Fiberglass molding basics for backyard projects

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I do dumpster diving where they are replacing a flat roof or roofing a new building. Like a school or office building. The roofers often use a yellow/buff colored foam material that has a cardboard like material glued to the top and bottom of the sheet. Roofers are very wasteful and often throw away full sheets of this stuff. The cardboard is a pain to remove but the foam is great for making one time parts. I just shape the part out of the foam and lay the glass up on top of the form. Most of the time I bust out all of the foam after the glass has set up. I have a large stack of this material behind the shop. It is free and it works, the resin does not attack this foam

John

 

I plan on carving my amrests out of the green foam used by fake flower arrangers, not sure how it will handle the resin but gotta experiment. there is also the "great stuff" expanding poly-iso-cynate insulation in cans......


Dave

 

A buddy of mine used some Polysyrine insulation foam to carve some pieces out of.
That stuff goes away right away with acetone, resin, etc.
But after he covered it with a couple of coats of Latex wallpaint it was OK...

 

That's correct. Most of the foam the poly resins will attack (very quickly) can be made to work with a few coats of latex paint which then acts as a barrier. Once the parts made, you can still go to the back side of it and dose it with acetone and make the foam go away.
I just don't like poly resins for anything, and do all of our work in epoxies. For production parts we use only prepreg; over kill for what most of you guys'd want.

 

I did an entire project in class with vacume molding of fiberglass bodies, pm me if your interested in info.

 

More in formation is allawys a good thing,Thanks.I m going to be starting a frp project soon and I need all the info I can get.

 

The green foam is perfect .The resin will not attack it. I have made many hoodscoops this way.

 

not to mention vinyl ester primer over polyeseter primer has a much better build in marine apps. 40 mils on one primer session! vinylester FTW! lol

 

I second this. A company gave me a chunk of it, it cuts and shapes really well, with very little dust. It has a little flex to it, slightly spongy, but holds it shape really well.

 

Awe man, now you've really got me jonesing for a flip clip. I think I may experiment with some smaller pieces soon. I really like the flex mold idea, since it is much cheaper and it ensures the part will come out. Any suggestions on the best materials for a one-time-use flexable mold?

 

Good stuff. I've been using strips of garbage bags spray glued to my forms as a release agent. Of course I've just made a few bits for sculptures, nothing complicated.

 

This old man is just sitting here shaking my head back and forth.............If I tried to make my 32 5-window bodies like this..............oh my God!!!!!!!!!

 

Yeah, I was wondering, what do you use to keep the expandi-foam from sticking to whatever you're spraying it on?? I think I may try doing this!

 

I don't blame you one bit. However I have used this poor boy technique to mold a many of cowl, quarter or roof panel in a hurry to fix someones' $10,000 to $20,000 kit car that was shaped like a banana. Its not what I'd call professional either but it does work and thats the point. Thats why I refer to it as being ghetto and don't take it too seriously. Its a reference point,thats how I learned, learning from another's "mistakes" can be just as useful as their triumphs. Its for those that haven't yet tired this to work from with what they think will work for them, take it or leave it.

Gibbons, Rat's Glass, Wescott, Super Rods etc. even those wavy over hyped no name swapmeet bodies, and the worst of the worst the Street Beasts, I've been there and done that. If you build bodies I know you have to have seen these too and most likely had to work on a few of them. I've never found a single one that worth the resin that was used to make them, certainly nothing I couldn't make lighter and stronger in my driveway. Not to mention my parts not only fit with a set 1/8 gap but they are the same on both sides of the car, the same set per set and don't wave at you as you walk past. Show me a kit car body company that does that, that doesn't mean there isn't one but I've never heard of it.

So what are your's made from and how are they molded? Company name? There was no thread on the subject so I started one. Instead of Oh my God, how about passing on some of that which makes you better?

 

These are a few reflection shots of the roof and side of the sedan. Its a Gibbons and though better than most the roof was once a duck pond, and lets just say the sides did not look this way when we got it.

I like to give credit where it due...this car was started before I actually worked at this shop and most of us that worked there had a hand in it at some point. A large part of the modifications and bodywork I did including laying up the floor to cover the custom chassis as this car was the reason I was hired . The shop owner made a mock up out of thin aluminum sheet to fit the frame and a buddy and I had at it. If you look at the earlier shots the whole car is glass except the hood and those goofing looking side panel headlights I got stuck making. Notice how the fenders and boards are all reworked from stock form.

