fiberglass mold

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Ol'fogasaurus
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Re: fiberglass mold

Post by Ol'fogasaurus » Fri Mar 01, 2013 1:31 pm

Larry, there have been two bits on forming fiberglass on Spike in the last few years. One was to make a hood, with mods, from another hood; that was on Musclecar (http://www.powerblocktv.com/episodes/MC ... torque-arm). The other fiberglass job I remember was on trucks on “how to build a better bumper” (http://www.powerblocktv.com/shows/?show=TK) but I think it is too new to be available to watch here.

There are more videos on building molds by do a search on fiberglass molds. http://www.bing.com/videos/search?q=fib ... &FORM=VDRE

Making a basic shape and using foam is one of the ways I have seen it done. You have to cover the foam with something as the heat from the chemical reaction can melt certain foams; other than that, it may be worth looking into if you want to make a one-off hood.

http://www.amazon.com/s?ie=UTF8&keyword ... d%20making

I did a quick search on Bing and it is surprising how many mold and molded parts that are for sale.

Lee

tikitime
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Re: fiberglass mold

Post by tikitime » Sat Mar 02, 2013 5:40 pm

For this car I first made a one-piece buck from foam, covered with plaster of paris then sanded & painted gloss black (to easily see imperfections), several coats of wax, & mold release. Then started the mold using 3 gel coats follwoed by 2 layers mat & 1 layer woven glass. Then I added wood bracing after the mold dried to stiffen the mold. After pulling the final part from the mold I cut the vents with a router and cut the rear decklid from the upper body part. Lots of itchy work!
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sandhopper
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Re: fiberglass mold

Post by sandhopper » Mon Mar 04, 2013 9:58 am

how do you make the curves in the foam ?
I was thinking using wire mesh fencing like 1/4 inch square to make a shape cover that with something then fiberglass that
could use tape to cover screen mesh then do Plaster of Paris , paint for the buck

Ol'fogasaurus
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Re: fiberglass mold

Post by Ol'fogasaurus » Mon Mar 04, 2013 12:29 pm

If you have ever watched some of the upholstry shops work with shaping foam they often use an angle grinder with a sanding disc on it to finish the shape. I wonder if that would work for you also.

Lee

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ALYKAT III
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Re: fiberglass mold

Post by ALYKAT III » Mon Mar 04, 2013 7:26 pm

I have rough shaped foam with a bondo grater. Fine tune with sand paper wrapped around a bit of flexable material so as to avoid flat spotting . Go easy as it can cut very quickly. The up side is, you can usually repair with bondo.

sandhopper
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Re: fiberglass mold

Post by sandhopper » Mon Mar 04, 2013 9:36 pm

thanks for all the ideas
I just can't get my head around how to start the basic form
There is not a stright line at the fender to start it has a slight curve
some say glue blocks of foam and then just sand down until you like the look
I know the dash will have to be a seperate part and then bonded together with the hood
I think the dash will be the easest part
Larry

Ol'fogasaurus
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Re: fiberglass mold

Post by Ol'fogasaurus » Mon Mar 04, 2013 9:53 pm

Having the dash separate is probably not a bad idea but you will have to have a lip on the hood for supporting the shape. AS far as the shape by the fenders cut some plywood to match the arc in the body/fenders that you want the match.

Lee

sandhopper
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Re: fiberglass mold

Post by sandhopper » Thu Mar 07, 2013 10:41 am

I don't understand plywood cut for ther edge
What I'm talking about if you are looking down at the body where the fender tranisions to the body say wher the gas tank goes there is a groove this has a slight cure to it. I need to have this curve and the roll over to go flat to the other side
This was why I thought of using wire mesh covered with tape or something then maybe drywall mud then paint
after all this I could do release agent the Fiberglass
Still working this out in my mine for the best way to not make a pile of crap
Larry

Ol'fogasaurus
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Re: fiberglass mold

Post by Ol'fogasaurus » Thu Mar 07, 2013 10:50 am

The reason I mentioned the wood (for forming the hood) would be for the hood to fender fitment and as a support for the rest of the build (on my buggy there is a length of body welting/bulb seal that goes between the hood and the fender area to absorb any hood to body contact what would cause wear to both). That edge has to be kept as those two edges bot both strength but also it is where the bolt goes through to join the hood to the body, that and the hook in the front are what holds the body and hood together and keeps them from flying off. Remember, the air flow not only goes over the hood but some air flow comes up from the bottom and can cause the hood to lift just like on any car that has an open spot for air to get in and under.

