Fibreglass for my car

[Ntrprise]

so..... I brought the complete materials in order to Fiberglass my car..... unfortunatly.... I hit a few delays in getting to the stage where I need to use these materials.

I understand that the shelf life for some of these materials is 6-12 months....
.... I have had them for 3 years..... and they have been in the loft of my garage... so have had some reasonably cold conditions....

Any ideas as to what would happen if I tried to us this? Or should I buy again?

[greenamex2]

Knock up a couple of small pieces as a test?

[Hitech]

I've never had a problem with out of date materials not perfoming as they should, at least with polyester resins. Curing times with old epoxy resins seems to change the older it gets (seems to speed up) but the end product seems satisfactory.
Phil

[JohnD]

Measure the amount of catalyst you put in very carefully and adjust it according to experience. I have access to disposable syringes and a 5 ml one is excellent, as 4% is the default amount, but I've varied it between 2 and 6%, according to the weather mainly (temperature). 4mls in 100mls resin, and I rarely mix more than that, even for a big job, as that's about the amount I can use before it starts to go off.
John

[phansa88]

I use to build racing yachts and kit cars out of grp for a living its 20cc a kg
for resin and the same bit less for gel coat on a normal day reduce catalyst
for hotter days. if resin has started to form crystals then do not use. agree with Denis do test pieces frist,on erith marsh is sprayglass international they do sell stuff to joe bloggs if in dout replace. wet or sticky grp is no fun as it wont set or cure if its gong off

[Bob Pearson]

Here's a tip, not sure where I learnt it from, but I always do it on a hot day. When you have mixed the resin and hardener in a pot, put that pot in another larger contaner with water in it for the period you are using it. That way you have effectively water cooled your resin mix while you are using it. It gives you that little longer.

[dtype38]

Originally Posted by Ntrprise

I understand that the shelf life for some of these materials is 6-12 months....
.... I have had them for 3 years..... and they have been in the loft of my garage... so have had some reasonably cold conditions....

My car has a fibreglass body and I've been making a remaking bits for it for years and have used materials of many different ages. First thing is that the matting isn't a problem so long as its been kept reasonably dry and it doesn't fall apart when you handle it (the bonding agent dissolves when you lay it up anyway). Next the lay up resin - this does age, but so long as its been kept in a moisture proof container in the dark it should be fine. The darkness thing is because uv light (also given off by flourescents) will eventually cause it to cure. You should be able to tell if your resin is still usable by pouring a little into a container. If it still flows freely (ie quite runny) then it should be fine. If its started to thicken though (say more like maple syrup) then you'll have problems getting to to wet the mat properly and get rid of bubbles. In this case you'd need to buy new. Lastly the gel goat resin. This seems to be the most sensitive and there isn't an easy way to tell if its ok without making up a small batch and seeing what happens. I had some in a sealed tin for a couple of years and when I went to use it, it looked fine but just didn't set at all :-(.

[Ntrprise]

Many thanks for all this.... very useful..... I'll post the results in the next month or 2.....

Any more suggestions / tips... keep em coming!

[dtype38]

OK.

Fibreglass tip of the day no 1 - Know Your Catalyst.

Did you know there are speeds of catalyst? In the winter my supplier gives me "fast" catalyst. This is great if its very cold in your garage and you don't want to wait days for your resin to harden... but don't keep it around once the weather gets warm. Get it mixed up and accidentally use it in the summer and you'll find yourself with your brush stuck in a solid pot of just mixed resin ;-)