The 33 Coupe I built the majority of from a kit with a basic frame up to final block. It's not a HAMB car or my type of car for that matter but it was a job. It's a Super Rod's body ripped off a Rat's glass car, to start with the cowl was two inches longer on one side than the other the hood and front panels were not left to cure long enough and curled up to useless. This a vacuum formed body that uses the vinylester I keep talking about. Realistically one of the higher end bodies you can buy but its still not worth a damn. The side panels I made and hood from Rootleib are steel. Every panel had to be cut and modified just to get it mocked up and its still one of the nicer kit bodies I've ever worked on.

 

My bodies are made in permanent molds with first line quality products not junk resin or old rags,curtians or paper towells.......My company doesnt matter as I'm booked for orders for the next 2 years..all by word of mouth advertising.

 

This is a link to a picture and a description of how I made the scoop for our Bonneville car. http://purplesagetradingpost.com/sumner/hooley/hooley-construction-2005-1.html It is the ugliest shaped piece I have ever made but it works and that is the important part. For some of you the air inlet may look small but at 250 mph that is all the opening you need and a bigger one would cause problems.

John

 

Yes it does because I'd bet I've worked one of those too and if not I've probably at least seen one! I hope you and your company the best, I don't know you to knock you and that is not what I want to do anyway. Its also good to hear about a shop that is doing well and your customers are happy, so I'm glad for you actually.

Seriously, if you have something to add do so. You're not helping me I can make anything I want, the idea is to help other people. I make professional molds too, this is a backyard trick to save money end of story. How much is one of your bodies and what is it made of? Why, because if you are running anything near the industry first line quality in composite materials or in molding processes you claim, STEEL is cheaper! Call Brookville, align a few things depending on pot luck and how picky you are and you will still be bucks ahead from building anyone's glass car, period.

It sounds like you'd rather trash a cheap method instead being of any help. Something tells me you use the same old BS everyone else uses regardless of quality they may be. Giving you the benefit of the doubt here, I really don't know, you may be the best in country, if you cough up something other than my stuff is better, I might have to say so too.

More importantly overpriced, nearly useless parts are the exact reason for this post as much making parts that don't exsist. Its to help guys that are not retired and sitting on social security make parts one time instead of shelling out hard earned money on high production, half cured, chopper gun junk or parts where the reinforcement shifted in the vacuum bag that they would have to rework anyway with a similar amount of labor in many cases.

Most companies don't stand behind their products, maybe you do. Cutting Edge would warranty any part short of in an accident for ten years. Matter of fact we fixed a guys sedan for free that was hit by a big rig, for the right to use it and pictures of the accident to prove how tough those bodies were for a short time. I'll be the first one to say those cars are junk too but the warranty was never used that I'm aware of.

Anyway you are probably as stubborn as I am, lets hear how you'd do it? How you do; do it or something?

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I could care less if this thread is closed or deleted for that matter. The HAMB ( Thanks Ryan ) is a really cool place, thought I'd share. I build everything myself from fabrication to interior in my garage with the exception of AC welding, and machine work that I don't have access to the machines to do so right now at all times. Like many tech posts this how to do something nice, the wrong way because either you have to or want to see if you can pull it off yourself. Not everyone has $75,000 grand to put in a fu-fu streetrod, many I don't think would want one either....

I've worked for several "pro" shops and still sub in others but I hate working for street rodders and on their cars. I still think GoodGuys types are the worst thing that ever happened in the history building cars. Most of my work now is done in a 24x24 garage with two of my own project cars in it that have to moved everytime I do a job. The idea is anyone can do this stuff with simple tools without building garbage. Pride in your work, and effort makes as much as a difference as anything else and when you are done you don't have the same thing the other guy does...

If I continue to add any tech it will most likely be off the wall and low brow, its the results that matter. If you want something done right do it yourself. Hotrods were built from scraps, but that doesn't mean they have to look bad when they are finished. There is always someone better and more that think they are, build whatever you want from whatever you can and have fun with it. CarCraft once did a full article on smearing POR-15 on a battery tray as tech, I thought it was lame, but it may have helped someone maybe this will too.

