C2 fiberglass repair

[Tony C.]

Hi
I made a plastic mold to help me repair the fiberglass jack storage compartment.
Is there some thing I can but on a plastic mold to release it from the new fiberglass when it dries or will it just pull off?
Thanks
Tony

[Scott Marzahl]

Re: C2 fiberglass repair

You can spray it with mold release or put a good coat of Johnsons Paste wax on it.

[Tony C.]

Re: C2 fiberglass repair

Thanks for the help
Tony

[Ralph Harlan]

alternate suggestions on barrier film layer

With something as small as the tubs, you can also wrap it with plastic sheet (assuming you made a male mold) - or shrink wrap it if you have shrink wrap & heat gun. Then when you finish molding the new part, all you have to do is turn the tubs right side up and "float" the mold from the new part using a garden hose to run water between the two. You can - gently - use a wooden or plastic wedge to separate the part from the mold in one place and then run water from the hose in. This barrier film method works particularly well if you do not have a very smooth finish on the working side of your mold as ripples, lumps, fuzz, and irregularities serve only to bind the two together as you try to separate them after cure of the new part. Bear in mind that typical molds are either gelcoated or finished with a very smooth surface of tooling resin, vynalester resin, or epoxy and then buffed prior to use.

If you made a female mold, it is a little tougher to get the plastic to lay tight to the new mold surface as you roll out the new glass, but it can be done with a little practice. Be sure to use a "bubble buster" or finned roller to roll out the new glass as you lay it up. (They come in both plastic and aluminum, but either works well - just be sure to clean it thoroughly if you want to reuse it. *nothing like finding your prized curved bubble buster fossilized in the bucket of what was an acetone bath only hours ago!*) This will compress the layers of mat/cloth as well as removing bubbles and forming the new part tightly to the mold. Again rolling out is easier on male molds than the female molds unless you have an assortment of rollers and some experience. For something like tubs I'd use alternating layers of mat and lightweight cloth - probably 3 - with the mat layers first and last for the texture.

Have fun!

[JOHN ARAUJO]

Re: alternate suggestions on barrier film layer

My cousin used to work in the fiberglass industry. He made the fiberglass enclosures that you see at a lot of pet stores that hold the animals that are for sale. I used to help him on occasion and what we would do is make sure we waxed the mold real good before spraying the gelcoat into the mold. We would then leave a small hole in the center of the mold aprox. 1/8". After the cage was dry we would insert a blow gun with a rubber tip supplied by an air compresssor into the small hole and it would pop off nice and clean. This method worked great for cages which were fairly large, I don't know how it would work on small projects.
John Araujo

[Mark Milner]

Re: alternate suggestions on barrier film layer

Maybe shoot them across the room?