stevebubs
|
| posted on 6/3/06 at 08:43 PM |
|
|
Smoothing/ filling Mould...
Grrr....finally made the last (I blooming hope) mould for my bonnet bulge.
Just 1 problem - after 8 coats of Maguirs Release Wax, the mould *still* stuck to the buck.
As a result of much acetone swilling and power file madness, I've finally managed to get the mould free of buck debris.
As a result, I now have a mould the right shape and size but with minor flaws - e.g. where powerfile dug into the gelcoat, and the acetone dissolved
it a bit.
Most of this I've resolved with vigorous sanding, but still have some deepish (2mm) holes.
What would be the best method of filling these so I can take a final part?
Just use plastic primer and build it up, or can I use body filler? Surely with bodyfiller I run the risk of it cracking off the mould?
Or is there a better way?
Many thanks
Stephen
|
|
|
|
|
Avoneer
|
| posted on 6/3/06 at 09:00 PM |
|
|
Try just PVA for release.
Worked for me.
Pat...
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
|
|
|
stevebubs
|
| posted on 6/3/06 at 09:07 PM |
|
|
quote:
Originally posted by Avoneer
Try just PVA for release.
Worked for me.
Pat...
Yep - the first one I did have PVA and worked perfectly. However, everyone has been raving about wax so I tried that this time. *BIG* mistake.
Works fine for mould-part release, but not convinced for mould-buck release.
Think (in the future) I would recommend:
PVA for releasing mould from buck
Wax for releasing final part from mould
Still not answered my original question, though 
S
|
|
|
k33ts
|
| posted on 7/3/06 at 12:05 AM |
|
|
use some gel coat, clean the holes well with acetone fill with gelcoat leave for a day flat and polish.
dont use to heavy paper though 800 w/d min.
and stick to pva or if you wana stick use wax
|
|
|
Syd Bridge
|
| posted on 7/3/06 at 09:28 AM |
|
|
I've only used pva twice in all my life. It gives a horrible finish to the mould, that has to be rubbed out and takes hours.
The trick with wax(and I've used Meguiars #8 all my life), is to put the wax on, THEN LEAVE IT TO DRY AT LEAST 30Mins. Polish it, and this
works best with a machine for some reason. THEN LET THE POLISHED WAX HARDEN UP FOR AT LEAST TWO HOURS(4 OR MORE IN COLD WEATHER).
I've released quick mouldings directly from bare mdf moulds using just wax using the method above.
The biggest mistake people make with wax is not letting it harden before polishing, hence you put it on then rub it straight off. And the wax MUST be
allowed to harden after polishing.
I lost a very expensive pattern, because the pair of youngsters I entrusted with preparing it, put ten coats of wax on, one after the other in less
than two hours as I came to find out. All that was achieved was a very clean pattern, with no wax on it!
You will never find pva anywhere near me. It's evil stuff, direct from the most evil one.
Syd.
|
|
|
Dutchman
|
| posted on 7/3/06 at 01:05 PM |
|
|
I use PVA all the time but I spray it like paint and it is water based quick to put it on a mould and quick to be washed away... I always paint my
fiberglas parts so don't see the point of using wax
Tarzan English with foreign accent!
|
|
|
stevebubs
|
| posted on 7/3/06 at 02:34 PM |
|
|
quote:
Originally posted by Syd Bridge
I've only used pva twice in all my life. It gives a horrible finish to the mould, that has to be rubbed out and takes hours.
The trick with wax(and I've used Meguiars #8 all my life), is to put the wax on, THEN LEAVE IT TO DRY AT LEAST 30Mins. Polish it, and this
works best with a machine for some reason. THEN LET THE POLISHED WAX HARDEN UP FOR AT LEAST TWO HOURS(4 OR MORE IN COLD WEATHER).
I've released quick mouldings directly from bare mdf moulds using just wax using the method above.
The biggest mistake people make with wax is not letting it harden before polishing, hence you put it on then rub it straight off. And the wax MUST be
allowed to harden after polishing.
I lost a very expensive pattern, because the pair of youngsters I entrusted with preparing it, put ten coats of wax on, one after the other in less
than two hours as I came to find out. All that was achieved was a very clean pattern, with no wax on it!
You will never find pva anywhere near me. It's evil stuff, direct from the most evil one.
Syd.
May well be the cold weather that's done me in then, Syd.
Was leaving the coats about 25 minutes between each other, and about a 2 hours gap in the middle between coats 4 and 5.
Only about 2 hours from the last coat going on to the gelcoat being applied, though
|
|
|
Syd Bridge
|
| posted on 14/3/06 at 03:29 PM |
|
|
As an add on to this discussion,
I've been waxing some patterns today. Temp in the workshop is 12c, and wax is taking near to 2 hours to dry enough to be polished. The coat I
put on at 9.00am was polished at 11.30, and is still not firm enough to put another coat on now, at 3.30.
I've still got to get a coat of gel on them, then into the oven so I can lay them up tomorrow. Long day still ahead!! 
Syd.
|
|
|
stevebubs
|
| posted on 14/3/06 at 08:41 PM |
|
|
Cheers, Syd - that'll be the source of my problem then - the garage was below 12 degrees when I was polishing....
|
|
|
%20(WinCE).JPG)
