115 replies to this topic

[Jairus]

Here we go again! Time to build another Gilbert/Sundance car and this time I have the chance to correct a couple of errors I made last time. The most glaring of course was the use of a different Ferrari body. The original Sundance “swoosh” paint was applied to a Kirby Ferrari 312P (not available), and my first replica applied to a MAC Ferrari 512.



I found this Ferrari 312P in my junk box left over from childhood. I believe it came to me mounted on a Dynamic floppy pan chassis so it’s being called a Dynamic body here. What I plan to do is convert it to look like a Kirby body, which I will call my “Kirby Klone”! Hopefully I will be able to make a decent enough master with which to pull a few bodies.
The first step was to back pour the body with Alumilite casting rubber. Since the body was really cut down I had to place the body upside down and carefully build side dams all around to hold the rubber in place until it cured, which took about 24 hours.



Here we have a rubber “male” mold pulled directly out of the Dynamic body.



Then a “female” mold is produced. This is the piece I will pour resin into . . .



And here we have the raw resin master! Only a little cleanup and sanding was done just to square up the sides. Lots of bodywork needed to remove the headrest, carve panel lines, and drill air relief holes in recesses to pull the hot Lexan down into details. (Any and all suggestions are accepted, Ron, because now I am shooting from the hip.)



In the meantime, I have put together a collection of hardware for this build including the closest thing to Associated wheels I have which are actually Riggen.



Back to sanding . . .. 8)

[dc-65x]

Hi Jarius,

I thought you might like some inspiration for your build :mrgreen:

[endbelldrive]

. . . I'm inspired!

[TSR]

Rick,
Electric Dreams has a replica of this body in the long list of molds being made now. Sorry you had to go through the trouble . . .

[Jairus]

All due respect but I simply cannot wait for E.D. to get around to this body . . . Rick either . . .

[Ron Hershman]

Lots of bodywork needed to remove the headrest, carve panel lines, and drill air relief holes in recesses to pull the hot Lexan down into details. (Any and all suggestions are accepted, Ron, because now I am shooting from the hip.)

The first thing is to mill a recessed cavity on the bottom side of the mold, 1/8" to 1/4" deep or so should do it and leave a "perimeter" of 1/4" to 1/2" wide along the outside edge around the mold.

Drill your suck holes whereever you want the Lexan to suck into. The smaller diameter the drill bit, the less you will see the suck holes in the pulled body.

Some pattern makers drill small holes and instead of milling a cavity, they drill lots of 3/8" holes from the bottom so the smaller suck holes line up with them.

Big cavity ALUMINUM-FILLED EPOXY molds heat up quicker, but don't retain heat as well versus a non-cavity mold that will hold heat longer, but take longer to heat up.

I have molds both ways and some in between, just be careful when heating your mold.

If it is a resin mold, I would not heat it at all as it will probably melt and give off some nasty gasses.

How are you going to polish it???

Did you have any "shrinkage" with the resin you used?

[Jairus]

Ron, shrinkage was about 1/16" total all around. Not expected, but not a problem either. The subject was 3" wide and I wanted to make a 3-1/8" wide master anyway so I will cut the resin in half down the middle and add a piece of 1/4" Plexi. Also going to route a cavity underneath as you suggest. The nose is too short compared to pictures of the Kirby body so length will change anyway as I add about 1/4 - 5/8" to the nose.

Suck holes . . . I like that term!

Ron, the back end is a big drop off and I was thinking of molding in a wedge shape to keep the Lexan from stretching soooo much and folding over on itself. Good idea or waste of time . . .?

[Ron Hershman]

Ron, the back end is a big drop off and I was thinking of molding in a wedge shape to keep the Lexan from stretching soooo much and folding over on itself. Good idea or waste of time . . .?

Should reduce any webbing you may encounter . . . if you have the space on the machine and don't care about losing any extra material . . . go for it . . . you could always make it a separate piece that you attach to the mold, pull a few that way, take it off, and pull a few to see which way works best.

[Foamy]

The holes should go in door lines, in the vents in the corner. That will help hide them.

Alumilite is OK for short runs pulling Lexan. Ten shots, or so is fine; more then that the tool gets too hot.

[S.O. Watt]

Ahhhhh . . .

Dona!

[TSR]

You guys are REALLY hurting, aren't you?

