A couple of quick fiberglassing tips?

[Jason1955]

I'm getting ready to do some minor fiberglassing using poly resin. I'm getting ready to apply some new mat to original fiberglass to close up the cap in the transon on my 85 Sunbird. My first question is are you supposed to sand between layers or do all the fiberglassing and then sand just before painting? Also....I had heard one time about if you were putting multiple layer down hat you shouls stagger the layers as far as length, for example make each layer 1" to 2" shorter? Is there anything to this?

Thanks,
Jason

 

[sdunt]

Re: A couple of quick fiberglassing tips?

Actually the sanding depends on whether the resin you are using has 'finishing' wax in it or not. Basicaly to get poly resin to totally cure they put 1 - 2 % parafin wax in the resin that floats to the surface and seals out the air.

If you are using off the shelf resin, Bondo, Elmers, etc they have the wax included. SO if you let it setup before you apply the next layer, you will have to remove the wax layer, usually by sanding so the next layer can bond to it.

as for stagering lengths of glass layers, the general practice when doing a repair is to grind a dish or taper on the area to be repaired and the process of bringing it back to level involves using progressively longer pieces of glass to fill in the tapered area.

Another practice that involves alternating is to alternate mat and cloth layers in a laminate as you build it up for added strength.

Depending on the size of your job and resin set time you can layup multiple layers of mat and cloth in one go.

The best thing to do if you have not done fiberglass work before or recently is to practice, especially so you have an idea of how fast your resin will setup.

Lots of details on lay up process in this post: http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=26;gtid=1107471