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NeilBlanchard 05-03-2011 07:48 AM

Q: Where To Buy Building Materials?
 
Hello folks,

I have asked at my local auto body shop, and they do not have a source for fiberglass. So, my question is: can you please post specific information on where to buy fiberglass building materials? In particular, I want to buy epoxy resin.

Thanks in advance.

Are there other materials that you have found useful? Please post the information for others to get them.

Bill in Houston 05-03-2011 11:20 AM

West Marine is a name I hear a lot. I have also seen it at really serious auto paint/ body repair supply stores. Depending where Maynard is, air permitting might be an issue, so you might have to travel to get it.

NeilBlanchard 05-03-2011 12:03 PM

Thanks
 
Hi Bill,

I'm in MAssachusetts -- I'm told that epoxy is much lower VOC than the typical ester resins? Plus, I'm working with EPS which is verboten with ester....

Bill in Houston 05-03-2011 12:30 PM

Yes, I think epoxy is lower VOC. And yeah, you don't want to put esters on your EPS... :)

Patch 05-03-2011 12:48 PM

Neil,

One source of materials you may try is Aircraft Spruce & Specialty. They sell all types of materials for aircraft homebuilders.

NeilBlanchard 05-20-2011 08:01 AM

Okay, I have some specific questions about the various fiberglass fabrics and epoxy resins:

Fiberglass Cloth

Epoxy :*Epoxy Resins and Hardeners

For the skin on my 1/4 scale CarBEN model, what weight and type of fiberglass fabric would be best?

For the full size shell of the CarBEN EV, what weight and type of fiberglass fabric would make sense? For the bottom and the surfaces where suspension components will be attached, I am thinking that using a heavier fabric will be good.

To make smooth wheel covers, or wheel strakes, or belly pan -- the same question?

I know I need to use epoxy resins since I am using EPS foam to build up and carve the forms; but should I use the medium set time thin epoxy, or the slow, or the fast? The outside will have the skin first, and then I'll skin the inside, as well. The inside of the hood area, the inside of the battery compartment in the floor, and the front and rear wheel wells and skirts, also will be fiberglassed.

Should I get the 1oz pumps? What applicators, rollers, gloves, masks, suits, etc. would you recommend?

Bill in Houston 05-20-2011 10:17 AM

When we laid up sailboats, we would start with a negative mold. we would spray in the gelcoat. Then we would put in a couple of layers of the random mat, then a couple of layers of woven cloth. They said that if we didn't put mat next to the surface, the weave texture of the fabric would start to show through the gelcoat after it sat in the sun for a while. We would only use roving (very coarse unidirectional cloth) on the very thickest pieces.

The cloth was plain weave, prolly the 6 oz.
The mat was that chopped strand mat stuff, prolly about 2 oz.

Since you are working on something smaller, you will prolly want to use lighter weights.

We used rollers to roll the resin into the cloth, and roll the air out. They were prolly 3/4" diameter and 3 inches long.

For resin we used polyester thinned with a little acetone, catalyzed with MEK peroxide. I would suggest that you figure out a way to use ester instead of epoxy, since epoxy is, i think, much more expensive and much harder to work with.

if you use epoxy, find out if there is a way to thin it, or see if you can get lower viscosity grades. if you try to use something that is too thick, it won't roll out well, and the fabric will tend to move around, and it will be too thick, and it will add a lot of weight.

When we needed to fill gaps, we would mix the resin with talc and microballoons, and use less catalyst, since that stuff would tend to really heat up when it kicked.

We eyeballed the volumes of resin, and measured the mek-p with basically plastic shotglasses, oh, there they are, the 1-oz graduated cups. we mixed by pouring the resin back and forth from one container to another, rather than trying to use a stirring tool.

any clothes you could be ruined. we would wear jeans and short sleeves, and wash our hands and arms with acetone. if i were going to do it now, i'd buy a bunch of cheap safety glasses and gloves with gauntlets to try to protect myself, but i'd still get a bunch of acetone for washing tools and such.

if you want it to be strong, then you are really trying to use as little resin as possible. you want the fabric wetted out, but no excess beyond that.

anyway, there are lots of great places to learn about this from people who have done this more recently, so i probably havent told you anything you didn't know. just feeling loquacious today.

NeilBlanchard 05-20-2011 10:29 AM

Thanks Bill. I really have to do the work on this first prototype in the "positive" mode, and this means I need to work with EPS, which means I have to work with epoxy. And I think by your description, that I will need to work with the slow setting epoxy.

Reading the description on US Composites site, it would seem that once the epoxy is spread on the form, you then have a longer time to work with it -- it is the "pot" time that is quite limited; even with the slow setting epoxy.