Anyone that has a better way in mind, or trick not listed, post it that's cool. Even if its permanent molds with wood frames that warp and twist, or good old Ed Roth plaster tricks. What works for you? The idea was to share ideas not whine and brag.

 

Thanks John, that stude is wicked looking!

 

Not a chance...

Thank you for the Info.

This is perfect for Racecar Parts, and some of the things you've Posted got me thinking about some Parts I could use.
( 1 to maybe 3 pieces...)
Building a $500 Mold for a $500 part has always held me back.
And once you have an expensive Mold you have to find a place to store it as well...

Long time ago I used Plaster of Paris to modify a excisting part ( about a 6" by 6" area ), brushed on Vaseline, and used more Plaster of Paris as a one off mold.

Do you think that could work for a bigger piece as well? ( something like a hood...)

 

Johnson's paste wax used to work as a pretty good mold release.
Odd shapes used to kick my butt, then I figured out keyed mold pieces.
the basic idea is that the center piece of wood, plaster,foam pulls out allowing the other pieces to move to the center and be removed.
Basically a 3-D puzzle block.
They are probably all in the storage trailer in Alabama.
If I find one, I'll post pics.

 

Algon, are you coming to the meet and greet? I'd love to pick your brain some more.

 

ugh.

 

Cool thread! I enjoy the smell of styrene as much as steel.

Great tip already mentioned about using the 3/4 oz mat first, and then the cloth, mat, etc. I laminated a few very trick light weight canoes this way, very important.

I was involved in fiberglass fabrication in a production shop for about a year over three decades ago. We made many molds out of plastic laminate for machine shrouds. For a couple dozen parts it was attached to particle board and had a steel frame. It was buffed, waxed and sprayed with PVA. About 20 years ago I widened a 'glass 27 Ford body to fit over '32 width rails using just the horizontal grade laminate with wood firing braces every 5" or so. The cut area of the glass body was beveled and the material laid up to overlap the joint well.

A cool trick is to make a frame out of whatever is handy, I like 1/2 x 1/2" strips of wood. Staple, hot glue, or whatever you like. Same process to attach corrugated (or card stock for small parts) to the wood frame. Lay up the part and tear the mold out from it when the time is right. A bit of sanding and you have a part. Works great for sub structure gussets, inner panels etc.

Hope this was useful.

 

I have used the Ed Roth drywall mud trick for making trike bodies for years.
Cardboard and duct tape works fine as the basic shape,
then a few skims over with gypsum plaster,
let it dry, sand, paint, flat, polish, and then glass it up.


I like the results Ed's trick produces,
it's low tech and fairly cheap.

 

O/T cars...

The Blue one is getting a Turbo, so it needs a taller scoop.
And since the white one is getting 4 Webers that wont fit under a stock hood either, I'm thinking about making a Glass hood for both of them ( but without the bulge )

Also the white one needs slightly wider flairs in the back ( about 1" or so...)
So I'm not sure if I'm going to cut & modify my very expensive flairs that I had shipped out of England, or if I should take a quicky mold and modify that...

 

Thanks, the yellow one is based on 1800 Subaru running gear while the blue is an 850cc inline four on an inverted VW axle.

Not Avenger, new front and rear body sections for my GT40 (awaiting re-build).

I hope that more hotrodders will have a go at the Ed Roth thing in time,
Ultimately I see limits to cutting and chopping stock steel bodies,
where as the plaster buck has no such limitations, nor does it require anything like the skill level.
I have plans to try a new slight variation on the Ed Roth game,
Thinking of making up coach-built style hoops and then steam bend fibreboard to the hoops and then glass over that.
The fibre board will also double as a tack strip for the trim on the inside.

 

This is awesome!

NOBODY makes repop '48 - '52 Ford F2 & F3 running boards for trucks with the 8' Express Bed. I have a nice pair coming out of paint soon, and thought about making a mold and offering 'em to people... or just selling the mold(s)!

Somebody that's making molds from original parts soon should take a few pics and post up a step-by-step for tech week!

~Jason

 

The Blue one isnt getting any Flaires.

The tires are sticking out, and thats the way I like it...


But the White one will need a bit more width because the 9" its getting is a little wider than the whimpy original axle thats under it right now ( and I dont want to narrow it more...)

Thanks for the Info...

I have been thinking about how to solve this, but I never thought about laying 'glass on top of the exciting Flairs and using that as a base to modify the new ones from.

I'm going to try that...