Fiberglass Question
Hi all. I am going to make a new body for my Lotus 61 as it is getting a little rough. My question is what weight of cloth should I use? I was thinking 6-8oz but want to make sure. I will be using cloth as it will be Epoxy resin not polyester. I have the mold. If any of you have made a body before, roughly how many yards would I need of material and how many layers should I have. Thanks for any help.
Graham
Making a mold first? Don't need epoxy or cloth for that. Best suggestion is to find local fiberglass fabricator and have them do the mold and a test splash. Years ago, I bought a Lotus 11 body from fellow up in Chattanoga, he had a guy on lake nearby doing all his glass work. When we stopped by, they were doing boats and architectural stuff. Don't recall name of shop, but worth looking for if near you...Lake was north of town. My 11 buddy, Craig K., passed away several years ago, so don't have a lead there... can use mat/chopper gun for mold.
Rest.... depends on # plys, and how reinforced...all body, including engine cover...and where you source the materials. Not sure epoxy is worth extra cost, if throwing money at it, why not carbon or kevlar? Estimate $800 to a grand for materials (in poly) to start, w/o mold. Will need lots of space to work. First step is to just measure the body, length, width, height... rough out total area, and go about 30% more on cloth. probably 2 ply min...
Have done this several times over the years...usually more work than I wanted...last few, have farmed out.
decent online source with some tech help/estimators.... http://www.fibreglast.com/
I had Aeroglass (apex advertiser) do a Tiga S2 body, think you could call and they'd chat with you about details...
West Marine makes good stuff, but costs out the ............
Bob L.
Well, since the OP says he already has the mold a new one isn't necessary. Since he is running vintage, carbon and Kevlar are probably not allowed.
When I built the body for my old DSR (much bigger than the Lotus 61!) I used epoxy and cloth. I started with two layers of cloth and then laminated pieces of foam to places that flexed. This is almost a necessity beneath things like mirrors. I used the 30 minute West epoxy (can't remember the product numbers) and measured it with their pumps.
I initially bought everything from Fiber Glast Developments but ended up buying from Soller Composites. With complex curves, try to find a harness-satin (sometimes called crows foot) cloth otherwise use a 9 oz twill.
Good luck and have fun.
Marty
Mold
Yup...missed that in first read, sorry.
Bob L.
I want to add that AC Spruce has Cloth that is multi directional in strength and better quality than the stuff you find generally, like at HD etc.. You can get away with fewer layers if you use better cloth. I use 3 layers but others use more.Originally Posted by Marty Nygard
Good stuff, thanks guys. I have done quite a bit of fiberglass work but mainly just repairs and making side scoops etc. The mold I have looks pretty good and the lower nose is two piece so should be pretty straight forward. Am I better to go one full piece to run from one side to the other oy overlap smaller pieces for ease of working it?
Depends on how much filler and paint you want to use. I assume you are doing a wet layup so if you want to minimize frayed edge lines try to find harness satin cloth and drape it to fill the mold.
M
As a hobbyist with a modest level of experience making fiberglass parts, one thing I found when making a new nose and a diffuser for a GT car, I found it difficult to work quickly enough to finish laying up the parts within the curing time for the epoxy resin I was using. Even though I had a couple hours working time. One thing to keep in mind.
I didn't see if you mentioned using a gel coat, but it's worthwhile in my opinion - it will save you hours of finish work on the body. Again keeping in my hobbyist level of experience, I found that resin alone does a decent job matching the contours of the mold, but you wind up with a million pinholes that you need to deal with in the finish work. Also, make sure you pick the right gel coat. Tooling gelcoat is very hard to sand, so don't use that.
Scott
West system epoxy is available in a variety of cure times. I was able to complete a two layer wet layup on the entire front half of a closed wheel sports racer using the 60 minute epoxy without any problem.
As far as gel coat goes, it's heavy and prone to cracking. I fill pinholes by spraying rattle can primer with my left hand and rubbing it in with a gloved right hand. larger voids can be filled with easy sandable fairing compound. This even works when draping harness satin over a single use male mold.
Another time saving tip I got from a local FSAE fabricator is to spray primer into the mold before the epoxy and cloth wet layup. He said that they originally used hair spray as a mold release but a waxed mold with primer worked easier.
M
Two layers plus foam and another layer
Graham,
I have typically tried to stay with two layers of 5-6 oz then 1/8" foam in areas where there are larger flat surfaces. Put a sheet of plastic on this and many little bags filled with sand to make the foam conform to the surface. Knife slits also OK in the foam to get it to conform. Once cured overnight remove the bags and the plastic and feather the foam edges with coarse sandpaper or a knife or both. Then one more layer of cloth. Two or three more layers in areas where you are doing fasteners.