Bill in Houston 05-20-2011 10:40 AM

yeah, i guess you could put something over the foam, like latex paint, or paint a single layer of epoxy on it and then work with esters, but maybe it's easier on this one to just go with epoxy.

temperature is a big, big factor in cure/pot time, as they hint at. if there is a way to compensate for temperatures, make sure you use it.

i would suggest buying some extra supplies and practicing. i know you will want the final version to come out perfect, so some practice will really pay off, especially on stuff like compound curves, sharp corners, etc.

you probably know this, but to get a smooth exterior, you may end up using quite a bit of filler material, so include that in your thoughts. you dont really want to ever be sanding actual fiberglass.

good luck. it will be exciting to see your idea take physical form and come to life.

Vekke 05-24-2011 03:32 PM

Few advices more.

1. If I remember corretcly acetone is not good for washing your hands. It cleans them but the resins go through your skin more easily after you have washed them with acetone. Always wash your hands with cold water first it closes your skin and glass fiber pieces wont go to your hands tiny holes (it wont ich so long). Loctite hand washing cream works well, it does not dry up your hands and cleans them.

2. Protective cloves and gear read suit is a must I would say with epoxy. Some people get epoxy allergy very easily. That aint fun at all when that happens.

3. If you arent making serial production parts the slow resing suits well for your purposes. Remember that bigger amount you mix the epoxy and hardener faster it starts to harden. If you mix too much at a time and arent able to lay it up, it can even start to burn.

4. For the whole car you will at least one roll of fiberglass cloth so I would buy one roll for starters. That goes for the resins also minimun need of 30 kg of resin. I would use fiberglass gloth something that weigths 300 grams is it 10 oz?

5. Buy this kind of electric scissors to help ease the pain on your fingers:
http://www.aliexpress.com/product-gs...olesalers.html

In finland you can find sometimes similar black and decker etc. under 15 dollars.

Bill in Houston 05-24-2011 03:36 PM

Yes, I really should have stated that washing one's hands is NOT a recommended practice. Thanks Vekke.

Vekke 05-24-2011 03:51 PM

I would quess that cheapest place to buy those materials is one of the nearest boat building shops:
massachusetts boat builders - Google Maps

Ring few of them and see if they are willing to sell the materials. Tell them what you are building first because they like to know it has helped when I have asked materials. Usually you get the materials at least half the price. They can also give better estimation how much materials you will be needing for your whole project.

You were first building that 1:4 model and after that 1:1 model and on both cases you first make glasfibre molds/tools?

NeilBlanchard 05-24-2011 07:59 PM

Have you used Elmer's glue (white or the waterproof yellow) to do fiberglass? I am interested in this, especially if it would mean that it was biodegradable. It certainly would be easier to wash up, and is very low VOC.

bryn 05-24-2011 08:26 PM

i have not tried elmers, might be worth a few sample squares to see how it compares, as for glass, there are two main types, e-glass, and s-glass. s is a little more expensive but much stronger, the only benefit to e-glass that i can think of would be that it is clear, s glass has a slight blueish tint. kevlar would be ideal for strength and impact resistance, carbon fiber for strength and stiffness but those are both very pricey! as for polyester resin vs. epoxy. epoxy wins every time. easier to work, easier to adjust set times, better adhesion, less voc, you can thicken it, repair it if need be, just follow instructions carefully, have fun.

small boat building books from the library can be a huge benefit when making slippery shapes, and they tend to deal a lot with one off designs and lots of ways to get around the same problems. you will come across with your project.

skyl4rk 05-24-2011 08:28 PM

Quote:

Originally Posted by NeilBlanchard (Post 235750)
Hello folks,

I have asked at my local auto body shop, and they do not have a source for fiberglass. So, my question is: can you please post specific information on where to buy fiberglass building materials? In particular, I want to buy epoxy resin.

Thanks in advance.

Are there other materials that you have found useful? Please post the information for others to get them.

Raka, Inc. 772-489-4070
Get 2:1 ratio resin to hardener, it is less toxic than 4:1. For example, from the site above, a good combination would be Resin 900 Medium and Hardener 608 Medium. Fast hardener can be too fast in warm weather, and Medium cures overnight just as well as Fast does. I have used Slow with good results too, it just takes a bit longer to cure in cold weather.

Get a small postal scale that reads out in half ounces. Use the scale to weigh out the amount of resin you need, then add half that weight in hardener. The pumps are convenient but then you have little control over how much or how little epoxy you make.

Buy a bag of cheap chip brushes, a bag of tounge depressors and a bag of pint plastic containers.