Lee

Ol'fogasaurus
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Re: fiberglass mold

Post by Ol'fogasaurus » Thu Mar 07, 2013 1:24 pm

If you watched the hood build on Powerblock the statement is made (I am going to paraphrase it here) that the buck can be any thickness, that doesn't matter as long as the finished form is perfect and what you want it to look like; but it could be heavier than heck but you would have to deal with that yourself.

Using chicken wire for a basic shape I think would work great. In the URL that I couldn't get to work they draped/stretched a certain fabric (a Christmas gift “Snuggy” which I seem to remember has some characteristic’s that other fabrics may not have) over part of a modified bumper abetted by some welding wire as a basic frame then glassed over the fabric.

With the chicken wire bent roughly to shape and glassed fabric to close the holes then you could build up your hood to any shape you wanted albeit it may be heavy, that doesn't matter. The hood had a lot of body filler in it as you probably remember. The main thing is the finished plug/buck (I am not sure of the right word here) does not have any reverse curves so you couldn't get the mold made and the buck out or the finished part out of the mold. You should have some draft to the mold (determined by the plug) that is less than 0°; we used a max of 2° in our drawings for this. 100% perpendicular is good but no return (more than 190° (I hope this is clear).

If you do a search on the web there are several videos on this. Another good one was done in England I think.

http://www.bing.com/videos/search?q=vid ... FORM=VIRE5

http://www.bing.com/videos/search?q=vid ... FORM=VIRE5

This talks about the “undercut” I was talking about (over 90°)

Anyway, some more information to think about.

Lee

sandhopper
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Re: fiberglass mold

Post by sandhopper » Thu Mar 07, 2013 9:21 pm

Thanks Lee , yes I have been looking at videos and searching the web for this project
I know there are more than a few ways to do what I want
I think the chicken wire and tape is the way I will go to start if it doesn't look like it will work I will only have a few $ down the old drain
Larry

Ol'fogasaurus
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Re: fiberglass mold

Post by Ol'fogasaurus » Thu Mar 07, 2013 10:33 pm

I wonder... there are a lot of old baja hoods on Craig's list; I wonder if one of them may be modified to fit or be modified as a plug also.

Lee

sandhopper
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Re: fiberglass mold

Post by sandhopper » Fri Mar 08, 2013 10:20 am

Lee we must think alike as I have pickup a hood from a baja but it is a bit wide so it would have to be sectioned
Not to sure if that is easy or not . After thinking about this way it maybe easyer to copy one I have for another buggy (that did not fit ) then modify the plug I get from that
So many options , I'm still looking for someone that can do this at a reasonal price
I have so many projects and the day job is getting in the way of hobbys and fun projects also the wheather here in so cal has been less than needed (rain and cool )
Larry

Ol'fogasaurus
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Re: fiberglass mold

Post by Ol'fogasaurus » Fri Mar 08, 2013 11:00 am

Larry, Central WA Baja has widened a hood et al on his widened and lengthened and whatever else that can or could be done Baja; maybe there is something in his posts on widening the hood and relocating the fender that could help. http://www.shoptalkforums.com/viewtopic ... start=1020 A quick check and I found this; it may start some pages before but as you have probably already noticed there is a lot of friendly jabber that goes on at STF so his string has a lot of pages. I hope this helps some.

Lee

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Dale M.
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Re: fiberglass mold

Post by Dale M. » Sun Mar 17, 2013 10:13 am

sandhopper wrote:Thanks
The body I have is very differnt in size in the front , I have tried to check the other hoods I have and none fit or even close
From what I can get so far it does not look like I will be doing more bodys from this one as no one has stepped up with wanting to do this
First step has always been to get a hood and dash so it is complete
I have been thinking maybe using a wire to make a frame then covering that with fiberglass or foam to make the buck
So far it has just been a lot of thinking how to make something out of this body
Larry
Late to the party... But if you can find a hood and have any fiberglass skills, make it fit.... If you want one that fits perfectly first take a impression off hood area of body and make your own hood.....

Personally I would find something that is close that you like and "make it fit"....

Dale
Lives his life vicariously through his own self.
1970 "Kellison Sand Piper Roadster"

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