Instead of gelcoat I wax the mold minimum 8 layers of wax then with a rattle can gray primer i lightly coat the inside of the mold. Almost dusty spray layers at first . Let them dry. Then go with a few heavier wet layers of the same primer. I have tested a spot with a finger nail to make sure the paint is sitting on top of the wax. Critical!. Then lay up the cloth and epoxy. The epoxy will stick great to the primer. Pull the part, dewax it and then proceed to wet sand with water with a bit of dish soap in it. As soon as you get to the epoxy stop sanding, and apply more primer if needed.
If this sounds scary do a test bit first to ensure you will release.
Steve
Resin
I like Resin Research 2000 ce and use a scale, not pumps to measure. The blue bulk needs to be used up in a month or two or it hardens up in the bottle, so I buy the quarts. Stuff is awesome to work with. I also like the West System but it is substantially more expensive
i've been doing a bunch of vacuum bagged carbon recently and have been getting supplies from compositeenvisions.com these days, found them on ebay but now just buy direct from their site. pretty good prices big selection of stuff and should have what you need. the epoxy they have is way cheaper than west systems
Awww, come on guys, it's so simple. Maybe you need a refresher course. Hey! It's all ball bearings nowadays.
John, can you recommend a part number?
V/r
Iverson
Microspheres in epoxy as a 'Gelcoat'
this afternoon while sanding a piece of bodywork I made years ago i was pleased at how well the microsphere filled epoxy repair sands and works. I will try mixing some (wearing a mask of course) in a spreadable consistency to see if I can paint it onto a waxed mold surface as an epoxy based gelcoat substitute. I have never successfully painted straight epoxy onto a mold. It doesn't wet out into a sheet like gelcoat does. My idea would be to get the microsphere mix painted into the mold and as soon as it is stable enough start laying up the cloth have at it. Let the entire epoxy mass cure simultaneously and not leave pinholes
Steve
^^^^ Keep us up to date on how it goes Steve.
try vacuum bagging, it will even out your resin coverage and distribution/saturation in the layers of glass/carbon. If you REALLY want to get fancy try resin infusion. I've yet to attempt it but it looks pretty wild.
Awww, come on guys, it's so simple. Maybe you need a refresher course. Hey! It's all ball bearings nowadays.
fiberglass cloth
Aircraft Spruce has bidirectional cloth #7725 and it is sometimes referred to as Rutan cloth. It comes in two widths and is 8.5 oz per yard and is perfect for race car bodies. Shop around for it as prices vary considerably. Suggest using at least two layers, maybe three and edges should be another layer or more to retain stiffness. Strips cut into two inch widths work well for edge reinforcement and stiffness. Be sure to wax the mold thoroughly with 6 - 8 coats and use Part-All or hair spray on top of the wax.
For the first layer (gel-coat) use Cabosil/Colloidal Silica Filler and possibly add pigment to it. Cloth can overlap in the mold if it makes it easier to install. Also, vent the area properly as this is epoxy - and a cooler temperature will slow down the cure even with the slow cure hardeners. The trick to any fiberglass work is to get as much resin out of the layup as it only adds weight. The strength is in the glass cloth and varying the direction of the cloth weave will enhance the strength. Using a 2 inch paint brush with the bristles cut short will help get air bubbles out of the layup if used properly.
Once the part is out of the mold and to fill pin holes, etc., Microlite 410 works very well when mixed with resin and applied with a brush or plastic scraper. A small amount of resin mixed with Microlite will make a lot of filler. It is not structural, but fills pin holes and is very easy to sand and get a great surface finish. It sands away like balsa.
Good luck with this!
After doing my own fiberglass in making the bodywork for my FV's I have learned a few things over the years. I would suggest that you use a gel coat since it will eliminate the millions of pin holes that appear as soon as you lightly sand the part so paint will stick to the part. I also would not use tooling gel coat since when I switched to that for my gel coat I started to notice that the parts seemed to not hold their shape especially the engine cover if removed and set aside while hot. I then switched to making my own gel coat by adding cabisol to whatever resign I was using polyester or vinylester to thicken it up so it won't run when applied. I do use a gel coat spray gun but you can brush it on or roll it as well, but you need to get an even uniform thickness so if it is to thin it will alligator as they call it and cause problems. You can add color pigment as well if you want to.
I always let the gel coat set up until it gets to where when touching it your finger print will be in the gel coat but will not be on you finger. I would then start laying up the cloth which I use 10 oz E glass and do four layers of cloth. If you have a part that has complex curves you might need to use several pieces instead of one large piece and if the part is large again use multiple pieces. I always work by myself so it is difficult to work with large pieces so I use multiple pieces to get the coverage.
