Mold building Dan's way.

General Composites Discussions Composites Talk
#1

Geez Evan I spent all this time taking pics and writing and I can’t post in the tutorial section :smiley:

Anyways thought I’d help some people out that may have questions. Here I am working on a Civic dash mold. I originally wanted to overlay but that’s another story.

Per Evan’s recommendation I started by drilling holes into the dash. This helps hold the fabric to the dash after resin is applied.

Next I layed down 7 oz cloth with the help of some 3m adhesive spray.

Vinyl ester resin with black pigment applied

After cure I’ve sanded the surface and cut down the high spots prior to adding body filler.

Now the body filler goes on, I forgot to take pictures besides it’s pretty boring anyway. After the body filler we start with the surfacing primer.

After you have your surfacing primer sanded smooth or to your liking it is time to move on to filling the areas such as the vent holes, gauge cluster and airbag. I’ve found it important to do this because it adds strength to your mold. To do this I prefer poster board and hotglue.

Now I didn’t take a picture but after these are in place I sealed the edges with clay and primed over the top.

Next we move onto making our flanges. Many fabricators develop their own methods of making flanges so feel free to experiment. There is no correct way to make these, the method I use works for me. In this case I decided it would be easiest to use 2” 7 oz cloth tape and again poster board.
First you have to decide where you want your flanges. I decided to break the dash down the middle for the first flange and then make a flange down near the front edge. I later decided not to go with the front edge flange as there is no negative angle and really wouldn’t have made a difference. Here we have our 2 in” tape layed up, if I remember correctly it is either 4 or 5 layers. I also choose to catalyze at 2% so I can cure quickly and move on.

After cure I remove the tape and traced the pattern onto posterboard cut it to shape and glued it the the edge.

Now the fun part. Clayin it up. Just a note, if you really enjoy playing with clay, walmart has non-drying modeling clay in a variety of colors for the low low price of $.75 a pound.

Same process goes for the next flange. Remember I did away with the one for the forward edge. I moved it to the top of the dash.

pva’d and gelcoated

layup so far 2 layers 4oz cloth, 3 layers 7 oz. Cloth, 2 layers 10 oz. Cloth

To be continued…

#2

Good job Mr. P, I’ll move this thread to the other forum once you’re done. I don’t know why you aren’t able to post in there. That’s strange.

#3

Back to the fun part. Flanging part 2, the same way I did it yesterday.

Note in this picture that the cardboard has been removed from the flange in the middle. Layup directly to this flange or else you’ll have a gap between the two parts.

Same deal again. Pva, Gelcoat, and layup.

To be continued…[/b]

#4

So you did’nt even buff and polish the plug before applying the pva and gel coat?
What pva are you using? Cause i’ve had some bad luck with molds bonding to the plugs…

#5

nah, I do things bassakwards :smiley: I will use another product to smooth out the mold when complete and then buff. The only purpose in laying the fiberglass on the dash was to provide space between the plug and the dash so the final piece will fit over the stock dashes. Kinda hard to explain but you’ll see when I’m done. In this application I used about 4 heavy coats of pva on top of mequiars mold release wax.

p.s. I’ve been sick the past week and haven’t gotten back to it but it’ll be finished soon so stay tuned.

#6

HEY MAN im sorry i didnt show up yesterday. my wife was sick and she has strep throat and made me stay up all night with her. maybe another time. i really wished i would have had some materials so i could have kept busy and learned a thing to two rather than just hovering over you and such. i get paid on friday and will be ordering some materials that weekend so maybe the weekend after that if you are not too busy. id like to make a single two piece mold for two side skirts i destroyed over the past year. what do you think.

will you be using vacuum for the dash board??? is that going in the s2k. if so that would be awesome.

#7

Do you brush on your pva or spray it on?

#8

lets bring the convo in here so I don’t have to ask Evan to delete all your posts http://www.icancomposites.com/forum/viewtopic.php?t=219

#9

You can keep it all in the same thread if you want. There would be no reason for me to delete the posts.

#10

Just 2 thoughts… Ive seen wax sheets that are formable to use instead of the initail layup, Just cover the part with the sheet wax and pull the mold. They came from .050 to .250 thich If i remember right.
Second if you hot glue a couple of bottle caps to your parting dams, they will leave an impression (register) that will make the molds easier to line up in the future, Once your bolt holes wear.

#11

I’ve never used sheet wax before but I don’t think it will work in this situation.

Notice the flanges are wavy, it would be impossible to misalign them.

#12

You use the sheet wax to make the plug, just smoothe it over the part with the help of a heat gun Then pull the mold off the wax. you can get teh wax in different thicknesses so you can make a mold for overlays without the work of making and finishing a plug. Wax smoothes very easy and can cover small holes and doesn’t destroy the gennie part. just thought it may save you some time.

#13

diggin up an old but excellent post,just to add that i have used 1mm thick sheet wax for a similar part and it gives fantastic results :slight_smile: we never did get the continuation or the final product :frowning: i would love to see it.

#14

I’ll try to get back to it in the next week or two. I had some contracts to take care of and this project just got tossed on the shelf.

#15

so basicly, your not making a dash replacement, you are making a dash cap, correct? Ive always wanted to make a mold of a dash, but there are so many clips and mounting points on the back of a dash, i figured it to be impossible. Never thought about making a cap though. Good job. Is it just going to be the top? Or are you doing the front too? When you make the part in CF, do u think there will be any problems with warping?

#16

That’s correct. I will be removing the vinyl and replacing with a cf cover basically. I will be covering about 95% of the dash. No it shouldn’t warp at all.

#17

ok, i’ll dig it up again, thanks dan for the new idea on how to make my flanges. making the form of the flange line with some glass tape and copying to the poster board. brilliant, i think that might change my life forever. maybe, i don’t know… I really do like it though

and as far as the finishing on the mold side, I’D LOVE TO SEE THAT. I often have molds that don’t come out exactly the way i want them too and ways that I can learn to speed up my surfacing would be great.

oh, and poster board and hot glue gun to fill in the holes, I like that too.

#18

Hey, I wasn’t using the forum for a long time during show season, and I guess I forgot about this thread. I’d like to add a step saver to the flanges.
I will often use flat stock (laminated stock that has been previously laminated).
I cut it to fit just like the poster board. I then put the rough side toward the edge I am going to be laminating first. If tyou squueze bondo on the edge of it, it will give you a good tight seal. clay it up or hot glue it to the smooth side.
now if you do it this way, all you have to do is remove the hot glue and or clay from the smooth side after the first side is laminated. the second side is ready to laminate as soon as the first few layers are gelled enough to remove the clay and hot glue. I have done it this way and gotten my mold to a point that all the surfaces are ready for a third layer at the same time and then I can give everything the same amount of layers all at once.

#19

the problem with that process is you can’t cut the already laminated stock with a razor.

#20

I take my bandsaw for granted. It was just another shortcut.