Fiberglassing question

[Breadstick]

Not sure where this belongs, but I'll just ask you gentlemen. I'm going to take my first foray into making a fan shroud out of fiberglass and have a question. I have my mold made, but I figure it should have at least two layers of the fiberglass mat for strength. Do I have to wait for the first layer to completely cure before laying the second, or can I just lay the second on top with a little more resin as soon as I lay down the first layer.

Also, I read somewhere that a layer of wax paper is sufficient to keep the mat from sticking to the mold. Is this true?

[BR3W CITY]

wax paper can work, just make sure it doesn't crinkle or fold on any edges, since that will transfer to the shape of the fiberglass. Petroleum jelly rubbed on tinfoil works, as does true "release agent" spray.

Are you using the woven fiberglass sheets, or the chopped mat (looks like cat hair)?
You can do layers over each other while wet, but its recommended that you take a roller and go over the layers, pressing them into each other and removing some of the excess resin. While you need enough to soak the layers and harden, too much resin will take longer to dry, and can cause bubbling or seperation of the layers if they aren't bonded well. Sanding big resin chunks off of glasswork sucks.

You can do CF with similar techniques, although there is a bit more work to get the CF to turn out "Show quality"

[Breadstick]

Thanks for the reply. I'm picking up the mat or kit (not sure which, whatever Lowe's has in stock) after work today and would like it get it laid down to cure tonight. I'm not worried about it being pretty. It's for a rad fan shroud, so I'm just going to rattle can it black when it's done. I just want something sturdy because it's too hot to drive my truck without it right now.

[Bugeyev8]

Originally Posted by Breadstick

Thanks for the reply. I'm picking up the mat or kit (not sure which, whatever Lowe's has in stock) after work today and would like it get it laid down to cure tonight. I'm not worried about it being pretty. It's for a rad fan shroud, so I'm just going to rattle can it black when it's done. I just want something sturdy because it's too hot to drive my truck without it right now.

I used saran wrap, check the last page of my build thread and see how I did the shroud

[64shortbox]

Here's another "Idea Page" on making your own fiberglass fan shroud.

http://www.cadvision.com/blanchas/54...FanShroud.html

[rustbucket66]

I have quite a bit of experience with fibreglass, If you have the mold made, cover it with corn syrup (no kidding), using a paint brush, and let the syrup harden overnight. It will harden enough to lay the fibreglass on, it will resist the fibreglass, and make an easy job to release it from the mold. It also doesnt crinkle up like tin foil or saran wrap, and keeps your piece very accurate, especially on corners and bends. Then just clean up the syrup after you release it with hot soapy water. As for the mat, I would do 3 layers, have all your pieces cut first, then lay it on one layer at a time, making sure to get the air bubbles out with a paint brush before putting the next layer on. You can chop up some extra mat with scissors into a fine pile of mat, then mix it with resin to make a paste that you can put on the mat where the joints are. The corn syrup is cheap, and works amazing, one of my best secrets. Trim the edges, then a little bondo on the outside to make it smooth, and paint.

[HEI451]

Simply, more info for those that want to modify stock "plastic" shrouds and parts. This black plastic the parts are made of, is called "ABS", and it is the same recipe as the black drain pipe most mobile homes have in them for their drain systems, available at any hardware/home improvement store.

Fiberglass resins do not stick/bond to ABS, no way. But, there is an ABS cement that does, quite well. And, fiberglass cloth, which is strong as all get out, will bond to the ABS cement. I both ride, and road race vintage Japanese motorcycles, which have fairings, parts and covers made of injection molded ABS plastic. Whenever I need to do a repair on a part that has been damaged, I thoroughly clean, degrease and dry the "wound". First, add a layer of ABS cement, then, fiberglass cloth, another layer of ABS cement, then, another layer of cloth, set at a 45 degree angle of the weave of the cloth, over the first layer, then, the last layer of ABS cement. This ABS cement/fiberglass cloth layering becomes many times stronger than the original part was in that repaired area.

Please realize, most stock parts made of ABS were injection molded in a machine, some were made in a mold, but all are repairable using the cement for the plastic, and fiberglass cloth. Although I prefer the fiberglass cloth over matte fiberglass, the matte works as good if you cross it over itself, 90 and 45 degree angles, just a lot harder to work with.

Just food for thought for those repairing/modifying stock ABS plastic parts.