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any tips on tidying up new fibreglass
daniel mason - 26/4/11 at 09:58 PM

i have just done my first bit of fibreglassing tonight,after appliying the fibre to the mould,i then brushed on the resin/hardener, and after a few coates its almost dry/hard but the finish is not perfect, it has slight raises from the brush strokes and the coating has a few small humps where the coat has been applied slightly thicker in certain areas.
is there anything i can do to get a smoother finish to paint on to? cheers

Chippy - 26/4/11 at 10:12 PM

Assume that you are glassing into a mould. You should stipple the resin onto the glass, and then use a "penny" roller, (or similar), to consolidate the mat, this should give a reasonable finish. HTH Ray

austin man - 26/4/11 at 10:19 PM

did you apply a gell coat first or just resin ? sounds like you may have a little too much hardner ie dying to quickly. You could sane the lines out or use a light skim of filler and sand down

daniel mason - 26/4/11 at 10:22 PM

no gel coat. just a resin/hardner mix brushed on. it said on the pack there was a seperate gel coat finish available but i dont have any. i could fill and sand though!

austin man - 26/4/11 at 10:49 PM

I believe the gell coat does flow better therefore giving a smoother finish from the mould

twybrow - 26/4/11 at 11:34 PM

Are you working on a male or female mould to produce this part? Ie are you concerned about a rough service that will be visible on the finished part, or a comment about the rough finish on what will become the inside face of the part?

If it is the former, then a few coats of lacquer on the finished part will fill any small pin holes, and give you a gloss finish. If the holes are larger, then use a tooth pick, and drop small dots of the resin into the holes. Then flat back when fully cured, polish it up etc...

By the way, are you using epoxy (resin + hardener) or polyester (resin + catalyst)... The mix ratio has to be really accurate with epoxies. With polyesters, you can get away with more, but a 'hot mix' will always shrink more, and therefore give you poorer surface finish.

If you are trying to use brush coated resin as a final layer on the outside of the part (and not using a mould), then it will be very difficult to get rid of the brush marks... Try a spray coat instead!

Fred W B - 27/4/11 at 06:44 AM

quote:

appliying the fibre to the mould,i then brushed on the resin/hardener, and after a few coates its almost dry/hard


You are applying just enough resin to "wet out" the matt you have applied? In you are then just adding more resin on the back it will not look good. If you want more thickness/build you have to apply more mat layers as you go

Also, as asked above, we are confused if you are working on a male or female mould

Cheers

Fred w B

twybrow - 28/4/11 at 08:51 AM

Daniel - a response would have been good!