You will find out that when using resin that depending on what the temperature and humidity is will affect how quick the resin sets up but you can adjust the amount of hardener to add to control working time. I also use 3" rollers instead of squeegees or the other type of rollers for doing mat. I buy 9" epoxy roller covers and cut then in thirds and have some cheap Harbor Frieght 1" and 2" chip brushes around for getting into places the roller won't get.. Also being a thrifty person I will put the roller in acetone to allow me to remove the roller cover so I can use the roller over with a new cover.
I also use a drill with a mixer shaft on it instead of trying to mix it up with sticks since it goes much quicker and when mixed put the mixer into acetone in a soda bottle with the top cut off and quickly clean off the resin.
Also you should know that using a release agent as in PVA which is poly vinyl alcohol is great if applied correctly but you can't spray it or brush it over most waxes but need a special wax that it won't bead up like water on car wax and also any plastic that is #2, resin will not stick to it and this includes packing tape. I use the two quart milk/juice jugs with the top cut off to mix and pour the resin from.
I learned most of my techniques from someone who supplied the white water kayak crowd and was very helpful. He supplied a nice article on how to make molds and do the layup which was a great guild for getting started. He sold his business and it is now Sweet Composites and the new owner does not sell anything but epoxy but has most everything else and he is in Bethesda MD. If you can find someone local for you resin purchase it will save you those hazmat shipping fee's. In a pinch you can get gallons of polyester resin at Home Depot and it works fine.
Ed
Gents;
I called the Fella that glassed my coach, and he used DDM9 catalyst, run of the mill resin, and 1.5 oz polyester mat. He also said a plastic roller is minimum mandatory.
Firstly, any touted resins out there, or your basic West Marine stuff ok.
Secondly, comments on the weight, ease of application and workability of the mat vs. the bidirectional 6-8 oz?
Lastly, best pneumatic tools to give a rookie a leg up?
V/r
Iverson
Hey "Rookie"...
I could loan you some.
I saw a compressor in your shop right?
I'd bring over the "Venturi-Press" version, and some reading materials.
Need to give me a week or so to dig it out of the garage.
Shoot me your email address and I'll send the pdfs.
Cheers - Jim
Last edited by phantomjock; 01.27.20 at 10:32 AM.
When I used to fly Phantoms, I was called an AVIATOR.
Now I race cars. So, am I now called a PAVIATOR?
No gelcoat images
Rolex 24 car close ups show function over beauty. Black is the Lexus door, red is the Risi Ferrari rear wing. The body on the Ferrari is immaculate but not the wing endplates. On the Lotus you want better, but for my car I think I stop fretting about the weave showing
Last edited by Roux; 01.27.20 at 11:33 AM.
When I was an official in the Ferrari garage at the 2001 USGP I can tell you that the composite parts back then were good 50/50 parts - looked good at 50ft and 50 mph. Weave showed through everywhere. I'm sure that was all about weight and possibly build time.
Even with a good gel coat the weave of cloth will eventually show thorough especially on the engine cover due to the heat behind the part.
If anyone wants a copy of the instructions I spoke about above, send me a private email with you email address and I will forward the three page instructions.
Ed
Surfacing veil
Fiberglass “surfacing veil”, which is a very fine fiber non woven mat, is advertised as effective in reducing the telegraphing of fiberglass cloth through to the outer surface. It goes on as the first layer between the gelcoat and the laminations.
No experience using it that way but I can vouch for its effectiveness in repairing spider cracks. Lightly grind the outer surface of the gelcoat, apply one or two layers of veil, finish bodywork as normal. (I use microspheres in resin). Obviously any underlying cause for the spider cracks need to be addressed.
There are also other uses. It is one of my favorite materials for fiddly fiberglass repairs.
John
Ed Womer gave some great tips. If you use gelcoat mske sure you use the proper gelcoat for the resin you're using. Most gelcoats you see advertised are for polyester or vinylester resin and you must let them setup completely if you laminate with epoxy resin. If you're using the polyester or vinylester you can start laminating as soon as the gelcoat is tacky. You can use veil for the first layer to avoid print through, it works well.
When you wax the mold use a non silicone wax made specifically for releasing the part from the mold, or mould if you're making a part for an English car. 8-10 coats is best so the chances of missing a spot are greatly reduced. The coat the waxed mold/mould with PVA. You can gently wipe it on with an old t shirt. Only one light coat or you'll make a mess of the surface.
Vacuum bagging is cool, if you want to go to all the extra material expense. If this is your first time making a body or body parts you may want to stay away from bagging or infusion...
The best way I've found to release the part from the mold/mould is with plastic wedges from Home Depot. They are usually in the door/screen door area and used as shims...cheap and wont scratch. If you have some trouble getting curved areas apart you can spray water between the mold/mould and the piece. The PVA is water soluble...
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