Raka, Inc. 772-489-4070

You will want a few different types of fillers. Silica is the strongest but is hard to sand. Wood flour is a middle ground and usable in most areas. Microballoons (glass bubbles) are for sanding and fairing. You don't need much of each. $10 buys enough filler for a big project. At a minimum you will need silica and glass bubbles. Make sure you wear a mask while mixing fillers, the powders get in your lungs if you don't.

Raka, Inc. 772-489-4070

6 oz plain weave is pretty much a standard glass cloth for covering plywood. You could go thinner, 4 oz, for example. You can cut tape (strips of glass cloth) with a quality scissors, it is usually cheaper than buying tape.

skyl4rk 05-24-2011 08:44 PM

Quote:

Originally Posted by NeilBlanchard (Post 239657)
Okay, I have some specific questions about the various fiberglass fabrics and epoxy resins:

Fiberglass Cloth

Epoxy :*Epoxy Resins and Hardeners

For the skin on my 1/4 scale CarBEN model, what weight and type of fiberglass fabric would be best?

4oz plain weave

For the full size shell of the CarBEN EV, what weight and type of fiberglass fabric would make sense? For the bottom and the surfaces where suspension components will be attached, I am thinking that using a heavier fabric will be good.

Use plywood or hardwood buried in multiple layers of glass cloth and silica filler for hard mount points. You can use 6oz plain weave for this as well as anything else, although a biaxial or triaxial woven roving may provide more bulk and strength. I would just use plain weave until you know what you are doing and can design a special layup.



To make smooth wheel covers, or wheel strakes, or belly pan -- the same question?

Thin plywood covered with one layer of lightweight cloth, 4 oz would work.

I know I need to use epoxy resins since I am using EPS foam to build up and carve the forms; but should I use the medium set time thin epoxy, or the slow, or the fast? The outside will have the skin first, and then I'll skin the inside, as well. The inside of the hood area, the inside of the battery compartment in the floor, and the front and rear wheel wells and skirts, also will be fiberglassed.

It is very difficult to get a smooth finish when covering foam with glass cloth. I would suggest testing the following for nonstructural parts: Sand the foam to shape. Cover with clear epoxy, let cure. Spread glass bubble filler over any rough spots, sand. Paint. I don't know what EPS foam is so I may be way off on this. Plan on using a lot of glass bubbles and doing a lot of dusty, dusty sanding to get glass cloth smooth. Take anything of value out of your workshop, it will be destroyed by the dust.

Should I get the 1oz pumps? What applicators, rollers, gloves, masks, suits, etc. would you recommend?

See above, get a decent respirator with a dust filter. Get a box of disposable gloves. Tyvek arm covers are useful, I seem to get a lot of epoxy on my sleeves. Wear clothes that can be thrown away after your project is done. Always change into throwaway clothes before using epoxy or sanding epoxy/glass.

I find that a bag of 1" and 3" chip brushes covers most of my needs. I don't use rollers.

Bill in Houston 05-24-2011 09:05 PM

Quote:

Originally Posted by NeilBlanchard (Post 240625)
Have you used Elmer's glue (white or the waterproof yellow) to do fiberglass? I am interested in this, especially if it would mean that it was biodegradable. It certainly would be easier to wash up, and is very low VOC.

Does the body have to do anything more strenuous than sit in a wind tunnel?

NeilBlanchard 05-27-2011 11:32 PM

The 1/4 scale model -- no nothing harder than that. But I am also going to be starting the full size actual shell soon; and it will be fully structural.

Is there such a thing as biodegradable foam, and if so is it available in sheets? If it is otherwise similar to EPS, than that would be great!

Bill in Houston 05-28-2011 08:57 AM

if it's going to just sit in a wind tunnel, glue and glass is fine.

you could make a paper mache form to put glass on instead of foam.

i have seen biodegradable foam packing pellets. they taste like corn pops. i don't know if that stuff comes in sheets.

NeilBlanchard 05-28-2011 04:12 PM

I Googled "biodegradable foam sheets" this morning and only came up with very thin sheets: 1/8" 3/16" and 1/2". Also, lots of packing materials.

I'll keep looking.

Vekke 05-30-2011 04:08 PM

Quote:

Originally Posted by NeilBlanchard (Post 241398)
Is there such a thing as biodegradable foam, and if so is it available in sheets? If it is otherwise similar to EPS, than that would be great!

Do you mean structural foam than can be melted off from inside beam structure to save weigth?

NeilBlanchard 05-30-2011 04:14 PM

No, I just would like it not to end up as a hunk of plastic at the end of it's useful life. The foam would stay in place for the lifespan of the chassis, providing strength and thermal insulation. EPS is possible to recycle, so if I cannot find biodegradable foam sheets that can work in this situation, then I'll use EPS.


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