Q: Where To Buy Building Materials?

[NeilBlanchard]

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]

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]

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]

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

[Patch]

Neil,

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

[NeilBlanchard]

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]

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]

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]

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]

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.