be advisable for you to read up on the subject of making molds before you do it yourself.

#13

I completely agree with you. Where can i find some more literature or some tutorials on mold making?

I was eventually going to start a post for some tips on material purchase for a high production quantity mold, but was going to wait until i was ready for that process.

What i need to know now is. Is buying the aluminum sheet metal the best material to mount my panel to? I really like this idea and its simplicity.

My experience in composites is in the layup process and even than i feel like i may be lacking. Only one way to learn.

#14

http://compositeforum.werksberg.com/showthread.php?t=1300

That post lists some books, dvds and other places to find info.

#15

I ordered two books and i already own the DVD my the Guru and the airetech DVD. I actually think the airtech is a better dvd for VIP b/c is shows start to finish steps where the Guru’s DVD skips the material lay up steps but goes into detail about the equipment and the bagging processes.

#16

Some final questions are:
Should i use sheet metal to eliminate the need for a poster board (i feel much more comfortable with this).

When i chop the excess clay off, should i chop at an angle to allow for easier part removal?

thanks to all who took the time to read and respond!

#17

I would suggest getting the Forbes Aird book “Fiberglass and Compostite Materials” (ISBN 1-55788-239-8), then make some simple moulds and parts out of CSM, using the hand lay up process, and only after mastering those basic first steps, start looking at more complex methods of production such as RTM.

Its very easy to make very poor quality items if you are not familiar with the basic techniques, and I think its pretty silly to be trying RTM before you know how to make a simple mould even.

#18

Dependent on the angle of the “draft” you have with your flange you should bevel your clay or not.

You want the part to slide out easy…real easy.

I like either for flanges, youre reading into the flimsy aspect of poster board. It only has to support the wet tooling gel until it hardens and then it gets to self supporting quickly as you add layers.

#19

Well dont you think that aluminum sheet metal would take the contour of the panel better? No cracks no breaks? Honestly if i had poster board i would use it, but since i have to buy either and i can and very likely will use the sheet metal in teh future, i met as well buy it.

#20

If you know the best thing to use already, and have decided on that, then why bother to ask on here?