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Steve Broad - 7/19/2018 8:33:01 PM

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Dinoman - 7/19/2018 8:07:54 PM

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Steve Broad - 7/19/2018 7:38:24 PM

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Warren (Staff) - 7/19/2018 4:31:15 PM

When you rub or break by hand a powder pound CSM, then usually you will get a white powder falling off as you rub or break it.

Vacuum bagging is generally not necessary.  For example, the putty if correctly applied, will fill the sharp corners and recesseses - thus no voids.  The laying up of the cloth is then much easier and just requires  good  quality laminating by hand to achieve a void free finish.  So there is little to gain from vacuum bagging that hasn't already been achieved through proper and good quality laminating.

In theory it may well help for very high temperature applications but this is rare and i have not heard of anyone vacuum bagging the moulds even in this situation.

I would expand on what Warren said - The important part is getting the gel coat into all the corners and crevices. As this is like a very thick paint when warm, you can't vacuum bag it as it will simply squish all over the place!. You then add the paste whilst the gel coat is still tacky (but firm enough that pushing on the paste doesn't disturb it- correct me if I am wrong Warren or Paul, but I use the fingerprint test, if my finger leaves a print but the gel doesn't come off on my finger it is ready for the next stage) and then add the fibreglass over the whole lot.

For smallish parts I use an old domestic oven bought from eBay. There are plenty on there, here is an example. Simply drill a hole through the side for the vacuum tube :-)

https://www.ebay.co.uk/itm/neff-Electric-oven-You-Arrange-Courier-Or-Collect/323346305953?hash=item4b48f113a1%3Ag%3AKUAAAOSwpz5bR6-N&_sacat=0&_nkw=domestic+oven+electric&_from=R40&LH_ItemCondition=4&rt=nc&_trksid=m570.l1313

Hi Steve, Don't get me wrong, but I know the basics as I have been doing Fiberglas for over 30 years, so I have lots of Moulds and am forever repairing then, mainly because they were not made well to start with, none have been Vacuum Bagged, so now I want to start learning the correct way and Materials to do CF, so want to start with Hand Layup and Air dry, and if I get on with then I will buy a large oven to accommodate large panels such as Bonnets, doors, Undertrays, the Ferrari Undertrays are very large approx 6ft X 4.5 ft, so I do not want to run before I can walk, Like I said to Warren the Mould is the most important tool as it is going to be used lots of times, and especially if you have a perfect item to Mould the last thing you want to be doing is repairs to a new Mould, so when I found this Forum I was hoping for some great advice, but when someone says no need to VB your Mould I find it very hard to believe that that is best practice, so anyway I will persevere and try VBing my Moulds, so thanks for all you advice and help, I will let you know how I get on, Regards DM

I don't get you wrong :-) This is a great place to throw around ideas. 

Once the gel coat has cured sufficiently so that you can add the paste, no amount of vacuum bagging will improve matters. However, there is no harm in vacuum bagging the fibreglass but you are wasting a lot of time and materials for no advantage, IMO.

The guys stating there is no need to vacuum the mould work at EC so they do know what they are talking about. Matt is the guy in the videos :-)

I made my own large oven (6' x 6' x 3') to accommodate my flip front. Easy to make and it is powered by 150w light bulbs :-) These are spread around the perimeter helping to even out the temp (this is also a large fan).