Need to learn about fibreglass

[RichMcc]

Any experts around?

All I know is you mix resin, hardner and glass fibre, or get premixed stuff I think... or sheets of matt or something. Dont know naff all tbh and never worked with the stuff....

Need to fill some indentations in an old bumper and build up some surfaces, also fix a section with a gap in it, was gonna stick that metal mesh stuff behind the gap to bridge the two sections then glass over the top.

Can anyone give me a crash course? Will experiment a lot before attempting the real deal. Any advice would be appriciated.

 

[edde]

Get one of those patch repair kits from halfords and have a go only cheap from memory.

 

[Middo]

to start i'd use the pre-mixed ones you can get. you need to use polyester resin to stick somthing over the back, and then fill up with resin fibre.

using the matting and resining it on will provide a stronger result but just needs a little practise. halfords do sell a fastglas pack for £15 or so which includes everything you need to have a bash with.

 

[Saundo]

Can always sand it back. If your building up layers get some good stuff as repair kits aint always the best.

Oh and wear a mask when sanding, nasty h** fibre glass!

 

[RichMcc]

Well the eventual project will be quite large, building up a big area of the bumper. I was thinking the mat would be easier and more uniform.
So you what you mix the resin, paint some on (with brush?) then lay the matt on top then paint it again with resin?
Can you do a few layers at a time or do you need to let it go off first?

 

[Fred@BTM]

i'm qualified in composites mate, give me a ring if you need any help

 

[Final Maxim]

bumper off, turn it over, clean up the back and scuff it up with some rough sandpaper.

find some plastic that will cover your holes, i generally use filler spreaders, and sikaflex (bonding stuff used in a mastic gun) the spreaders over the hole from the back.

turn bumper back over, scuff up the outside with p80 or something and scuff the bits of spreaders you can see too and slap in some fibreglass resin. basically comes in a tin and you mix it with hardener that comes with it (just like bodyfiller).

let that go off then sand it all back level with p80's, then start skimming it with easy sand filler, working your way down to about P320. primer it with high build primer, let that go off . going off times depend on whether your using heat/air dry or cellulose or 2k primer.

* also wouldnt recommend using the fibreglass sheets that you cut yourself as they are just really messy and fall to bits.

 

[Neil G]

Very, very messy job with the glass kit

Also got to get the mix of resin & hardener spot on

 

[RichMcc]

Sweet cheers for the advice chaps. Guess I'll need to experiment to get it right. Ive used sikaflex its awesome stuff.

Funny enough theres a couple of small businesses right behind my house, ones a fibreglass/upvc place and the others a car spray/repair place so how handy is that! Will go up and have a chat with em.
Am I right that primer absorbs water so shouldn't get it wet? Sure I read that some where.

Might see if I can lend an experts ear or maybe bag some cheep materials since I woke up the other day to find a load of glass strand in my back garden, figure they owe me one!

Then the spray bay is next door to them when Im finished

 

[Final Maxim]

primer is fine wet aslong as its fully dry