[dc-65x]

There's nothing wrong with enjoying beauty when we see it.

[S.O. Watt]

Ahhhh . . . Dona!

Yes, there were some fun times back then. I "enjoyed" making suds witth Dona, errrrr, for Dona's "Chassis Cleaning".

But there was a very downside then also. While Lee hung out and went to Highline College, and lived next door to campus . . . we did meet a lot of the locals, especially when the latest batch of home brew was ready to drink. :spin: . The neighbor down the hall, the one that looked like he should have been sitting on the aft deck of his yacht, got busted for sales of canned mushrooms, not some you'd find at the corner market.

The downside to these times? One of the young girls in our circle (heck, we were all young back then) was Brenda Ball, another bueatimas young lady with long brunette hair. Just the kind of victim Ted Bundy liked. Yes, we knew one of his vics. The other crowd I hung with frequented the Flame Tavern, one of the better places for music and good times then. We danced there the night she disappeared. If I could have given her a lift home that night, oh so long ago.

[Prof. Fate]

Hi,

First time I talked to Lee in recent times, the first thing I asked was . . .

"Come on, DONA?"

Fate

[Ron Hershman]

You guys are REALLY hurting, aren't you?

This might be a good place to post pics of our "Retro Donnas".

[Jairus]

"Dona, Dona, Dona, it's always Dona!

Ok, back to the hobby . . .
Here I have taken the master and cut it in half with a band saw.
I will spread the sides apart and fill with epoxy putty but first have to mount the halves on a piece of Plexi (not shown) for support and a common flat surface.



As Ron suggested, the bottom was milled out with my router. Made a huge mess in my garage with resin flakes all over the place! Of course the Plexi will also be opened up as well because we need a vacuum chamber for all the little suck holes . . .



8)

[Jairus]

UPDATE:
The resin master halfs are now attached to a plex base and the gap between filled with epoxy filler. I have been sanding on this baby filling bubbles and cracks but thought a coat of primer might help me see where more sanding is needed. Holy Cow! I got a lot of sanding still to do!

[Ron Hershman]

but thought a coat of primer might help me see where more sanding is needed. Holy Cow! I got a lot of sanding still to do!]

Oh Yes!!!! Now the the fun begins.

[Jairus]

Actually Ron, I do like this part of the project. Spreading putty and wet sanding is a strangely soothing process.

Anyway, I have an update. The latest primer job shows a nice smooth shape. Tiny bit more sanding and then I get to drill some suck holes all over the place.
Looking forward to trying a shot with PETG first to get the hang of the mold and see where the weak points in the mold are first before moving up to the more difficult Lexan.


The air scoops and air vents still need some work and I know there are tiny imperfections here and there, but I can almost taste it!!! 8)

[Jairus]

I made my first pull with PETG. Tiny bits of the mold were effected by the heat, expanded and stuck to the plastic. :x Also left little bumps... not the effect of any dust unfortunately.
I used epoxy putty and sadly this brand of putty has tiny bits that do not get mixed up no matter how carefully you mix it. Works fine for model cars but for moldmaking... not the best choice. :roll:

Question for Ron: Is there a temp resistant paint that you think I can spray over the mold?


:?:

[TSR]

Jairus,
Use dental plaster inside the finished body to make a new mold. It is incredibly strong and takes the heat.

[rdmac]

...Tiny bits of the mold were effected by the heat, expanded and stuck to the plastic. :x

Are you using any type of Mold Release?

Nice looking body. :up:

[Jairus]

Actually guys, I only plan to make a few bodies off this so creating ANOTHER mold seems like too much work however I just happen to have a can of spray mold release.... I'll give that a shot. I am also going to try and coat it real good with some sort of paint... maybe a gloss coat of clear will help hold it together.

Tomorrow: I try the Lexan!

[Ron Hershman]

There is no paint/clear coat that I know of that will work. I tried clear laquer once upon a time and that made the mold stick to the lexan like crazy and I didn't heat the mold.

Maybe that hi temp BBQ paint may work, but I have never tried it.

How hot are you getting the mold.

I use a silicone mold release spray on new molds. Made by Zip.

[Jairus]

I am not heating the mold at all! Heat is being transferred through the plastic.
Going to try some mold release with just a good coat of gray primer in the morning. See what that gives me.